Spatially modulated touch responses in parietal cortex

Cortical neurons with low-threshold, cutaneous receptive fields on the fingers were recorded in areas 5 and 7b of the parietal lobe in two awake monkeys, trained in a visually guided reach task. 72% (81/113) of the cells responded when targets displayed on a videomonitor were actively touched. Of these, 20 neurons discharged preferentially when target contact was made on one side of the screen compared with the other. This spatial modulation of the cutaneous modality may have originated in neighboring joint-related neurons which were directionally selective.