LGN cells were recorded with micropipettes filled with 0.2M KCl having impedances of about 50-200 megaohms. Multiple tests were performed to measure spatiotemporal receptive field properties. These include: small spots flashed darker than, equal to, and brighter than the background; sinusoidal luminance modulation of the same spots; drifting gratings; sparse noise stimulation with bright and dark bars or spots of 40ms duration; and other tests.

Attempts were made to categorize cells as ON or OFF, X or Y, and lagged or nonlagged. In many cells these classifications were not obvious, and in some cases should be regarded as subjective.

Ages ranged from 33 to 94 days. For purposes of analysis, subjects were grouped according to age categories formed around rather arbitrary gaps in the database, but roughly corresponding to evenly spaced ages on a log scale.

Eccentricities ranged out to 36°, but were concentrated in the central 15°. All cells were recorded in the A-layers except for a few C-layer cells included in the population results here.

Stimuli were presented at 15cd/m2 on a Tektronix 608 monitor driven by a Picasso at 200Hz, generally at contrasts of 0.4-0.8.


Back to index

Date created: November 5, 1997
Last modified: November 5, 1997
Copyright © 1997, Alan Saul
Maintained by: Alan Saul
Alan Saul