Damage to the cerebellum causes lack of coordination and balance. ○ All these so far are older brain functions which occur w/o conscious effort - the brain processes most info outside our awareness (we’re aware of the result like an image but not how we made that). The brainstem does the basic stuff so that the newer brain parts can do more complex things ● Limbic System: the newest and highest regions of the brain are the cerebral hemispheres (the 2 halves of the brain). Between the oldest and the newest brain areas is the limbic system. ○ The hippocampus processes conscious memories - loss of the hippocampus causes loss of ability to form new memories of facts and events. ○ The amygdala are 2 lima bean sized neural clusters - linked to aggression and fear, including the perception of these emotions and the processing of emotional
memories. Removing the amygdala in animals caused them to be much more mellow. But when we feel aggressive this corresponds to other areas of the brain. ○ The hypothalamus is below the thalamus - this is an important link in the command chain governing body maintenance. Some neural clusters in the hypothalamus influence hunger, some regulate thirst, temp, and sex behavior. Together they maintain a steady internal state. The hypothalamus monitors the state of the body by tuning into blood chemicals or signals from the brain. Ex: it picks up signals from the cerebral cortex that you are thinking about sex so the hypothalamus secretes hormones which in turn trigger the pituitary to influence sex glands to release their hormones which intensifies the thoughts of sex in the cerebral cortex. The hypothalamus is also the part of the brain that produces pleasurable rewards - called reward centers . This was discovered by doing an electrical stimulus to a rat’s brain and observing how much pleasure they get from it. ■ Other limbic system reward centers include the nucleus accumbens (which is in front of the hypothalamus). ■ Dopamine is released when animals do certain activities like eating so that they get rewards for doing activities necessary for survival. ■ Addictive disorders stem from malfunctions in natural brain systems - genetically predisposed to reward deficiency syndrome ● Cerebral Cortex: the cerebrum (the hemispheres) has newer neural networks. Like all structures above the brainstem the hemispheres come as a pair. Covering those hemisphere like bark on a tree is the cerebral cortex (a thin surface layer of interconnected neural cells. It is the body’s ultimate control and info-processing center). Moving up to more complex life, the cerebral cortex expands and the org becomes more adaptable, less dependent on preprogrammed genetic instructions. The rest of the hemispheres are mostly axons that connect the cortex to the other regions of the brain.
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- Fall '18
- Makoto Ogura