The atmosphere is quite dusty, giving the Martian sky a light brown or orange-red color when seen from the surface; data from the Mars Exploration Rovers indicate that suspended dust particles of roughly 1.5 micrometres diameter.
Glutamate is a powerful excitatory neurotransmitter that is released by nerve cells in the brain. It is responsible for sending signals between nerve cells, and under normal conditions it plays an important role in learning and memory.
Glutamate exerts its effects by binding to specific receptors on nerve cells. There are various types of glutamate receptors. Here we will concern ourselves with two types of glutamate receptors, which are called the NMDA receptor and the non-NMDA receptor.