Abstract
Whisker and forelimb movements in rats have distinct behavioral functions that suggest differences in the neural connections of the brain regions that control their movements. To test this hypothesis, retrograde tracing methods were used to characterize the bilateral distribution of the cortical neurons that project to the whisker and forelimb regions in primary motor (MI) cortex. Tracer injections in each MI region revealed labeled neurons in more than a dozen cortical areas, but most labeling was concentrated in the sensorimotor areas. Cortical projections to the MI forepaw region originated primarily from the primary somatosensory (SI) cortex in the ipsilateral hemisphere. In contrast, most projections to the MI whisker region originated from the MI whisker region in the contralateral hemisphere. Tracer injections in the MI whisker region also revealed a higher proportion of labeled neurons in the claustrum and in the posterior parietal cortex. Injections of different tracers into the MI whisker and forepaw regions of some rats revealed a topographic organization of neuronal labeling in several sensorimotor regions. Collectively, these findings indicate that the MI whisker and forepaw regions receive different sets of cortical inputs. Whereas the MI whisker region is most strongly influenced by callosal projections, presumably to mediate bilateral coordination of the whiskers, the MI forepaw region is influenced mainly by ipsilateral SI inputs that convey somatosensory feedback.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 423-439 |
| Number of pages | 17 |
| Journal | Brain Structure and Function |
| Volume | 213 |
| Issue number | 4-5 |
| DOIs | |
| State | Published - Sep 1 2009 |
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All Science Journal Classification (ASJC) codes
- Anatomy
- Neuroscience(all)
- Histology
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Differential topography of the bilateral cortical projections to the whisker and forepaw regions in rat motor cortex. / Colechio, Elizabeth M.; Alloway, Kevin.
In: Brain Structure and Function, Vol. 213, No. 4-5, 01.09.2009, p. 423-439.Research output: Contribution to journal › Article
TY - JOUR
T1 - Differential topography of the bilateral cortical projections to the whisker and forepaw regions in rat motor cortex
AU - Colechio, Elizabeth M.
AU - Alloway, Kevin
PY - 2009/9/1
Y1 - 2009/9/1
N2 - Whisker and forelimb movements in rats have distinct behavioral functions that suggest differences in the neural connections of the brain regions that control their movements. To test this hypothesis, retrograde tracing methods were used to characterize the bilateral distribution of the cortical neurons that project to the whisker and forelimb regions in primary motor (MI) cortex. Tracer injections in each MI region revealed labeled neurons in more than a dozen cortical areas, but most labeling was concentrated in the sensorimotor areas. Cortical projections to the MI forepaw region originated primarily from the primary somatosensory (SI) cortex in the ipsilateral hemisphere. In contrast, most projections to the MI whisker region originated from the MI whisker region in the contralateral hemisphere. Tracer injections in the MI whisker region also revealed a higher proportion of labeled neurons in the claustrum and in the posterior parietal cortex. Injections of different tracers into the MI whisker and forepaw regions of some rats revealed a topographic organization of neuronal labeling in several sensorimotor regions. Collectively, these findings indicate that the MI whisker and forepaw regions receive different sets of cortical inputs. Whereas the MI whisker region is most strongly influenced by callosal projections, presumably to mediate bilateral coordination of the whiskers, the MI forepaw region is influenced mainly by ipsilateral SI inputs that convey somatosensory feedback.
AB - Whisker and forelimb movements in rats have distinct behavioral functions that suggest differences in the neural connections of the brain regions that control their movements. To test this hypothesis, retrograde tracing methods were used to characterize the bilateral distribution of the cortical neurons that project to the whisker and forelimb regions in primary motor (MI) cortex. Tracer injections in each MI region revealed labeled neurons in more than a dozen cortical areas, but most labeling was concentrated in the sensorimotor areas. Cortical projections to the MI forepaw region originated primarily from the primary somatosensory (SI) cortex in the ipsilateral hemisphere. In contrast, most projections to the MI whisker region originated from the MI whisker region in the contralateral hemisphere. Tracer injections in the MI whisker region also revealed a higher proportion of labeled neurons in the claustrum and in the posterior parietal cortex. Injections of different tracers into the MI whisker and forepaw regions of some rats revealed a topographic organization of neuronal labeling in several sensorimotor regions. Collectively, these findings indicate that the MI whisker and forepaw regions receive different sets of cortical inputs. Whereas the MI whisker region is most strongly influenced by callosal projections, presumably to mediate bilateral coordination of the whiskers, the MI forepaw region is influenced mainly by ipsilateral SI inputs that convey somatosensory feedback.
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UR - http://www.scopus.com/inward/citedby.url?scp=69949132945&partnerID=8YFLogxK
U2 - 10.1007/s00429-009-0215-7
DO - 10.1007/s00429-009-0215-7
M3 - Article
VL - 213
SP - 423
EP - 439
JO - Zeitschrift fur Anatomie und Entwicklungsgeschichte
JF - Zeitschrift fur Anatomie und Entwicklungsgeschichte
SN - 0177-5154
IS - 4-5
ER -