Experimental Models of Status Epilepticus
Steven L. Peterson, Timothy E. Albertson in Neuropharmacology Methods in Epilepsy Research, 2019
The perforant path stimulation model results in cell death, primarily in the ipsilateral dentate hilus.19 While vulnerable cell populations include hilar mossy cells, and somatostatin- and neuropeptide Y (NPY)-containing neurons, GABA-containing neurons in the hilus and granule cell layer and granule cells survive.19 The lesion induced by perforant path stimulation is similar to the lesion found in sclerotic hippocampi removed from cryptogenic epileptic patients.90,113 The survival of GABAergic neurons led to the formation of the dormant basket cell hypothesis to explain the seizure-induced loss of inhibition.91 The dormant basket cell hypothesis states that inhibition in the dentate gyrus depends on the tonic activation of inhibitory interneurons by hilar mossy cells. A loss of mossy cells results in a functional loss of inhibition not because the inhibitory neurons are dead but because the inhibitory neurons are not receiving sufficient activation to respond to remaining inputs.
Wheels of Motion: Oscillatory Potentials in the Motor Cortex
Alexa Riehle, Eilon Vaadia in Motor Cortex in Voluntary Movements, 2004
A difficulty with the basket cell mechanism is that it does not explain the lack of polarity reversal with cortical depth that is sometimes reported for gamma oscillations in neocortex.94 Tallon-Baudry, Bertrand, and Pernier suggest an alternative model consisting of a ring-shaped distribution of dipoles oriented horizontally within the cortex.94 Such a source would generate a field potential that does not reverse through cortical depth, and would generate no magnetic field, or only a weak one, at the surface. Gamma rhythms are not seen as consistently in MEG as in EEG or in LFPs.3 The geometry of the proposed ring of dipoles would correspond to horizontally oriented dendritic fields, but as yet there is no physical substrate to support the model. Furthermore, it seems that at least some gamma rhythms do exhibit phase reversals at the bottom of layer 4.6495
Antibodies to Glutathione: Production, Characterization, and Immunocytochemical Application to the Central Nervous System
Christopher A. Shaw in Glutathione in the Nervous System, 2018
Gold particles signaling glutathione immunoreactivity occured in glial well as in neuronal elements (Fig. 4). The highest labeling intensities were found in glial processes, particularly in perivascular glia, and in subpopulations of myelinated axons (Fig. 4 C). All neuronal populations exhibited significant immunolabeling. The labeling intensity of Purkinje-cell somata was relatively high (Fig. 4 D) and comparable to that of the adjacent glial cell bodies (Golgi epithelial cells). Mossy fiber terminals [putatively glutamatergic; (Ji et al. 1991)] also displayed relatively strong glutathione immunoreactivity (Fig. 4 A), whereas basket-cell axons (GABAergic) were weakly labeled.
Redox status on different regions of the central nervous system of obese and lean rats treated with green tea extract
Published in Nutritional Neuroscience, 2019
Rita Cassia Macedo, Eduardo Fernandes Bondan, Rosemari Otton
The cerebellum region was slightly affected by both the obese condition and GT treatment. We observed a tendency toward oxidative stress due to the cafeteria diet, as indicated by reduced free thiol groups and an increase in the GSH/GSSG ratio (Fig. 4). The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions, such as attention and language, and in regulating fear and pleasure responses. In contrast with the cerebral cortex, it seems that the cerebellum was modestly and equally affected by the cafeteria diet and GT. Both the GT treatment and the obese condition appear to affect this brain region only minimally. Contrasting results between cerebral cortex and cerebellum were observed mainly for MnSOD which was decreased in both GT-treated groups in the cortex and increased in the same groups in the cerebellum. The biological relevance of those contrast remains to be elucidated. This can be correlated with the type of neuron that is present in this region, as well as the type of neuronal activity. The cerebellum is composed of different cell types, mainly granule cells, which are very small, densely packed neurons that account for the huge majority of neurons in the cerebellum, and Purkinje cells, which are one of the most striking cell types in the mammalian brain, with apical dendrites forming a large fan of finely branched processes. In addition to the major cell types (granule cells and Purkinje cells), the cerebellum also contains glial cells and various interneuron types, including the Golgi cell, the basket cell, and the stellate cell. Whether these cell types are less prone to oxidative stress, inflammation or phytochemical action remains to be investigated. However, in contrast with our results, Miller et al.39 reported structural changes in the cerebellum in childhood obesity leading to reduced cerebellar volume. In addition, findings from Mueller et al.1 can be interpreted as a confirmation of the vulnerability of the cerebellum to neuronal injury linked with obesity in young adulthood. It is important to note that these results were obtained from humans with a body mass index (BMI) > 33 kg/m2 and the analyses were performed by magnetic resonance imaging.