No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
A primary model of THz and far-infrared signal generation and conduction in neuron systems based on the hypothesis of the ordered phase of water molecules on the neuron surface I: signal characteristics
Abstract
In this paper, we use the theory of quantum optics and electrodynamics to study the electromagnetic field problem in the nervous system based on the assumption of an ordered arrangement of water molecules on the neuronal surface. Using the Lagrangian of the water molecule-field ion, the dynamic equations for neural signal generation and transmission are derived. Perturbation theory and the numerical method are used to solve the dynamic equations, and the characteristics of high-frequency signals (the dispersion relation, the time domain of the field, the frequency domain waveform, etc.) are discussed. This model predicts some intrinsic vibration modes of electromagnetic radiation on the neuronal surface. The frequency range of these vibration modes is in the THz and far-infrared ranges.
... Recent advances have underscored the intriguing sensitivity of these ion channels to electromagnetic fields [3], particularly within the terahertz (THz) spectrum [4][5][6] ranging from 0.1 to 100 THz [2]. The THz wave has attracted substantial interest due to its non-ionizing nature and deep penetration capabilities. ...
... Proteins, sensitive to THz due to their intricate structures and non-covalent bonding, undergo changes in molecular dynamics, affecting their structure and function [55,56]. THz radiation also impacts cellular functions, including genetic stability, membrane permeability, metabolism, and neuronal excitability [4,57]. Despite being non-ionizing, intense THz radiation's electric field strengths pose potential cell health risks [47]. ...
... Their insights into the electromagnetic fields engendered by orderly-arranged water molecules on neuron membranes led them to postulate that the electromagnetic radiation on neuron surfaces resides within the generalized terahertz range. They posited the congruence of electromagnetic signal processes in neurons with electromagnetic fields and quantum theory, suggesting that terahertz waves resonate with the eigenmodes of the nervous system, invoking an array of intricate physical responses [4,[78][79][80][81][82]. ...
In neurons and myocytes, selective ion channels in the plasma membrane play a pivotal role in transducing chemical or sensory stimuli into electrical signals, underpinning neural and cardiac functionality. Recent advancements in biomedical research have increasingly spotlighted the interaction between ion channels and electromagnetic fields, especially terahertz (THz) radiation. This review synthesizes current findings on the impact of THz radiation, known for its deep penetration and non-ionizing properties, on ion channel kinetics and membrane fluid dynamics. It is organized into three parts: the biophysical effects of THz exposure on cells, the specific modulation of ion channels by THz radiation, and the potential pathophysiological consequences of THz exposure. Understanding the biophysical mechanisms underlying these effects could lead to new therapeutic strategies for diseases.
... This characteristic eliminates the need for additional sample manipulation, such as staining or labeling, thereby minimizing damage to biological tissues and negating the requirement for external contrast agents, in contrast to imaging modalities like X-rays and magnetic resonance imaging [10,11]. Furthermore, many biomolecules exhibit vibrational and rotational activity at resonant frequencies within the terahertz range, allowing for effective identification and characterization through their distinct terahertz spectral fingerprints [12][13][14]. Among the various applications of terahertz technology, terahertz imaging techniques play a crucial role. ...
Terahertz (THz)-based near-field imaging technology exhibits significant potential for applications in biomedical detection. This study investigates biological cells utilizing the rapid imaging capabilities, high resolution, and non-destructive characteristics inherent to terahertz scattering-based scanning near-field optical microscopy (s-SNOM). The findings indicate that the integration of terahertz near-field microscopy with nanoprecision probes and a high-power terahertz radiation source transcends the size and resolution constraints of traditional terahertz far-field imaging systems, which typically achieve resolutions in the range of hundreds to tens of microns for smaller biological tissues. Furthermore, this approach addresses the intrinsic complexities associated with biological cells, such as the presence of numerous intracellular constituents and high water content, thereby facilitating clear and non-destructive imaging of both the surfaces and interiors of individual human sperm at resolutions on the order of tens of nanometers. The simultaneous acquisition of terahertz imaging data is accomplished in approximately 11 min, representing a substantial enhancement in imaging speed. This work not only serves as a compelling example but also presents an effective methodology for imaging medical biological samples using THz near-field microscopy.
... THz photons have emerged as a promising tool, garnering significant attention in biosensing [17][18][19][20][21] and neural research [22,23]. Recent research suggests that THz photons hold the ability to influence biomolecular functions and cellular activities, representing an emerging area in neurobiological research [24,25]. ...
Neurite outgrowth and synapse formation constitute the cellular basis for the establishment and plasticity of neural networks, crucially involved in cognitive functions. However, the techniques currently available to effectively and specifically modulate these processes remain limited. In this work, we propose a non-drug and non-thermal terahertz (THz) photon modulation approach that enhances neuronal growth and synaptogenesis. Frequency screening experiments show that 34.5 THz photon stimulation could effectively promote neurite elongation and postsynaptic density protein 95 (PSD95) expression by 26.0% in rat hippocampal neurons. Subsequent cellular experiments reveal an upregulation of the cyclic adenosine monophosphate (cAMP) signaling pathway and adenylyl cyclase type 1 (AC1) activity after 34.5 THz photon irradiation. Molecular dynamics simulations suggest that 34.5 THz photons promote the binding between AC1 and ligand, accelerating cAMP generation. In vivo experiments further confirm an increase in hippocampal cAMP levels and dendritic spine density after THz photon stimulation, accompanied by a significant improvement in cognitive performance. Overall, our results suggest THz photon stimulation as an effective and specific method for neuromodulation, promising for future applications in the treatment of cognitive dysfunction.
... Application of the terahertz spectrum began in the late 20th century. Terahertz radiation has been extensively researched for its potential applications in biomedicine [1][2][3], component design [4], nondestructive testing [5][6][7], high-resolution imaging [8], industrial applications [9,10], security inspection [11], and communications [12] because of its low energy, short wavelength, and low dielectric loss. Additionally, terahertz radiation has promising applications in cellular and genetic engineering because of its safety and high resolution [13][14][15]. ...
Achieving a high resolution is crucial in the increasingly popular field of terahertz imaging, and diffraction-limited imaging remains a significant practical challenge. In synthetic aperture radar imaging, antennas are typically treated as point sources, and the effect of the antenna aperture is ignored. This study illustrates the impact of the applied antenna on imaging performance and provides a method for achieving super-resolution imaging through compensation within the aperture field of the antenna. Simulation experiments verify the robustness of the algorithm under low SNR conditions. The image contrast can be used for deconvolution kernel iteration. Iteration over target distances and deconvolution kernels accelerates the process of blind deconvolution imaging. By distinguishing from time-domain pulse and stepped-frequency continuous wave measurements, the proposed algorithm allows accurate calculation of the distance to the target under single-frequency measurement conditions. The algorithm improves the resolution from a theoretical value of 5.5–3 mm.
... In common terahertz (THz) systems, the intensity of THz waves shows a Gaussian distribution in the cross section perpendicular to the direction of propagation, that is, the central region is strong and the marginal region is weak. In practical applications (e.g., nondestructive testing) [1][2][3][4][5][6], this will cause a saturation of the central region of the detector and a weakened edge response, severely reducing the image quality [7], even damaging the detector. On the other hand, the THz detector chip is usually rectangular, which mismatches with the circular spot and will cause a decrease in detection efficiency and a waste of energy. ...
This paper reviews recent developments and key advances in terahertz (THz) science, technology, and applications, focusing on 3 core areas: astronomy, telecommunications, and biophysics. In THz astronomy, it highlights major discoveries and ongoing projects, emphasizing the role of advanced superconducting technologies, including superconductor–insulator–superconductor (SIS) mixers, hot electron boundedness spectroscopy (HEB), transition-edge sensors (TESs), and kinetic inductance detectors (KIDs), while exploring prospects in the field. For THz telecommunication, it discusses progress in solid-state sources, new communication technologies operating within the THz band, and diverse modulation methods that enhance transmission capabilities. In THz biophysics, the focus shifts to the physical modulation of THz waves and their impact across biological systems, from whole organisms to cellular and molecular levels, emphasizing nonthermal effects and fundamental mechanisms. This review concludes with an analysis of the challenges and perspectives shaping the future of THz technology.
The objective was to investigate immediate ocular damage in exposed to 34.5-terahertz (THz) electromagnetic wave generated by quantum cascade laser (QCL). This research developed the damage porcine model for THz exposure, and its damage occurrence threshold values of time dimension and energy dimension were obtained. The right eyes were exposed to 34.5-THz spot from fiber, and the contralateral eyes were used as control eyes. Slit-lamp examination 5 min after THz exposure revealed a semicircular area of opacity characterized by fluorescein staining, indicating damaged corneal epithelial cells in the irradiated area and encircling by corneal edema. Hematoxylin-eosin (HE) staining suggested the irradiated corneas over 2 min exposure contained fewer epithelial cell layers with vacuolated cells, swollen endothelium, and edematous stroma, compared to contralateral corneas. In vivo evidence suggested exposure time over 6 min or energy over 40 mW leaded to full-thickness detachment of the corneal epithelium. The damage was present when the energy of THz wave was greater than 20 mW or the exposure time was longer than 2 min.
In this article, a three-stage depressed collector for a 340-GHz traveling wave tube (TWT) is designed, and thermal analysis is finished to test the thermal reliability. To quickly finish the design of the collectors with high efficiency, low reflux rate, and heat dissipation, the back-propagating (BP) neural network (NN) and a multiobjective optimization algorithm are combined to optimize the collector. First, BP NN is used to construct an approximate calculation model between the ten input parameters of the collector and the three target values: 1) recovery efficiency; 2) reflux rate; and 3) heat balance. Then, the nondominated sorting genetic algorithm III (NSGA-III) was used to find Pareto optimal solutions for the three targets. The proposed method’s optimal recovery efficiency is 88.17%, the reflux rate is 0.09%, and the temperature difference inside the collector is only 16
C, achieving thermal balance. It provides a reference for the fast and accurate design of a multistage depressed collector (MDC) of a 340-GHz TWT.
The generation and propagation of physical signals in living biosystems are continuous issues. Traditional Hodgkin-Huxley model based on ionic current conduction could not explain the fast transmission of action potential in myelinated axons and factors influencing action potential velocity. We propose that the ion flow induced by Nav channel generates near field quasi-static electric field at extracellular space, termed as an ephaptic field which is able to excite nearby passive axons. Our simulation indicates that the static electric field produced by sodium ion channels in one node of Ranvier is improbable to stimulate the ion channels in the adjacent neighboring node. However, the ion channel ring in one node of Ranvier could induce the shift of membrane potential (0.01 mV) on the node at nearby axons (100 μm) in a bundle of axon synchronously, suggesting zig-zag propagation of action potential. Together with the superposition effect of ephaptic feedback field generated by the synchronized movement of adjacent parallel axons stimulate the adjacent node of the original axon, strengthen the action potential to travel in a zig-zag pattern. Our model also provides an explanation for the rapid velocity of action potential propagation reported in experimental studies.
The traveling-wave tube (TWT) is an important amplifier for the THz wave (0.1–1 THz). A multistage depressed collector (MDC) is a significant component in TWT for collecting energy. When the MDC is working, its temperature will rise, causing thermal problems. The ordinary method for solving the high-temperature problem is adding the radiators outside the TWT’s MDC. In the previous design, most of the radiators were designed as straight panels, whose utility rate of space is poor and leads to bigger sizes. Moreover, there is always external vibration excitation from the outside environment, and the ability of the traditional straight radiator is not enough to resist the outside vibration excitation. This article designs a novel curving radiator to enhance the space utility rate and obtain lower temperature in the MDC and uses a new parameter space utilization ratio (SUR) to measure the heat dissipation ability of the radiators. A complete reliability analysis is carried out for this structure in ANSYS, including: 1) thermal analysis; 2) modal analysis; and 3) random vibration analysis.
In this article, a novel terahertz (THz) dark-field imaging method is proposed to achieve the THz high-contrast imaging. The novel THz dark-field imaging is built based on a classical 4
f
imaging system, and the beam stop is placed in the Fourier plane acted as a spital filter. In the Fourier plane, the low-frequency content of the target is in the center of the THz beam and other areas are the high-frequency content of the target. The beam stop in the Fourier plane can block the low-frequency content of the target and only keep the high-frequency content to achieve high-contrast imaging. The size of beam stop determines the image quality, which is the key component of the system. The larger beam stop blocks more low-frequency content, and can get higher contrast image, but also cause lower signal to noise ratio (SNR) of the image. The letters with different contrasts are simulated and the resultant image shows the remarkable contrast enhancement. At the same time, the proposed THz dark-field imaging method is compared with the traditional dark-field imaging, which verifies the superiority of the imaging method that proposed in this article. Proof-of-principle experiment is carried out by our designed THz dark-field imaging system, and validates the effectiveness of target contrast enhancement on the THz images. A metal target, an HDPE piece with a scratch, and a leaf are imaged. The contrast is improved perfectly, which are extremely consistent with the THz dark-field imaging theory.
J. Li and H. Li, “Liquid Crystal Coaxial Phase Shifter Designs at 0.3 THz,” Proceedings of the 5th China and International Young Scientist Terahertz Conference, Volume 2. Springer Proceedings in Physics, Springer Nature, July 2024, vol. 401, pp. 147–151, Print ISBN: 978-981-97-3912-7, Online ISBN: 978-981-97-3913-4. doi: 10.1007/978-981-97-3913-4_28
Electromagnetic radiation, in the visible and infrared spectrum, is increasingly being investigated for its possible role in the most evolved brain capabilities. Beside experimental evidence of electromagnetic cellular interactions, the possibility of light propagation in the axon has been recently demonstrated using computational modelling, although an explanation of its source is still not completely understood. We studied electromagnetic radiation onset and propagation at optical frequencies in myelinated axons, under the assumption that ion channel currents in the node of Ranvier behave like an array of nanoantennas emitting in the wavelength range from 300 to 2500 nm. Our results suggest that the wavelengths below 1600 nm are most likely to propagate throughout myelinated segments. Therefore, a broad wavelength window exists where both generation and propagation could happen, which in turn raises the possibility that such a radiation may play some role in neurotransmission.
Since regular radio broadcasts started in the 1920s, the exposure to humanmade electromagnetic fields has steadily increased. These days we are not only exposed to radio waves but also other frequencies from a variety of sources, mainly from communication and security devices. Considering that nearly all biological systems interact with electromagnetic fields, understanding the affects is essential for safety and technological progress. This
paper systematically reviews the role and effects of static and pulsed radio frequencies (100–109 Hz), millimetre waves (MMWs) or gigahertz (109– 1011 Hz), and terahertz (1011–1013 Hz) on various biomolecules, cells and tissues. Electromagnetic fields have been shown to affect the activity in cell membranes (sodium versus potassium ion conductivities) and non-selective channels, transmembrane potentials and even the cell cycle. Particular attention is given to millimetre and terahertz radiation due to their increasing utilization and, hence, increasing human exposure. MMWs are known to alter active transport across cell membranes, and it has been reported that terahertz radiation may interfere with DNA and cause genomic instabilities. These and other phenomena are discussed along with the discrepancies and controversies from published studies.
Anesthesia blocks consciousness and memory while sparing non-conscious brain activities. While the exact mechanisms of anesthetic action are unknown, the Meyer-Overton correlation provides a link between anesthetic potency and solubility in a lipid-like, non-polar medium. Anesthetic action is also related to an anesthetic's hydrophobicity, permanent dipole, and polarizability, and is accepted to occur in lipid-like, non-polar regions within brain proteins. Generally the protein target for anesthetics is assumed to be neuronal membrane receptors and ion channels, however new evidence points to critical effects on intra-neuronal microtubules, a target of interest due to their potential role in post-operative cognitive dysfunction (POCD). Here we use binding site predictions on tubulin, the protein subunit of microtubules, with molecular docking simulations, quantum chemistry calculations, and theoretical modeling of collective dipole interactions in tubulin to investigate the effect of a group of gases including anesthetics, non-anesthetics, and anesthetic/convulsants on tubulin dynamics. We found that these gases alter collective terahertz dipole oscillations in a manner that is correlated with their anesthetic potency. Understanding anesthetic action may help reveal brain mechanisms underlying consciousness, and minimize POCD in the choice and development of anesthetics used during surgeries for patients suffering from neurodegenerative conditions with compromised cytoskeletal microtubules.
We studied an influence of continuous terahertz (THz) radiation (0.12 – 0.18 THz, average power density of 3.2 mW/cm²) on a rat glial cell line. A dose-dependent cytotoxic effect of THz radiation is demonstrated. After 1 minute of THz radiation exposure a relative number of apoptotic cells increased in 1.5 times, after 3 minutes it doubled. This result confirms the concept of biological hazard of intense THz radiation. Diagnostic applications of THz radiation can be restricted by the radiation power density and exposure time.
The structure of the post-mortem human brain can be preserved by immersing the organ within a fixative solution. Once the brain is perfused, cellular and histological features are maintained over extended periods of time. However, functions of the human brain are not assumed to be preserved beyond death and subsequent chemical fixation. Here we present a series of experiments which, together, refute this assumption. Instead, we suggest that chemical preservation of brain structure results in some retained functional capacity. Patterns similar to the living condition were elicited by chemical and electrical probes within coronal and sagittal sections of human temporal lobe structures that had been maintained in ethanol-formalin-acetic acid. This was inferred by a reliable modulation of frequency-dependent microvolt fluctuations. These weak microvolt fluctuations were enhanced by receptor-specific agonists and their precursors (i.e., nicotine, 5-HTP, and L-glutamic acid) as well as attenuated by receptor-antagonists (i.e., ketamine). Surface injections of 10 nM nicotine enhanced theta power within the right parahippocampal gyrus without any effect upon the ipsilateral hippocampus. Glutamate-induced high-frequency power densities within the left parahippocampal gyrus were correlated with increased photon counts over the surface of the tissue. Heschl’s gyrus, a transverse convexity on which the primary auditory cortex is tonotopically represented, retained frequency-discrimination capacities in response to sweeps of weak (2μV) square-wave electrical pulses between 20 Hz and 20 kHz. Together, these results suggest that portions of the post-mortem human brain may retain latent capacities to respond with potential life-like and virtual properties.
The nature of interfacial water is critical in several natural processes, including the aggregation of lipids into the bilayer, protein folding, lubrication of synovial joints, and underwater gecko adhesion. The nanometer-thin water layer trapped between two surfaces has been identified to have properties that are very different from those of bulk water, but the molecular cause of such discrepancy is often undetermined. Using surface-sensitive sum frequency generation (SFG) spectroscopy, we discover a strongly coordinated water layer confined between two charged surfaces, formed by the adsorption of a cationic surfactant on the hydrophobic surfaces. By varying the adsorbed surfactant coverage and hence the surface charge density, we observe a progressively evolving water structure that minimizes the sliding friction only beyond the surfactant concentration needed for monolayer formation. At complete surfactant coverage, the strongly coordinated confined water results in hydration forces, sustains confinement and sliding pressures, and reduces dynamic friction. Observing SFG signals requires breakdown in centrosymmetry, and the SFG signal from two oppositely oriented surfactant monolayers cancels out due to symmetry. Surprisingly, we observe the SFG signal for the water confined between the two charged surfactant monolayers, suggesting that this interfacial water layer is noncentrosymmetric. The structure of molecules under confinement and its macroscopic manifestation on adhesion and friction have significance in many complicated interfacial processes prevalent in biology, chemistry, and engineering.
Significance
It is still unclear why human beings hold higher intelligence than other animals on Earth and which brain properties might explain the differences. The recent studies have demonstrated that biophotons may play a key role in neural information processing and encoding and that biophotons may be involved in quantum brain mechanism; however, the importance of biophotons in relation to animal intelligence, including that of human beings, is not clear. Here, we have provided experimental evidence that glutamate-induced biophotonic activities and transmission in brain slices present a spectral redshift feature from animals (bullfrog, mouse, chicken, pig, and monkey) to humans, which may be a key biophysical basis for explaining why human beings hold higher intelligence than that of other animals.
Given that many fundamental questions in neuroscience are still open, it seems pertinent to explore whether the brain might use other physical modalities than the ones that have been discovered so far. In particular it is well established that neurons can emit photons, which prompts the question whether these biophotons could serve as signals between neurons, in addition to the well-known electro-chemical signals. For such communication to be targeted, the photons would need to travel in waveguides. Here we show, based on detailed theoretical modeling, that myelinated axons could serve as photonic waveguides, taking into account realistic optical imperfections. We propose experiments, both \textit{in vivo} and \textit{in vitro}, to test our hypothesis. We discuss the implications of our results, including the question whether photons could mediate long-range quantum entanglement in the brain.
Abstract
Phosphenes are experienced sensations of light, when there is no light causing them. The physiological processes underlying this phenomenon are still not well understood. Previously, we proposed a novel biopsychophysical approach concerning the cause of phosphenes based on the assumption that cellular endogenous ultra-weak photon emission (UPE) is the biophysical cause leading to the sensation of phosphenes. Briefly summarized, the visual sensation of light (phosphenes) is likely to be due to the inherent perception of UPE of cells in the visual system. If the intensity of spontaneous or induced photon emission of cells in the visual system exceeds a distinct threshold, it is hypothesized that it can become a conscious light sensation. Discussing several new and previous experiments, we point out that the UPE theory of phosphenes should be really considered as a scientifically appropriate and provable mechanism to explain the physiological basis of phosphenes. In the present paper, we also present our idea that some experiments may support that the cortical phosphene lights are due to the glutamate-related excess UPE in the occipital cortex.
In order to determine the limits of the biologically safe maximum allowable levels of pulsed terahertz (THz) radiation, a prototype of apparatus has been developed for the irradiation of cell cultures immersed in a liquid medium with broad-band THz radiation in the 0.05-1.2 THz frequency range. The action of THz radiation on the functional activity of the cells of a number of biological cultures, including mouse thymocytes and splenocytes, has been investigated. This was evaluated by means of flow-through cytometry, using fluorescence-intensity analysis of DNA-binding stains. It is shown that THz radiation with a mean power density of up to 10 mu W/cm(2) and a time of action of 1 min has no effect on the variation of the functional activity of the cells. No statistically reliable variations were detected in the relationship of living cells and cells at different stages of apoptosis or in the distribution of cells over the phases of the cellular cycle. It is concluded that THz radiation with such characteristics can be used for medical spectroscopy. (C) 2014 Optical Society of America.
Non-thermal probing and stimulation with subnanosecond electric pulses and terahertz electromagnetic radiation may lead to new, minimally invasive diagnostic and therapeutic procedures and to methods for remote monitoring and analysis of biological systems, including plants, animals, and humans. To effectively engineer these still-emerging tools, we need an understanding of the biophysical mechanisms underlying the responses that have been reported to these novel stimuli. We show here that subnanosecond (≤500 ps) electric pulses induce action potentials in neurons and cause calcium transients in neuroblastoma-glioma hybrid cells, and we report complementary molecular dynamics simulations of phospholipid bilayers in electric fields in which membrane permeabilization occurs in less than 1 ns. Water dipoles in the interior of these model membranes respond in less than 1 ps to permeabilizing electric potentials by aligning in the direction of the field, and they re-orient at terahertz frequencies to field reversals. The mechanism for subnanosecond lipid electropore formation is similar to that observed on longer time scales-energy-minimizing intrusions of interfacial water into the membrane interior and subsequent reorganization of the bilayer into hydrophilic, conductive structures.
It has been suggested that quantum coherence in the selectivity filter of ion
channel may play a key role in fast conduction and selectivity of ions.
However, it has not been clearly elucidated yet why classical coherence is not
sufficient for this purpose. In this paper, we investigate the classical
vibrational coherence between carbonyl groups oscillations in the selectivity
filter of KcsA ion channels based on the data obtained from molecular dynamics
simulations. Our results show that classical coherence plays no effective role
in fast ionic conduction.
There are many controversial and challenging discussions about quantum
effects in microscopic structures in neurons of the human brain. The challenge
is mainly because of quick decoherence of quantum states due to hot, wet and
noisy environment of the brain which forbids long life coherence for brain
processing. Despite these critical discussions, there are only a few number of
published papers about numerical aspects of decoherence in neurons. Perhaps the
most important issue is offered by Max Tegmark who has calculated decoherence
times for the systems of "ions" and "microtubules" in neurons of the brain. In
fact, Tegmark did not consider ion channels which are responsible for ions
displacement through the membrane and are the building blocks of electrical
membrane signals in the nervous system. Here, we would like to re-investigate
decoherence times for ionic superposition states by using the data obtained via
molecular dynamics simulations. Our main approach is according to what Tegmark
has used before. In fact, Tegmark didn't consider the ion channel structure and
his estimates are only simple approximations. In this paper, we focus on the
small nano-scale part of KcsA ion channels which is called "selectivity filter"
and has a key role in the operation of an ion channel. Our results for
superposition states of potassium ions indicate that decoherence times are in
the order of picoseconds which are 10-100 million times bigger than the order
calculated by Tegmark. This decoherence time is still not enough for cognitive
processing in the brain, however it can be adequate for quantum states of
cooled ions in the filter to leave their quantum traces on the filter and
action potentials.
This paper presents a historical perspective on the development and application of quantum physics methodology beyond physics, especially in biology and in the area of consciousness studies. Quantum physics provides a conceptual framework for the structural aspects of biological systems and processes via quantum chemistry. In recent years individual biological phenomena such as photosynthesis and bird navigation have been experimentally and theoretically analyzed using quantum methods building conceptual foundations for quantum biology. Since consciousness is attributed to human (and possibly animal) mind, quantum underpinnings of cognitive processes are a logical extension. Several proposals, especially the Orch OR hypothesis, have been put forth in an effort to introduce a scientific basis to the theory of consciousness. At the center of these approaches are microtubules as the substrate on which conscious processes in terms of quantum coherence and entanglement can be built. Additionally, Quantum Metabolism, quantum processes in ion channels and quantum effects in sensory stimulation are discussed in this connection. We discuss the challenges and merits related to quantum consciousness approaches as well as their potential extensions.
The processing of neural information in neural circuits plays key roles in neural functions. Biophotons, also called ultra-weak photon emissions (UPE), may play potential roles in neural signal transmission, contributing to the understanding of the high functions of nervous system such as vision, learning and memory, cognition and consciousness. However, the experimental analysis of biophotonic activities (emissions) in neural circuits has been hampered due to technical limitations. Here by developing and optimizing an in vitro biophoton imaging method, we characterize the spatiotemporal biophotonic activities and transmission in mouse brain slices. We show that the long-lasting application of glutamate to coronal brain slices produces a gradual and significant increase of biophotonic activities and achieves the maximal effect within approximately 90 min, which then lasts for a relatively long time (>200 min). The initiation and/or maintenance of biophotonic activities by glutamate can be significantly blocked by oxygen and glucose deprivation, together with the application of a cytochrome c oxidase inhibitor (sodium azide), but only partly by an action potential inhibitor (TTX), an anesthetic (procaine), or the removal of intracellular and extracellular Ca(2+). We also show that the detected biophotonic activities in the corpus callosum and thalamus in sagittal brain slices mostly originate from axons or axonal terminals of cortical projection neurons, and that the hyperphosphorylation of microtubule-associated protein tau leads to a significant decrease of biophotonic activities in these two areas. Furthermore, the application of glutamate in the hippocampal dentate gyrus results in increased biophotonic activities in its intrahippocampal projection areas. These results suggest that the glutamate-induced biophotonic activities reflect biophotonic transmission along the axons and in neural circuits, which may be a new mechanism for the processing of neural information.
Application of terahertz radiation for the creation of medical equipment
and solving of biological problems has become widely spread. From this
point of view, the influence of THz radiation on the nerve fibers is of
primary concern. In addition, several studies indicated both stimulating
and depressive effects on nerve cells. However, the mechanism of this
effect has not yet been studied, including the dose and exposure time.
Our research was devoted to the impact of broadband pulsed THz radiation
in the frequency range of 0.05 to 2 THz on the neurite growth in the
sensory ganglia of 10-12-day chicken embryos. Dependence of changes in
functional responses of cells on the average output power has been
found. An increase in the stimulating effect was observed at the lowest
power density used (0.5 μW/cm2). Through non-destructive
process and choosing the correct parameters of THz radiation, potential
control of neural response becomes possible, which can subsequently lead
to new medical treatments.
The nature of consciousness, the mechanism by which it occurs in the brain, and its ultimate place in the universe are unknown. We proposed in the mid 1990's that consciousness depends on biologically 'orchestrated' coherent quantum processes in collections of microtubules within brain neurons, that these quantum processes correlate with, and regulate, neuronal synaptic and membrane activity, and that the continuous Schrödinger evolution of each such process terminates in accordance with the specific Diósi-Penrose (DP) scheme of 'objective reduction' ('OR') of the quantum state. This orchestrated OR activity ('Orch OR') is taken to result in moments of conscious awareness and/or choice. The DP form of OR is related to the fundamentals of quantum mechanics and space-time geometry, so Orch OR suggests that there is a connection between the brain's biomolecular processes and the basic structure of the universe. Here we review Orch OR in light of criticisms and developments in quantum biology, neuroscience, physics and cosmology. We also introduce a novel suggestion of 'beat frequencies' of faster microtubule vibrations as a possible source of the observed electro-encephalographic ('EEG') correlates of consciousness. We conclude that consciousness plays an intrinsic role in the universe.
This paper has served as the 1988 midpoint-review of a rigorous ongoing investigation into Brain-and-Intelligence. This project has been guided by the notion that having a coherent set of well-defined theories is just as important as the related labwork, and that theoretical progress requires attention to detail — especially the micro-detail, and with some emphasis on explaining anomalous findings. That has led to (i) building upon Piaget's account of intellectual development (based on biological and Darwinian mechanisms); (ii) using interdisciplinary knowledge to "redesign" plausible biological mechanisms apparently-capable of achieving such self-educat-ion tasks unaided; and (iii) exploring the theoretical consequ-ences of such mechanisms — some of them branching into other disciplines such as embryology. That has meant swimming against the empiricist tide which dominated science for much of the twentieth century; but it is interesting to note that other theorists who emerge from that empiricist tide, have occasionally come to similar conclusions via different lines of reasoning. E.g. compare: ♦This paper's interest in infrared stemmed from earlier arguments based on molecular energy levels and myelin geometry (and hence it cites findings of bio-emissions 48–51 merely as supporting evid-ence, without inquiring any further) — whereas ♦Other invest-igators such as vanWijk (2001 and earlier) {57} started from the bio-emissions and developed their theory on that basis instead, with no thought of myelin geometry. (And both works cite the same 1978/79 book 48 for some of their evidence). It may be useful to note that two parallel streams of study have emerged during this project, and these will tend to inter-est two different types of audience. • Firstly there is the obvious field of Piagetian Psychology and Epistemology. 30,{58} • The second stream began by using an ensemble of Physio-logy/Physics/Infotech concepts to find technically-plausible micromechanisms for the storage and retrieval involved in the above-mentioned advanced human thought, 30,{58,59,60(ch8)} — in contrast to the textbook accounts which still offer no comprehensive account of plausible micro-management of detail. However it was then necessary to go further to cope with some resulting logistical complications in intercommunic-ation, {61–63} and in growth-control, {60(ch7), 64} etc. The current text served as a convenient summary for both streams at "the end of the beginning" of this project, so it may be a useful starting-point for those investigating its arguments.
Research into terahertz technology is now receiving increasing attention around the world, and devices exploiting this waveband are set to become increasingly important in a very diverse range of applications. Here, an overview of the status of the technology, its uses and its future prospects are presented.
Voltage-gated channel proteins cooperate in the transmission of membrane potentials between nerve cells. With the recent progress in atomic-scaled biological chemistry, it has now become established that these channel proteins provide highly correlated atomic environments that may maintain electronic coherences even at warm temperatures. Here we demonstrate solutions of the Schrödinger equation that represent the interaction of a single potassium ion within the surrounding carbonyl dipoles in the Berneche-Roux model of the bacterial KcsA model channel. We show that, depending on the surrounding carbonyl-derived potentials, alkali ions can become highly delocalized in the filter region of proteins at warm temperatures. We provide estimations on the temporal evolution of the kinetic energy of ions depending on their interaction with other ions, their location within the oxygen cage of the proteins filter region, and depending on different oscillation frequencies of the surrounding carbonyl groups. Our results provide the first evidence that quantum mechanical properties are needed to explain a fundamental biological property such as ion selectivity in transmembrane ion currents and the effect on gating kinetics and shaping of classical conductances in electrically excitable cells.
Despite a large body of work, the exact molecular details underlying
ion-selectivity and transport in the potassium channel have not been fully laid
to rest. One major reason has been the lack of experimental methods that can
probe these mechanisms dynamically on their biologically relevant time scales.
Recently it was suggested that quantum coherence and its interplay with thermal
vibration might be involved in mediating ion-selectivity and transport. In this
work we present an experimental strategy for using time resolved infrared
spectroscopy to investigate these effects. We show the feasibility by
demonstrating the IR absorption and Raman spectroscopic signatures of potassium
binding model molecules that mimic the transient interactions of potassium with
binding sites of the selectivity filter during ion conduction. In addition to
guide our experiments on the real system we have performed molecular
dynamic-based simulations of the FTIR and 2DIR spectra of the entire KcsA
complex, which is the largest complex for which such modeling has been
performed. We found that by combing isotope labeling with 2D IR spectroscopy,
the signatures of potassium interaction with individual binding sites would be
experimentally observable and identified specific labeling combinations that
would maximize our expected experimental signatures.
Recently it was demonstrated that long-lived quantum coherence exists during excitation energy transport in photosynthesis. It is a valid question up to which length, time and mass scales quantum coherence may extend, how to one may detect this coherence and what if any role it plays for the dynamics of the system. Here we suggest that the selectivity filter of ion channels may exhibit quantum coherence which might be relevant for the process of ion selectivity and conduction. We show that quantum resonances could provide an alternative approch to ultrafast 2D spectroscopy to probe these quantum coherences. We demonstrate that the emergence of resonances in the conduction of ion channels that are modulated periodicallly by time dependent external electric fields can serve as signitures of quantum coherence in such a system. Assessments of experimental feasibility and specific paths towards the experimental realization of such experiments are presented. We show that this may be probed by direct 2-D spectroscopy or through the emergence of resonances in the conduction of ion channels that are modulated periodically by time dependent external electric fields. Comment: Under review for New Jorunal of Physics
Using a specially designed phase-contrast light microscope with an infrared spot illuminator we found that approximately 25% of 3T3 cells were able to extend pseudopodia towards single microscopic infrared light sources nearby. If the cells were offered a pair of such light sources next to each other, 47% of the cells extended towards them. In the latter case 30% of the responding cells extended separate pseudopodia towards each individual light source of a pair. The strongest responses were observed if the infrared light sources emitted light of wavelengths in the range of 800-900 nm intermittently at rates of 30-60 pulses per min. The temperature increases of the irradiated spots can be shown to be negligible. The results suggest that the cells are able to sense specific infrared wavelengths and to determine the direction of individual sources.
We show that the usually neglected interaction between the electric dipole of the water molecule and the quantized electromagnetic radiation field can be treated in the context of a recent quantum field theoretical formulation of collective dynamics. We find the emergence of collective modes and the appearance of permanent electric polarization around any electrically polarized impurity.
The Penrose-Hameroff (`Orch OR') model of quantum computation in brain microtubules has been criticized as regards the issue of environmental decoherence. A recent report by Tegmark finds that microtubules can maintain quantum coherence for only s, far too short to be neurophysiologically relevant. Here, we critically examine the assumptions behind Tegmark's calculation and find that: 1) Tegmark's commentary is not aimed at an existing model in the literature but rather at a hybrid that replaces the superposed protein conformations of the `Orch OR' theory with a soliton in superposition along the microtubule, 2) Tegmark predicts decreasing decoherence times at lower temperature, in direct contradiction of the observed behavior of quantum states, 3) recalculation after correcting Tegmark's equation for differences between his model and the `Orch OR' model (superposition separation, charge vs. dipole, dielectric constant) lengthens the decoherence time to s and invalidates a critical assumption of Tegmark's derivation, 4) incoherent metabolic energy supplied to the collective dynamics ordering water in the vicinity of microtubules at a rate exceeding that of decoherence can counter decoherence effects (in the same way that lasers avoid decoherence at room temperature), and 5) phases of actin gelation may enhance the ordering of water around microtubule bundles, further increasing the decoherence-free zone by an order of magnitude and the decoherence time to s. These revisions bring microtubule decoherence into a regime in which quantum gravity can interact with neurophysiology.
We report results from molecular dynamics simulations of the freezing transition of TIP5P water molecules confined between two parallel plates under the influence of a homogeneous external electric field, with magnitude of 5 V/nm, along the lateral direction. For water confined to a thickness of a trilayer we find two different phases of ice at a temperature of T=280 K. The transformation between the two, proton-ordered, ice phases is found to be a strong first-order transition. The low-density ice phase is built from hexagonal rings parallel to the confining walls and corresponds to the structure of cubic ice. The high-density ice phase has an in-plane rhombic symmetry of the oxygen atoms and larger distortion of hydrogen bond angles. The short-range order of the two ice phases is the same as the local structure of the two bilayer phases of liquid water found recently in the absence of an electric field [J. Chem. Phys. 119, 1694 (2003)]. These high- and low-density phases of water differ in local ordering at the level of the second shell of nearest neighbors. The results reported in this paper, show a close similarity between the local structure of the liquid phase and the short-range order of the corresponding solid phase. This similarity might be enhanced in water due to the deep attractive well characterizing hydrogen bond interactions. We also investigate the low-density ice phase confined to a thickness of 4, 5, and 8 molecular layers under the influence of an electric field at T=300 K. In general, we find that the degree of ordering decreases as the distance between the two confining walls increases.
Fluid phase transitions inside single, isolated carbon nanotubes are predicted to deviate substantially from classical thermodynamics. This behaviour enables the study of ice nanotubes and the exploration of their potential applications. Here we report measurements of the phase boundaries of water confined within six isolated carbon nanotubes of different diameters (1.05, 1.06, 1.15, 1.24, 1.44 and 1.52 nm) using Raman spectroscopy. The results reveal an exquisite sensitivity to diameter and substantially larger temperature elevations of the freezing transition (by as much as 100 °C) than have been theoretically predicted. Dynamic water filling and reversible freezing transitions were marked by 2-5 cm(-1) shifts in the radial breathing mode frequency, revealing reversible melting bracketed to 105-151 °C and 87-117 °C for 1.05 and 1.06 nm single-walled carbon nanotubes, respectively. Near-ambient phase changes were observed for 1.44 and 1.52 nm nanotubes, bracketed between 15-49 °C and 3-30 °C, respectively, whereas the depression of the freezing point was observed for the 1.15 nm nanotube between -35 and 10 °C. We also find that the interior aqueous phase reversibly decreases the axial thermal conductivity of the nanotube by as much as 500%, allowing digital control of the heat flux.
We investigate the dielectric profile of water confined between two planar polar walls using atomistic molecular dynamics simulations. For a water slab thickness below 1 nm the dielectric response is highly asymmetric: while the parallel component slightly increases compared to bulk, the perpendicular one decreases drastically due to anticorrelated polarization of neighboring water molecules. We demonstrate the importance of the dielectric contribution due to flexible polar headgroups and derive an effective dielectric tensorial box model suitable for coarse-grained electrostatic modeling.
Understanding phase transitions of fluids confined within nanopores is important for a wide variety of technological applications. It is well known that fluids confined in nanopores typically demonstrate freezing point depressions, ΔTf, described by the Gibbs-Thomson (GT) equation. Herein, we highlight and correct several thermodynamic inconsistencies in the conventional use of the GT equation, including the fact that the enthalpy of melting, ΔHm, and the solid-liquid surface energy, γ_(SL ), are functions of pore diameter, complicating their prediction. We propose a theoretical analysis that employs the Turnbull coefficient, originally derived from metal nucleation theory, and show its consistency as a more reliable quantity for the prediction of ΔTf. This analysis provides a straightforward method to estimate ΔTf of nanoconfined organic fluids. As an example, we apply this technique to ibuprofen, an active pharmaceutical ingredient (API), and show that this theory fits well to the experimental ΔTf of nanoconfined ibuprofen.
The concept of using nanomachines consisting of nanoscale components to have interaction with biological tissues is considered. Bio-inspired approach contributes to the development of nanomachines and systems for specific purposes. It is anticipated that nanonetworks composed of nanomachines can be useful in medical treatment of neuronal impairments. However, interaction between nanodevices and neuronal cells within in-vivo environment is a challenging task. Relying on computational neuroscience, mathematical modeling of neuronal systems and electrical circuit theory, we investigate the neuronal behavior due to injected currents by nanoscale stimulator. Favorable input signal shapes and frequencies are derived and discussed. Furthermore, the investigations on using radio frequency (RF) based signaling and their non-thermal effects are considered to design an interface for nanomachine-to-neuron communication.
The transmission and processing of neural information in the nervous system plays a key role in neural functions. It is well accepted that neural communication is mediated by bioelectricity and chemical molecules via the processes called bioelectrical and chemical transmission, respectively. Indeed, the traditional theories seem to give valuable explanations for the basic functions of the nervous system, but difficult to construct general accepted concepts or principles to provide reasonable explanations of higher brain functions and mental activities, such as perception, learning and memory, emotion and consciousness, etc. Therefore, many unanswered questions and debates over the neural encoding and mechanisms of neuronal networks remain. Cell to cell communication by biophotons, also called ultra-weak photon emissions, has been demonstrated in several plants, bacteria and certain animal cells. Recently, both experimental evidence and theoretical speculation have suggested that biophotons may play a potential role in neural signal transmission and processing, contributing to the understanding of the high functions of nervous system. In this paper, we review the relevant experimental findings and discuss the possible underlying mechanisms of biophoton signal transmission and processing in the nervous system.
The freezing of liquid water into ice was studied inside a gap of nanometer spacing under the control of electric fields and gap distance. The interfacial water underwent a sudden, reversible phase transition to ice in electric fields of 106 V m-1 at room temperature. The critical field strength for the freezing transition was much weaker than that theoretically predicted for alignment of water dipoles and crystallization into polar cubic ice (>109 V m-1). This new type of freezing mechanism, occurring in weak electric fields and at room temperature, may have immediate implications for ice formation in diverse natural environments.
The quality of frozen food and the preservation of the microstructure of the tissue depend on the nucleation rate. As the nucleation rate is related to supercooling, the control of supercooling is highly desirable. In this study, a novel approach is proposed to control ice nucleation using high electrostatic field. Distilled water has been considered as a model food. An original experimental set-up, consisting of pair of plate electrodes and cooling–heating system (Peltier element), has been designed. During sample cooling, high DC voltage was applied to a flat electrode located above the sample. The electrostatic field used in the experiments ranged from 0V/m to 6.0×106V/m. It was found that with the increase of applied voltage, nucleation temperature was shifted towards higher values. Other tests were conducted to clarify the capability of electrostatic field to induce ice nucleation at a desired supercooling degree. Our experimental results revealed that utilization of sufficiently high electrostatic field is a reliable method to control ice nucleus formation.
This article concludes a series of papers concerned with the flow of electric current through the surface membrane of a giant nerve fibre (Hodgkinet al., 1952,J. Physiol.116, 424–448; Hodgkin and Huxley, 1952,J. Physiol.116, 449–566). Its general object is to discuss the results of the preceding papers (Section 1), to put them into mathematical form (Section 2) and to show that they will account for conduction and excitation in quantitative terms (Sections 3–6).
A technique for the direct measurement of the difference between the velocity of sound in two liquids is described. By choosing for a reference a dispersionless liquid, such as water, the technique becomes a sensitive method for measurement of the change of velocity with frequency in the test liquid. In practice the method is sufficiently sensitive so that changes in the velocity smaller than one part in 104 can be detected. Illustrative measurements are presented for an NaCl solution, sperm oil, and evaporated milk.
The coupling of the electromagnetic field to matter polarization (dipole interaction) is examined in order to assess the possibility of setting up a coherent state as envisaged by Preparata and coworkers [G. Preparata, QED Coherence in Matter, World Scientific, 1995, and references therein]. It is found that coherence domains may set up in matter, their phases being arranged in a periodic lattice, as a consequence of, basically, a two-level interaction, which leads to a long-range ordered state, governed by a macroscopic occupation of both the photon state and the two levels. The non-linear equations of motion are solved for the new, non-perturbative ground-state, which is energetically favourable, provided the coupling strength exceeds a critical value. The elementary excitations with respect to this ground-state are derived, their energy being non-trivially affected by interaction. The “thermodynamics” of the coherent phase is computed and the super-radiant phase transition is re-derived in this context. Except for the general suggestion of coherence, the present results differ appreciably from Preparata's, loc cit.
Recent advances in satellite remote sensing at near-millimeter and sub-millimeter wavelengths (∼100–3000 GHz) require accurate complex permittivity for ice and liquid water at these frequencies for different temperatures, especially for cold atmospheric conditions. This paper summarizes the existing experimental permittivity data in the literature and provides an updated empirical ice permittivity model for radiative transfer calculations for ground and space remote sensing experiments. Applications of this permittivity model to Microwave Limb Sounder (MLS) cloud measurements are discussed. Copyright © 2004 Royal Meteorological Society
The conventional Clausius–Mossotti polarization equation of state is known to be unstable for polar liquids having molecules with high polarizability. Room temperature water is an important example. The instability in the polarization equation of state is of the typical loop form requiring an “equal area” construction for studying the stable ordered phase. The ordered phase of a Clausius–Mossotti polar liquid then consists of domains each having a net polarization. The polarization may vary in direction from domain to domain. The ordered phases are quite similar to those previously discussed on the basis of Dicke superradiance.
Although ice melts and water freezes under equilibrium conditions at 0°C, water can be supercooled under homogeneous conditions
in a clean environment down to –40°C without freezing. The influence of the electric field on the freezing temperature of
supercooled water (electrofreezing) is of topical importance in the living and inanimate worlds. We report that positively
charged surfaces of pyroelectric LiTaO3 crystals and SrTiO3 thin films promote ice nucleation, whereas the same surfaces when negatively charged reduce the freezing temperature. Accordingly,
droplets of water cooled down on a negatively charged LiTaO3 surface and remaining liquid at –11°C freeze immediately when this surface is heated to –8°C, as a result of the replacement
of the negative surface charge by a positive one. Furthermore, powder x-ray diffraction studies demonstrated that the freezing
on the positively charged surface starts at the solid/water interface, whereas on a negatively charged surface, ice nucleation
starts at the air/water interface.
BHK cells were inoculated sparsely on one face ("sparse- or s-face") of a thin glass film whose opposite face was covered with a 2- to 3-day-old confluent layer of BHK cells ("confluent- or c-face"). After 7 hr of attaching and spreading in the absence of visible light, most of the cells on the s-face traversed with their long axes the direction of the whorls of the confluent cells on the c-face directly opposed. The effect was inhibited by a thin metal coating of the glass films. The results suggest that the cells were able to detect the orientation of others by signals that penetrated glass but not thin metallic films and, therefore, appeared to be carried by electromagnetic radiation. In contrast, the effect was not influenced by a thin coat of silicone on the glass, suggesting that the wavelength of this radiation is likely to be in the red to infrared range. The ability of cells to detect the direction of others by electromagnetic signals points to a rudimentary form of cellular "vision."
Biological information processing, storage, and transduction are theorized to occur by “computer-like” transfer and resonance among subunits of polymerized cytoskeletal proteins: microtubules. Biological information functions (ciliary and flagellar control, axoplasmic transport, conscious awareness) could be explained by comparing microtubule structure and activities to Boolean switching matrices, parallel computers, and such technologies as transistor circuits, magnetic bubble memory, charge transfer devices, surface acoustic wave resonators, and/or holography.
From any kind of living organisms, very weak spontaneous light emission without excitation light (ultraweak biochemiluminescence) is observed. We succeeded to detect ultraweak biochemiluminescence from rat hippocampal slice preparation at the order of 10(-19) W/mm2 by a single-photon detector using a silicon avalanche photodiode. It was shown that depolarization induced by the high concentration of potassium caused an increase in the intensity of biochemiluminescence from the rat hippocampal slice, and that suppression of neural activity by tetrodotoxin elicited a decrease of its luminescence. These findings suggest that correlation between the intensity of ultraweak biochemiluminescence and neural metabolic activity.
We discuss the possibility of quantum-mechanical coherence in Cell MicroTubules (MT), based on recent developments in quantum physics. We focus on potential mechanisms for 'energy-loss-free' transport along the microtubules, which could be considered as realizations of Frohlich's ideas on the role of solitons for superconductivity and/or biological matter. In particular, by representing the MT arrangements as cavities, we review a novel scenario, suggested in collaboration with D.V. Nanopoulos, concerning the formation of macroscopic (or mesoscopic) quantum-coherent states, as a result of the (quantum-electromagnetic) interactions of the MT dimers with the surrounding molecules of the ordered water in the interior of the MT cylinders. We suggest specific experiments to test the above-conjectured quantum nature of the microtubular arrangements inside the cell. These experiments are similar in nature to those in atomic physics, used in the detection of the Rabi-Vacuum coupling between coherent cavity modes and atoms. Our conjecture is that a similar Rabi-Vacuum-splitting phenomenon occurs in the absorption (or emission) spectra of the MT dimers, which would constitute a manifestation of the dimer coupling with the coherent modes in the ordered-water environment (dipole quanta), which emerge due to the phenomenon of 'super-radiance'.
Living cells spontaneously emit ultraweak light during the process of metabolic reactions associated with the physiological state. The first demonstration of two-dimensional in vivo imaging of ultraweak photon emission from a rat's brain, using a highly sensitive photon counting apparatus, is reported in this paper. It was found that the emission intensity correlates with the electroencephalographic activity that was measured on the cortical surface and this intensity is associated with the cerebral blood flow and hyperoxia. To clarify the mechanism of photon emission, intensity changes from whole brain slices were examined under various conditions. The removal of glucose from the incubation medium suppressed the photon emission, and adding 50 mM potassium ions led to temporal enhancement of emission and subsequent depression. Rotenone (20 microM), an inhibitor of the mitochondrial electron transport chain, increased photon emission, indicating electron leakage from the respiratory chain. These results suggest that the photon emission from the brain slices originates from the energy metabolism of the inner mitochondrial respiratory chain through the production of reactive oxygen. Imaging of ultraweak photon emission from a brain constitutes a novel method, with the potential to extract pathophysiological information associated with neural metabolism and oxidative dysfunction of the neural cells.
Based on a calculation of neural decoherence rates, we argue that the degrees of freedom of the human brain that relate to cognitive processes should be thought of as a classical rather than quantum system, i.e., that there is nothing fundamentally wrong with the current classical approach to neural network simulations. We find that the decoherence time scales ( approximately 10(-13)-10(-20) s) are typically much shorter than the relevant dynamical time scales ( approximately 10(-3)-10(-1) s), both for regular neuron firing and for kinklike polarization excitations in microtubules. This conclusion disagrees with suggestions by Penrose and others that the brain acts as a quantum computer, and that quantum coherence is related to consciousness in a fundamental way.
Living organisms have been known to spontaneously emit ultraweak photons in vivo and in vitro. Origin of the photon emission remains unclear, especially in the nervous system. The spontaneous ultraweak photon emission was detected here from cultured rat cerebellar granule neurons using a photomultiplier tube which was highly sensitive to visible light. The photon emission was facilitated by the membrane depolarization of neurons by a high concentration of K+ and was attenuated by application of tetrodotoxin or removal of extracellular Ca2+, indicating the photon emission depending on the neuronal activity and likely on the cellular metabolism. Furthermore, almost all the photon emission was arrested by 2,4-dinitrophenylhydrazine, indicating that the photon emission would be derived from oxidized molecules. Detection of the spontaneous ultraweak photon emission will realize noninvasive and real-time monitoring of the redox state of neural tissue corresponding to the neuronal activity and metabolism.