20140415認知神經科學與認知模擬 (I)

Ju-Chi Yu

Dissociable neural mechanisms underlying response-based and familiarity-based

conflict in working memory

Nelson, J. K., Reuter-Lorenz, P. A., Sylvester, C.-Y. C., Jonides, J. & Smith, E. E. (2003) Procedings of the National Academy of

Sciences of the United States of America 100,11171-11175

Take home message

• The neural mechanisms of response-based and familiarity-based conflict in working memory are different.

Introduction

• Cognitive control requires the resolution of interference among competing and potentially conflicting representations.

– Stimulus input– Response generation

Previous research

• Anterior cingulate cortex (ACC) is associated to cognitive conflict.

• Error detection hypothesis– ACC response to errors– ACC has greater activation during high-

conflict conditions

Previous research

• Jonides and coworkers:– Verbal working memory

– no activation in the ACC was found– associated with activation in the left inferior frontal

gyrus (IFG)

Previous research

• These various findings can be explained by the existence of at least two separable source of cognitive conflict:– Response based: conflict occurs at response

processing level– Familiarity-based: conflict occurs at a

preceding level of processing

Previous research

• The ACC is typically characterized in conflict accounts as dealing with response conflict.

• Milham et al., 2001: the ACC monitors for conflict specifically at the response level

Question

• Possibility that this activation is closely related to increased task difficulty

• Is this ACC activation really specific to response conflict?

Experiment

• Verbal working-memory task (Jonides et al., 1998, 2000)

• The familiarity-conflict and highly familiar trials are included

Expectation

• Familiarity-based conflict left IFT, no ACC– Familiarity-conflict & highly familiar trials

• Response-based conflict ACC, no left IFT– Response-conflict trials

EXPERIMENT

Experiment

• 17 participants• 10 practice + 48 trials*4 blocks =10+192 trials• 2 8-min run of a verb generation task

• 50% answer “yes”• 50% answer “no”

Procedure and design

•

• “yes” 50%• “no” 12.5%• “no” 12.5% • “no” 12.5% • “no” 12.5%

RESULT

Behavioral

Neuroimaging

Discussion

• Other explanation:

subjects are more aware of the response-conflict manipulation than the familiarity manipulation, and that the ACC is correlated with conscious monitoring of conflict.

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