Resection of the medial temporal lobe disconnects the rostral superior temporal gyrus from some of its projection targets in the frontal lobe and thalamus

Munoz, M. , Mishkin, M. and Saunders, R. C. (2009) Resection of the medial temporal lobe disconnects the rostral superior temporal gyrus from some of its projection targets in the frontal lobe and thalamus. Cerebral Cortex, 19(9), pp. 2114-2130. (doi: 10.1093/cercor/bhn236) (PMID:19150921) (PMCID:PMC2722427)

Abstract

Auditory memory in the monkey does not appear to extend beyond the limits of working memory. It is therefore surprising that this ability is impaired by medial temporal lobe (MTL) resections, because such lesions spare working memory in other sensory modalities. To determine whether MTL ablations might have caused the auditory deficit through inadvertent transection of superior temporal gyrus (STG) projections to its downstream targets, and, if so, which targets might have been compromised, we injected anterograde tracer (biotinylated dextran amine) in the STG of both the normal and MTL-lesioned hemispheres of split-brain monkeys. Interhemispheric comparison of label failed to show any effect of the MTL ablation on efferents from caudal STG, which projects to the inferior prefrontal convexity. However, the ablation did consistently interrupt the normally dense projections from rostral STG to both the ventral medial prefrontal cortex and medial thalamic nuclei. The findings support the possibility that the auditory working memory deficit after MTL ablation is due to transection of downstream auditory projections, and indicate that the candidate structures for mediating auditory working memory are the ventral medial prefrontal cortical areas, the medial thalamus, or both.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Munoz, Dr Monica
• Authors: Munoz, M., Mishkin, M., and Saunders, R. C.
• College/School: College of Medical Veterinary and Life Sciences > School of Life Sciences
• Journal Name: Cerebral Cortex
• Publisher: Oxford University Press
• ISSN: 1047-3211
• ISSN (Online): 1460-2199
• Published Online: 15 January 2009
• Copyright Holders: Copyright © 2009 The Authors
• First Published: First published in Cerebral Cortex 19(9):2114-2130
• Publisher Policy: Reproduced under a Creative Commons License