Tone-evoked Fos labeling in the central auditory pathway : effects of stimulus intensity and auditory fear conditioning

Understanding intensity coding and auditory learning are basic concerns of research on the auditory central pathway. There is no unifying model of intensity coding but several mechanisms have been proposed to play a role. The first aim of this thesis was to determine the mechanisms of intensity coding in the central auditory pathway from the cochlear nucleus to the auditory cortex. The Fos labeling method was used to assess neuronal activation in the central auditory system. This technique allows one to study large regions of the brain in awake animals. Increasing sound pressure level led to: (1) spreading of labeling towards neurons with higher best frequencies; (2) spread of labeling orthogonal to the tonotopic axis; (3) and increased density of labeling within the tonotopic band. In addition to encoding the physical features of a stimulus, it is fundamental for survival that we learn about the meaning of sounds and put them in a behavioral context. The second aim of this thesis was to study how learning, in particular auditory fear conditioning, changes the pattern of neuronal activation of neurons, as measured with Fos labeling, in the central nervous system. Conditioning led to an increase in Fos labeling in central auditory nuclei.

Department dc:contributor.department

Harvard University--MIT Division of Health Sciences and Technology.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Santos, Teresa P. G

Advisor dc:contributor.advisor

• M. Christian Brown.

• Harvard University--MIT Division of Health Sciences and Technology.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/37905

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/37905