Contrast response and direction tuning in macaque MT/V5
Center for Neural Science
New York University
4 Washington Place, Room 809
New York, NY 10003

Support: NIH grant EY02017; Howard Hughes Medical Institute

ANIMAL Macaca fascicularis (w/ 1 M. nemestrina), adult male
PREP anesthetized (sufentanil), paralyzed (vecuronium)
DATA TYPE extracellular spike times
N 57 cells
Available since: 29 Apr 2004

There are three data sets here:

The stimulus for each subset is described in detail below.


2004.6.a - The visual stimulus for one experimental run can be thought of as a sequence of contiguous epochs, each containing a drifting sinusoidal grating. A set of values specifying grating contrast (typically from 100% to 3.1% in octave steps and sometimes including 0) were randomly shuffled and assigned to each epoch. Thus, in one experimental run, each contrast value was tested once. Each epoch contained typically 8 or 16 complete drift cycles of the grating at the specified contrast, and there was no gap between epochs. Thus, the stimulus appeared as a steady drifting grating whose contrast changed randomly after a set number of drift cycles.

In the data files here, each trial represents an epoch in the experimental run, and spike times are given relative to the first video frame of the epoch. No account is made in these data files for visual latency; therefore, spikes that occur in the first 30ms or so of each trial are likely to represent the response to the grating in the previous epoch (or the spontaneous rate for the case of the first epoch in any run). The duration of the trial, typically 1280 ms, is determined by the number of drift cycles divided by the temporal frequency of the drifting grating. The number of experimental runs comprising each file can be deduced from the number of times that each contrast value is represented in the data files. The ordering of trials in the data files reflects the actual order of the epochs within the experimental run. File names for this data subset end in "gc".

2004.6.b - The presentation of the stimulus was similar to that described above, except that 16 evenly-spaced directions of motion and one blank (mean gray) were shuffled randomly among the contiguous epochs on each trial. File names for this data subset end in "gd".

2004.6.c - The presentation of the stimulus was similar to that described for 2004.6.b, except that a sparse dot pattern was moved in stead of a sinusoidal grating. The dots were bright on a black background, and the blank stimulus was black. File names for this data subset end in "dd".

Note - File names beginning "524" are for M. nemestrina.

Electrophysiological Methods

Kohn A, Movshon JA (2003) Neuronal adaptation to visual motion in area MT of the macaque. Neuron 39:681--691.

Published analyses