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
OPN1LW LWS cone cells into horizontal cells, bipolar cells, amacrine cells, and finally ganglion cells before continuing to the brain via the optic nerve. Ganglion cells compile the signal from the LWS cones with all other cone signals that occurred in response to the light that was seen, and pass the overall signal into the optic nerve. The cones themselves do not process colour, it is the brain that decides what colour is being seen by the signal combination it receives from the ganglion cells. Before humans evolved to be a trichromatic species, our vision was dichromatic and consisted of only