IV.Neuroscience The relationship between brain and behavior.

A. Earliest work... n Brain/body and behavior connection. –Hippocrates: brain injury and behavior –Phrenology (Franz Gall – 1800’s) n What does your skull say about you?

B. The body’s basic communication network. n The nervous system: n 1. “Communication system”. n Encounter a bear in the woods..... n Coordinates the body and environment. –“Electrochemical” n receives messages n organizes messages n sends out messages

B. The body’s basic communication network. n 2. Two components: –a. Central Nervous System (CNS) n Brain and spinal cord.

B. The body’s basic communication network 2. Two components: –b. Peripheral Nervous System. n Connects CNS with rest of body. n Controls skeletal movement and internal organs.

C. Basic Building Blocks of Neural Communication n THE NEURON –Nerve or Neuron? –A neuron is a single nerve cell –A nerve is a bundle of neurons Nerve cell - most basic component. Information carrier and integrator. “Talks” to other cells, muscles, etc. “Talks” to other cells, muscles, etc. n 1. 3 different kinds of neurons: –Sensory: receiving –Interneuron: organizing –Motor:sending

2. Structure of a Neuron

C. Basic Building Blocks of Neural Communication n 2. Structure of neuron: –Dendrites receive signals. n Carry info to cell body. –Cell body synthesizes these signals. –Signal travels down axon. n Away from cell body. –Helped along by myelin sheath. n Made up of glial cells.

C. Basic Building Blocks of Neural Communication n 3. How neurons communicate. n a. Chemistry-to-electricity process. –Within neuron part: –Neuron at rest – electrically charged. n Resting potential. n Ions exist outside/inside of cell membrane. n More negative ions inside of membrane. –Gets stimulated (by light, heat, pressure, chemicals from other neurons).

C. Basic Building Blocks of Neural Communication n 3. How neurons communicate (with neuron). n a. Chemistry-to-electricity process. –Positive ions move into cell – if strong enough – causes depolarization n FIRES! –But – strong enough means must reach: –Threshold  –Fires signal/electric impulse down axon  n called Action potential. n “All-or-none process”

C. Basic Building Blocks of Neural Communication n 3. How neurons communicate. n b. Importance of neurotransmitters. (Between neuron communication). n Synapse: Junction between axon tip of sending neuron and dendrites of receiving neuron. Synaptic Gap - tiny gap between neurons. n Action potential fires, travels down axon – releases  n Neurotransmitters - chemical messengers  cross the synaptic gap, binds to sites on receiving neuron.

3. How neurons communicate n a. Importance of Neurotransmitters. Found in different places, do different jobs. - Acetylcholine (learning, memory, muscle contraction,) - Endorphins (mood/pain) - Dopamine (smooth movement) - - Norepinephrine (alertness, arousal) - Serotonin (mood, hunger, sleep)

3. How neurons communicate n c. Neurotransmitters and drugs. n n Agonist: EXCITES. Drug/toxin mimics the effects of neurotransmitter, or heightens activity of neurotransmitters. n n Antagonists: INHIBITS Drug/toxin that inhibits or blocks release of neurotransmitters. n n Examples:

n Influence of drugs on neurotransmitters: n Importance of REUPTAKE. –Agonists heighten neurotransmitter activity by blocking reuptake of the chemical. n Examples: Cocaine

COCAINE

D. Brain n 2. Structure n a. Lower Level –Brainstem: oldest, innermost region n controls arousal. –Thalamus: “switchboard” –Cerebellum: little brain n coordinates movement and balance

2a. Lower level brain structure –Limbic system: n amygdala - aggression, fear n hypothalamus - hunger, thirst, sexual behavior. –“reward center” n hippocampus - memory.

2. Structure of brain: a. Lower Level

2. Structure of Brain: b. Cerebral Cortex n 1. “Bark” of the brain

2. Structure of Brain: b. Cerebral Cortex n 2. Function of 4 Lobes: Frontal: Motor Cortex Specific areas stimulate movement. Parietal: Sensory Cortex Receives information from skin and body parts (touch/movement).

2. Structure of Brain: b. Cerebral Cortex n 2. Functions of 4 Lobes, cont’d. Occipital: processes visual information, sends it elsewhere to be decoded. Temporal: processes sound. Sensory and motor cortex, and visual and auditory areas take up 1/4 of brain.

2. Structure of Brain: b. Cerebral Cortex n Association Areas: Other “3/4” of cerebral cortex. Integrates, interprets, acts on information. (i.e. important to communication). Areas and their associated behaviors have been identified based on what happens when those areas are damaged.

B. Association Areas Frontal Lobe: - cannot plan or judge. - alters personality - Phinneas Gage - speech production- Broca’s Area Temporal Lobe: - can’t recognize faces. - speech understanding - Wernicke’s Area

C. Two Hemispheres of Brain n Brain’s sides (left and right) serve different purposes. n n Stroke? n n Damage to left side - reading, writing, speaking, understanding. - considered “major”, verbal hemisphere n n Damage to right side - not as dramatic

C. Two Hemispheres of Brain n Important - how sides communicate with each other. –Corpus Callosum: bundle of neural fibers connecting both sides, carries messages between them. –If severed, demonstrates how both sides work together. Corpus callosum

c. Two Hemispheres of Brain n Talents of each hemisphere. Right: perceptual picture recognition picture recognition emotion, expression, creativity emotion, expression, creativity Left: speaking, calculating numbers word recognition word recognition analytical, logical analytical, logical

Conclusions n There is no psychology without biology. n From the neuron to the brain: –How information/stimuli are taken in, integrated, and responses (behavior) are generated based on the body’s communication system – nervous system.