Human Brain Mapping 2002
June 10-16, 2002
Scott Makeig1, Phan Luu2 & Don Tucker2,
1Institute for Neural Computation, UCSD & 2Department of Psychology, University of Oregon
Do 'Brainstorms' Help Turn Intentions Into Attentions?
Introduction: Implementing intentions to actively attend and respond appears to require dynamic tuning of cortical receptivity. Such tuning and retuning doubtless accompanies our every change of intention. For example, a soccer player kicking the ball towards the goal "concentrates on" the relevant somatomotor and visual parameters while his brain "ignores" irrelevant parameters such as crowd noise. Most likely, such transient (re)focusing of attention to maximize the chance of achieving his intention (goal!) may affect the dynamic state of nearly every cortical area. Behavioral attention experiments demonstrate that normal subjects can change their attentional tuning rapidly if sufficiently motivated. Synchronous field activity in cortex giving rise to EEG signals at the scalp appear to accompany this top-down focusing of attention produced by changes in intention (in turn occasioned by events and their perceived consequences).
Methods: Data from six subjects participating in a 128-channel event-related EEG experiment involving the Erikson flanker speeded response task (Luu et al., 2000) were analyzed using independent component analysis (ICA) followed by time/frequency analysis (Makeig et al., 2002).
Results: During and immediately following response errors (late and/or incorrect responses), theta band (5-6 Hz) bursts were observed in the EEG. ICA applied to the unaveraged EEG data revealed that these bursts occurred in otherwise maximally temporally independent frontal and parietal EEG domains. Further, these bursts exhibited transient, event-related coherence which proceeded from anterior to posterior domains. The central midline post-response theta bursts were also partially phase reset by the motor response, giving rise to the so-called Error-Related Negativity (ERN) feature of the averaged event-related potential (ERP). Event-related coherence between maximally independent EEG domains was not simply a consequence of common entrainment to phase resetting by the response -- and thus was not reflected in features of the response-locked ERP. Similar dynamics appear in other task paradigms in response to transient cognitive challenges.
Conclusion: We suggest that transient, frontal-parietal theta-band 'brainstorms' may facilitate attentional refocusing, here occasioned by subject awareness of the consequences of their motor errors (reduced pay and/or self-approval) in light of their intentions (to earn money and/or to experience approval). Transient changes in the spatiotemporal pattern of synchronized macroscopic field activity across cortical (and, doubtless, subcortical) regions is a new and intriguing model of event-related top-down brain dynamics.
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