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- J Physiol Paris 2001 Jan-Dec;95(1-6):499.
Dynamical changes and temporal precision of synchronized spiking activity in monkey motor cortex during movement preparation.
Riehle A, Grammont F, Diesmann M, Grun S.
Center for Research in Cognitive Neuroscience, CRNC-CNRS, Marseille, France. firstname.lastname@example.org
preparation is considered to be based on central processes which are
responsible for improving motor performance. For instance, it has been
shown that motor cortical neurones change their activity selectively in
relation to prior information about movement parameters. However, it is
not clear how groups of neurones dynamically organize their activity to
cope with computational demands. The aim of the study was to compare
the firing rate of multiple simultaneously recorded neurones with the
interaction between them by describing not only the frequency of
occurrence of epochs of significant synchronization, but also its
modulation in time and its changes in temporal precision during an
instructed delay. Multiple single-neurone activity was thus recorded in
monkey motor cortex during the performance of two different delayed
multi-directional pointing tasks. In order to detect conspicuous spike
coincidences in simultaneously recorded spike trains by tolerating
temporal jitter ranging from 0 to 20 ms and to calculate their
statistical significance, a modified method of the 'Unitary Events'
analysis was used. Two main results were obtained. First,
simultaneously recorded neurones synchronize their spiking activity in
a highly dynamic way. Synchronization becomes significant only during
short periods (about 100 to 200 ms). Several such periods occurred
during a behavioural trial more or less regularly. Second, in many
pairs of neurones, the temporal precision of synchronous activity was
highest at the end of the preparatory period. As a matter of fact, at
the beginning of this period, after the presentation of the preparatory
signal, neurones significantly synchronize their spiking activity, but
with low temporal precision. As time advances, significant
synchronization becomes more precise. Data indicate that not only the
discharge rate is involved in preparatory processes, but also temporal
aspects of neuronal activity as expressed in the precise
synchronization of individual action potentials.
PMID: 11165921 [PubMed - indexed for MEDLINE]