Raudel Sánchez-Campusano

Universidad Pablo de Olavide | UPO · Department of Physiology, Anatomy and Cell Biology

Altered functioning of GABAergic interneurons expressing parvalbumin (PV) in the basal ganglia-thalamo-cortical circuit are likely to be involved in several human psychiatric disorders characterized by deficits in attention and sensory gating with dysfunctional decision-making behavior. However, the contribution of these interneurons in the ability...

It is assumed that the claustrum (CL) is involved in sensorimotor integration and cognitive processes. We recorded the firing activity of identified CL neurons during classical eyeblink conditioning in rabbits, using a delay paradigm in which a tone was presented as conditioned stimulus (CS), followed by a corneal air puff as unconditioned stimulus...

The objective of this study was to identify the functional properties of the prefrontal cortex that allow animals to work together to obtain a mutual reward. We induced pairs of male rats to develop a cooperative behavior in two adjacent Skinner boxes divided by a metallic grille. The experimental boxes allowed the two rats to see and to smell each...

The development of inhibitory circuits depends on the action of a network of transcription factors and epigenetic regulators that are critical for interneuron specification and differentiation. Although the identity of many of these transcription factors is well established, much less is known about the specific contribution of the chromatin-modify...

Spike sorting is one of the most important data analysis problems in neurophysiology. The precision in all steps of the spike-sorting procedure critically affects the accuracy of all subsequent analyses. After data preprocessing and spike detection have been carried out properly, both feature extraction and spike clustering are the most critical su...

Pattern recognition of neuronal discharges is the electrophysiological basis of the functional characterization of brain processes, so the implementation of a spike-sorting algorithm is an essential step for the analysis of neural codes and neural interactions in a network or brain circuit. We developed an unsupervised automatic computational algor...

Proper performance of acquired abilities can be disturbed by the unexpected occurrence of external changes. Rats trained with an operant conditioning task (to press a lever in order to obtain a food pellet) using a fixed-ratio (1:1) schedule were subsequently placed in a Skinner box in which the lever could be removed randomly. Field postsynaptic p...

GABAB receptors are the G-protein-coupled receptors for GABA, the main inhibitory neurotransmitter in the central nervous system. Pharmacological activation of GABAB receptors regulates neurotransmission and neuronal excitability at pre- and postsynaptic sites. Electrophysiological activation of GABAB receptors in brain slices generally requires st...

It is commonly accepted that associative learning is able to evoke more-or-less stable changes in synaptic weights in selected cortical and subcortical sites. It has also been shown during classical eyeblink conditioning that these changes depend on the specific and timed activation of multiple hippocampal synaptic contacts, evoking a precise map o...

We were interested in determining whether rostral medial prefrontal cortex (rmPFC) neurons participate in the measurement of conditioned stimulus– unconditioned stimulus (CS-US) time intervals during classical eyeblink conditioning. Rabbits were conditioned with a delay paradigm consisting of a tone as CS. The CS started 50, 250, 500, 1000, or 2000...

Although it is generally assumed that the hippocampus is involved in associative learning, the specific contribution of the different synapses present in its intrinsic circuit or comprising its afferents and efferents is poorly defined. We studied here activity-dependent changes in synaptic strength of 9 hippocampal synapses (corresponding to the i...

Learning and decisions are precise functional states of brain cortical circuits that can only be approached by the use of multidisciplinary and complementary tools. The availability of genetically manipulated mice and rats, of mathematical and computational neuroscience methods, and of advanced electrophysiological techniques  susceptible of being...

Introduction: It commonly accepted that classical conditioning is able to evoke more-or-less stable changes in synaptic weights and that these changes depend on the specific and timed activation of the multiple hippocampal synaptic contacts, evoking a precise map of synapticlearning states (Gruart et al., Cerebral Cortex, doi:10.1093/cercor/bhu054)...

Although much is known about the neural spike sorting in most areas of the brain, the patterns of activity of the rostral medial prefrontal cortex (rmPFC) neurons are still poorly studied. In this study, the spike sorting allowed the classification of the rmPFC neuronal spikes and to obtain the distribution of the different firing rates during eyeb...

Although data collected from different types of experiments indicate that wide brain areas - including cerebral and cerebellar cortices, as well as basal ganglia - are involved in different aspects of timing and time perception, the information on the actual neural mechanisms supporting those timed behaviors is rather scarce. In particular, the cer...

In the present paper, we examine the role of the cerebellar interpositus nucleus (IN) in motor and non-motor domains. Recent findings are considered, and we share the following conclusions: IN as part of the olivo-cortico-nuclear microcircuit is involved in providing powerful timing signals important in coordinating limb movements; IN could partici...

The complexity of brain functions can only be approached by a multidisciplinary and complementary approach. The availability of genetically manipulated mammals (mostly mice) and of sophisticated electrophysiological techniques, susceptible of being applied in behaving animals during the acquisition of different learning paradigms, has largely facil...

Operant conditioning is a type of associative learning involving different and complex sensorimotor and cognitive processes. Because the hippocampus has been related to some motor and cognitive functions involved in this type of learning (such as object recognition, spatial orientation, and associative learning tasks), we decided to study in behavi...

The perception of time is crucial for everyday activities from the sleep–wake cycle to playing and appreciating music, verbal communication, to the determination of the value of a particular behavior. With regard to the last point, making decisions is heavily influenced by the duration of the various options, the duration of the expected delays for...

Transcranial direct-current stimulation (tDCS) is a noninvasive brain stimulation technique that has been successfully applied for modulation of cortical excitability. tDCS is capable of inducing changes in neuronal membrane potentials in a polarity-dependent manner. When tDCS is of sufficient length, synaptically driven after-effects are induced....

The presence of two antagonistic groups of deep cerebellar nuclei neurons has been reported as necessary for a proper dynamic control of learned motor responses. Most models of cerebellar function seem to ignore the biomechanical need for a double activation-deactivation system controlling eyelid kinematics, since most of them accept that, for clos...

The cerebellum-red nucleus-facial motoneuron (Mn) pathway has been reported as being involved in the proper timing of classically conditioned eyelid responses. This special type of associative learning serves as a model of event timing for studying the role of the cerebellum in dynamic motor control. Here, we have re-analyzed the firing activities...

Understanding the role played by the cerebellum in the genesis and control of learned motor responses requires a precise knowledge of interdependent relationships between kinetic neural commands and the performance (kinematics) of the acquired movements. The eyelid motor system is a useful model for studying how simple motor responses are generated...

Young adult heterozygous Lurcher mice constitute an excellent model for studying the role of the cerebellar cortex in motor performance-including the acquisition of new motor abilities-because of the early postnatal degeneration of almost all of their Purkinje and granular cells. Wild-type and Lurcher mice were classically conditioned for eyelid re...

We assessed here true causal directionalities in cerebellar-motoneuron (MN) network associations during the classical conditioning of eyelid responses. For this, the firing activities of identified facial MNs and cerebellar interpositus (IP) nucleus neurons were recorded during the acquisition of this type of associative learning in alert behaving...

The role played by the cerebellum in movement control requires knowledge of interdependent relationships between kinetic neural commands and the performance (kinematics) of learned motor responses. The eyelid motor system is an excellent model for studying how simple motor responses are elaborated and performed. Kinetic variables (n = 24) were dete...

Objectives: Clinical validation of quantitative VEP (Q-VEP) based on Biophysical modeling of visual system at cortical macro columnar level using Duffing Oscillator Model. Background: VEP has been often described by limited number of parameters (latency, amplitude and morphology) with useful clinical relevance, in visual system disorders. The prop...

Transgenic mice over-expressing a mutated form of the human amyloid precursor protein (APP, 695 isoform) bearing a mutation associated with Alzheimer's disease (V642I, so-called London mutation, hereafter APPLd2) and wild-type controls were studied at age periods (3 and 10 months) prior to the overt development of neuritic amyloid plaques. Both 3-...

In this paper we propose a computational model to describe the propagation process of bioelectrical responses in the sensorial receivers and pathways of the brain induced by external stimulus. We supposed that the electrical potential inside the brain satisfies the non linear, damped and non homogeneous wave equation. The Finite Difference Method i...

The description of Pattern Reversal steady state Visual Evoked Potential (PR - ssVEP) in terms of functional significant parameters is very important in theoretical and practical neuroscience research. A dynamical approach could explain by the descriptive parameters, the temporal evolution of PR - ssVEP, which could offer information about the func...

Transcraneal Magnetic Stimulation (TMS) is a potential tool for the non-invasive exploration of the electric responses of neural masses in the CNS. The actual forward problem defined for this technique consists in the estimation of the IEFs during the magnetic stimulation for arrangements and coil fixed. The IEFs inside the brain by the low frequen...

Numerosos autores reportan la presencia de procesos oscilatorios no lineales en los PEV. Se presenta una modelación mesoscópica de la dinámica de los neurogeneradores del PEV, tomando como modelo físico de los neurosistemas implicados, una membrana elástica lineal con resortes oscilantes no lineales acoplados. Bajo ciertas consideraciones funcional...