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

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, May 16, 2007, 27(20):5301-5312; doi:10.1523/JNEUROSCI.0376-07.2007

This Article Full Text Full Text (PDF) Supplemental Data 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 ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Liu, Y. Articles by Tao, H. W. Search for Related Content PubMed PubMed Citation Articles by Liu, Y. Articles by Tao, H. W.

 Previous Article  |  Next Article 

Development/Plasticity/Repair
Heterosynaptic Scaling of Developing GABAergic Synapses: Dependence on Glutamatergic Input and Developmental Stage

Yan Liu,¹ Li I. Zhang,^1,3 and Huizhong W. Tao^1,2

¹Zilkha Neurogenetic Institute and Departments of ²Ophthalmology and ³Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California 90033

Correspondence should be addressed to Huizhong W. Tao, 1501 San Pablo Street, Zilkha Neurogenetic Institute 439, Los Angeles, CA 90033. Email: htao{at}usc.edu

A proportionality or balance between coactivated excitatory and inhibitory inputs is often observed for individual cortical neurons and is proposed to be important for their functions. This feature of neural circuits may arise from coordinated modulation of excitatory and inhibitory synaptic inputs, a mechanism that remains unknown. Here, in vivo whole-cell recordings from tectal neurons of young Xenopus tadpoles reveals activity-dependent bidirectional modifications of GABAergic inputs. At early developmental stages when GABAergic inputs dominate visually evoked responses, repetitive visual stimulation leads to long-term depression of GABAergic inputs. At later stages when convergent glutamatergic inputs are much stronger, long-term potentiation (LTP) of GABAergic inputs is induced. The polarity of GABAergic plasticity depends on the ratio between the magnitude of coactivated glutamatergic and GABAergic inputs (E/I ratio) to the tectal cell: LTP is induced only when the E/I ratio is above a threshold, and the level of LTP correlates linearly with the logarithm of the E/I ratio. The induction of LTP requires the activation of postsynaptic NMDA receptors, as well as presynaptic TrkB signaling likely through retrograde BDNF (brain-derived neurotrophic factor) and is achieved by overcoming a predominant depression process mediated by NMDA receptors on the presynaptic GABAergic neurons. Our results indicate that the strength of developing GABAergic synapses can be scaled in accordance to coactivated convergent glutamatergic input. This mechanism may contribute to the formation of functional neural circuits with correlated excitatory and inhibitory inputs.

Key words: balanced excitation and inhibition; GABAergic modulation; plasticity; development; NMDA receptors; BDNF; visual system; optic tectum

---

Received Jan. 27, 2007; revised March 29, 2007; accepted April 11, 2007.

Correspondence should be addressed to Huizhong W. Tao, 1501 San Pablo Street, Zilkha Neurogenetic Institute 439, Los Angeles, CA 90033. Email: htao{at}usc.edu

This article has been cited by other articles:

				X. Jiang, F. Tian, Y. Du, N. G. Copeland, N. A. Jenkins, L. Tessarollo, X. Wu, H. Pan, X.-Z. Hu, K. Xu, et al. BHLHB2 Controls Bdnf Promoter 4 Activity and Neuronal Excitability J. Neurosci., January 30, 2008; 28(5): 1118 - 1130. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help