The Inner Brain
Deep within the skull, lie structures that are the gatekeepers between the spinal cord and the cerebral hemispheres. They determine our emotional state, and modify our perceptions and responses depending on that state. They allow us to initiate movements without thinking about them.
Like the cerebral lobes, the center-brain structures are twins as well: each is duplicated in the opposite half of the brain:
The pearl-sized hypothalamus twins wake you up in the morning, and get the adrenaline flowing during an exam. As a center of emotion, they control the molecules that make you feel exhilarated, angry, unhappy, thirsty, and hungry.
Near the hypothalamus lie the thalamus twins, a major clearinghouse for info going to and from the spinal cord and the cerebrum.
An arching tract of nerve cells leads from those two to the hippocampus twins. These nubs send short-term memories to the cerebral hemisphere for long-term storage and retrieval, important for learning.
Below the temporal lobe are the amygdala twins. These two almond shaped pieces make us experience survival feelings, like fear and anger, as a reaction to an event. Events that have to do with food, sex partners, rivals, distress, etc.
The basal ganglia are clusters of nerve cells surrounding the thalamus, in charge of initiating and integrating movements.
See also the previous images
