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

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, November 19, 2008, 28(47):12212-12223; doi:10.1523/JNEUROSCI.3612-08.2008

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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Larimer, P. Articles by Strowbridge, B. W. Search for Related Content PubMed PubMed Citation Articles by Larimer, P. Articles by Strowbridge, B. W.

 Previous Article  |  Next Article 

Cellular/Molecular
Nonrandom Local Circuits in the Dentate Gyrus

Phillip Larimer and Ben W. Strowbridge

Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio 44106

Correspondence should be addressed to Dr. Ben W. Strowbridge, Department of Neurosciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106. Email: bens{at}case.edu

The dentate hilus has been extensively studied in relation to its potential role in memory and in temporal lobe epilepsy. Little is known, however, about the synapses formed between the two major cell types in this region, glutamatergic mossy cells and hilar interneurons, or the organization of local circuits involving these cells. Using triple and quadruple simultaneous intracellular recordings in rat hippocampal slices, we find that mossy cells evoke EPSPs with high failure rates onto hilar neurons. Mossy cells show profound synapse specificity; 87.5% of their intralamellar connections are onto hilar interneurons. Hilar interneurons also show synapse specificity and preferentially inhibit mossy cells; 81% of inhibitory hilar synapses are onto mossy cells. Hilar IPSPs have low failure rates, are blocked by the GABA_A receptor antagonist gabazine, and exhibit short-term depression when tested at 17 Hz. Surprisingly, more than half (57%) of the mossy cell synapses we found onto interneurons were part of reciprocal excitatory/inhibitory local circuit motifs. Neither the high degree of target cell specificity, nor the significant enrichment of structured polysynaptic local circuit motifs, could be explained by nonrandom sampling or somatic proximity. Intralamellar hilar synapses appear to function primarily by integrating synchronous inputs and presynaptic burst discharges, allowing hilar cells to respond over a large dynamic range of input strengths. The reciprocal mossy cell/interneuron local circuit motifs we find enriched in the hilus may generate sparse neural representations involved in hippocampal memory operations.

Key words: dentate gyrus; EPSP; IPSP; short-term plasticity; paired-recording; local circuits; two-photon imaging

---

Received July 31, 2008; revised Sept. 17, 2008; accepted Oct. 6, 2008.

Correspondence should be addressed to Dr. Ben W. Strowbridge, Department of Neurosciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106. Email: bens{at}case.edu

This article has been cited by other articles:

				J. Kowalski, M. Geuting, S. Paul, S. Dieni, J. Laurens, S. Zhao, A. Drakew, C. A. Haas, M. Frotscher, and I. Vida Proper Layering Is Important for Precisely Timed Activation of Hippocampal Mossy Cells Cereb Cortex, February 1, 2010; (2010): bhp267v2 - bhp267. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help