"Prolonged sound exposure has different effects on increasing neuronal size in the auditory cortex and brainstem"Paul W.F. Poon 博士(臺灣國立成功大學)-2014.5.8

時間：2014年5月8日 10:00

地點：腦功能基因組學教育部重點實驗室一樓會議室

報告題目：Prolonged sound exposure has different effects on increasing neuronal size in the auditory cortex and brainstem

報告人：Paul W.F. Poon 博士 臺灣國立成功大學

主持人：周曉明 教授

報告人簡介：1979年獲得美國Indiana University哲學博士學位，1994年起為臺灣國立成功大學（National Cheng Kung University）生理學系教授。其研究工作主要采用單細胞電生理記錄和免疫組織學技術，以大鼠聽覺系統為模型，研究語音識別的神經基礎和中樞語音識別的可塑性，以及新一代人工耳及助聽器的開發，是一位具有豐碩研究成果的科學家。

報告簡介：Tone, at moderate levels, presented to young rats in postnatal week 4 can enlarge neurons in the auditory cortex. It remains unclear whether this change occurs only in the cortex, or reflects a change taking place in the auditory brainstem. We compared sound-exposure effects on neuronal size in the auditory cortex and the midbrain. Starting from postnatal day 22, young rats were exposed to a low-frequency tone (4 kHz at 65 dB SPL) for a period of 3 (postnatal day 22 to 25) or 7 (postnatal day 22 to 29) days before being sacrificed. Neurons were analyzed morphometrically from 7 um-thick histological sections. After sound-exposure for 3 days, cell enlargement (perikaryon) was found in the high-frequency region of the auditory cortex away from the representation of the exposing tone with no similar change in the midbrain. After exposure for 7 days, cell enlargement (perikaryon and nucleus alike) was found in both the cortex and the midbrain which extended to all frequency regions. In the cortex, greater changes were again found in the high-frequency region. No changes in neuronal size were detected in the cochlear nucleus or the visual midbrain. Such differential effects of sound-exposure in the auditory centers across cortical and subcortical levels cannot be explained by a simple driven activity occurring earlier in the brainstem and might involve the function of other structures, for example, the descending auditory system