AP Psych Unit 1 Part 1

Genetics, Nervous Systems, Neurons, Neurotransmitters, Drugs, Parts of Brain

Behavioral Genetics

study of genetics and environmental influences on behavior

Certain environmental factors encourage the expression of specific genetic dispositions

Epigenetics

how new processes or things in the environment alter expression of a gene without producing a change in genetic sequence.

Genetic Predisposition

Humans are born with a tendency toward certain characteristics or behaviors, but only a tendency not a mandate.

Heritability

The amount of difference within a group that can be attributed to Heredity.

Genetic Determinism

Traits that are genetically determined

ex: eye color, ear shape

Nervous systems

• Allows information to be carried throughout your body

• Central nervous system (CNS), peripheral nervous system (PNS)

Central nervous system (CNS)

• Brain and spinal cord

  • Spinal cord: connects brain and peripheral NS

  • Brain:divided into hindbrain, midbrain, forebrain

Peripheral Nervous System

• all nerves in you body (excluding brain + spinal cord)

• divided into autonomic and somatic

Reflexes

• Messages strong enough to activate a message in a neuron

• do not need processing by brain

• controlled directly by spinal cord

Reflex Arc

• fast, automatic neural pathway that controls an involuntary response to a stimulus

• how reflex messages are sent through the PNS

• does not reach brain, sends directly to body

Autonomic Nervous System

• Automatic and involuntary actions

• ex: digestion, heart rate, breathing

• divided into sympathetic and parasympathetic NS

Somatic Nervous System

• Voluntary function'

• ex: walking, talking, running

Sympathetic NS

• activated in stressful situations (fight or flight response)

• functions well over short-term, bad for immune system long-term

• overactive in people with anxiety

Parasympathetic NS

• returns body to normal resting state

• brings breathing and heart rate back to normal, increases digestion and salivation

• antagonist to sympathetic NS

Fight or Flight Response

emergency response system

• increasing heart rate and breathing

• dilated pupils

• inhibited digestion and salivation

• increased perspiration

How does FF response help prepare body

increased breathing/heart rate —> pump extra oxygen and blood directly to your major muscles

pupils dilate —> sharpens your vision and heightens your awareness

inhibited digestion + salivation —> conserve energy for survival

Homeostasis

our bodies seek a constant state of balance

Afferent (sensory) Neurons

Carry messages to the CNS

Efferent (motor) Neurons

carry messages out from CNS to the muscles and glands

Interneurons

• can intercept messages quickly

• prevents damage

• neurons in the CNS that communicate between sensor and motor neurons

• party of reflex arc in your spinal cord

• ex: when touching something hot, it sends an immediate communication to pull away and save from a burn before the message reaches your brain.

Neuron

• building blocks of nervous system

• ~100billion in the body

Dendrites/dendrite branches

• projections that recieve messages from other neurons and send them to the neuron

• “ears of the neurons”

Soma

• cell body

• made up of nucleus that determines when neuron has reached threshold to fire

• carries out basic metabolic functions of the neuron

Axon

• “tail” of the neuron along which electrical signals are conducted

• signals results from the brief change in electrical charge of the cell at the axon hillock

• signals called action potentials carry messages to other neurons

Axon Terminals (buttons)

• knobs at each end of axon

• houses chemical messengers/neurotransmitters

• during action potentials neurotransmitters are released to synapses

Myelin Sheath

• white fatty substance that wraps most neurons

• insulates axons and increases action potential speed —> faster communication

• myelin develops very time (myelination) —> children don’t have completely myelinated cells

• dysfunction causes multiple sclerosis, an autoimmune disease

  • degrades myelin sheaths and neurons

  • wearing muscles

  • loss of muscle control

Synapse

• microscopic gap between terminal buttons of presynaptic (sending) neurons and postsynaptic (receiving)neurons

• each neuron can have thousands

Glial “Glue” Cells

• Support cells that hold together message sending neurons and support their functions

• Keep neurons in place

• Provide nutrients to message sending neurons

• Helps form and build myelin

• Immune cells in brains

• Cleans up excess potassium

Resting State

• Has resting potential

• Slight negative charge in the cell due to presence of potassium ions

• Outside resting neuron is positive charge due to high concentration of positively charged sodium ions

• Neuron is polarized

• Has impermeable membrane

Firing Threshold

When soma determines threshold reached the resting neuron activates

Depolarization

• Started by cell excitation

• Positively charged Na ions rush into cell, K ions temporarily flow out until cell has positive charge inside

• Causes an action potential in the neuron

Action Potential

• Message/electrical impulse moving down ten axon of a neuron

• Caused by depolarization

All or None response

• A neuron only fires completely or not at all. No middle ground

• Happens at up to 260 mph

Refractory Period

• Period after firing where neuron cannot fire again

• Allows neuron to reset before accepting new messages

• Must push out all Na+ ions so the overall charge is negative again (repolarization)

Neurotransmitters

• Chemicals that allow for communication between neurons

• Housed in vesicles of terminal buttons at the end of axons

• find to specific receptor sites of postsynaptic neuron

• Only specific neurotransmitter is allowed in each synapse

• Some are broken down by enzymes in the synapse

Reuptake

• Neurotransmitters left in synapse return to vessels on presynaptic action terminals in a process called reuptake

• Once polarization and reuptake are done, the refractory period is over

Antagonist

• A drug that blocks activity of natural neurotransmitters

• Similar enough structure to fit receptor sites, but not to work as a national neurotransmitter

Agonist

• Mimic the activity/effect of natural neurotransmitters

• Are similar enough in shape that they fit in receptor sites and can work as a natural neurotransmitter

• EX: antidepressants

Excitatory

stimulating the firing of messages/neural activity

Inhibitory

Restricting the transmission of neural messages/slows neural activity

Acetylcholine

• excitatory

• learning and memory, voluntary muscle action

• low levels associated with alzheimers disease

Norepinephrine

• excitatory

• alertness and arousal, or fight or flight

• low levels correlated with depression (and seretonin)

• increases heart rate, constricts blood vessels (increases bp and flow)

Endorphins

• inhibitory

• blocks pain messages and is linked to pleasure

• “body’s natural painkillers”

• levels increase during stress

• low levels associated with chronic pain (fibromyalgia)

Seretonin

• inhibitory

• linked to mood regulation, appetite, sleep-and-wake cycles

• low levels associated with depression and anxiety

• antidepressants are agonists for seretonin receptors

Dopamine

• Excitatory

• linked to pleasure, muscle control, learning, attention

• high levels associated with schizophrenia —> treated by dopamine agonists

• low levels associated with parkinsons

GABA

• inhibitory

• primary inhibitory neurotransmitter in brain

• low levels involved in seizure activity, anxiety disorders, and insomnia

Glutamate

• excitatory

• primary excitatory neurotransmitter in brain

• high levels associated with seizure disorders

• worsens manic episodes

• plays a role in neurodegenerative disorders of Central nervous system and brain

Substance P

• excitatory

• sends pain messages

• high levels link to chronic pain, inflammation, migraines

Psychoactive/Psychotropic Drugs

chemical substance that acts on the brain to impact behavior, perceptions, moods, or mental processes

Blood-Brain Barrier

• blocks certain material in the blood from entering brain tissues

• drug chamicals must be small enough to pass through the barrier to have an effect

• barrier exists to protect the brain from certain materials

Substance Use Disorders

• caused by addictive nature of drugs

• categorized by constant misuse of the drug

• physical dependence

  • intense cravings/biological need for the drug

  • need to alleviate psychical pain

• Physiological dependence

  • spending all their time thinking about it and wanting to get high

  • uses drugs as a way to cope or relieve mental stress and emotions

Tolerance

• with repeated use people build tolerance to substances

• require more and more each tie to feel the full/original effect

• characteristic of dependence

Substance Abuse

• impacts ability to fulfill responsibilities

• puts in dangerous situations

• legal difficulties

Withdrawl

• distressing or painful side effects when stopping taking a substance suddenly after long term use, ex: teeth chattering

• body may not produce as much of a neurotransmitter after prolonged use, and person does not have enough without supplement of drug

• can take weeks/months for body to return to baseline levels of NT

• characteristic of dependence

Depressants

• reduces neural activity and slows body functions

• Ex: alcohol

  • stimulates GABA activity (GABA agonist)

  • slower physical and mental reaction times

  • disrupts REM

  • impairs judgement and influences risky decision

  • impairs ability of cerebellum to work at full capacity, causing reduction in motor ability and coordination

• EX: barbiturates (tranquilizers), benzodiazepines (anti-anxiety)

Opiates

• suppresses pain

• agonists for endorphins (leading to severe withdrawal symptoms)

• induces state of euphoria and sleep

• delayed cognitive processing and slurred speech

• highly addictive, addiction can happen after one use

• EX: morphine, opium, oxycodone, heroin

Hallucinogens

• EX: LSD, PCP, THC

• alters perceptions and causes hallucinations

LSD

• can lead to panic and paranoia

• disrupts seretonin: LSD molecules are chemically similar to serotonin, so it locks into receptors

• glutamine antagonist

• giving serotonin helps hallucinations

THC

• mild hallucinogen

• impairs motor coordination, perceptual skills, reaction time, memory

• differences in taste and sensory experiences

• stays I bloodstream up to a month

• less likely to build tolerance to it

Stimulants

• activate nervous systems

• increases arousal and surprises apetite

• act like excitatory NTs

• repeated use can cause log lasting structual damage to dopamine neurons

• highly addictive

• EX: caffeine, nicotine, cocaine, amphetamines, MDMA

Caffeine

• adenosine antagonist

• inhbitory

Nicotine

• acetylcholine agonist

• boosts alertness, mental efficiency, arousal, has calming effect

cocaine

• dopamine agonist

• elevated mood and increased energy

• can heighten aggressive reactions

• damages transporters and causes dopamine floods

amphetamines

• elevated mood and increased energy

• have aftereffect of aggression

• increases dopamine an norepinephrine

MDMA

• dopamine and serotonin agonist

Hindbrain

pons, cerebellum, medulla, thalamus, reticular formation

pons

bridge between brain regions

movement, sleep and dreams

Medulla

controls heartbeat, breathing, blood circulation, digestion

reticluar formation/activating system

controls alertness and attanetion to stimuli

affected by alcohol

Thalamus

“Sensory switchboard”

recieves sensory info (except smell), sorts it, and directs it to appropriate sensory receiving areas of brain

Cerebellum

center for balance, coordination, smooth muscle movements

affected by alcohol

where implicit/movement related memories are stored (how to ride a bike/brush teeth)

Midbrain (limbic system)

recieves/integrates types of sensory info

bridge between hind and forebrain

Endocrine system

glands and organs that produce and release hormoenes into blood

slow way of bodily communiaction

pituitary gland

signals other glands/organs to release/produce hormones

oxytocin made here —> happy/love hormone

Hippocampus

creates new memories

transfer of short to long term activities

Amygdala

fear, anger, agression

helps form emotional memories

Hypothalamus

appetite and thirst

sex drive

fight or flight response

Cerebrum

shell of brain

allows for higher level thinking and complex cognitive ability

Cerebral Cortex

outside later of cerebellum, like tree bark

allows for more neural connections that a smooth surface

Frontal lobes

largest lobes

speech production and motor activity

complex thinking and decision making

motor cortex

voluntary movement

motor neurons take messages away from brain and spinal cord

right hemisphere controls left side of body and vice versa

Broca’s Area

in frontal lobe

speech production

Broca’s Aphasia

inability to understand/express speech

Parietal lobes

sensory info about touch, temperature, pain

somatosensory cortex (sensory strip)

evaluates incoming sensory info from skin

more sensitive areas have more touch receptors and take up more space on the cortex

Occipital lobe

rear of forebrain

primary visual-processing center

Primary visual cortex

in occipital lobe

processing of visual info

visual agnosia: difficulty recognizing whole objects, while able to identify distinct parts

Temporal lobes

processes auditory information, helps form and retrieve memories, and enables language comprehension

houses Wernicke’s area and primary auditory cortexes, hippocampus, kinda amygdala

Auditory cortexes

processes info from ears

Wernicke’s area

speech comprehension

Wernicke’s aphasia

can produce speech, but not understanding after damage (propagnosia)

Corpus Callosum

thick C-shaped bundle of neurons that links the two hemispheres of the brain

Split-brain

severed corpus callosum

limits damage of seizures or controls them

Lateralization

each hemisphere has some specific functions

right: visual, spatial, artistic, musical ability

left: mathematical, logistic, analytical, linguistic ability

localization/specificity

belief that certain abilities are only held in one area of the brain

supported by phineas gage case, personality changed after damage

Association Areas

areas with specialized functions

majority of forebrain

Electroencephalograph (EEG)

placing electrodes on skull to identify electrical activity in part s of the brain

provides recording of activity, not brain image

used in sleep studies to identify types of brain waves

diagnoses sleep disorders an seizures

Computerized Axial Tomography (CAT/CT)

identifies issues with brain structure ex: tumors and blood clots

black and white scan

overlaps x-rays on top of one another

Magnetic resonance imaging (MRI)

places person in a tube with strong magnetic forces that take atoms out of rotation

produces detailed image when atoms return to original rotations

Positron Emission Topography

first patients get a non harmful injection of radioactive substance

helps track metabolism of glucose that fuels the brain

glucose flows to parts of brain activated during tasks

computer tracks glucose and makes colorful images