For many years we have functionally imaged barrel cortex activation in response to single whisker stimulation and we have repeatedly found that such stimulation evokes an unexpectedly large, symmetric part of cortex (see for the example Brett-Green et al. 2001, Chen-Bee et al. 2007). Using our integrative approach, we have recently demonstrated the underlying reason for the imaging findings. We have shown that the rat somatosensory cortex is functionally and anatomically organized by a spatial motif of very large, symmetrical, subthreshold activity spreads that can be imaged and electrophysiologically recorded following stimulation of a single whisker. Further, these activity spreads are supported by underlying, intracortical long-range axonal projections. Surprisingly, such activity spreads and their underlying connections project beyond the somatosensory cortex's anatomical (cytoarchitectonic) borders into (sometimes deeply) primary auditory, primary visual, and primary motor cortices. Therefore, for this cortical motif of organization, the cortex can be viewed as a borderless continuum rather than the traditional view of cortex as parceled into discrete modules within clear cytoarchitectonic borders. For more details and further implications of these findings, (see Frostig et al. 2008)
Examples of our research: (click for deatils)
1) Click here for our emerging view on the large scale functional and anatomical organization of somatosensory cortex.
2) Click here for a new type of plasticity: how stimulation of a single whisker can completely protect the cortex from an impending ischemic stroke.
3) Click here for plasticity induced by transferring animals from their cages to our naturalistic habitat.
4) Click here for a clip showing the 3 phases (intial dip, overshoot and undershoot) of the whisker functional representation evoked within barrel cortex following 1 second of single whisker activation. Based on Chen-Bee et al. (2007).