 The brainstem: is the oldest and innermost region of the brain  It begins where the spinal cord swells slightly after entering the skull  This swelling is the medulla, which controls heartbeat and breathing  Next lies the pons, which helps to coordinate movement

 The brainstem is a crossover point, where nerves to and from each side of the body connect with the body’s opposite side  The reticular formation is a network of neurons that extends from the spinal cord through the brainstem and into the thalamus. As sensory input travels to the thalamus, the reticular formation, filters incoming stimuli and relays important information to other areas of the brain.  Based on research from cats in the 1940’s, the reticular formation is believed to be connected to arousal.

 The midbrain is composed of the thalamus, cerebellum and the limbic system  Thalamus: it lies at the top of the brainstem, this joined pair of egg shaped structures act as the brain’s sensory switchboard. It receives sensory information from the senses, except smell, and relays them to the higher brain regions that deal with those senses. The thalamus also receives some of the higher brain’s replies, which it directs to the medulla and the cerebellum.

 The cerebellum extends from the rear of the brainstem. It is about the size of a baseball and it’s name means “little brain”.  The cerebellum enables one type of nonverbal learning and memory. Implicit memory formation needs the cerebellum. (nondeclarative or procedural memory)  It helps us judge time, modulate emotions, and discriminate sounds and textures. It works with the pons to coordinate voluntary movement.

 The limbic system is made up of the hippocampus, pituitary gland, amygdala and hypothalamus.  Amygdala: 2 lima bean sized neural clusters, located in the temporal lobe, influence aggression and fear.  Animal studies where the amygdala has been lesioned have shown that aggression is eliminated. In other studies, the amygdala was stimulated, to cause aggression in an otherwise placid animal, such as a cat. Moving the stimulation, could then cause the cat to cower in fear of a mouse.

 Aggressive and fearful behavior involves neural activity in many brain levels. The brain is not neatly organized into areas that correspond to behaviors. Although studies show that the amygdala is connected to aggression and fear, even in the limbic system stimulating structures other than the amygdala can evoke such behavior.  The amygdala creates connections between stimuli and their emotional value. This occurs through memories, which most often include an emotional aspect.

 The hypothalamus sits just below the thalamus and helps to govern bodily maintenance. Neural clusters in the hypothalamus regulate thirst, influence hunger and regulate body temperature and sexual behavior.  The hypothalamus regulates the pituitary gland, which hangs from the hypothalamus and secretes several hormones that control bodily functions

 The hypothalamus monitors brain chemistry and can interpret messages from your brain, release hormones itself, then send the hormones/messages to your pituitary gland, which releases hormones or sends messages to the other endocrine system glands  Look up studies by Olds on the hypothalamus of rats (1954, 1958), read over the information and be prepared to discuss or write about the studies.

 The hippocampus is a temporal lobe neural center that is part of the brain’s limbic system.  The hippocampus is lateralized, meaning there are two of them. They are located above the ear, about an inch and a half straight in.  New explicit memories of names, images and events are laid down via the hippocampus.

 Damage to the hippocampus, affects some types of memory. Damage to one or the other seems to have a different effect.  Damage to the left, people have trouble recalling verbal information but have no trouble recalling visual designs and locations. Damage to the right produces the opposite effect.  The hippocampus is active during slow wave sleep, as memories are processed and filed for later retrieval. The better the sleep, the better the next day’s memory. Memories are not stored in the hippocampus, it acts as a dock for holding and registering the memories, until the brain transfers them to permanent storage in the cortex.