Prof. Dr. Schwarz (D)
Prof. Dr. Cornelius
Werner Reichardt Centrum f. Integrative Neurowissenschaften
Hertie-Institut für Klinische Hirnforschung
in the rat barrel cortex
Rats are highly skilled in discriminating objects and textures by palpatory movements of their vibrissae. Recent evidence indicates that they employ different kinds of vibrissal motor programs depending on the required task. Thus, the choice of palpatory movements expresses the "perceptual hypothesis" of the subject. In a first step, we want to investigate which parameters of the motor program are adjusted to tackle different discrimination tasks. In a second step, we want to determine (i) how these task-specific movement-dependent neuronal signals are processed in the barrel column, (ii) how they transmit information about critical changes in the motor program and (iii) how these task-specific signals are used to optimize sensory signals for perception. The key approach to investigate these relationships is to simultaneously measure the motor strategy, set the sensory input, record extracellular single units in the barrel column, and assess the percept of the animal. These conditions will be realized by modifying and combining psychophysical and electrophysiological methods that have been established by the work group during the last couple of years. We will train head-fixed rats to palpate virtual objects in defined discrimination tasks while simultaneous single and multi unit recordings are performed in the associated cortical barrels. The animals will perform spatial frequency discrimination of different types using their choice of whisker movements (active perception). This kind of data will allow the comparison of neurometric and psychometric sensitivities depending on the tactile task and employed motor strategies.