V1 (n = 48) | MT (n = 40) | |
---|---|---|
Spontaneous rate (spikes/sec) | 4.9 ± 7.1 | 8.2 ± 6.1 |
Maximum rate (spikes/sec) | 87 ± 46 | 57 ± 19 |
Modulation index | 0.21 ± 0.15 | 0.21 ± 0.10 |
Direction index | 0.99 ± 0.09 | 1.09 ± 0.14 |
Direction bandwidth (degrees) | 70 ± 26 | 98 ± 39 |
RF eccentricity (degrees) | 7 ± 6 | 15 ± 12 |
CRF diameter (degrees) | 1.8 ± 1.7 | 8.0 ± 4.2 |
Optimal SF (cycles/degree) | 1.9 ± 1.1 | 0.9 ± 0.6 |
Optimal TF (Hz) | 7.8 ± 5.5 | 11.5 ± 7.9 |
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Values are mean ± SD. Spontaneous rate is the response to a mean gray field. Maximum rate is the average response during the first 2 sec of the optimal drifting grating. See Materials and Methods for modulation and direction indices. Direction bandwidth is the width at half-height of the peak in the direction tuning curve. RF eccentricity is the visual angle between the fixation point and the center of the RF, which ranged from 1.0 to 21° in V1 and from 2.2 to 35° in MT. Optimal SF and TF are those that produced the maximum firing rate for drifting gratings. CRF, Classical receptive field.