28th International Congress of Psychology August 8 ... - U-netSURF

contraction, Sasa Radovanovic 1 , Alexandar Korotkov 2 , Milos Ljubisavljevic 1 , Eugene
Lyskov 3 , Hakan Johansson 3 , 1 Institute for Medical Research, Belgrade, Yugoslavia; 2 Institute of
the Human Brain, Russian Academy of Sciences, S-Petersburg, Russia; 3 University of Gavle,
Umea, Sweden
The role of central structures in fatigue is unclear. We studied changes in brain rCBF after muscle
contractions of different force levels and durations, and compared them with the fatigue condition.
Twelve subjects were studied under 4 conditions: rest; contraction of biceps at 30% MVC, for 60 s;
30%, for 120 s; 50%, for 120 s. The level of rCBF gradually increased with the level and duration
of contraction. Central fatigue might be a consequence of activation of excitatory and inhibitory
circuits. Their interactions contribute to the generation and transmission of descending signals
from cortical cells to motoneurons.
1028.170 Perceptual rivalry induced by saccadic mislocalisation, Markus Lappe, Simone
Kuhlmann, Wilhelms-Universitaet, Muenster, Germany
Multiple identical visual stimuli flashed before a saccade merge perceptually into one object. How
is perception organized when stimuli are not identical? Observers performed saccades while a
computer-generated stimulus was flashed. It contained 1-3 vertical bars (or small squares) of
identical or different color. Observers reported number of bars and perceived colors. Shortly
before the saccade observers often perceived a single bar with multiple color patches. This
tendency was reduced for smaller objects. We conclude that perisaccadic compression affects the
position of stimuli but retains color attributes which then perceptually rival at the (mis-)perceived
position.
1028.171 Hand-eye dominance and brain electrical asymmetries, Diego Martin Dutto, Patricio
Perez Leguizamon, Diego Fassa, Claudia Marro, Alberto Yorio, Buenos Aires
University ?School of Psychology, Argentina
Relationships among hand-eye dominance and asymmetries of the spontaneous EEG and the
visual evoked potentials were studied. 28 healthy right handed subjects (59.37% right-eye and
28.15% left-eye dominance) voluntarily participated. EEG and PEV records were done: right-left
visual field and right-left eye stimulation. EEG exhibited diminution of the alpha activity
associated with visual stimulation. PEV asymmetries were evident in 44.4 % of with hand-eye
direct dominance subjects, and in 75 % of crossed dominance subjects (ji2= 4.16, p