[Abstract Title]. - Society for Neuroscience

present study we tested the hypothesis that striatal dopamine is particularly important for the
manipulation of information in working memory in a pharmacological, event-related fMRI
study. Twenty healthy human subjects were scanned twice, once after placebo and once after
sulpiride 400 mg, a selective DA D2 receptor antagonist, while performing a working memory
task requiring different levels of manipulation. We found a significant correlation between
sulpiride plasma levels and process-specific BOLD signal bilaterally in the striatum, suggesting a
dose-dependent effect of D2 antagonism on a striatally-based manipulation process. When
subjects with high sulpiride plasma levels were examined separately we observed the predicted
interaction between drug and condition, whereby striatal BOLD signal was lower during
manipulation trials than during simple retrieval trials after sulpiride but not after placebo. No
significant drug effects were observed in the PFC. These results support models of dopamine
function which posit a „gating‟ function for dopamine D2 receptors in the striatum, which
enables the flexible updating and manipulation of information in working memory.
Disclosures: C.M. Dodds , None; U. Muller, None; L. Clark, None; T.W. Robbins, None.
Poster
288. Working Memory: Disorders, Genes and Connectivity
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 288.10/RR17
Topic: F.01.f. Working memory
Support: DAAD research scholarship
Title: An fMRI study of transcranial direct current stimulation effects on planning performance
and associative learning
Authors: *C. DOCKERY, T. GABER, B. VARKUTI, R. HÜCKEL-WENG, N.
BIRBAUMER;
Inst. Med. Psychology, Univ. Tuebingen, Tuebingen, Germany
Abstract: Transcranial direct current stimulation (tDCS) applied over the cortex transiently
modifies cortical excitability via altering the membrane potential of underlying neurons.
Different cortical areas can be targeted by tDCS, and it‟s pairing with fMRI imaging supports
further understanding of the effect by providing a tool to evaluate neuropathologies,
pathophysiology of disease and tDCS mechanisms of action. Baudewig et al. (2001) reported
reduced motor cortex activity after cathodal tDCS on sensorimotor activity shown by fMRI
BOLD signal changes post-stimulation. Combined fMRI and tDCS to study cognitive function
can expand knowledge about the efficacy of tDCS.