Presentation Title

Substantial Nerve Fiber Loss In The Rat Brainstem Following Early Section Of The Chorda Tympani Taste Nerve

Advisor Information

Suzanne Sollars

Location

Dr. C.C. and Mabel L. Criss Library

Presentation Type

Poster

Start Date

3-3-2017 12:30 PM

End Date

3-3-2017 1:45 PM

Abstract

The brains of young animals contain an abundance of neural connections that become refined throughout development. Neurons appear to compete with each other for connections, particularly at early ages. For example, the area where taste nerves terminate in the brain (terminal fields) reorganizes when the chorda tympani taste nerve (CT) is sectioned (CTX). However, this change in terminal fields only takes place when CTX occurs very early in development, at five days of age, but not at ten days of age. To better understand the age-dependence of terminal field plasticity, the CT was stained after sectioning the nerve early in development. Rats at five or ten days of age received either CTX or a control surgery. After 50-51 days, the CT was accessed in the middle ear, cut, and labeled with dye. Following dye transport, brain tissue was removed, sectioned, and processed to visualize the CT terminal field. Terminal field volumes were calculated and compared between surgical conditions. There was a significant and dramatic reduction in terminal field volume for CTX rats compared to controls. There was no significant difference in CT volume between rats sectioned at five or ten days of age. These findings indicate that changes in the organization of other nerves’ terminal fields after early CTX are dependent on the timing of CT terminal field loss rather than the pattern of loss. There appears to be a window shortly after birth where neural inputs can alter their organization in response to neural loss.

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Mar 3rd, 12:30 PM Mar 3rd, 1:45 PM

Substantial Nerve Fiber Loss In The Rat Brainstem Following Early Section Of The Chorda Tympani Taste Nerve

Dr. C.C. and Mabel L. Criss Library

The brains of young animals contain an abundance of neural connections that become refined throughout development. Neurons appear to compete with each other for connections, particularly at early ages. For example, the area where taste nerves terminate in the brain (terminal fields) reorganizes when the chorda tympani taste nerve (CT) is sectioned (CTX). However, this change in terminal fields only takes place when CTX occurs very early in development, at five days of age, but not at ten days of age. To better understand the age-dependence of terminal field plasticity, the CT was stained after sectioning the nerve early in development. Rats at five or ten days of age received either CTX or a control surgery. After 50-51 days, the CT was accessed in the middle ear, cut, and labeled with dye. Following dye transport, brain tissue was removed, sectioned, and processed to visualize the CT terminal field. Terminal field volumes were calculated and compared between surgical conditions. There was a significant and dramatic reduction in terminal field volume for CTX rats compared to controls. There was no significant difference in CT volume between rats sectioned at five or ten days of age. These findings indicate that changes in the organization of other nerves’ terminal fields after early CTX are dependent on the timing of CT terminal field loss rather than the pattern of loss. There appears to be a window shortly after birth where neural inputs can alter their organization in response to neural loss.