Mechanism of anoxic depolarization in the brain intracellular Na and Ca ions, and extracellular glutamate and aspartate. Glutamate and aspartate are normally present as the brain's primary excitatory neurotransmitters, but high concentrations activate a number of downstream apoptotic and necrotic pathways. This results in neuronal dysfunction and death. Neurons function in the central nervous system by generating signals from synapses, and this only works in the proper chemical environment. An electrical signal is mediated by the sodium channels and leaky potassium channels in which intracellular K ion concentration is higher than its corresponding extracellular concentration, whereas extracellular concentrations of Na, Ca, and Cl ions are higher than
Cochlear implant sound into movements of hair cells in the cochlea; the inside-portion of these hair cells release potassium ions in response to the movement of the hairs, and the potassium in turn stimulates other cells to release the neurotransmitter, glutamate, which makes the cochlear nerve send signals to the brain, which creates the experience of sound. Instead, the devices pick up sound and digitize it, convert that digitized sound into electrical signals, and transmit those signals to electrodes embedded in the cochlea. The electrodes electrically stimulate the cochlear nerve, causing it to send signals to the brain. There are several systems