Functional neuroimaging and behavioral correlates of capacity decline in visual short-term memory after sleep deprivation

doi:10.1073/pnas.0610712104

Functional neuroimaging and behavioral correlates of capacity decline in visual short-term memory after sleep deprivation

Cognitive Neuroscience Laboratory, Duke–National University of Singapore Graduate Medical School and Singapore Health Services, Singapore 169611

Edited by Marcus E. Raichle, Washington University School of Medicine, St. Louis, MO, and approved April 16, 2007 (received for review December 8, 2006)

Abstract

Sleep deprivation (SD) impairs short-term memory, but it is unclear whether this is because of reduced storage capacity or processes contributing to appropriate information encoding. We evaluated 30 individuals twice, once after a night of normal sleep and again after 24 h of SD. In each session, we evaluated visual memory capacity by presenting arrays of one to eight colored squares. Additionally, we measured cortical responses to varying visual array sizes without engaging memory. The magnitude of intraparietal sulcus activation and memory capacity after normal sleep were highly correlated. SD elicited a pattern of activation in both tasks, indicating that deficits in visual processing and visual attention accompany and could account for loss of short-term memory capacity. Additionally, a comparison between better and poorer performers showed that preservation of precuneus and temporoparietal junction deactivation with increasing memory load corresponds to less performance decline when one is sleep-deprived.

Footnotes

*To whom correspondence should be addressed. E-mail: mchee{at}pacific.net.sg
Author contributions: M.W.L.C. and Y.M.L.C. designed research; Y.M.L.C. performed research; M.W.L.C. contributed new reagents/analytic tools; M.W.L.C. and Y.M.L.C. analyzed data; and M.W.L.C. and Y.M.L.C. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/cgi/content/full/0610712104/DC1.
Abbreviations:

VSTM,

visual short-term memory;

IPS,

intraparietal sulcus;

VAC,

visual array-size control;

VO,

ventral occipital;

SD,

sleep deprivation;

PC,

precuneus;

PCC,

posterior cingulate cortex;

RW,

rested wakefulness.
Freely available online through the PNAS open access option.