[Abstract Title]. - Society for Neuroscience

Poster
288. Working Memory: Disorders, Genes and Connectivity
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 288.3/RR10
Topic: F.01.f. Working memory
Support: NIH T32 MH019879 (AK)
NARSAD Young Investigator Award (JWB)
Title: The influence of working memory on error-likelihood prediction in the anterior cingulate
cortex and its disturbance in schizophrenia
Authors: *A. KRAWITZ 1 , T. S. BRAVER 2 , D. M. BARCH 2 , J. W. BROWN 1 ;
1 Psychological & Brain Sci., Indiana Univ., Bloomington, IN; 2 Psychology, Washington Univ.,
St. Louis, MO
Abstract: Recent research has shown that anterior cingulate cortex (ACC) modulates the degree
to which top-down cognitive control systems, including working memory (WM) in dorsolateral
prefrontal cortex (DLPFC), are brought to bear in particular task contexts. Specifically,
according to the error-likelihood model (Brown & Braver, 2005), the magnitude of ACC output
in a given situation is proportional to the perceived probability of making an error. It has
remained unknown whether ACC may use WM contents to guide error-likelihood prediction and
thus complete a reciprocal loop between DLPFC and ACC, as predicted by recent work with the
error-likelihood model. Furthermore, past studies suggest that the cognitive impairment found in
schizophrenia involves WM-related deficits in DLPFC and performance monitoring deficits in
ACC, but the impact of these deficits on the reciprocal interaction between the two areas remains
unclear.
We investigated whether information in WM is used as context by ACC to inform its evaluation
of error likelihood in schizophrenia patients and in non-psychiatric controls. In a modified
version of the change-signal task of Brown and Braver (2005), a cue predicting error likelihood
was incidentally encoded into WM by participants in order to perform a secondary delayed
match-to-sample (DMTS) task. Following the cue, a blank-screen delay period occurred prior to
the change-signal trial. Using a rapid event-related fMRI design with partial trial decomposition,
we looked for error-likelihood related activity at the time of cue presentation and at the time of
response to the change-signal target.
In controls, we found an area of ACC whose activation at the response predicted error likelihood
as indicated by the initial cue, even for trials without errors or response conflict. This area did
not show error-likelihood related activity at the cue presentation. This illustrates that, in controls,