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Granule Cell Dispersion
Granule cell dispersion is one of the abnormal structural changes that has been shown in brains of patients with temporal lobe epilepsy. It has also been shown in different animal models, such as the kainic acid model, pilocarpine model, and kindling model. But granule cell dispersion was not found by using perforant pathway stimulation. It was first described by Houser. In a normal situation, the granule cells in dentate gyrus should be tightly packed. But in granule cell dispersion, the compact formation was lost, and the axons need to extend longer to reach the neighboring granule cells. Mechanism of formation There are currently two hypotheses for the mechanism. It might be a consequence of a migration disorder, and the first hypothesis considers an initial injury that release toxin(s) that affect the normal migration of granule cells. The second hypothesis concerns the role of reelin (see below). Reelin role in temporal lobe epilepsy Reelin Reelin, encoded by the ''RELN' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Lobe Epilepsy
In the field of neurology, temporal lobe epilepsy is an enduring brain disorder that causes unprovoked seizures from the temporal lobe. Temporal lobe epilepsy is the most common type of focal onset epilepsy among adults. Seizure symptoms and behavior distinguish seizures arising from the mesial (medial) temporal lobe from seizures arising from the lateral (neocortical) temporal lobe. Memory and psychiatric comorbidities may occur. Diagnosis relies on electroencephalographic (EEG) and neuroimaging studies. Anticonvulsant medications, epilepsy surgery, and dietary treatments may improve seizure control. Types Under the International League Against Epilepsy (ILAE) 2017 classification of the epilepsies, focal onset epilepsy occurs from seizures arising from a biological neural network within a single cerebral hemisphere. Temporal lobe epilepsy occurs from seizures arising within the temporal lobe. Temporal lobe epilepsy is the most common focal onset epilepsy, and 80% of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kainic Acid
Kainic acid, or kainate, is an acid that naturally occurs in some seaweed. Kainic acid is a potent neuroexcitatory amino acid agonist that acts by activating receptors for glutamate, the principal excitatory neurotransmitter in the central nervous system. Glutamate is produced by the cell's metabolic processes and there are four major classifications of glutamate receptors: NMDA receptors, AMPA receptors, kainate receptors, and the metabotropic glutamate receptors. Kainic acid is an agonist for kainate receptors, a type of ionotropic glutamate receptor. Kainate receptors likely control a sodium channel that produces excitatory postsynaptic potentials (EPSPs) when glutamate binds. Kainic acid is commonly injected into laboratory animal models to study the effects of Ablative brain surgery, experimental ablation. Kainic acid is a direct agonist of the glutamic kainate receptors and large doses of concentrated solutions produce immediate neuronal death by overstimulating neurons to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pilocarpine
Pilocarpine, sold under the brand name Pilopine HS among others, is a lactone alkaloid originally extracted from plants of the Pilocarpus genus. It is used as a medication to reduce pressure inside the eye and treat dry mouth. As an eye drop it is used to manage angle closure glaucoma until surgery can be performed, ocular hypertension, primary open angle glaucoma, and to constrict the pupil after dilation. However, due to its side effects, it is no longer typically used for long-term management. Onset of effects with the drops is typically within an hour and lasts for up to a day. By mouth it is used for dry mouth as a result of Sjögren syndrome or radiation therapy. Common side effects of the eye drops include irritation of the eye, increased tearing, headache, and blurry vision. Other side effects include allergic reactions and retinal detachment. Use is generally not recommended during pregnancy. Pilocarpine is in the miotics family of medication. It works by activ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kindling Model
Kindling is a commonly used model for the development of seizures and epilepsy in which the duration and behavioral involvement of induced seizures increases after seizures are induced repeatedly. Kindling is also referred as an animal visual model of epilepsy that can be produced by focal electrical stimulation in the brain. This is mainly used in visualising epilepsy in humans. The kindling model was first proposed in the late 1960s by Graham V. Goddard and colleagues. Although kindling is a widely used model, its applicability to human epilepsy is controversial. Method The word ''kindling'' is a metaphor: the increase in response to small stimuli is similar to the way small burning twigs can produce a large fire. It is used by scientists to study the effects of repeated seizures on the brain. A seizure may increase the likelihood that more seizures will occur; an old saying in epilepsy research is "seizures beget seizures". Repeated stimulation "lowers the threshold" for m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentate Gyrus
The dentate gyrus (DG) is one of the subfields of the hippocampus, in the hippocampal formation. The hippocampal formation is located in the temporal lobe of the brain, and includes the hippocampus (including CA1 to CA4) subfields, and other subfields including the dentate gyrus, subiculum, and presubiculum. The dentate gyrus is part of the trisynaptic circuit, a neural circuit of the hippocampus, thought to contribute to the formation of new episodic memories, the spontaneous exploration of novel environments and other functions. The dentate gyrus has toothlike projections from which it is named. The subgranular zone of the dentate gyrus is one of only two major sites of adult neurogenesis in the brain, and is found in many mammals. The other main site is the subventricular zone in the ventricular system. Other sites may include the striatum and the cerebellum. However, whether significant neurogenesis takes place in the adult human dentate gyrus has been a matter of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Migration Of Granule Cells
Migration, migratory, or migrate may refer to: Human migration * Human migration, physical movement by humans from one region to another ** International migration, when peoples cross state boundaries and stay in the host state for some minimum length of time Natural sciences Biology * Migration (ecology), the large-scale movement of species from one environment to another ** Animal migration ** Bird migration * Plant migration, see Seed dispersal, the movement or transport of seeds away from the parent plant * Gene migration, a process in evolution and population genetics * Cell migration, a process in the development and maintenance of multicellular organisms ** Collective cell migration, describing the movements of group of cells Physics and chemistry * Molecular diffusion, in physics * Migration (chemistry), type of reaction in organic chemistry * Seismic migration, in seismic and ground penetrating radar data processing * Microscopic motion of material caused by an external f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reelin
Reelin, encoded by the ''RELN'' gene, is a large secreted extracellular matrix glycoprotein that helps regulate processes of neuronal migration and positioning in the developing brain by controlling cell–cell interactions. Besides this important role in early Developmental biology, development, reelin continues to work in the adult brain. It modulates synaptic plasticity by enhancing the induction and maintenance of long-term potentiation. It also stimulates dendrite and dendritic spine development in the hippocampus, and regulates the continuing migration of neuroblasts generated in adult neurogenesis sites of the subventricular zone, subventricular and subgranular zones. It is found not only in the brain but also in the liver, Thyroid, thyroid gland, adrenal gland, fallopian tube, breast and in comparatively lower levels across a range of anatomical regions. Reelin has been suggested to be implicated in pathogenesis of several brain diseases. The expression of the protein has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
