Hilar mossy cell circuitry controlling dentate granule cell excitability
Glutamatergic hilar mossy cells of the dentate gyrus can either excite or inhibit distant granule cells, depending on whether their direct excitatory projections to granule cells or their projections to local inhibitory interneurons dominate. However, it remains controversial whether the net effect...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2013-02-01
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| Series: | Frontiers in Neural Circuits |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fncir.2013.00014/full |
| _version_ | 1818176997088559104 |
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| author | Seiichiro eJinde Veronika eZsiros Kazu eNakazawa |
| author_facet | Seiichiro eJinde Veronika eZsiros Kazu eNakazawa |
| author_sort | Seiichiro eJinde |
| collection | DOAJ |
| description | Glutamatergic hilar mossy cells of the dentate gyrus can either excite or inhibit distant granule cells, depending on whether their direct excitatory projections to granule cells or their projections to local inhibitory interneurons dominate. However, it remains controversial whether the net effect of mossy cell loss is granule cell excitation or inhibition. Clarifying this controversy has particular relevance to temporal lobe epilepsy, which is marked by dentate granule cell hyperexcitability and extensive loss of dentate hilar mossy cells. Two diametrically opposed hypotheses have been advanced to explain this granule cell hyperexcitability – the dormant basket cell and the irritable mossy cell hypotheses. The dormant basket cell hypothesis proposes that mossy cells normally exert a net inhibitory effect on granule cells and therefore their loss causes dentate granule cell hyperexcitability. The irritable mossy cell hypothesis takes the opposite view that mossy cells normally excite granule cells and that the surviving mossy cells in epilepsy increase their activity, causing granule cell excitation. The inability to eliminate mossy cells selectively has made it difficult to test these two opposing hypotheses. To this end, we developed a transgenic toxin-mediated, mossy cell-ablation mouse line. Using these mutants, we demonstrated that the extensive elimination of hilar mossy cells causes granule cell hyperexcitability, although the mossy cell loss observed appeared insufficient to cause clinical epilepsy. In this review, we focus on this topic and also suggest that different interneuron populations may mediate mossy cell-induced translamellar lateral inhibition and intralamellar recurrent inhibition. These unique local circuits in the dentate hilar region may be centrally involved in the functional organization of the dentate gyrus. |
| first_indexed | 2024-12-11T20:25:04Z |
| format | Article |
| id | doaj.art-16de403669504ed182ed5897419a688a |
| institution | Directory Open Access Journal |
| issn | 1662-5110 |
| language | English |
| last_indexed | 2024-12-11T20:25:04Z |
| publishDate | 2013-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neural Circuits |
| spelling | doaj.art-16de403669504ed182ed5897419a688a2022-12-22T00:51:58ZengFrontiers Media S.A.Frontiers in Neural Circuits1662-51102013-02-01710.3389/fncir.2013.0001438449Hilar mossy cell circuitry controlling dentate granule cell excitabilitySeiichiro eJinde0Veronika eZsiros1Kazu eNakazawa2The University of TokyoNational Institute of Mental HealthNational Institute of Mental HealthGlutamatergic hilar mossy cells of the dentate gyrus can either excite or inhibit distant granule cells, depending on whether their direct excitatory projections to granule cells or their projections to local inhibitory interneurons dominate. However, it remains controversial whether the net effect of mossy cell loss is granule cell excitation or inhibition. Clarifying this controversy has particular relevance to temporal lobe epilepsy, which is marked by dentate granule cell hyperexcitability and extensive loss of dentate hilar mossy cells. Two diametrically opposed hypotheses have been advanced to explain this granule cell hyperexcitability – the dormant basket cell and the irritable mossy cell hypotheses. The dormant basket cell hypothesis proposes that mossy cells normally exert a net inhibitory effect on granule cells and therefore their loss causes dentate granule cell hyperexcitability. The irritable mossy cell hypothesis takes the opposite view that mossy cells normally excite granule cells and that the surviving mossy cells in epilepsy increase their activity, causing granule cell excitation. The inability to eliminate mossy cells selectively has made it difficult to test these two opposing hypotheses. To this end, we developed a transgenic toxin-mediated, mossy cell-ablation mouse line. Using these mutants, we demonstrated that the extensive elimination of hilar mossy cells causes granule cell hyperexcitability, although the mossy cell loss observed appeared insufficient to cause clinical epilepsy. In this review, we focus on this topic and also suggest that different interneuron populations may mediate mossy cell-induced translamellar lateral inhibition and intralamellar recurrent inhibition. These unique local circuits in the dentate hilar region may be centrally involved in the functional organization of the dentate gyrus.http://journal.frontiersin.org/Journal/10.3389/fncir.2013.00014/fullexcitabilitylateral inhibitionEpileptogenesismossy cellsPattern Separationgranule cells |
| spellingShingle | Seiichiro eJinde Veronika eZsiros Kazu eNakazawa Hilar mossy cell circuitry controlling dentate granule cell excitability Frontiers in Neural Circuits excitability lateral inhibition Epileptogenesis mossy cells Pattern Separation granule cells |
| title | Hilar mossy cell circuitry controlling dentate granule cell excitability |
| title_full | Hilar mossy cell circuitry controlling dentate granule cell excitability |
| title_fullStr | Hilar mossy cell circuitry controlling dentate granule cell excitability |
| title_full_unstemmed | Hilar mossy cell circuitry controlling dentate granule cell excitability |
| title_short | Hilar mossy cell circuitry controlling dentate granule cell excitability |
| title_sort | hilar mossy cell circuitry controlling dentate granule cell excitability |
| topic | excitability lateral inhibition Epileptogenesis mossy cells Pattern Separation granule cells |
| url | http://journal.frontiersin.org/Journal/10.3389/fncir.2013.00014/full |
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