Series of Talks on Cognitive Control
by Professor Albert Kok

Cognitive control (By Prof. Albert Kok)

The talks focus on three different aspects of cognitive control, namely selective attention, response inhibition  and error monitoring. The major part of this work has been carried out by my graduate students Helene Slagter, Jennifer Ramautar and Sander Nieuwenhuis with the assistance of Richard Ridderinkhof  between 2002 and 2006.

Talks will be held on 11th (1-2pm) and 12th (10am-12pm) April in AS6-03-33

Refreshments will be served.

1. Cueing of spatial and non spatial visual attention (Wed 11th April 1-2pm AS6-03-33)
   
   The principal question of this study was to identify control mechanisms in the brain underlying the (re) directing of visual attention, using a cued attention paradigm. This paradigm allows separation in time of neural signals for task specification en preparation, and the neural response to the target stimulus that the subjects must detect and identify. The first  experiment was an ERP experiment and the second experiment a fMRI experiment carried out at Duke University (Marty Woldorff lab). We used three different tasks in which the colour or location of visual target stimuli were cued in a repeated, transient and mixed fashion. The ERP study showed that attentional control was associated with dorsal posterior positivity starting  at 260 ms post cue. This positivity probably reflects processes involved in the generation of an attentional set/updating of  rules in working memory. Having to switch attention (within trials analysis) called more strongly  on  these processes.  The fMRI study showed that cueing of attention elicited  switch-specific preparatory activity in a network of dorsal-frontal and parietal brain areas
   
2. 
   Response inhibition: the isolation of ERP component  associated with successful and unsuccessful inhibition of motor responses. (Thurs 12th April 10-11am AS6-03-33)
   
   In this study we used different versions of the stop signal paradigm in which an imperative stimulus is followed at variable delays by a stop signal telling the subject to abort his response.  In three experiments we  tried to answer the following questions. Can we isolate ERP reflections of stop signal processing?  In what respect are stop signal ERPs different for unsuccessful stop trials (UST) and successful stop trials (SST)?  Is unsuccessful stopping manifested in additional error-related activity (ERN/Ne, Pe)?  The main findings can be summarized as follows:  a) Stop signals always elicited a  N2/P3 complex, b) unsuccessful stopping was associated with a frontocentral N2 and posterior P3 resembling ERN/Ne and Pe respectively, while successful stopping  elicited a frontocentral P3 resembling the nogoP3 Time permitting we shall also briefly report results of a fMRI follow up study  with the stop task.
    
3. Error monitoring:  ERP findings, major theories and neural  basis (Thurs 12th April 11am-12pm  AS6-03-33)
   The last 5 years have witnessed a growing interest in the functional interpretation and  brain mechanisms underlying error- related  potentials of the brain (ERN/Ne, Pe). In addition many studies shave focused on hemodynamic (fMRI) reflections of performance in tasks tapping various aspects of response conflict and/or error monitoring. In this talk I shall first report some ERP studies carried out in our lab dealing with errors in performance in the antisaccade and Eriksen tasks. I shall then briefly  review the role of anterior cingulate cortex in  error monitoring, and discuss  some unresolved issues  such as the differential roles of prefrontal cortex  and  anterior cingulate in the  monitoring and  adjustment of  errors in performance.

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Further information about the speaker:
 (http://home.medewerker.uva.nl/a.kok/)

Professor Albert Kok is a professor at the Faculty of Social & Behavioral Sciences  (Psychology) at the University of Amsterdam. His research interests centre around event-related-potential (ERP) reflections of selective attention and executive control processes, neuroimaging and ERP manifestations of response inhibition and modelling of the P300 component of the ERP.

His research in the past decade has examined the following topics:

Psychophysiology of mental effort, modelling of P300, sleep and information processing (using ERPs, EEG), electrophysiology of visual selective attention (using event-related potentials: ERPs), caffeine and alcohol: effects on information processing and selective attention, electrocortical reflections of normal aging (using ERPs), cognitive control, inhibition and prefrontal cortex (using ERPs and functional imaging); and inhibition (no-go N2, P3) and error related brain potentials (ERN/Ne, Pe).

His CV can be obtained at http://users.fmg.uva.nl/akok/Curriculum%20vitae.htm.