No abstract available.
Dendrites* ; Hippocampus* ; Interneurons*

No abstract available.
Child* ; Dendrites* ; Epilepsy* ; Humans ; Interneurons*

The developmental expression of calcium-binding protein, calbindin D-28k (CB), during the first 6 months was studied in the canine hippocampus by immunohistochemistry. CB immunoreactivity appeared from on P0 in the dentate granule cells, mossy fibers in CA 3 area, CA 2 and CA 1 pyramidal cells, and interneurons in all regions. According to their morphology and location, these could represent the presumptive pyramidal cells and interneurons. From on P7, the CB immunoreactive pyramidal cells clearly distinguished and started to form two rows in CA 1 area as time progressed, while scattered multipolar neurons gradually decreased. CB immunoreactive cell processes increased in length up to P28. The adult-like distribution of CB immunoreactivity was established about P60. After P60, CB immunoreactivity appeared in dentate granule cells, mossy fibers in CA 3 area and pyramidal cells in CA 1 where formed two rows and CA 2 areas as well as in interneurons of the strata oriens and pyramidale. Taken together, developmental expression of CB in the canine hippocampus was summarized that CB imunoreactivity was observed in all regions on P0 and reached adult-like distribution about P60. These data also suggested the possibility of prenatal expression of CB on the basis of the staining pattern at P0.
Calbindins* ; Hippocampus* ; Immunohistochemistry ; Interneurons ; Neurons ; Pyramidal Cells

PURPOSE: Excitotoxic injury of the dendrites of inhibitory interneurons could lead to decrease in their synaptic activation, and explain subsequent local circuit hyperexcitability and epilepsy. A hallmark of dendrotoxicity at least in principal neurons of the hippocampus and cortex are focal or varicose swellings of dendritic abors. This research was designed to study morphologic changes of interneuron dendrite in kainate-treated hippocampal slice culture overtime. METHODS: Cultures aged to 15-16 Equivalent Postnatal Day (EPD) were exposed to 10microM kainic acid (KA), and were analyzed at 0, 8, 24, 48, 72 hours after transient (1 hour) KA exposure. Neuronal injury was determined by morphologic changes of parvalbumin (PV) positive interneuron dendrites in area CA1 of PV-immunohistochemically stained sections. RESULTS: 1) Transient (1 hour) exposure of hippocampal explant cultures to KA produced marked focal swellings of the dendrites of PV-immunoreactive interneurons in a highly reproducible manner. 2) The presence of focal swellings was reversible with kainate washout. The dendrites of KA treated explants were no longer beaded at 8, 24, 48, 72hours after KA exposure.3) The number of cells in PV-immunoreactive interneuron was decreased at 0, 8, 24 hours after exposure. But there was no significant difference among 48hr and 72hr recovery group compare with control group.4) The total length of dendrites was decreased between 0 and 8hours after exposure. But there was no significant difference among 24, 48, and 72hr recovery group compare with control group.5) The branches of dendrites were decreased just after exposure. But there was no significant difference among 8hr, 24hr, 48hr, and 72hr recovery group compare with control group. CONCLUSION: The presence of focal swellings was reversible with kainate washout, and was not accompanied by interneuronal cell death.
Cell Death ; Dendrites* ; Epilepsy ; Hippocampus ; Interneurons* ; Kainic Acid ; Neurons

BACKGROUND: This study was designed to understand the possible pathways of R2 responses by testing the blink reflex in patients with a thalamic hemorrhage. METHOD: Blink reflexes were obtained in 11 patients with a thalamic hemorrhage. The mean interval of the first test of the thalamic hemorrhage was 21.7(24.4days, and follow-up tests were performed in 5 patients about 10 months later. RESULTS: All subjects showed normal R1 responses on affected or normal sides. However, R2 responses were abnormal in 9 patients (81.8%). R2 responses were not recorded in 4, and prolonged in 3. Two patients showed both absent and prolonged R2 responses. The abnormal R2 responses were grouped as follows. First, R2 was abnormal bilaterally by the stimulation on the affected side (afferent type, N=4). Second, R2 was abnormal bilaterally by the stimulation on the affected side and abnormal contralaterally by the stimulation on the normal side (mixed type, N=2). Third, R2 was abnormal contralaterally by the stimulation on the affected side (undetermined type, N=2). One showed abnormal R2 bilaterally by the stimulation on the affected and normal side (coma type). On follow-up tests, all showed normalized R2 responses. CONCLUSIONS: Thalamic hemorrhages caused various abnormal R2 responses in blink reflexes, which were normalized in several months. It is suggested that the abnormal R2 responses of thalamic hemorrhage result from the removal of crossed cortical facilitation on brainstem interneurons rather than an interrupted central pathway of the R2 response.
Blinking* ; Brain Stem ; Follow-Up Studies ; Hemorrhage* ; Humans ; Interneurons

PURPOSE: Excitotoxic injury of the dendrites of inhibitory interneurons could lead to decrease in their synaptic activation, and explain subsequent local circuit hyperexcitability and epilepsy. A hallmark of dendrotoxicity at least in principal neurons of the hippocampus and cortex are focal or varicose swellings of dendritic abors. This research was designed to study morphologic changes of interneuron dendrite in kainate-treated hippocampal slice culture overtime. METHODS: Cultures aged 15-16 Equivalent Postnatal Days (EPD) were exposed to 10 microM kainic acid (KA), and analyzed at 0, 8, 24, 48, 72 hours after transient (1 hour) KA exposure. Neuronal injury was determined by morphologic changes of interneuron dendrites in area CA1 of DiI stained sections. RESULTS: 1) Transient (1 hour) exposure of hippocampal explant cultures to KA produced marked focal swellings of the dendrites of DiI stained interneurons in a highly reproducible manner. 2) The presence of focal swellings was reversible with kainate washout. The dendrites of KA treated explants were no longer beaded at 8, 24, 48, 72 hours after KA exposure. 3) There was no significant difference in the thickness of dendrites in DiI stained interneuron among 8hr, 24hr, 48hr and 72hr recovery group, compared with control group. CONCLUSION: The presence of focal swellings was reversible with kainate washout, and was not accompanied by interneuronal cell death.
Cell Death ; Dendrites* ; Epilepsy ; Hippocampus ; Interneurons* ; Kainic Acid ; Neurons

Cortical interneurons can be categorized into distinct populations based on multiple modalities, including molecular signatures and morpho-electrical (M/E) properties. Recently, many transcriptomic signatures based on single-cell RNA-seq have been identified in cortical interneurons. However, whether different interneuron populations defined by transcriptomic signature expressions correspond to distinct M/E subtypes is still unknown. Here, we applied the Patch-PCR approach to simultaneously obtain the M/E properties and messenger RNA (mRNA) expression of >600 interneurons in layer V of the mouse somatosensory cortex (S1). Subsequently, we identified 11 M/E subtypes, 9 neurochemical cell populations (NCs), and 20 transcriptomic cell populations (TCs) in this cortical lamina. Further analysis revealed that cells in many NCs and TCs comprised several M/E types and were difficult to clearly distinguish morpho-electrically. A similar analysis of layer V interneurons of mouse primary visual cortex (V1) and motor cortex (M1) gave results largely comparable to S1. Comparison between S1, V1, and M1 suggested that, compared to V1, S1 interneurons were morpho-electrically more similar to M1. Our study reveals the presence of substantial M/E variations in cortical interneuron populations defined by molecular expression.
Mice ; Animals ; Neocortex/physiology* ; Mice, Transgenic ; Interneurons/physiology*

Autapses selectively form in specific cell types in many brain regions. Previous studies have also found putative autapses in principal spiny projection neurons (SPNs) in the striatum. However, it remains unclear whether these neurons indeed form physiologically functional autapses. We applied whole-cell recording in striatal slices and identified autaptic cells by the occurrence of prolonged asynchronous release (AR) of neurotransmitters after bursts of high-frequency action potentials (APs). Surprisingly, we found no autaptic AR in SPNs, even in the presence of Sr²⁺. However, robust autaptic AR was recorded in parvalbumin (PV)-expressing neurons. The autaptic responses were mediated by GABA_A receptors and their strength was dependent on AP frequency and number. Further computer simulations suggest that autapses regulate spiking activity in PV cells by providing self-inhibition and thus shape network oscillations. Together, our results indicate that PV neurons, but not SPNs, form functional autapses, which may play important roles in striatal functions.
Parvalbumins/metabolism* ; Corpus Striatum/metabolism* ; Interneurons/physiology* ; Neurons/metabolism* ; Neostriatum

Fentanyl as a synthetic opioid works by binding to the mu-opioid receptor (MOR) in brain areas to generate analgesia, sedation and reward related behaviors. As we know, cerebellum is not only involved in sensory perception, motor coordination, motor learning and precise control of autonomous movement, but also important for the mood regulation, cognition, learning and memory. Previous studies have shown that functional MORs are widely distributed in the cerebellum, and the role of MOR activation in cerebellum has not been reported. The aim of the present study was to investigate the effects of fentanyl on air-puff stimulus-evoked field potential response in the cerebellar molecular layer using in vivo electrophysiology in mice. The results showed that perfusion of 5 μmol/L fentanyl on the cerebellar surface significantly inhibited the amplitude, half width and area under the curve (AUC) of sensory stimulation-evoked inhibitory response P1 in the molecular layer. The half-inhibitory concentration (IC
Animals ; Cerebellum ; Evoked Potentials ; Fentanyl/pharmacology* ; Interneurons ; Mice ; Physical Stimulation

Dysfunctional neural circuitry has been found to be involved in abnormalities of perception and cognition in patients with schizophrenia. Gamma oscillations are essential for integrating information within neural circuits and have therefore been associated with many perceptual and cognitive processes in healthy human subjects and animals. This review presents an overview of the neural basis of gamma oscillations and the abnormalities in the GABAergic interneuronal system thought to be responsible for gamma-range deficits in schizophrenia. We also review studies of gamma activity in sensory and cognitive processes, including auditory steady state response, attention, object representation, and working memory, in animals, healthy humans and patients with schizophrenia.
Animals ; Cognition ; Humans ; Interneurons ; Memory, Short-Term ; Schizophrenia