Large-Scale Brain Networks

Large-scale brain networks are collections of widespread brain regions showing functional connectivity by statistical analysis of the fMRI BOLD signal or other recording methods such as EEG, PET and MEG. An emerging paradigm in neuroscience is that cognitive tasks are performed not by individual brain regions working in isolation but by networks consisting of several … Continue reading Large-Scale Brain Networks

Neuroregenaration

Neuroregeneration refers to the regrowth or repair of nervous tissues, cells or cell products. Such mechanisms may include generation of new neurons, glia, axons, myelin, or synapses. Neuroregeneration differs between the peripheral nervous system (PNS) and the central nervous system (CNS) by the functional mechanisms involved, especially in the extent and speed of repair. Neuroregeneration … Continue reading Neuroregenaration

Nerve Net

Nerve net consists of interconnected neurons lacking a brain or any form of cephalization. While organisms with bilateral body symmetry are normally associated with a condensation of neurons or, in more advanced forms, a central nervous system, organisms with radial symmetry are associated with nerve nets. The nerve net is the simplest form of a … Continue reading Nerve Net

Neurogenesis

Neurogenesis is the process by which nervous system cells, the neurons, are produced by neural stem cells (NSCs). It occurs in all species of animals except the porifera (sponges) and placozoans. Types of NSCs include neuroepithelial cells (NECs), radial glial cells (RGCs), basal progenitors (BPs), intermediate neuronal precursors (INPs), subventricular zone astrocytes, and subgranular zone … Continue reading Neurogenesis

Central Nervous System

Central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. Not all animals with a central nervous system have a brain, although the large majority do. It is a structure composed of nervous tissue, especially white and gray matter, positioned along the rostral to caudal axis … Continue reading Central Nervous System

Synaptic plasticity

Synaptic plasticity is the ability of synapses to strengthen or weaken over time, in response to increases or decreases in their activity. Since memories are postulated to be represented by vastly interconnected neural circuits in the brain, synaptic plasticity is one of the important neurochemical foundations of learning and memory. Plastic change often results from the alteration of the number of neurotransmitter receptors located on a synapse. There are several underlying … Continue reading Synaptic plasticity

Coma

Coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. General symptoms of a person in a comatose state are: Inability to voluntarily open the eyesA non-existent sleep-wake cycleLack of response to … Continue reading Coma

Hydrocephalus

Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. Hydrocephalus is usually due to blockage of CSF outflow in the ventricles or in the subarachnoid space over the brain. In a person without hydrocephalus, CSF continuously circulates through the brain, its ventricles and the spinal cord and is … Continue reading Hydrocephalus

Brain Implant

Brain implants are technological devices that connect directly to a biological subject's brain – usually placed on the surface of the brain, or attached to the brain's cortex. Brain implants electrically stimulate, block or record (or both record and stimulate simultaneously) signals from single neurons or groups of neurons (biological neural networks) in the brain. … Continue reading Brain Implant