Human brain potentials of spatial location encoding into memory.
Event-related potentials (ERP) were elicited by little vertical bars located randomly in 1 of 4 positions (top, bottom, left or right) relative to a central fixation point. There were 4 experimental conditions requiring the subjects either to press a button if the stimulus was in the target location, count the number of stimuli appearing in the target location, look at the stimuli passively or memorize the location of the stimulus. The interstimulus interval was 2 sec for all tasks. In the memory condition subjects had to consider stimuli as pairs, memorize the location of the first stimulus of every pair and press a button if the second stimulus was in the same location. Our results indicate that ERPs corresponding to the memorization and retention of spatial location are different from those of the other 3 tasks in the presence of a long duration negativity mainly distributed bilaterally over O1, O2, T5 and T6 electrodes. This negativity seems to develop gradually several milliseconds before stimulus onset, reaches its highest value when the spatial location is assumed to be analyzed, and continues with uniform scalp distribution until the end of the recording (822 msec after stimulus onset).
Martin-Loeches
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M
Unidad de Cartografía Cerebral, Instituto Pluridisciplinar, Universidad Complutense de Madrid, Spain.
Gomez-Jarabo
G
G
Rubia
F J
FJ
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D013028:Space Perception / Q000502:physiology*; D013647:Task Performance and Analysis