More than a million people suffer traumatic brain injury in the US every year, and among young adults head injury is the leading cause of death and disability. Of head injury survivors, 5% develop post-traumatic epilepsy, and following penetrating head injuries this number increases to 53%, presenting an enormous social and medical problem. However, the mechanisms by which head injury gives rise to epilepsy are poorly understood. The dentate gyrus of the hippocampal formation plays a central role in the regulation of excitability in the epilepsy-prone cortico-limbic system. The excitability of dentate granule cells, the principal output neurons of the dentate gyrus, is controlled by inhibitory cells called interneurons and excitatory cells named mossy hilar cells. In the previous funding period of this grant, we showed that surviving mossy cells play a crucial role in post-traumatic hyperexcitability in the dentate gyrus. Here we propose to test hypothesis that in the post-traumatic dentate gyrus a compromised dendritic inhibition to both granule cells and mossy cells constitutes a key mechanism underlying trauma-induced hyperexcitability. The hypothesis will be tested using the lateral fluid percussion model of head trauma in rodents, and the assessment will be carried out with electrophysiological and immunocytochemical methods at various time points after injury, complemented by biophysically realistic, large-scale computational modeling approaches. Our preliminary data indicate that head injury persistently modifies the dendritic excitability of mossy hilar cells and the feed-forward and feedback dendritic inhibition of granule cells in the dentate gyrus. The experiments of this proposal are designed to specifically target cellular-synaptic mechanisms underlying trauma-induced hyperexcitability. It is anticipated that defining the functional effects of head trauma on neurons, especially those in epilepsy-prone brain regions such as the hippocampal formation, will help the future development of novel anti-epileptic treatment strategies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37NS035915-10
Application #
7066092
Study Section
Clinical Neuroplasticity and Neurotransmitters Study Section (CNNT)
Program Officer
Fureman, Brandy E
Project Start
1997-06-01
Project End
2009-05-31
Budget Start
2006-06-01
Budget End
2007-05-31
Support Year
10
Fiscal Year
2006
Total Cost
$315,916
Indirect Cost
Name
University of California Irvine
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
046705849
City
Irvine
State
CA
Country
United States
Zip Code
92697
Neubrandt, Máté; Oláh, Viktor János; Brunner, János et al. (2018) Single Bursts of Individual Granule Cells Functionally Rearrange Feedforward Inhibition. J Neurosci 38:1711-1724
Neumann, Adam R; Raedt, Robrecht; Steenland, Hendrik W et al. (2017) Involvement of fast-spiking cells in ictal sequences during spontaneous seizures in rats with chronic temporal lobe epilepsy. Brain 140:2355-2369
Bui, Anh D; Alexander, Allyson; Soltesz, Ivan (2017) Seizing Control: From Current Treatments to Optogenetic Interventions in Epilepsy. Neuroscientist 23:68-81
Szabo, Gergely G; Du, Xi; Oijala, Mikko et al. (2017) Extended Interneuronal Network of the Dentate Gyrus. Cell Rep 20:1262-1268
Maroso, Mattia; Szabo, Gergely G; Kim, Hannah K et al. (2016) Cannabinoid Control of Learning and Memory through HCN Channels. Neuron 89:1059-73
Alexander, A; Maroso, M; Soltesz, I (2016) Organization and control of epileptic circuits in temporal lobe epilepsy. Prog Brain Res 226:127-54
Krook-Magnuson, Esther; Soltesz, Ivan (2015) Beyond the hammer and the scalpel: selective circuit control for the epilepsies. Nat Neurosci 18:331-8
Lee, Sang-Hun; Ledri, Marco; Tóth, Blanka et al. (2015) Multiple Forms of Endocannabinoid and Endovanilloid Signaling Regulate the Tonic Control of GABA Release. J Neurosci 35:10039-57
Bui, Anh; Kim, Hannah K; Maroso, Mattia et al. (2015) Microcircuits in Epilepsy: Heterogeneity and Hub Cells in Network Synchronization. Cold Spring Harb Perspect Med 5:
Varga, Csaba; Oijala, Mikko; Lish, Jonathan et al. (2014) Functional fission of parvalbumin interneuron classes during fast network events. Elife 3:

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