The somatosensory cortex of the mammalian brain is a major area concerned with touch on the body, and shows a 'map' of activity. Neurons, or nerve cells, become active in a location that correlates with the relative location of the part of the body that is stimulated. It has been know for a long time that this map is plastic, and so it can change with experience; responding areas of the map may increase in size if there is a lot of stimulation over time, or decrease when the stimulation is blocked or removed. Sometimes these changes are rather rapid, over hours, yet the mechanisms for that rapid change still are not understood. This project uses electrophyisological, local pharmacological, and neuroanatomical techniques to explore how the inputs to particular neurons can reorganize quickly. A novel approach includes using a reversible sensory blockage by a small cold probe. The hypotheses to test are whether some of this rapid change results from 'unmasking' of inputs that have before been inhibited, whether the subthreshold inputs are regulated by control of the inhibitory neurotransmitter molecule called GABA, and whether most of the regulatory connections lie within the cortex itself. Results from these studies will be important to understanding plasticity in the brain, and so will be important beyond simply sensory physiology, extending their impact to developmental neuroscience, and to relevance to mechanisms underlying learning.
