Biomedical subjects
Publications and source records attributed to Erika E Fanselow.
Touch is an active process, but how do the body's somatic sensors influence its movement? In this issue of Neuron, Nguyen and Kleinfeld show that afferent activity from the whiskers on a rat's face trigger rapid and prolonged excitation of the motor neurons that drive movements of the same whiskers. Positive feedback through this sensorimotor loop may serve to optimize the interaction between sensors and stimuli.
Recent experiments in our laboratory have indicated that as rats shift the behavioural strategy employed to explore their surrounding environment, there is a parallel change in the physiological properties of the neuronal ensembles that define the main thalamocortical loop of the trigeminal somatosensory system. Based on experimental evidence from several laboratories, we propose that this concurrent shift in behavioural strategy and thalamocortical physiological properties provides rats with an efficient way to optimize either the detection or analysis of complex tactile stimuli.
We propose a conceptual model that describes the operation of the main thalamocortical loop of the rat somatosensory system. According to this model, the asynchronous convergence of ascending and descending projections dynamically alters the physiological properties of thalamic neurons in the ventral posterior medial (VPM) nucleus as rats shift between three behavioral states. Two of these states are characterized by distinct modes of rhythmic whisker movements. We posit that these simultaneous shifts in exploratory behavioral strategy and in the physiological properties of VPM neurons allow rats to either (i) optimize the detection of stimuli that are novel or difficult to sense or (ii) process complex patterns of multi-whisker stimulation.