Stimulus complexity effects on the orienting response
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1
Institute for Psychology, Hungarian Academy of Sciences, Hungary
The orienting response is an involuntary shift of attention to unpredictable, new or unexpected stimuli, enabling the event to enter the consciousness. If the event is deemed significant, this could lead to appropriate behavioral action. The neurocognitive changes induced by the orienting response enable the organism to respond appropriately to a variety of familiar or unfamiliar environmental events. We investigated this response by using the method of event related potentials (ERP) of the brain. The brain electrical activity correlate of this response is a component (P3a) elicited by task irrelevant stimuli that is of maximum amplitude over the frontal/central areas with a peak latency of about 300-400 ms. In our experiments participants were asked to perform auditory and visual discrimination tasks. All subjects were given 3 task conditions in each modality. In conditions 1 and 2 the tasks consisted of simple standards (80%) and targets (10%) and the task irrelevant stimuli (10%) were more complex. In condition 1 complex stimuli were identical. However in condition 2 they were different each time. In contrast in condition 3 the standards and targets were more complex and the task irrelevant infrequent stimuli were identical and simpler. The irrelevant infrequent stimuli elicited the P3a component in conditions 1 and 2 but not in condition 3. In the auditory modality variable irrelevant stimuli evoked larger P3a compared to non-variable ones. In contrast, in the visual tasks the identical irrelevant stimuli evoked bigger P3a. Our results show that infrequency and irrelevance are not enough to elicit orienting response per se, complexity plays a significant role.
Keywords:
Cognition,
EEG
Conference:
XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011.
Presentation Type:
Poster Presentation
Topic:
Poster Sessions: Neurophysiology of Cognition and Attention
Citation:
Barkaszi
I,
Czigler
I and
Balázs
L
(2011). Stimulus complexity effects on the orienting response.
Conference Abstract:
XI International Conference on Cognitive Neuroscience (ICON XI).
doi: 10.3389/conf.fnhum.2011.207.00425
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Received:
24 Nov 2011;
Published Online:
28 Nov 2011.