Document Detail

Gaze shift duration, independent of amplitude, influences the number of spikes in the burst for medium-lead burst neurons in pontine reticular formation.
MedLine Citation:
PMID:  21842410     Owner:  NLM     Status:  MEDLINE    
Changes in the direction of the line of sight (gaze) allow successive sampling of the visual environment. Saccadic eye movements accomplish this goal when the head does not move. Medium-lead burst neurons (MLBs) in the paramedian pontine reticular formation (PPRF) discharge a high frequency burst of action potentials starting ~12 ms before the saccade begins. A subgroup of MLBs rostral of abducens nucleus monosynaptically excites oculomotor neurons. The number of spikes in the presaccadic burst is correlated with the amplitude of the horizontal component of the saccade, and the peak discharge rate is correlated with peak eye velocity. During head-unrestrained gaze shifts, a linear relationship between the number of action potentials in MLB bursts and gaze (but not eye) amplitude has been reported. The anatomical connection of MLBs to motor neurons and the similarity between the phasic motor neuron burst and MLB discharge have raised questions about the usefulness of counting spikes in MLBs to determine their role in eye-head coordination. We investigated this issue using a behavioral technique that permits a dissociation of eye movement amplitude and duration during constant vector gaze shifts. Surprisingly, during gaze shifts of constant amplitude and direction, we observe a nearly linear, positive correlation between saccade duration and spike number associated with a negative correlation between spike number and saccade amplitude. These data constrain models of the oculomotor controller and may further define the time-dependence of hypothesized neural integration in this system.
Mark M G Walton; Edward G Freedman
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2011-08-14
Journal Detail:
Title:  Experimental brain research     Volume:  214     ISSN:  1432-1106     ISO Abbreviation:  Exp Brain Res     Publication Date:  2011 Oct 
Date Detail:
Created Date:  2011-09-16     Completed Date:  2012-06-26     Revised Date:  2013-12-13    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  225-39     Citation Subset:  IM    
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MeSH Terms
Action Potentials / physiology*
Head Movements / physiology
Macaca mulatta
Neurons / physiology*
Pons / cytology,  physiology*
Psychomotor Performance / physiology
Reticular Formation / physiology*
Saccades / physiology*
Time Factors
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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