Lesions of cortical area LIP affect reach onset only when the reach is accompanied by a saccade, revealing an active eye-hand coordination circuit.
Proc Natl Acad Sci U S A
; 110(6): 2371-6, 2013 Feb 05.
Article
in En
| MEDLINE
| ID: mdl-23341626
ABSTRACT
The circuits that drive visually guided eye and arm movements transform generic visual inputs into effector-specific motor commands. As part of the effort to elucidate these circuits, the primate lateral intraparietal area (LIP) has been interpreted as a priority map for saccades (oculomotor-specific) or a salience map of space (not effector-specific). It has also been proposed as a locus for eye-hand coordination. We reversibly inactivated LIP while monkeys performed memory-guided saccades and reaches. Coordinated saccade and reach reaction times were similarly impaired, consistent with a nonspecific role. However, reaches made without an accompanying saccade remained intact, and the relative temporal coupling of saccades and reaches was unchanged. These results suggest that LIP contributes to saccade planning but not to reach planning. Coordinated reaches are delayed as a result of an eye-hand coordination mechanism, located outside of LIP, that actively delays reaches until shortly after the onset of an associated saccade. We conclude with a discussion of how to reconcile specificity for saccades with a possible role in directing attention.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Parietal Lobe
/
Psychomotor Performance
/
Saccades
Type of study:
Qualitative_research
Limits:
Animals
Language:
En
Journal:
Proc Natl Acad Sci U S A
Year:
2013
Document type:
Article
Affiliation country:
Estados Unidos