Brain Advance Access originally published online on August 27, 2009
Brain 2009 132(11):3002-3010; doi:10.1093/brain/awp230
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Prefrontal cortex is critical for contextual processing: evidence from brain lesions
1 Department of Psychology and the Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, USA 2 Department of Psychology, University of La Coruña, Spain
Correspondence to: Noa Fogelson, PhD, Helen Wills Neuroscience Institute, 132 Barker Hall, Berkeley, CA 94720-3190, USA E-mail: nfogelson{at}udc.es
We investigated the role of prefrontal cortex (PFC) in local contextual processing using a combined event-related potentials and lesion approach. Local context was defined as the occurrence of a short predictive series of visual stimuli occurring before delivery of a target event. Targets were preceded by either randomized sequences of standards or by sequences including a three-stimulus predictive sequence signalling the occurrence of a subsequent target event. PFC lesioned patients were impaired in their ability to use local contextual information. The response time for controls revealed a larger benefit for predictable targets than for random targets relative to PFC patients. PFC patients had reduced amplitude of a context-dependent positivity and failed to generate the expected P3b latency shift between predictive and non-predictive targets. These findings show that PFC patients are unable to utilize predictive local context to guide behaviour, providing evidence for a critical role of PFC in local contextual processing.
Key Words: context; prefrontal cortex; P3b; EEG; context positivity
Abbreviations: CP, context-dependent positivity; ERP, event-related potential; PFC, prefrontal cortex
Received January 29, 2009. Revised July 16, 2009. Accepted July 23, 2009.