Group research focus
Our group has been devoted to the study of the neurophysiological basis of animal behavior, from the generation of simple motor responses to the neuronal control of complex behaviors. Our experimental approach is both comparative and multidisciplinary, including the use of electrophysiological, histological, behavioral, and modeling techniques. An important aspect of our research activities is the design of specific instrumentation for Neuroscience.
A particular attention is paid to the study of adaptive properties of the nervous tissue, mainly those underlying motor associative learning, as well as those involved in appetitive and cognitive processes. The main scientific contributions of the group in the past 15 years can be divided in three blocks:
Kinematics and kinetic properties in the time and frequency domains of the eyelid motor system. In a now classic study, we identified the complete facial premotor system with the help of tiny injections of attenuated rabies virus in the upper eyelid of rats. We have used calcium-fixing proteins to identify oculomotor- and facial-related neurons. We have also shown C-Fos expression in the hippocampus and in the perirrinal, entorrinal, and somatosensory cortices during eyelid classical conditioning in the rabbit. The latter studies have allowed the selection of eyeblink neural microzones for their electrophysiological study.
Roles of cerebellum and hippocampus in motor and cognitive learning. We have studied the role of cerebellum as a reinforcer of on-going eyelid responses using lesion, pharmacological, and electrophysiological recording techniques. With respect to the hippocampus, we have studied changes in synaptic plasticity that take place between Schaffer collaterals and CA1 pyramidal cells in wild-type mice during the learning process, as well as the putative relationships of these learning dependent changes in synaptic plasticity and those evoked by experimentally evoked long-term potentiation. These foundlings were recognized by Science Magazine as one of the ten breakthroughs of year 2006 (Science, 12/21/2006).
Role of other cortical sites in motor learning. We have also studied the role of selected (non-hippocampal) cortical sites during the classical conditioning of the corneal reflex. In the past few years, we have advanced the electrophysiological study of the roles of the somato-sensory and the medial prefrontal cortices in associative learning (both classical and instrumental). We have also advanced the modeling of the different cortical and subcortical neural centers involved in associative learning.
The main rationale of the future objectives of our group is that neuronal phenomena taking place in cortical and subcortical ensembles during motor and/or cognitive learning tasks has to be studied in behaving animals at the precise moment of acquisition or remembering. On the other hand, it is also assumed that in order to properly deal with the neural basis of learning processes this study should have a comparative (different species) and multidisciplinary (different and complementary techniques) approach. Specifically, we plan to study activity dependent changes in synaptic strength occurring in hippocampal, prefrontal, and related cortical circuits during the acquisition and storage of associative learning in alert behaving wild type and genetically manipulated mice, rats, and rabbits. The simultaneous recording of synaptic, unitary, and LFP activities at the indicated neural sites will offer an still unknown picture of the specific functional states taking place during the actual acquisition process.
We will use home-developed mathematical tools to obtain the state functions characterizing the acquisition of new motor and/or cognitive skills. In addition, we support the contention that learning and memory processes are the result of selective functional states evoked by the joint activation of distributed brain circuits and not of the local activation of the multiple synaptic contacts present in those circuits (i.e. the synaptic plasticity paradigm). We will address this later question with genetic tools aimed to inducible and reversible silencing of synaptic transmission applied in behaving rabbits during learning, and recall, of a classical eyeblink conditioning test.