Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-27T17:56:45.265Z Has data issue: false hasContentIssue false

Visual signals used in time-interval discrimination

Published online by Cambridge University Press:  01 July 2000

GERALD WESTHEIMER
Affiliation:
Division of Neurobiology, University of California–Berkeley, Berkeley

Abstract

Thresholds for the detection of differences in the duration of visual stimuli were determined for a variety of programs of stimulus onset and offset. Performance suffers when a time interval begins with an ON step and ends with another ON stimulus, compared to the standard ON–OFF stimulation, but the decrement is reversed when the light is ramped down to background during the interval. Neither the magnocellular nor the parvocellular streams can be excluded because there is relatively little impairment of duration discrimination when the stimulus has low contrast or is heterochromatic at isoluminance. Performance at a variety of intensity levels suggests that sustained neural firing in an early stage of visual processing provides a background activity, which prevents good temporal precision of signals.

Type
Research Article
Copyright
© 2000 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)