Modality-specific circadian rhythmicities influence mechanisms of attention and memory for interval timing


Journal Article

Two groups of male Sprague-Dawley rats (n's = 10) were trained to discriminate between 2-s and 8-s signal durations at one of two different phases of a 14:10 light:dark (LD) cycle with lights on at 7:00 am. One group of rats was trained beginning at 8:00 am and the other group of rats was trained beginning at 8:00 pm. Signals were composed of either a 2-s or an 8-s duration of light (6-or 7.5-W lamp onset) or sound (80-dB white noise onset) presented with equal probability in a random order during a 2-h session. Five intermediate signal durations, in addition to the two anchor points, were presented by means of the bisection method with discrete trials separated by a random-interval 45-s intertrial interval (ITI). After baseline response functions for both auditory and visual signals were obtained at the two training phases, test sessions were conducted at eight different times during the LD cycle. These test sessions were conducted in order to determine whether any of the psychological processes involved in the discrimination of signal duration in the seconds to minutes' range exhibit a cirdadian rhythm. The results obtained from the test stage revealed no circadian rhythmicity in clock speed (Λ) for either signal modality; whereas, the variability or temporal memory for sound signals (γK* | S) and the probability of attention to light signals (p(A) | L)-as estimated from the application of a scalar expectancy model of temporal bisection-showed circadian rhythmicities that interacted with the circadian phase of initial baseline training. © 1991.

Full Text

Cited Authors

  • Meck, WH

Published Date

  • January 1, 1991

Published In

Volume / Issue

  • 22 / 1-2

Start / End Page

  • 153 - 179

International Standard Serial Number (ISSN)

  • 0023-9690

Digital Object Identifier (DOI)

  • 10.1016/0023-9690(91)90021-Y

Citation Source

  • Scopus