Task-related temporal and topographical changes of cortical activity during ultra-rapid visual categorization
| Autor: | Edina T. Varga, Andrea Antal, Z Chadaide, Tamás Z. Kincses, Walter Paulus |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Adult
Male Time Factors media_common.quotation_subject Stimulus (physiology) Choice Behavior behavioral disciplines and activities Brain mapping 050105 experimental psychology 03 medical and health sciences 0302 clinical medicine Event-related potential Perception Reaction Time medicine Humans 0501 psychology and cognitive sciences Evoked Potentials Molecular Biology media_common Cerebral Cortex Brain Mapping General Neuroscience 05 social sciences Electroencephalography Electrophysiology medicine.anatomical_structure Pattern Recognition Visual Categorization Go/no go Scalp Female Neurology (clinical) Psychology Neuroscience Photic Stimulation psychological phenomena and processes 030217 neurology & neurosurgery Developmental Biology Cognitive psychology |
| Zdroj: | Brain Research. 1112:191-200 |
| ISSN: | 0006-8993 |
| DOI: | 10.1016/j.brainres.2006.07.044 |
| Popis: | The aim of our study was to provide electrophysiological evidence about the modulation of the categorization process by task requirements in the human brain. Event-related potentials (ERP) were recorded during three different categorization tasks using matched stimulus sets. In all cases, the subjects were required to differentiate between "animal" and "non-animal" stimuli. In the first task (two-choice task), they were asked to press corresponding buttons to each stimulus types. The second task was a go/no-go paradigm, only animal stimuli required motor response. The third task was a counting task; participants had to count the animal stimuli without any motor response. The reaction times in the go/no-go paradigm were significantly shorter. ERP differences between animal and non-animal pictures in the go/no-go task also appeared earlier and were localized at more posterior scalp positions compared to the two-choice task. Comparing animal responses in the two-choice task and in the go/no-go paradigm, we found a significant difference in the 130- to 170-ms time window over the fronto-central, centro-parietal regions. Similar differences were found between the responses to animal pictures in the two-choice task and in the counting paradigm. We used brain electric source analysis (BESA) algorithm on difference waves to localize the best fitting dipoles and determine the localization of brain areas contributing to scalp potential differences. The results show that different task requirements evoke different activity in the medial part of the temporal pole. The data we provided here draw attention to the careful handling of results obtained from categorization experiments, because different task requirements can affect the early categorization process itself. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect