Intracerebral Recordings of the Bereitschaftspotential and Related Potentials in Cortical and Subcortical Structures in Human Subjects

2003 ◽  
pp. 61-77 ◽  
Author(s):  
Ivan Rektor
Keyword(s):  
Human Subjects ◽  
Subcortical Structures ◽  
Related Potentials

scholarly journals Parallel Information Processing in Motor Systems: Intracerebral Recordings of Readiness Potential and CNV in Human Subjects

2000 ◽  
Vol 7 (1-2) ◽  
pp. 65-72 ◽  
Author(s):  
Ivan Rektor
Keyword(s):  
Basal Ganglia ◽  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Human Subjects ◽  
Anterior Cingulate ◽  
Readiness Potential ◽  
Task Context ◽  
Subcortical Structures ◽  
Depth Electrodes ◽  
Simultaneous Activation

We performed intracerebral recordings of Readiness Potential (RP) and Contingent Negative Variation (CNV) with simple repetitive distal limb movement in candidates for epilepsy surgery. In 26 patients (in Paris), depth electrodes were located in various cortical structures; in eight patients (in Brno), in the basal ganglia and the cortex. RPs were displayed in the conteral primary motor cortex, conteral somato-sensory cortex, and bilaterally in the SMA and the caudal part of the anterior cingulate cortices. CNVs were recorded in the same cortical regiom as the RP, as well as in the ipsilateral primary motor cortex, and bilaterally in the premotor fronto-lateral, parietal superior, and middle temporal regions. In the basal ganglia, the RP was recorded in the putamen in six of seven patients, and in the head of the caudate nucleus and the pallidum in the only patient with electrodes in these recording sites. We suggest that our results are consistent with a long-lasting, simultaneous activation of cortical and subcortical structures, before and during self-paced and stimulus-triggered movements. The particular regiom that are simultaneously active may be determined by the task context.

Modulation of event-related potentials in normal human subjects by visual divided attention to spatial and color factors

2001 ◽  
Vol 311 (3) ◽  
pp. 198-202 ◽  
Author(s):  
Shu Omoto ◽  
Yoshiyuki Kuroiwa ◽  
Mei Li ◽  
Hiroshi Doi ◽  
Megumi Shimamura ◽  
...  
Keyword(s):  
Divided Attention ◽  
Human Subjects ◽  
Event Related Potentials ◽  
Related Potentials ◽  
Normal Human

Event-related potentials during auditory and somatosensory discrimination in sighted and blind human subjects

1996 ◽  
Vol 4 (2) ◽  
pp. 77-93 ◽  
Author(s):  
Brigitte Röder ◽  
Frank Rösler ◽  
Erwin Hennighausen ◽  
Fritz Näcker
Keyword(s):  
Human Subjects ◽  
Event Related Potentials ◽  
Related Potentials

Effects of Feature-selective and Spatial Attention at Different Stages of Visual Processing

2011 ◽  
Vol 23 (1) ◽  
pp. 238-246 ◽  
Author(s):  
Søren K. Andersen ◽  
Sandra Fuchs ◽  
Matthias M. Müller
Keyword(s):  
Spatial Attention ◽  
Visual Processing ◽  
Human Subjects ◽  
Event Related Potentials ◽  
Attentional Selection ◽  
Coherent Motion ◽  
False Alarms ◽  
Related Potentials ◽  
Trial Participants ◽  
Selection Of

We investigated mechanisms of concurrent attentional selection of location and color using electrophysiological measures in human subjects. Two completely overlapping random dot kinematograms (RDKs) of two different colors were presented on either side of a central fixation cross. On each trial, participants attended one of these four RDKs, defined by its specific combination of color and location, in order to detect coherent motion targets. Sustained attentional selection while monitoring for targets was measured by means of steady-state visual evoked potentials (SSVEPs) elicited by the frequency-tagged RDKs. Attentional selection of transient targets and distractors was assessed by behavioral responses and by recording event-related potentials to these stimuli. Spatial attention and attention to color had independent and largely additive effects on the amplitudes of SSVEPs elicited in early visual areas. In contrast, behavioral false alarms and feature-selective modulation of P3 amplitudes to targets and distractors were limited to the attended location. These results suggest that feature-selective attention produces an early, global facilitation of stimuli having the attended feature throughout the visual field, whereas the discrimination of target events takes place at a later stage of processing that is only applied to stimuli at the attended position.

scholarly journals Post-saccadic face processing is modulated by pre-saccadic preview: Evidence from fixation-related potentials

2019 ◽  
Author(s):  
Antimo Buonocore ◽  
Olaf Dimigen ◽  
David Melcher
Keyword(s):  
Eye Movements ◽  
Gender Discrimination ◽  
Peripheral Vision ◽  
Human Subjects ◽  
Reaction Times ◽  
Relevant Information ◽  
Visual Object ◽  
Central Visual Field ◽  
Viewing Condition ◽  
Related Potentials

AbstractHumans actively sample their environment with saccadic eye movements to bring relevant information into high-acuity foveal vision. Despite being lower in resolution, peripheral information is also available prior to each saccade. How pre-saccadic extrafoveal preview of a visual object influences its post-saccadic processing is still an unanswered question. Here, we investigated this question by simultaneously recording behavior and fixation-related brain potentials while human subjects made saccades to face stimuli. We manipulated the relationship between pre-saccadic “previews” and post-saccadic images to explicitly isolate the influences of the former. Subjects performed a gender discrimination task on a newly foveated face under three preview conditions: phase-scrambled face, incongruent face (different identity from the foveated face), and congruent face (same identity). As expected, reaction times were faster after a congruent-face preview compared to the phase-scrambled and incongruent conditions. Importantly, a face preview (either incongruent or congruent) resulted in a strong reduction of post-saccadic neural responses. Specifically, we analyzed the classic face-selective N170 component at occipito-temporal EEG electrodes, which was still present in our experiments with active looking. We found that this component was strongly attenuated for face preview conditions compared to scrambled conditions. This large and long-lasting decrease in evoked activity is consistent with an active prediction mechanism influencing category-specific neural processing at the start of a new fixation. These findings constrain theories of visual stability and show that the extrafoveal preview methodology can be a useful tool to investigate its underlying mechanisms.Significance StatementNeural correlates of object recognition have traditionally been studied by flashing stimuli to the central visual field. This procedure differs in fundamental ways from natural vision, where viewers actively sample the environment with eye movements and also obtain a low-resolution preview of soon-to-be-fixated objects. Here we show that the N170, a classic electrophysiological marker of the structural processing of faces, also occurs during a more natural viewing condition but is massively reduced due to extrafoveal preprocessing (preview benefit). Our results therefore highlight the importance of peripheral vision during trans-saccadic processing in building a coherent and stable representation of the world around us.

Components of Attentional Set-switching

2005 ◽  
Vol 52 (2) ◽  
pp. 83-98 ◽  
Author(s):  
M. F. S. Rushworth ◽  
R. E. Passingham ◽  
A. C. Nobre
Keyword(s):  
Task Switching ◽  
Human Subjects ◽  
Event Related Potentials ◽  
Neural Correlates ◽  
Stimulus Dimension ◽  
Task Switch ◽  
Attentional Set ◽  
Set Switching ◽  
Related Potentials ◽  
The Way

Abstract. A series of distinct event-related potentials (ERPs) have been recorded from the scalp of human subjects as they switch from one task to another. It is possible that task switching may depend on different mechanisms depending on whether the switch requires a change in attentional set, in other words the redirecting of attention to different aspects of a sensory stimulus, or whether it requires a change in intentional set, in others words a change in the way that responses are selected. To address this issue, the current study recorded ERPs while subjects switched between attentional sets and the results were compared with those of a previous investigation in which subjects switched between intentional sets. Subjects selected stimuli according to two conflicting attentional sets, each emphasizing one visual stimulus dimension (colour, shape). Pairs of stimuli, only one of which was to be attended, were presented for between eight and seventeen trials then either a switch or a stay cue was shown. The switch cue instructed subjects to switch from the current attentional set to the other set, while the stay cue instructed subjects to maintain the current set. Comparing ERPs time-locked to the switch and stay cues revealed neural correlates of the initiation of a task switch. Comparing the ERPs time locked to the first stimuli after either stay or switch cues identified neural correlates of the implementation of a task switch. A similar modulation over parietal electrodes was seen when subjects were switching between either attentional or intentional sets. While an intentional set switch began with a medial frontal modulation, attentional set switching began with a lateral frontal modulation. Implementing a new attentional set was associated with modulation of relatively early visual potentials, while implementing a new intentional set was associated with modulation of later response-related potentials. The results confirm that task switching consists of a number of constituent processes which may be taxed to different degrees depending on whether a task-switch paradigm requires subjects to change the way in which they select stimuli or responses.

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