Brain

Evolution of the Brain

Brain Parts

Hypothalamus
Thalamus
Cerebellum - major role in motor control. May also be involved in cognitive functions, such as attention and language as well as emotional control

Cerebral Hemispheres/Cerebral Cortex - concerned with higher mental functions: perception, action, language, and planning. Contains about 100 billion neurons, each with about a thousand synapses, making a total of about 100 trillion synaptic connections
- Frontal lobe - part of the neural circuit governing social judgements, planning and organization of activities, aspects of language, control of movement, and a form of short-term memory called working memory
- Parietal lobe - receives sensory information about touch, pressure, and space around the body and helps integrate that information into coherent perceptions
  - somatosensory cortex - a strip in the parietal lobe contains Wilder Penfield's sensory homunculus.
- Occipital lobe in involved in vision
- Temporal lobe is involved with auditory processing and aspects of language and memory.
- Basal ganglia - help regulate motor performance
- Hippocampus - involved with aspects of memory storage
- Amygdala - coordinates autonomic and endocrine responses in the context of emotional states

Brain Functions

The brain provides coherent control over the actions of an animal. Information from the sense organs is collected in the brain, where it is processed to extract information about the structure of the environment. It combines the processed information with info about the current needs of the animal and with memory of past circumstances, and then generates motor responses. The main functions are:

Perception - The brain collects info from the senses.
Motor control - Motor systems are areas of the brain, mainly in the spinal cord and hindbrain, that initiate body movements by activating muscles.
Sleep - The brain controls the transitions from sleeping to waking in a daily cycle
Homeostasis - maintaining parameters (such as temperature, water content, salt concentration in the bloodstream, blood glucose levels, blood oxygen level) within a limited range of variation, through negative feedback
Motivation - The brain activates behaviors to meet any needs that arise, generally through a reward-punishment mechanism. The basal ganglia inihibit most of the motor systems in the brain, and then release the inhibition for a specific motor system to allow its action to be carried out.
Learning and memory - modifying behavior based on experience:
- Working memory - maintaining a temporary representation of information about the task that you are currently working on
- Episodic memory - remembering the details of specific events. The Hippocampus is heavily involved.
- Semantic memory - remembering facts and relationships. Mainly in the Cerebral Cortex
- Instrumental learning - allowing rewards and punishments to modify behavior
- Motor learning - refining patterns of body movement by practicing or repetition