Behavioral and electrophysiological evidence of a right hemisphere bias for the influence of negative emotion on higher cognition

Authors:

• Emiliana R. Simon-Thomas

• Kemi O. Role

• Robert T. Knight

Date: 2005

PubMed: 15814010

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Abstract:

We examined how responses to aversive pictures affected performance and stimulus-locked event-related potentials (ERPs) recorded during a demanding cognitive task. Numeric Stroop stimuli were brief ly presented to either left or right visual hemifield (LVF and RVF, respectively) after a centrally presented aversive or neutral picture from the International Affective Picture System. Subjects indicated whether a quantity value from each Stroop stimulus matched the preceding Stroop stimulus while passively viewing the pictures. After aversive pictures, responses were more accurate for LVF Stroops and less accurate for RVF Stroops. Early-latency extrastriate attention-dependent visual ERPs were enhanced for LVF Stroops. The N2 ERP was enhanced for LVF Stroops over the right frontal and parietal scalp sites. Slow potentials (300-800 msec) recorded over the frontal and parietal regions showed enhanced picture related modulation and amplitude for LVF Stroops. These results suggest that emotional responses to aversive pictures selectively facilitated right hemisphere processing during higher cognitive task performance.

Affective and cognitive modulation of performance monitoring: behavioral and ERP evidence

Authors:

• Emiliana R. Simon-Thomas

• Robert T. Knight

Date: 2005

PubMed: 16396095

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Abstract:

This study investigates the effects of negative affect on performance monitoring. EEG was acquired during a lateralized, numeric Stroop working memory task that featured task-irrelevant aversive and neutral pictures between stimuli. Performance accuracy showed a right-hemisphere advantage for stimuli that followed aversive pictures. Response-locked event-related potentials (ERPs) from accurate trials showed an early negative component (CRN; correct response/conflict-related negativity) followed by a positive wave comparable to the Pe (error positivity). The CRN was bi-peaked with an earlier peak that was sensitive to aversive pictures during early portions of the experiment and a later peak that increased with error likelihood later in the experiment. Pe amplitude was increased with aversive pictures early in the experiment and was sensitive to picture type, Stroop interference, and hemisphere of stimulus delivery during later trials. This suggests that ERP indices of performance monitoring, the CRN and Pe, are dynamically modulated by both affective and cognitive demands.

Distributed neural activity during object, spatial and integrated processing in humans

Authors:

• Emiliana R. Simon-Thomas

• Kim Brodsky

• Cammy Willing

• Rashmi Sinha

• Robert T. Knight

Date: 2003

PubMed: 12706225

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Abstract:

Information about the form and the spatial location of objects is seamlessly integrated during visual perception. We used event-related potentials (ERPs) to explore neural activity related to processing form, location or the combination of both kinds of features. Healthy subjects performed three versions of a 'match-to-sample' task: a two-object task, a two-location task and an integrated object-location task. Responses were quickest and most accurate during the integrated task, slower and less accurate in the two-location task and slowest and least accurate in the two-object task. ERPs locked to the 'sample' stimulus at encoding, and to the 'target' stimulus during feature comparison differentiated between tasks. 'Sample' stimulus ERPs exhibited task-specific posterior cortical involvement in processing distinct visual features. 'Target' stimulus ERPs revealed task-related differences in features associated with frontal lobe mediated attentional processes: an early latency P300 showed increased amplitude during the integrated task. Results from this experiment support the view that distinct neural circuits mediate form vs. location processing and that form-location integration engages both pathways and upregulates frontal-parietal association networks.