What Do Barrels REALLY Do?

The time delay between the arrival of the thalamic input signal and the recruitment of strong intrabarrel inhibition creates a window of opportunity for initially synchronous thalamic firing to engage, albeit momentarily, positive feedback circuitry within the barrel, allowing the development of an excitatory response.
Thus, barrel circuitry enhances contrast between temporally synchronous and dispersed thalamic inputs.  This sensitivity to input timing produces a spatial focusing of receptive field size and other signal transformations that form the basis of more spatially and temporally complex receptive fields in other layers of the cortical column.

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