QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, April 15, 2009, 29(15):4888-4896; doi:10.1523/JNEUROSCI.0167-09.2009

This Article Full Text Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ma, X. Articles by Suga, N. Search for Related Content PubMed PubMed Citation Articles by Ma, X. Articles by Suga, N.

 Previous Article  |  Next Article 

Behavioral/Systems/Cognitive
Specific and Nonspecific Plasticity of the Primary Auditory Cortex Elicited by Thalamic Auditory Neurons

Xiaofeng Ma and Nobuo Suga

Department of Biology, Washington University, St. Louis, Missouri 63130

Correspondence should be addressed to Xiaofeng Ma, Department of Biology, Washington University, One Brookings Drive, St. Louis, MO 63130. Email: xfma{at}biology.wustl.edu

The ventral and medial divisions of the medial geniculate body (MGBv and MGBm) respectively are the lemniscal and nonlemniscal thalamic auditory nuclei. Lemniscal neurons are narrowly frequency tuned and provide highly specific frequency information to the primary auditory cortex (AI), whereas nonlemniscal neurons are broadly frequency tuned and project widely to auditory cortical areas including AI. The MGBv and MGBm are presumably different not only in auditory signal processing, but also in eliciting cortical plastic changes. We electrically stimulated MGBv or MGBm neurons and found the following: (1) electric stimulation of narrowly frequency-tuned MGBv neurons evoked the shift of the frequency-tuning curves of AI neurons toward the tuning curves of the stimulated MGBv neurons. This shift was the same as that in the central nucleus of the inferior colliculus and AI elicited by focal electric stimulation of AI or auditory fear conditioning. The widths of the tuning curves of the AI neurons stayed the same or slightly increased. (2) Electric stimulation of broad frequency-tuned MGBm neurons augmented the auditory responses of AI neurons and broadened their frequency-tuning curves which did not shift. These cortical changes evoked by MGBv or MGBm neurons slowly disappeared over 45–60 min after the onset of the electric stimulation. Our findings indicate that lemniscal and nonlemniscal nuclei are indeed different in eliciting cortical plastic changes: the MGBv evokes tone-specific plasticity in AI for adjusting auditory signal processing in the frequency domain, whereas the MGBm evokes nonspecific plasticity in AI for increasing the sensitivity of cortical neurons.

---

Received Jan. 12, 2009; revised March 2, 2009; accepted March 18, 2009.

Correspondence should be addressed to Xiaofeng Ma, Department of Biology, Washington University, One Brookings Drive, St. Louis, MO 63130. Email: xfma{at}biology.wustl.edu

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help