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Abstract:
Contextual Cueing is an implicit learning paradigm used to
assess how a repeated context or configuration can guide attention
to an associated target location. Behaviorally, subjects are faster
and more accurate when searching for a target in an repeated
configuration relative to a novel configuration (Chun & Jiang,
1998). In the present study we examine the anatomical location and
temporal dynamics of contextual cueing using intracranial event
related potentials (ERPs). Epilepsy patients with electrodes
implanted subdurally on the cortical surface for presurgical
localization of seizures performed a visual search task over 384
trials. All subjects were unaware that some distractor
configurations covaried with target location. ERP$E2s were averaged
for patients who showed the behavioral effect (a decrease in
response time for repeated configurations). Task-related changes in
waveform were seen at electrodes located on the lingual and
fusiform gyri. Implicitly learned configurations resulted in a
greater positivity of the waveform around 200 ms and continued
until about 800 ms. These findings coincide with brain imaging
studies of repetition priming where increased repetition leads to
decreased activity in extrastriate areas. Our paradigm reveals
similar effects for global context information. Importantly, old
contexts are differentiated from novel contexts within 200 ms of
stimulus onset.
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