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Ascending projections to the medial geniculate body of the cat: Evidence for multiple, parallel auditory pathways through thalamus


Calford, MB and Aitkin, LM, Ascending projections to the medial geniculate body of the cat: Evidence for multiple, parallel auditory pathways through thalamus, Journal of Neuroscience, 3, (11) pp. 2365-2380. ISSN 0270-6474 (1983) [Refereed Article]


The sources of ascending input to the medial geniculate body (MGB) of the cat were studied using the retrograde transport of horseradish peroxidase (HRP). Hrp injections were made iontophoretically through micropipettes which were also used to record physiological properties at the injection sites. This technique produced small injections which appeared to be restricted to single subnuclei. The tectothalamic projection of the auditory system was found to consist of at least four distinct and separate pathways. The ventral division of the MGB receives a topographical projection from the central nucleus of the inferior colliculus (ICC) which preserves tonotopicity and provides short latency, sharply frequency-tuned responses. The medial part of the ICC projects to the deep dorsal nucleus, which contains only units tuned to high frequencies. The major inputs to the caudodorsal nucleus (DC) stem from nucleus sagulum and the pericentral nucleus of the inferior colliculus (ICP). Units in DC and the ventrolateral nucleus, which also receive input from ICP, have very broad tuning properties and late, habituating responses. Injections of HRP into the medial division (MGM) produced labeled cells scattered throughout the external nucleus of the inferior colliculus and the ventral part of ICC. This widespread input is reflected in the wide range of auditory responses found in MGM. Auditory responses in the suprageniculate nucleus were poorly defined and many units did not respond to tonal stimuli; following HRP injections no filled cells were found in the inferior colliculus, but labeled cells were found in the deeper layers of the superior colliculus and in the interstitial nucleus of the brachium of the inferior colliculus. Together with recent findings on the auditory thalamocortical projection, these results provide evidence for multiple parallel auditory pathways through the thalamus.

Item Details

Item Type:Refereed Article
Keywords:horseradish peroxidase; animal experiment; auditory system; cat; central nervous system; medial geniculate body; nonhuman; peripheral nervous system; sensory nerve; thalamus; Afferent Pathways; Animal; Auditory Pathways; Brain Mapping
Research Division:Biomedical and Clinical Sciences
Research Group:Neurosciences
Research Field:Neurology and neuromuscular diseases
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Calford, MB (Professor Mike Calford)
ID Code:91246
Year Published:1983
Web of Science® Times Cited:215
Deposited By:Research Division
Deposited On:2014-05-13
Last Modified:2014-05-13

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