Orientation Tuning in Macaque Somatosensory Cortex

Previous work has shown that many neurons in the second somatosensory (S2) cortical region show orientation tuning, somewhat akin to that observed in the visual cortex.

This week Pramodsingh et al. honed in on a single finger pad of two rhesus monkeys and show that this orientation tuning involves multiple mechanisms. They indented the skin of a finger pad with a motorized bar at eight different orientations and nine different locations and recorded from single neurons in the macaque S2 region. Some cells had simple cell-like receptive fields, but many neurons showed position invariant responses. That is, their firing was selective for a narrow band of orientations, and the preferred orientation was the same in any location across the finger pad. The range of response properties indicated that tuning results from a region of pure position invariance, bands of excitation and inhibition that are not centered on the finger pad, or a combination of these mechanisms.

By Society for Neuroscience