Related Experiment Videos
On the directional selectivity of cells in the visual cortex to drifting dot patterns
B C Skottun1, J Zhang, D H Grosof
1Department of Psychology, University of California, Berkley.
Visual Neuroscience
|September 1, 1994
Summary
Cortical neurons show directional selectivity to drifting dots and gratings. This study found that linear filtering properties explain responses to dot patterns, suggesting shared mechanisms with grating responses.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Visual Cortex Research
Background:
- Cortical neurons exhibit distinct preferred drift directions for random dot and grating stimuli.
- Dot stimuli often elicit two preferred directions, symmetrically flanking grating preferred directions.
Purpose of the Study:
- To estimate the optimal direction for drifting dots in cat striate cortex neurons.
- To determine if linear filtering properties explain directional selectivity to drifting dot patterns.
Main Methods:
- Analysis of filter properties in three-dimensional (3-D) Fourier space.
- Examination of 3-D power spectra of drifting dot patterns.
- Estimation of optimal drift directions for ten neurons in adult cat striate cortex.
Main Results:
- Estimated optimal directions for drifting dots frequently yielded two peaks, flanking the grating optimal direction.
- The angular separation between these two peaks increased with stimulus drift speed.
- Predicted angles showed good agreement with actual observed angles.
Conclusions:
- Directional selectivity of cortical neurons to drifting dot patterns is explainable by linear filtering properties.
- The mechanisms underlying responses to drifting dot patterns are likely shared with those for sinusoidal gratings.
- A separate directional mechanism for dot patterns is not required.