Synchronized spike selection in a hippocampal dentate gyrus network model in the theta frequency range

Abstract: Neuroplasticity research in connection with mental disorders has recently bridged the gap between basic neurobiology and applied neuropsychology. A non-invasive method in the gerbil (Meriones unguiculus) - the restricted versus enriched breading and the systemically applied single methamphetamine dose - offers an experimental approach to investigate psychoses. Acts of intervening affirm an activity dependent malfunctional reorganization in the prefrontal cortex and in the hippocampal dentate gyrus and reveal the dopamine position as being critical for the disruption of interactions between the areas concerned. From the extent of plasticity effects the probability and risk of psycho-cognitive development may be derived. Advance may be expected from insights into regulatory mechanisms of neurogenesis in the hippocampal dentate gyrus which is obviously to meet the necessary requirements to promote psycho-cognitive functions/malfunctions via the limbo-prefrontal circuit.

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Voltage-activated potassium currents in acutely dissociated hippocampal dentate gyrus neurons from neonatal rats

Developmental Brain Research ◽

10.1016/0165-3806(94)90316-6 ◽

1994 ◽

Vol 81 (2) ◽

pp. 309-313 ◽

Cited By ~ 6

Author(s):

Scott C. Baraban ◽

Eric W. Lothman

Keyword(s):

Dentate Gyrus ◽

Potassium Currents ◽

Neonatal Rats ◽

Hippocampal Dentate Gyrus

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Neuronal maturation in the hippocampal dentate gyrus via chronic oral administration of Artemisa annua extract is independent of cyclooxygenase 2 signaling pathway in diet-induced obesity mouse model

IBRO Reports ◽

10.1016/j.ibror.2019.07.1005 ◽

2019 ◽

Vol 6 ◽

pp. S325

Author(s):

Pan Soo Kim ◽

Dong-Hwa Choi ◽

Sang-Kyu Park ◽

Hyeok Jin Kwon ◽

Sun Shin Yi

Keyword(s):

Mouse Model ◽

Oral Administration ◽

Dentate Gyrus ◽

Signaling Pathway ◽

Cyclooxygenase 2 ◽

Neuronal Maturation ◽

Hippocampal Dentate Gyrus ◽

Diet Induced Obesity ◽

Artemisa Annua

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In your phase: neural phase synchronisation underlies visual imagery of faces

Scientific Reports ◽

10.1038/s41598-021-81336-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Andrés Canales-Johnson ◽

Renzo C. Lanfranco ◽

Juan Pablo Morales ◽

David Martínez-Pernía ◽

Joaquín Valdés ◽

...

Keyword(s):

Long Range ◽

Visual Imagery ◽

Brain Activity ◽

Neural Connectivity ◽

Frequency Range ◽

Subjective Impression ◽

Gamma Frequency ◽

Gamma Range ◽

Theta Frequency ◽

Socially Relevant

AbstractMental imagery is the process through which we retrieve and recombine information from our memory to elicit the subjective impression of “seeing with the mind’s eye”. In the social domain, we imagine other individuals while recalling our encounters with them or modelling alternative social interactions in future. Many studies using imaging and neurophysiological techniques have shown several similarities in brain activity between visual imagery and visual perception, and have identified frontoparietal, occipital and temporal neural components of visual imagery. However, the neural connectivity between these regions during visual imagery of socially relevant stimuli has not been studied. Here we used electroencephalography to investigate neural connectivity and its dynamics between frontal, parietal, occipital and temporal electrodes during visual imagery of faces. We found that voluntary visual imagery of faces is associated with long-range phase synchronisation in the gamma frequency range between frontoparietal electrode pairs and between occipitoparietal electrode pairs. In contrast, no effect of imagery was observed in the connectivity between occipitotemporal electrode pairs. Gamma range synchronisation between occipitoparietal electrode pairs predicted subjective ratings of the contour definition of imagined faces. Furthermore, we found that visual imagery of faces is associated with an increase of short-range frontal synchronisation in the theta frequency range, which temporally preceded the long-range increase in the gamma synchronisation. We speculate that the local frontal synchrony in the theta frequency range might be associated with an effortful top-down mnemonic reactivation of faces. In contrast, the long-range connectivity in the gamma frequency range along the fronto-parieto-occipital axis might be related to the endogenous binding and subjective clarity of facial visual features.

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Increase in extracellular dopamine levels during clozapine-induced potentiation in the hippocampal dentate gyrus of chronically prepared rabbits

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y08-036 ◽

2008 ◽

Vol 86 (5) ◽

pp. 249-256 ◽

Cited By ~ 2

Author(s):

Takashi Kubota ◽

Itsuki Jibiki ◽

Akira Ishikawa ◽

Tomomi Kawamura ◽

Sonoko Kurokawa ◽

...

Keyword(s):

Electrical Stimulation ◽

Nmda Receptor ◽

Dentate Gyrus ◽

Negative Symptoms ◽

Clinical Effect ◽

Perforant Path ◽

Hippocampal Dentate Gyrus ◽

Extracellular Dopamine ◽

Stimulation Of ◽

Synaptic Responses

We previously found that 20 mg/kg clozapine i.p. potentiated the excitatory synaptic responses elicited in the dentate gyrus by single electrical stimulation of the perforant path in chronically prepared rabbits. We called this phenomenon clozapine-induced potentiation and proved that it was an NMDA receptor-mediated event. This potentiation is presumably related to clozapine’s clinical effect on negative symptoms and cognitive dysfunctions in schizophrenia. In the present study, to investigate the mechanisms underlying clozapine-induced potentiation, we examined whether extracellular dopamine and 5-HT levels changed during the potentiation by using a microdialysis technique in the dentate gyrus. The extracellular concentrations of dopamine and 5-HT levels were measured every 5 min during all experiments. Extracellular 5-HT levels did not change, but dopamine levels eventually increased significantly during clozapine-induced potentiation. The increase in the dopamine levels occurred almost simultaneously with the induction of clozapine-induced potentiation. These results suggest that clozapine-induced potentiation is at least partly attributable to a dopamine-mediated potentiation of excitatory synaptic transmission. The present study implies that such phenomena occur also in the perforant path–dentate gyrus pathway.

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Survival of mossy cells of the hippocampal dentate gyrus in humans with mesial temporal lobe epilepsy

Journal of Neurosurgery ◽

10.3171/2008.11.jns08779 ◽

2009 ◽

Vol 111 (6) ◽

pp. 1237-1247 ◽

Cited By ~ 17

Author(s):

László Seress ◽

Hajnalka Ábrahám ◽

Zsolt Horváth ◽

Tamás Dóczi ◽

József Janszky ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Dentate Gyrus ◽

Temporal Lobe ◽

Pyramidal Neurons ◽

Hippocampal Sclerosis ◽

Mesial Temporal Lobe Epilepsy ◽

Drug Resistant ◽

Hippocampal Dentate Gyrus ◽

Mossy Cells ◽

Mesial Temporal Lobe

Object Hippocampal sclerosis can be identified in most patients with mesial temporal lobe epilepsy (TLE). Surgical removal of the sclerotic hippocampus is widely performed to treat patients with drug-resistant mesial TLE. In general, both epilepsy-prone and epilepsy-resistant neurons are believed to be in the hippocampal formation. The hilar mossy cells of the hippocampal dentate gyrus are usually considered one of the most vulnerable types of neurons. The aim of this study was to clarify the fate of mossy cells in the hippocampus in epileptic humans. Methods Of the 19 patients included in this study, 15 underwent temporal lobe resection because of drug-resistant TLE. Four patients were used as controls because they harbored tumors that had not invaded the hippocampus and they had experienced no seizures. Histological evaluation of resected hippocampal tissues was performed using immunohistochemistry. Results Mossy cells were identified in the control as well as the epileptic hippocampi by using cocaine- and amphetamine-regulated transcript peptide immunohistochemistry. In most cases the number of mossy cells was reduced and thorny excrescences were smaller in the epileptic hippocampi than in controls; however, there was a significant loss of pyramidal cells and a partial loss of granule cells in the same epileptic hippocampi in which mossy cell loss was apparent. The loss of mossy cells could be correlated with the extent of hippocampal sclerosis, patient age at seizure onset, duration of epilepsy, and frequency of seizures. Conclusions In many cases large numbers of mossy cells were present in the hilus of the dentate gyrus when most pyramidal neurons of the CA1 and CA3 areas of the Ammon's horn were lost, suggesting that mossy cells may not be more vulnerable to epileptic seizures than the hippocampal pyramidal neurons.

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