Christopher Petkov

Newcastle University | NCL · Institute of Neuroscience

Laser thermal ablation has become a prominent neurosurgical treatment approach, but in epilepsy patients it cannot currently be safely implemented with intracranial recording electrodes that are used to study interictal or epileptiform activity. There is a pressing need for computational models of laser interstitial thermal therapy (LITT) with and...

Low-intensity Transcranial Ultrasound Stimulation (TUS) is a promising non-invasive technique for deep-brain stimulation and focal neuromodulation. Research with animal models and computational modelling has raised the possibility that TUS can be biased towards enhancing or suppressing neural function. Here, we first conduct a systematic review of...

The cerebral cortex displays a bewildering diversity of shapes and sizes across and within species. Despite this diversity, we present a universal multi-scale description of primate cortices. We show that all cortical shapes can be described as a set of nested folds of different sizes. As neighbouring folds are gradually merged, the cortices of 11...

The cerebral cortex displays a bewildering diversity of shapes and sizes across and within species. Despite this diversity, we present a parsimonious and universal multi-scale description of primate cortices in full agreement with empirical data, by expressing cortical shapes explicitly as hierarchical compositions of folds across spatial scales. A...

The cerebral cortex displays a bewildering diversity of shapes and sizes across and within species. Despite this diversity, we present a parsimonious and universal multi-scale description of primate cortices in full agreement with empirical data, by expressing cortical shapes explicitly as hierarchical compositions of folds across spatial scales. A...

The human brain extracts meaning using an extensive neural system for semantic knowledge. Whether broadly distributed systems depend on or can compensate after losing a highly interconnected hub is controversial. We report intracranial recordings from two patients during a speech prediction task, obtained minutes before and after neurosurgical trea...

Activity-induced gene expression underlies synaptic plasticity and brain function. Here, using molecular sequencing techniques, we define activity-dependent transcriptomic and epigenomic changes at the tissue and single-cell level in the human brain following direct electrical stimulation of the anterior temporal lobe in patients undergoing neurosu...

The hippocampus plays a key role in integrating spatial and temporal information, however, in natural scenarios different rules apply under different contexts. Contextual information could be hippocampal dependent, if it is integrated into a context-guided memory sequence (Eichenbaum, 2017: PMID 28655882). The prefrontal cortex could also be involv...

Understanding how the brain represents and binds complex information distributed over time is a challenging problem, requiring computationally and neurobiologically informed approaches to solve. Human language is a salient example, whereby syntactic knowledge facilitates “movement” and transformation of sequential information into hierarchical ment...

Ethical frameworks are the foundation for any research with humans or nonhuman animals. Human research is guided by overarching international ethical principles, such as those defined in the Helsinki Declaration by the World Medical Association. However, for nonhuman animal research, because there are several sets of ethical principles and national...

The primate cerebral cortex can take on a bewildering diversity of shapes and sizes within and across species, whilst maintaining archetypal qualities that make it instantly recognisable as a "brain". Here we present a new way of expressing the shape of a cortex explicitly as the hierarchical composition of structures across spatial scales. In comp...

The human brain extracts meaning from the world using an extensive neural system for semantic knowledge. Whether such broadly distributed systems crucially depend on or can compensate for the loss of one of their highly interconnected hubs is controversial. The strongest level of causal evidence for the role of a brain hub is to evaluate its acute...

Whether human and nonhuman primates process the temporal dimension of sound similarly remains an open question. We examined the brain basis for the processing of acoustic time windows in rhesus macaques using stimuli simulating the spectrotemporal complexity of vocalizations. We conducted functional magnetic resonance imaging in awake macaques to i...

Open science initiatives are creating opportunities to increase research coordination and impact in nonhuman primate (NHP) imaging. The PRIMatE Data and Resource Exchange community recently developed a collaboration-based strategic plan to advance NHP imaging as an integrative approach for multiscale neuroscience.

Figure-ground segregation, the brain’s ability to group related features into stable perceptual entities, is crucial for auditory perception in noisy environments. The neuronal mechanisms for this process are poorly understood in the auditory system. Here, we report figure-ground modulation of multi-unit activity (MUA) in the primary and non-primar...

Functional localizers are invaluable as they can help define regions of interest, provide cross-study comparisons, and most importantly, allow for the aggregation and meta-analyses of data across studies and laboratories. To achieve these goals within the non-human primate (NHP) imaging community, there is a pressing need for the use of standardize...

Brain perturbation studies allow detailed causal inferences of behavioral and neural processes. Because the combination of brain perturbation methods and neural measurement techniques is inherently challenging, research in humans has predominantly focused on non-invasive, indirect brain perturbations, or neurological lesion studies. Non-human prima...

Welcome to Current Research in Neurobiology (CRNEUR), the gold open access, sibling journal to Current Opinion in Neurobiology, a journal for timely original research in neuroscience. At its very core, CRNEUR is a journal for creativity and innovation in science and publishing. As a journal, we ambitiously aim for CRNEUR to be a vehicle for what ma...

Information from Magnetic Resonance Imaging (MRI) is useful for diagnosis and treatment management of human neurological patients. MRI monitoring might also prove useful for non-human animals involved in neuroscience research provided that MRI is available and feasible and that there are no MRI contra-indications precluding scanning. However, MRI m...

Human brain pathways supporting language and declarative memory are thought to have differentiated substantially during evolution. However, cross-species comparisons are missing on site-specific effective connectivity between regions important for cognition. We harnessed functional imaging to visualize the effects of direct electrical brain stimula...

Background Neuroscience studies with macaque monkeys may require cranial implants to stabilize the head or gain access to the brain for scientific purposes. Wound management that promotes healing after the cranial implant surgery in non-human primates can be difficult as it is not necessarily possible to cover the wound margins. New Method Here, w...

Mapping the causal effects of one brain region on another is a challenging problem in neuroscience that we approached through invasive direct manipulation of brain function together with concurrent whole-brain measurement of the effects produced. Here we establish a unique resource and present data from 26 human patients who underwent electrical st...

Mapping the causal effects of one brain region on another (effective connectivity) is a challenging problem in neuroscience, since it requires invasive direct manipulation of brain function, together with whole-brain measurement of the effects produced. Here we establish a unique resource and present data from 26 human patients who underwent electr...

Mapping the causal effects of one brain region on another (effective connectivity) is a challenging problem in neuroscience, since it requires invasive direct manipulation of brain function, together with whole-brain measurement of the effects produced. Here we establish a unique resource and present data from 26 human patients who underwent electr...

The human arcuate fasciculus pathway is crucial for language , interconnecting posterior temporal and inferior frontal areas. Whether a monkey homolog exists is controversial and the nature of human-specific specialization unclear. Using monkey, ape and human auditory functional fields and diffusion-weighted MRI, we identified homologous pathways o...

Cognitive pathways supporting human language and declarative memory are thought to have uniquely evolutionarily differentiated in our species. However, cross-species comparisons are missing on site-specific effective connectivity between regions important for cognition. We harnessed a new approach using functional imaging to visualize the impact of...

Human languages all have a grammar, that is, rules that determine how symbols in a language can be combined to create complex meaningful expressions. Despite decades of research, the evolutionary, developmental, cognitive, and computational bases of grammatical abilities are still not fully understood. “Artificial Grammar Learning” (AGL) studies pr...

Nonhuman primate neuroimaging is on the cusp of a transformation, much in the same way its human counterpart was in 2010, when the Human Connectome Project was launched to accelerate progress. Inspired by an open data-sharing initiative, the global community recently met and, in this article, breaks through obstacles to define its ambitions.

Figure-ground segregation, the brain’s ability to group related features into stable perceptual entities, is crucial for auditory perception in noisy environments. The neuronal mechanisms for this process are poorly understood in the auditory system. Here, we report figure-ground modulation of multi-unit activity (MUA) in the primary and non-primar...

Understanding how the brain forms representations of structured information distributed in time is a challenging endeavour for the neuroscientific community, requiring computationally and neurobiologically informed approaches. The neural mechanisms for segmenting continuous streams of sensory input and establishing representations of dependencies r...

A unique overview of the human language faculty at all levels of organization. Language is not only one of the most complex cognitive functions that we command, it is also the aspect of the mind that makes us uniquely human. Research suggests that the human brain exhibits a language readiness not found in the brains of other species. This volume br...

Understanding how the brain binds complex information distributed over time is a challenging problem facing the neuroscientific community, requiring computationally and neurobiologically informed approaches to solve. The combinatorial binding problem is particularly salient in language, whereby human syntactic knowledge supports the encoding and de...

In this study, we show direct electrophysiological evidence of figure-ground segregation in primary and non-primary auditory cortex, with a systematic effect of figure saliency in the anterior, non-primary areas.

Human language is a salient example of a neurocognitive system that is specialized to process complex dependencies between sensory events distributed in time, yet how this system evolved and specialized remains unclear. Artificial Grammar Learning (AGL) studies have generated a wealth of insights into how human adults and infants process different...

In natural settings, the prospect of reward often influences the focus of our attention, but how cognitive and motivational systems influence sensory cortex is not well understood. Also, challenges in training nonhuman animals on cognitive tasks complicate cross-species comparisons and interpreting results on the neurobiological bases of cognition....

The interactions of many social animals critically depend on identifying other individuals to approach or avoid. Recognizing specific individuals requires extracting and integrating cross-sensory indexical cues from richly informative communication signals such as voice and face content. Knowledge on how the brain processes faces and voices as unis...

Segregating the key features of the natural world within crowded visual or sound scenes is a critical aspect of everyday perception. The neurobiological bases for auditory figure-ground segregation are poorly understood. We demonstrate that macaques perceive an acoustic figure-ground stimulus with comparable performance to humans using a neural sys...

The past decades have seen an explosion of research into the psychological, cognitive, neural, biological, and technical mechanisms of voice perception. These mechanisms refer to the general ability to extract information from voices expressed by other living beings or by technical systems. Voice perception research is now a lively area of research...

Non-human primate neuroimaging is a rapidly growing area of research that promises to transform and scale translational and cross-species comparative neuroscience. Unfortunately, the technological and methodological advances of the past two decades have outpaced the accrual of data, which is particularly challenging given the relatively few centers...

TE, echo time; TR, repetition time; PE, phase encoding; RO, read out direction; Reconstructed resolution (RR; mm) and image dimensions refer to the images after they have been reconstructed from the k-space data, the matrix size, and resolution used for the acquisition may differ. For these categories, RO, read out direction; PE, phase encoding dir...

FA, flip angle; TE, echo time; TR, repetition time; BW, bandwidth per pixel; ES, echo spacing; PA, parallel acquisition; PF, partial Fourier (half scan); PE, phase encoding direction; FS, fat suppression; SO, slice orientation; SA, slice acquisition order; Gap, gap between slices; RO, read out direction; Nacq, number of volumes collected; Ndisc, nu...

FA, flip angle; TE, echo time; TR, repetition time

FA, flip angle; TI, inversion time; TE, echo time; ES, echo spacing; BW, bandwidth per pixel; TR, repetition time; PA, parallel acquisition; PF, partial Fourier (half scan); SO, slice orientation; PE, phase encoding direction; RO, read out direction; SL, slice direction. Reconstructed resolution (RR; mm) and image dimensions (RID; px) refer to the...

Neuroscience research in non-human primates (NHPs) has delivered fundamental knowledge about human brain function as well as some valuable therapies that have improved the lives of human patients with a variety of brain disorders. Research using NHPs, although it is facing serious challenges, continues to complement studies in human volunteers and...

Empirical advances have been made in understanding how human language, in its combinatorial complexity and unbounded expressivity, may have evolved from the communication systems present in our evolutionary ancestors. However, a number of cognitive processes and neurobiological mechanisms that support language may not have evolved specifically for...

Predicting the occurrence of future events from prior ones is vital for animal perception and cognition. Although how such sequence learning (a form of relational knowledge) relates to particular operations in language remains controversial, recent evidence shows that sequence learning is disrupted in frontal lobe damage associated with aphasia. Al...

Natural environments elicit both phase-locked and non-phase-locked neural responses to the stimulus in the brain. The interpretation of the BOLD signal to date has been based on an association of the non-phase-locked power of high-frequency local field potentials (LFPs), or the related spiking activity in single neurons or groups of neurons. Previo...

Non-human primate neuroimaging is a rapidly growing area of research that promises to transform and scale translational and cross-species comparative neuroscience. Unfortunately, the technological and methodological advances of the past two decades have outpaced the accrual of data, which is particularly challenging given the relatively few centers...

In this study, we demonstrate that macaques are, similar to humans, able to extract auditory objects from complex acoustic scenes. Moreover, we present evidence that perceptual organisation takes place in rostral parts of the auditory belt and parabelt.

Patients with non-fluent aphasias display impairments of expressive and receptive grammar. This has been attributed to deficits in processing configurational and hierarchical sequencing relationships. This hypothesis had not been formally tested. It was also controversial whether impairments are specific to language, or reflect domain general defic...

Language flexibly supports the human ability to communicate using different sensory modalities, such as writing and reading in the visual modality and speaking and listening in the auditory domain. Although it has been argued that nonhuman primate communication abilities are inherently multisensory, direct behavioural comparisons between human and...

This work examined the mechanisms underlying auditory motion processing in the auditory cortex of awake monkeys using functional magnetic resonance imaging (fMRI). We tested to what extent auditory motion analysis can be explained by the linear combination of static spatial mechanisms, spectrotemporal processes, and their interaction. We found that...

Learning complex ordering relationships between sensory events in a sequence is fundamental for animal perception and human communication. While it is known that rhythmic sensory events can entrain brain oscillations at different frequencies, how learning and prior experience with sequencing relationships affect neocortical oscillations and neurona...

Distributions of frequency of phase and amplitude for the PAC response in humans and monkeys. The distributions of peak PAC values were calculated per phase (A, C) or amplitude (B, D) separately. The error bars denote the standard deviation. No obvious differences are seen between the results in the two monkeys or the two humans. (TIF)

Topography of PAC frequency of phase and amplitude in human Heschl’s Gyrus. The distributions of peak PAC values were calculated at postero-medial (blue) and antero-lateral (red) recording sites separately per phase (A, C) or amplitude (B, D). The error bars denote the standard deviation. The boundaries in the two subjects between the postero-media...

Control experiment in human participant H3 and resulting PAC effects. A. Time course of the experiments. The testing conditions were identical, with the key difference what the subject experienced before testing: either exposure to random transitions between the nonsense words in a sequence or structured sequences consistent with the artificial gra...

Control experiment in human participant H3 and resulting PAC effects. Number of sites with significant PAC responses and sequencing context PAC effects during the same type of testing phase after exposure to structured sequences consistent with the AG ordering relationships. (XLSX)

Effects of the acoustical elements preceding the probe stimulus analysis window. (DOCX)