[Abstract Title]. - Society for Neuroscience

288. Working Memory: Disorders, Genes and Connectivity
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 288.12/RR19
Topic: F.01.f. Working memory
Support: NSERC Canadian Graduate Scholarship
Natural Sciences and Engineering Research Council (NSERC)
Michael Smith Foundation for Health Research (MSFHR)
Canada Research Chairs (CRC) Program
Title: Spatiotemporal brain dynamics underlying online maintenance
Authors: L. RIGGS 1,2 , *A. T. HERDMAN 3 , J. RYAN 1,2 ;
1 The Rotman Res. Inst., Toronto, ON, Canada; 2 Univ. of Toronto, Toronto, ON, Canada; 3 Simon
Fraser Univ., Burnaby, BC, Canada
Abstract: The spatiotemporal dynamics underlying online maintenance of relations among
objects were outlined using magnetoencephalography (MEG). Subjects were presented with an
initial scene of three abstract objects overlaid on a real-world background context. Following a
delay of two seconds, a repeated or manipulated version of the original scene was presented.
Performance accuracy was above 90%. MEG single trial data from 12 subjects were averaged
with respect to stimulus onset. Neural activity during the two second delay was assessed. Online
maintenance, relative to a baseline period before the onset of the first scene, was associated with
sustained activity in many of the same regions implicated for processing of the scene such as the
lingual gyrus, cuneus, precuneus, inferior parietal gyrus and regions in the prefrontal cortex.
Activity in these regions peaked during the 500 ms immediately following first scene offset, and
remained significantly above baseline for the remaining 1500 ms during the delay period. These
findings suggest active maintenance of visual representations even in the absence of external
stimuli.
Disclosures: L. Riggs, None; J. Ryan, None; A.T. Herdman , None.
Poster
288. Working Memory: Disorders, Genes and Connectivity
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm