Differential Pattern of Interhemispheric Connections Between Homotopic Layer V Regions in the Forelimb Representation in Rat Barrel Field Cortex

Tina M. Decosta-Fortune, Cheng X. Li, Amy Curry, Robert Waters

Research output: Contribution to journalArticle

Abstract

Layer V neurons in forelimb and shoulder representations in rat first somatosensory cortex (SI) project to the contralateral SI. However, few studies have addressed whether projections from specific subregions of the forelimb representation, namely forepaw, wrist, or forearm, terminate at homotopic sites in the contralateral SI. Neuroanatomical retrograde (cholera toxin B subunit [CT-B]) or anterograde (biodextran amine [BDA]) tracers were injected into physiologically identified sites in layer V in specific forelimb and/or shoulder representations in SI to examine the projection to contralateral SI in young adult rats (N=17). Injection and target sites were flattened and cut in a tangential plane to relate labeling to the body map or cut along a coronal plane to relate labeling to cortical layers. Results indicate that layer V neurons project to cortical laminae II-VI in contralateral SI, with the densest labeling in layer V followed by layer III. In contrast, layer V neurons send sparse projections to layer IV. Furthermore, layer V neurons in wrist, forearm, and shoulder project to homotopic sites in contralateral layer V, while neurons in the forepaw representation project largely to sites in perigranular and dysgranular cortex adjacent to their homotopic territory. Our results provide evidence for a differential pattern of interhemispheric projections from forelimb and shoulder representations to the opposite SI and a detailed description of areal and laminar projection patterns of layer V neurons in the SI forelimb and shoulder cortices.

Original languageEnglish (US)
Pages (from-to)1885-1902
Number of pages18
JournalAnatomical Record
Volume298
Issue number11
DOIs
StatePublished - Nov 1 2015

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Forelimb
forelimbs
shoulders
cortex
neurons
Neurons
rats
Wrist
Forearm
Substantia Gelatinosa
cholera toxin
Somatosensory Cortex
Cholera Toxin
laminae (animals)
amines
young adults
Amines
tracer techniques
Young Adult
injection

All Science Journal Classification (ASJC) codes

  • Anatomy
  • Biotechnology
  • Histology
  • Ecology, Evolution, Behavior and Systematics

Cite this

Differential Pattern of Interhemispheric Connections Between Homotopic Layer V Regions in the Forelimb Representation in Rat Barrel Field Cortex. / Decosta-Fortune, Tina M.; Li, Cheng X.; Curry, Amy; Waters, Robert.

In: Anatomical Record, Vol. 298, No. 11, 01.11.2015, p. 1885-1902.

Research output: Contribution to journalArticle

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