Program in Neuroscience, University of Fribourg, Switzerland
Dr. Eric M. Rouiller
Institute of Physiology
University of Fribourg
1700 FRIBOURG
SWITZERLAND
phone +41-26-300 8609
email Eric.Rouiller@unifr.ch
Website
Functions and plasticity of cortical motor areas, and investigation of auditory pathways
An important issue to be resolved in behavioural neuroscience is the mechanism whereby information from the environment is relayed to the brain and processed therein to generate an appropriate, but discretionary, behavioural response. Plasticity of the brain is crucial not only in this context, but also for the partial recovery of the nervous system following injury. We are investigating the roles of the primary, supplementary, premotor and cingulate motor cortical areas in controlling the uni- and bimanual movements instigated by sensory (e.g., visual) cues in monkeys. Extracellular activity generated by single neurones in these motor areas is recorded during a conditional motor task, requiring, for instance, coordination between both hands and ocular fixation of a target. Similarly, in conditional motor tasks instructed acoustically, activity generated within the same motor cortical areas, as well as within the auditory ones, is recorded. In a more clinical direction, we are studying the plastic mechanisms underlying restitution of motor skills following lesion of a motor cortical area or of the corticospinal tract, using a unimanual precision-grip task and bimanual reach and grasp motor sequences. With respect to the auditory system, we are exploring means of optimizing electrical stimulation of the cochlea, using cochlear implants in a rat model. The deaf cochlea is stimulated electrically, and the activity thereby generated in the auditory pathways compared to that produced by natural auditory stimulation. Using an in-vitro, whole-brain, guinea-pig model, we are also investigating how different, anatomically-defined, cell types of the cochlear nucleus behave in response to electrical stimulation of the auditory nerve. These studies are multidisciplinary and draw on the following techniques: single-unit extracellular recording in monkeys, pharmacological reversible inactivations, behavioural assessment of motor performance, neuroanatomical tract-tracing, c-fos functional mapping and, in vitro, intracellular labeling and recording from individual neurones.
Selected publications
Rouiller E.M., Yu X.Y., Moret V., Tempini A., Wiesendanger M. & Liang F. Dexterity in adult monkeys following early lesion of the motor cortical hand area: the role of the cortex adjacent to the lesion. Europ. J. Neurosci. 10: 729-740, 1998
Kermadi, I., Y. Lui, A. Tempini, E. Calciati & E.M. Rouiller. Neuronal activity in the primate supplementary motor area and the primary motor cortex in relation to spatio-temporal bimanual coordination. Somatosens. and Motor Res. 15: 287-308, 1998
Carretta, D., A. Hervé-Minvielle, V. Bajo, A.E.P. Villa & E.M. Rouiller. Preferential induction of Fos-like immunoreactivity (FLI) in granule cells of the cochlear nucleus by acoustic stimulation in behaving rats. Neurosci. Lett. 259: 123-126, 1999