Purpose: Previously we showed that some complex cells responded more reliably to edges than to gratings. Here we extend our investigation to include simple cells and to compare their reliability distribution with complex cells. Furthermore, we have expanded our analysis to use a more general set of measures, including principal components. Methods: Visual responses of single units were extracellularly recorded in the primary visual cortex of anaesthetized macaque monkey. Responses to sinewave grating stimuli were compared with responses to drifting squarewaves (edges). Spike rate and principal components were used as response measures; d′ and the inverse of the coefficient of variation were used as measures of reliability of a response. Results: Regardless of the measures used, medium-to-strong responses of the majority of both simple and complex cells were more reliable to edges than to gratings. However, the average reliability ratio of complex cells was greater than for simple cells. Conclusions: These results indicate that primary visual cortical neurons may be better suited to signal sharp, rather than smooth, luminance variation in the visual scene. RELIABILITY RATIO OF V1 CELL RESPONSES EDGES vs. GRATINGS (Graph Presented) RELIAB. RATIO (ρEDGE/ρGRATING).
|Investigative Ophthalmology and Visual Science
|Published - Feb 15 1996
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience