Neuroscience 2004 Abstract
| Presentation Number: | 754.5 |
|---|---|
| Abstract Title: | Thalamic and cortical inputs to primate striatum: Single-axon tracing studies. |
| Authors: |
Parent, M.*1
; Parent, A.1
1Dept Anat/Physiol, Laval Univ, Beauport, Canada |
| Primary Theme and Topics |
Motor Systems - Basal Ganglia -- Anatomy |
| Session: |
754. Basal Ganglia: Anatomy Poster |
| Presentation Time: | Tuesday, October 26, 2004 1:00 PM-2:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # V7 |
| Keywords: | BASAL GANGLIA, THALAMOSTRIATAL, CORTICOSTRIATAL, AXONAL COLLATERALIZATION |
Electrophysiological recording followed by BDA microiontophoretic injections in neurons of the primary motor cortex (M1) of cynomolgus monkeys (Macaca fascicularis) and in the centre median/parafascicular thalamic complex (CM/Pf) of squirrel monkeys (Saimiri sciureus) have revealed the following facts. (1) Thalamostriatal projections. The majority of individually labeled axons that emerged from CM/Pf complex in squirrel monkeys innervated both motor cortex and striatum. These axons emitted, in some cases, a few collaterals in the reticular thalamic nucleus and bifurcated within the internal capsule. One branch ascended via the corona radiata to the cerebral cortex, where it arborized moderately in layers V and VI, and much less profusely in layer I. The other branch entered the striatum, where it broke out into 3-5 smaller collaterals. These thin branches divided into numerous shorter collaterals that displayed pedunculated varicosities organized as dense, cluster-like terminal fields. Axons from the CM and the Pf nucleus arborized in the dorsolateral sector of the putamen and in the caudate nucleus respectively. (2) Corticostriatal projections. Axons that emerged from M1 in cynomolgus monkeys projected either directly or indirectly to the striatum. These two types of axons occurred in about equal number and arborized mainly in the same dorsolateral sector of the putamen than the one targeted by CM axons. Axons that projected directly and solely to the striatum remained uniformly thin and unbranched along their entire trajectory to the striatum, whereas axons that reached the striatum indirectly were in fact thin collaterals emitted within the corona radiata by thick, long-range fibers that descended toward the brainstem. At striatal level, axons of both types branched moderately but occupied vast striatal territories. These findings reveal that both corticostriatal and thalamostriatal systems in primates are formed by axons that are not solely dedicated to the striatum.
Supported by CIHR, NSERC, FRSQ
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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