Functional organization of receptive fields in the cat somatosensory cortex. I: Integration within the coronal region.

The receptive fields (RF) of the neurons in the coronal region of the first somatosensory cortex (SI) were studied in a preparation of unanesthetized paralyzed cats. The majority of units responded to simple light mechanical stimuli to the hairy or glabrous skin. There were units with slightly larger RFs and more complex properties, such as those preferentially responding to the moving skin stimuli with directional selectivity. The receptive fields tend to be larger in the more rostral (area 3a) or medial coronal (area 3b) region than in the caudal region (area 3b). The largest RFs intermingled among focal ones included other smaller RFs in the vicinity. Their configurations were different at different loci in the coronal region. It is suggested that the coronal SI region is organized in terms of multiple clusterings of units, each with particular receptive field characteristics. The representation of a single peripheral locus on the forepaw can thus be multiple, if it appeared in more than one of such clusterings of receptive fields.