Fig. 4.

Curvature direction tuning in somatosensory cortex. A, left: responses of a neuron in area 2 to curvature fragments (2D angles and arcs) sorted by curvature direction. A, right: gray scale indicates the average response rates for angles and arcs. This neuron responds best to curvature fragments pointing leftward (135–180°). B: time courses of normalized spiking activity (black) and curvature signaling (gray) in a population of neurons in area 2. Curvature modulation is computed by taking the difference between the maximum and minimum responses and normalizing it by the sum of these. Population activity peaks relatively quickly while curvature signals build gradually and peak more slowly (adapted from Yau et al. 2013a).