Cells within the nervous system are generally divided into two types: Neurons and glia. Neurons have the capacity to change their electrical potential, hence to be "active," and have received the bulk of attention from researchers. However, recent evidence shows that one form of glial cell, the astrocyte, contributes to communication within the nervous system in a fashion that is increasingly characterized as "active." Astrocytes were previously regarded as passive supporting elements. Metaphorical descriptions of the cells changed from lifeless "packing material" to "housekeepers," "nursemaids," and other social roles characterized by female gender and subordinate status.
A turning point in the conceptualization of glial cells came when researchers reported that chemicals released from glial cells appeared to regulate the formation of synapses, the communication points between neurons. With this evidence that glial cells not only contributed to, but actively regulated, a process highly valued by neuroscientists, glial cells moved up in social rank and changed gender, becoming "masters of the synapse" and "architects of the brain." The metaphors clearly imply that as cells become more valuable to nervous system function, they become metaphorically masculine.