AP Psych - Biological Basis of Behavior

Myers Psychology 9th Edition - modules 4-6

Neuron

nerve cell, building block of the nervous system

sensory neurons (afferent)

carry incoming information from sensory receptors to brain and spinal cord

motor neurons (efferent)

carry outgoing information from brain and spinal cord to muscles and glands

interneurons

only in brain and spinal cord, communicate internally between sensory inputs and motor outputs

diagram of a neuron

dendrites

receive information and conduct it towards cell body

soma (cell body)

contains **nucleus**

nucleus

has genetic material

axon

transfers electrochemical messages

myelin sheath

layer of fat that speeds up transmission

node of ranvier

gaps in **myelin sheath** that sped up transmission

schwann cell

produces **myelin sheath**

axon terminal (synaptic knobs, etc.)

very end of **axon**

synapse

allow for communication between nerve cells

action potential

neural impulse, brief electrical charge that travels down the **axon**

resting potential

* outside has more positive sodium ions, inside has more negative ions
* polarized

depolarization

positive Na+ ions enter cell

repolarization

return of + outside, - inside

excitatory signals

push charge above -70mv

inhibitory signals

push charge below -70mv

refractory period

the time in which a nerve cell is unable to fire an **action potential** (nerve impulse)

threshold

about -55 mv

"all or none" phenomenon

the **action potential** either fires or it doesn't, no middle ground

When action potential reaches knoblike terminals at end of axon, triggers release of...

chemical messages called **neurotransmitters**

Neurotransmitter: Acetylcholine (ACh)

* Function: enables muscle action, learning, memory
* Examples of malfunction: Alzheimer's - ACh producing neurons deteriorate

Neurotransmitter: Dopamine

* Function: influences movement, learning, attention, emotion
* Examples of malfunction:
* Excess dopamine receptor activity is linked to Schizophrenia.
* When starved of dopamine, the brain produces tremors and decreased mobility of Parkinson's.

Neurotransmitter: Serotonin

* Function: affects mood, sleep, hunger, arousal (consciousness)
* Examples of malfunction: undersupply linked to depression

Neurotransmitter: Norepinephrine

* Function: helps control alertness and arousal
* Examples of malfunction: undersupply can depress mood

Neurotransmitter: GABA (gamma-aminobutyric acid)

* Function: major inhibitory neurotransmitter
* Examples of malfunction: undersupply linked to seizures, tremors, insomnia

Neurotransmitter: Glutamine

* Function: major excitatory neurotransmitter, involved in memory
* Examples of malfunction: oversupply can overstimulate brain, producing migraines or seizures

Neurotransmitter

* chemical messengers
* Fit receptor site much like a key fits a lock

Agonist

__Excites__, similar enough in structure to fit neurotransmitter and mimic effects of neurotransmitter on receiving neuron

(ex. nicotine)

Antagonist

__Inhibits__, similar enough structure to occupy receptor site but not similar enough to stimulate receptor

(ex. beta blockers)

reuptake inhibitors

block reabsorption of neurotransmitters into sending neurons

(ex. SSRIs or cocaine)

Peripheral Nervous System (PNS)

* nerves connecting **CNS** to muscles and organs
* **sensory** (afferent) and **motor** (efferent) neurons

Central Nervous System (CNS)

* contains interneurons (basically can't regenerate)
* brain and spinal cord

Somatic (skeletal)

Part of PNS

- nerves to voluntary muscles and sensory receptors
- both voluntary and reflex movements

Autonomic

Part of PNS

* nerves to heart, blood vessels, etc.
* involuntary functions (heartbeat, blood pressure, respiration, etc.)

Sympathetic

Part of Autonomic

* "Fight or flight:

Parasympathetic

Part of Autonomic

* "rest and digest"

X-ray

Black/white

Captures structure

EEG (electroencephalogram)

Black/white (pen + paper)

Captures activity/function

Most commonly map altered states of consciousness (REM)

CAT (or CT)

Black/white

Captures structure

Composite view of x-ray photos

PET (positron emission tomography)

Color

Captures activity/function

Displays brain activity, shows where radioactive form of glucose goes

SPECT

Color

Captures activity/function

Displays brain activity, shows where radioactive substance goes

MRI (magnetic resonance imaging)

Black/white

Captures structure

fMRI (functional magnetic resonance imaging)

Color

Captures activity/function

Revels blood flow (thus brain activity) by comparing successive MRI scans

Brainstem

* Oldest part of brain, central core, responsible for automatic survival functions
* Contains **medulla**, **pons**, **reticular formation**

Medulla

* Base of **brainstem**
* Heartbeat and breathing

Pons

* Above **medulla**
* breathing, motor control, sleep and dreams

reticular formation

nerve network that controls arousal

Cerebellum

* "little brain" attached to back of **brainstem**
* voluntary movement, balance, implicit procedural memories

Thalamus

* above **brainstem**
* brain's sensory switchboard, directs messages to **sensory cortex** and transmits replies to **cerebellum** and **medulla**

Limbic system

* emotion
* contains **hippocampus**, **amygdala**, **hypothalamus**

hippocampus

* part of **limbic system**, hook like structure
* responsible for storage and process of explicit memory

amygdala

* part of **limbic system**, almond shaped neural clusters
* linked to emotion (fear and aggression)

hypothalamus

eating, drinking, body temperature, helps to govern endocrine system

cerebral cortex (neocortex, cerebrum)

contains **frontal** lobe, **parietal** lobe, **occipital** lobe, **temporal** lobe

glial cells

cells in nervous system that support, nourish, protect neurons

frontal lobe

speaking, muscle movement, plans and judgements

* **broca's** **area** - speaking
* **motor** **cortex** - back of ______ lobe, voluntary movement
* **prefrontal** **cortex** - plans and judgements

parietal lobe

**sensory cortex** (somatosensory) front of _______ lobe, registers and processes body sensations

occipital lobe

the ______ lobe contains the **visual cortex**

temporal lobes

the ______ lobe contains the **auditory** **cortex**

corpus callosum

large band of neural fibers that connect the two hemispheres and carry messages between them