We defined spatial patterns of organization of projections from somatosensory cerebral cortex (SI) to the somatosensory cerebellar cortex of anesthetized albino rats using microelectrode (stimulation and recording) micromapping methods and low-threshold cutaneous (tactile) stimulation. Two sampling strategies were used: (1) a single cerebral SI locus in layers V-VI was stimulated electrically, while a responding region of the cerebellar granule cell (GC) layer was systematically mapped with a recording electrode; (2) the SI stimulating electrode was used as the mapping electrode while the cerebellar GC eletrode remained fixed. We found highly specific patterns of connections between somatotopically organized SI cortex and the somatotopically fractured tactile cerebellar cortex. Using threshold stimulating currents in SI, the projections from small populations of neural elements were found to be highly restricted, terminating within the confines of only those tactile cerebellar hemispheric locations having the same receptive fields (RFs). These SI-GC projections conform to the patchy mosaic pattern of organization previously shown for peripheral tactile projections. SI projections to GC patches were either contralateral or ipsilateral, depending on the laterality of the peripheral projections to that patch. Each SI focus projected to only a portion of a patch; projections from several adjacent SI loci overlapped serially within a patch. As with the peripherally evoked GC layer responses, SI-evoked GC responses were organized in a columnar fashion and were maximal at middle levels of the GC layer; SI-GC latencies were 5–8 ms. These data reveal that this tactile-related cerebro-cerebellar circuit exhibits precisely organized patterns of projection.

Keywords:
Cerebellum, Cerebro-cerebellar circuit, Cutaneous, Somatosensory, Somatotopy, Micromapping, SI, Rat
This content is only available via PDF.
© 1981 S. Karger AG, Basel
1981
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.