Publication details
Hippocampal P300 recorded during a simple auditory reaction time task (intracerebral study).
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| Year of publication | 2011 |
| Type | Conference abstract |
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| Citation | |
| Description | This paper attempts to make possible time relationship of hippocampal P300, evoked by 1 kHz tone during a simple sensorimotor task, to stimulus or motor response. In 9 patients with medically intractable epilepsies, depth electrodes were implanted to localize the seizure origin prior to surgical treatment. 19 of 70 electrodes were targeted into the hippocampus. Each subject was instructed to respond to the 1 kHz tone by pressing a button in the dominant hand. P300 components recorded in the hippocampus were analyzed both in stimulus-locked and response-locked averages, which were separately averaged for fast and slow responses. Local generation of hippocampal P300 was demonstrated in all 19 electrodes. The mean latency was 415 ms (SD=58 ms), the mean amplitude was 108 mV (SD=87 mV). Three different types of time relationships of hippocampal P300 were found: 1) time-locked to the stimulus - in 12 cases/6 patients; 2) time-locked to the motor response - in 2 cases/1 patient; and 3) ambiguous time relationship to stimulus and motor response - in 5 cases/3 patients. The three types of relationships were found in both left and right hemispheres. Our results show that the hippocampus in all the patients evoked a response during a simple sensorimotor task. The finding of the three different types of time relationships to stimulus and to motor response is in accordance with the results we obtained during visual oddball task. It may suggest that at least certain parts of this structure are involved in simple sensorimotor tasks in all steps of information processing |
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