In consciousness, awareness and control are closely linked. It is useful to consider a spectrum of consciousness from fully conscious at one end to a deep state of unconsciousness, known as coma, at the other. Some survivors who regain consciousness may make a full recovery, whereas others may be left with some degree of neurological deficit that they must then learn to overcome. The most important brain area involved in consciousness is the cerebral cortex, and it is worth thinking of this large area as the conscious brain. Spindle neurons are also found in the dorsolateral prefrontal cortex. The function of these cells is not fully understood, but they appear to be fast-acting cells that form part of the emotional pathway that extends between the amygdala and the frontal cortex, which provides sophisticated responses to emotions. There are many different neurotransmitters, but the main chemical in the cerebral cortex is glutamate.