Receptive fields and functional architecture of macaque V2

Abstract

1. Visual area V2 of macaque monkey cerebral cortex is the largest of the extrastriate visual areas, yet surprisingly little is known of its neuronal properties. We have made a quantitative analysis of V2 receptive field properties. Our set of measurements was chosen to distinguish neuronal responses reflecting parvocellular (P) or magnocellular (M) inputs and to permit comparison with similar measurements made in other visual areas; we further describe the relationship of those properties to the laminar and cytochrome oxidase (CO) architecture of V2. 2. We recorded the activity of single units representing the central 5 degrees in all laminae and CO divisions of V2 in anesthetized, paralyzed macaque monkeys. We studied responses to geometric targets and to drifting sinusoidal gratings that varied in orientation, spatial frequency, drift rate, contrast, and color. 3. The orientation selectivity and spatial and temporal tuning of V2 neurons differed little from those in V1. As in V1, spatial and temporal tuning in V2 appeared separable, and we identified a population of simple cells (more common within the central 3 degrees) similar to those found in V1. Contrast sensitivity of V2 neurons was greater on average than in V1, perhaps reflecting the summation of inputs in V2's larger receptive fields. Many V2 neurons exhibited some degree of chromatic opponency, responding to isoluminant color variations, but these neurons differed from V1 in the linearity with which they summate cone signals. 4. In agreement with others, we found that neurons with selective responses to color, size, and motion did seem to cluster in different CO compartments. However, this segregation of qualitatively different response selectivities was not absolute, and response properties also seemed to depend on laminar position within each compartment. As others also have noted, we found that CO stripe widths in the macaque (unlike in the squirrel monkey) did not consistently appear different. We relied on the segregation of qualitatively distinct cell types, and in some cases the pattern of Cat-301 staining as well, to distinguish CO stripes when the staining pattern of CO alone was ambiguous. Although all cell types were found in all CO compartments and laminae, unoriented cells were more prominent in layers 2-4 of "thin" stripes, direction-selective cells in layers 3B/4 of "thick" stripes, color-selective cells in the upper layers of thin and pale stripes, and end-stopped cells mainly outside of layer 4 in thin stripes.(ABSTRACT TRUNCATED AT 400 WORDS)

Modular Organization of Occipito-Temporal Pathways: Cortical Connections between Visual Area 4 and Visual Area 2 and Posterior Inferotemporal Ventral Area in Macaque Monkeys

“…For example, DeYoe and Van Essen (1985) reported that V2 thin stripe and interstripes both contain chromatic selective neurons (86% vs 64%), and similar proportions of cells in thin stripes (80%) and interstripes (83%) were orientation selective. Similarly, Levitt et al (1994) reported significant overlap in the response properties of neurons in V2 thin stripes and interstripes, although thin stripes tended to have lower spatial resolution and contrast sensitivity yet tended to have a lower incidence orientation selectivity. In contrast, optical recording studies of V2 functional architecture typically rely on differences in thin stripe and interstripe responses to isoluminant color and luminance contrast gratings.…”

Signals in Macaque Striate Cortical Neurons that Support the Perception of Glass Patterns

“…Optimal sizes for Glass pattern and random dot stimuli were chosen in the same manner. We also fit descriptive f unctions to spatial frequency tuning curves for gratings to find the optimal spatial period, (the inverse of the optimal spatial frequency), for each cell (Levitt et al, 1994).…”

Adaptation to contingencies in macaque primary visual cortex

“…Methods for single-cell recording in paralysed anaesthetized macaque monkeys in our laboratory have been described elsewhere (Levitt et al 1994). Stimuli were either single drifting gratings or sums of two drifting gratings (compound stimuli), generated by a Truevision ATVista graphics controller (7526582 pixels, 107 Hz) and displayed on a gamma-corrected Nanao T560i monitor (mean luminance 72 cd m 72 ).…”