Skip Nav Destination
Close Modal
Update search
NARROW
Format
Journal
TocHeadingTitle
Date
Availability
1-4 of 4
John J. Foxe
Close
Follow your search
Access your saved searches in your account
Would you like to receive an alert when new items match your search?
Sort by
Journal Articles
Publisher: Journals Gateway
Journal of Cognitive Neuroscience (2009) 21 (1): 93–104.
Published: 01 January 2009
Abstract
View article
PDF
Disentangling the component processes that contribute to human executive control is a key challenge for cognitive neuroscience. Here, we employ event-related potentials to provide electrophysiological evidence that action errors during a go/no-go task can result either from sustained attention failures or from failures of response inhibition, and that these two processes are temporally and physiologically dissociable, although the behavioral error—a nonintended response—is the same. Thirteen right-handed participants performed a version of a go/no-go task in which stimuli were presented in a fixed and predictable order, thus encouraging attentional drift, and a second version in which an identical set of stimuli was presented in a random order, thus placing greater emphasis on response inhibition. Electrocortical markers associated with goal maintenance (late positivity, alpha synchronization) distinguished correct and incorrect performance in the fixed condition, whereas errors in the random condition were linked to a diminished N2–P3 inhibitory complex. In addition, the amplitude of the error-related negativity did not differ between correct and incorrect responses in the fixed condition, consistent with the view that errors in this condition do not arise from a failure to resolve response competition. Our data provide an electrophysiological dissociation of sustained attention and response inhibition.
Journal Articles
Publisher: Journals Gateway
Journal of Cognitive Neuroscience (2009) 21 (1): 105–118.
Published: 01 January 2009
Abstract
View article
PDF
Using event-related potentials (ERPs), we investigated the neural response associated with preparing to switch from one task to another. We used a cued task-switching paradigm in which the interval between the cue and the imperative stimulus was varied. The difference between response time (RT) to trials on which the task switched and trials on which the task repeated (switch cost) decreased as the interval between cue and target (CTI) was increased, demonstrating that subjects used the CTI to prepare for the forthcoming task. However, the RT on repeated-task trials in blocks during which the task could switch (mixed-task blocks) were never as short as RTs during single-task blocks (mixing cost). This replicates previous research. The ERPs in response to the cue were compared across three conditions: single-task trials, switch trials, and repeat trials. ERP topographic differences were found between single-task trials and mixed-task (switch and repeat) trials at ∼160 and ∼310 msec after the cue, indicative of changes in the underlying neural generator configuration as a basis for the mixing cost. In contrast, there were no topographic differences evident between switch and repeat trials during the CTI. Rather, the response of statistically indistinguishable generator configurations was stronger at ∼310 msec on switch than on repeat trials. By separating differences in ERP topography from differences in response strength, these results suggest that a reappraisal of previous research is appropriate.
Journal Articles
Publisher: Journals Gateway
Journal of Cognitive Neuroscience (2004) 16 (5): 776–785.
Published: 01 June 2004
Abstract
View article
PDF
The present study investigated the relationships between attention and other preparatory processes prior to a response inhibition task and the processes involved in the inhibition itself. To achieve this, a mixed fMRI design was employed to identify the functional areas activated during both inhibition decision events and the block of trials following a visual cue introduced 2 to 7 sec prior (cue period). Preparing for successful performance produced increases in activation for both the cue period and the inhibition itself in the frontoparietal cortical network. Furthermore, preparation produced activation decreases in midline areas (insula and medial prefrontal) argued to be responsible for monitoring internal emotional states, and these cue period deactivations alone predicted subsequent success or failure. The results suggest that when cues are provided to signify the imminent requirement for behavioral control, successful performance results from a coordinated pattern of preparatory activation in task-relevant areas and deactivation of task-irrelevant ones.
Journal Articles
Publisher: Journals Gateway
Journal of Cognitive Neuroscience (2000) 12 (4): 615–621.
Published: 01 July 2000
Abstract
View article
PDF
Object recognition is achieved even in circumstances when only partial information is available to the observer. Perceptual closure processes are essential in enabling such recognitions to occur. We presented successively less fragmented images while recording high-density event-related potentials (ERPs), which permitted us to monitor brain activity during the perceptual closure processes leading up to object recognition. We reveal a bilateral ERP component (N cl ) that tracks these processes (onsets ∼ 230 msec, maximal at ∼290 msec). Scalp-current density mapping of the N cl revealed bilateral occipito-temporal scalp foci, which are consistent with generators in the human ventral visual stream, and specifically the lateral-occipital or LO complex as defined by hemodynamic studies of object recognition.