Glutamic acid
Glutamate is also a neurotransmitter (see below), which makes it one of the most abundant molecules in the brain. Malignant brain tumors known as glioma or glioblastoma exploit this phenomenon by using glutamate as an energy source, especially when these tumors become more dependent on glutamate due to mutations in the gene "IDH1".
Neocortex
In the human brain, the neocortex is the largest part of the cerebral cortex which is the outer layer of the cerebrum, with the allocortex making up the rest. The neocortex is made up of six layers, labelled from the outermost inwards, I to VI. Of all the mammals studied to date (including humans), a species of oceanic dolphin known as the long-finned pilot whale has been found to have the most neocortical neurons.