unit 1: biological bases of behavior

nature

genetic factors that influence human development and behaviors

nurture

environmental factors that influence human development and behaviors; nurture works on what nature provides

evolutionary psychology

focus mostly on what makes us so much alike as humans

natural selection

charles darwin theory of evolution; the stronger trait will be passed as weaker traits die off

eugenics

discriminatory selective breeding of humans to promote certain traits

heredity

genetic transfer of characteristics from parents to offsprin

genetic predisposition

an increased chance a person will develop a disease based upon their genetics

twin studies; how are identical (monozygotic) twins developed?

they develop from a single fertilized egg that splits

twin studies; how are fraternal (dizygotic) twins developed?

they develop from two separate fertilized eggs

adoption studies

from studies of hundreds of adoptive families that, apart from identical twins, people who grow up together, whether biologically related or not, do not much resemble one another in personality. for example, people who have been adopted are more similar to their biological parents than to their caregiving adoptive parents

nervous system hierarchy

look at image

nervous system

contains interneurons; we have 5 kinds of nervous systems

peripheral nervous system

contains sensory and motor neurons; sensation and vision from the side and makes up the automatic and somatic nervous system

central nervous system (CNS)

our brain and spinal

automatic nervous system (ANS)

“self regulating”; controls self-regulated actions in body; the heart muscles, smooth muscle, and glands

somatic nervous system

motor output; controls our skeletal muscles which are volunteerly

sympathetic nervous system

arousal and expends energy; fight-or-flight

sympathetic response

pupils dilate, heartbeat accelerates, slows digestion, raises blood sugar, secretion epinephrine and norepinephrine (noradrenaline) → sweat increases, bladder relaxes, ready and alert

parasympathetic nervous system

conserving energy as it calms you (think “rest and digest”) The sympathetic and parasympathetic nervous systems work together to keep our bodies in a steady internal state called homeostasis.

what nervous system works together to keep our body in a steady internal state (homeostasis)?

the parasympathetic and sympathetic nervous system

parasympathetic responses

pupils contract, heartbeat slows, stimulates digestion, bladder contracts, allows blood flow

reflex arc

a simple spinal reflex pathway is composed of a single sensory neuron and a single motor neuron; these often communicate through a spinal cord interneuron

sensory neurons

carry messages from the body’s tissues and sensory receptors inward (afferent) to the brain and spinal cord for processing

motor neurons

(which are efferent) carry instructions from the CNS outward to the body’s muscles and glands

interneurons

between the sensory input and motor output, information is processed by our interneurons

neurons

known as nerves; transmit information and are the basic building blocks of the nervous system

multiple sclerosis

inability to control muscle and deteriorates the myelin sheathe; body's immune system mistakenly attacks and damages the myelin sheath (the fatty, insulating layer around axons)

glia(l) cells

supports out nerve cells; glia also plays a role in learning, thinking, and memory

neurotransmitters

chemical messengers that cross the synapse between neurons

action potential

a neural impulse; a brief electrical charge that travels down an axon

all-or-nothing response

a neuron's reaction of either firing or not firing

depolarization

a change in the inside/outside charge difference

refractory period

a brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state

resting potential

the electrical charge difference across a neuron's membrane when it is inactive and not firing an impulse

threshold

the level of stimulation required to trigger a neural impulse

reuptake

a neurotransmitter's reabsorption by the sending neuron

inhibitory neurotransmitter

a chemical messenger that reduces the likelihood of a neuron firing an action potential; (ex) serotonin and GABA —IN SJMPLE WORDS they reduce activity of neurons to prevent neurons to prevent over-excitation, anxiety, and stress; “calm” substance

excitatory neurotransmitter

glutamate; excites neurons

acetycholine (ACh)

enables learning, memory, and muscle action (through motor neurons); can cause alzheimer’s

dopamine

influences movement, learning, attention, and emotion; oversupply can lead to schizophrenia and undersupply can lead to tremors and immobility in parkinson’s disease

serotonin

affects hunger, mood, sleep, and arousal; undersupply leads to depression but drugs that raise serotonin levels are use to treat depression

norepineprine

helps control alertness and arousal; undersupply can depress mood

GABA

a major inhibitory neurotransmitter; undersupply links to seizures, tremors, and insomnia

glutamate

a major excitatory neurotransmitter; involved in memory; oversupply can overstimulate the brain, producing migraines to seizures

endorphins

neurotransmitter that influence the perception of pain or pleasure; oversupply with opioids can supress the body’s natural endorphins supply

substance p

involved in pain perception and immune response; oversupply can lead to chronic pain

myasthenia gravis

muscle cannot contract leading to weakness, paralysis, or difficulty with muscle control due to ACh being blocked

agonist

increase a neurotransmitter’s action; some agonists increase the production or release of neurotransmitters, or block synaptic reuptake. other agonists may be similar enough to a neurotransmitter to bind to its receptor and mimic its excitatory or inhibitory effects such as opiods

antagonist

decrease neurotransmitter’s action by blocking production or release

hormones

the endocrine system’s glands and fat tissue secrete hormones, which travel through the bloodstream and affect other tissues, including the brain

how is adrenaline produced?

ANS orders the adrenal glands on top of the kidneys to release epinephrine (adrenaline) and norepinephrine (noradrenaline)

oxytoxicin

in women, stimulates labor contractions and milk flow while nursing; also aids social support; promoting social bonding, oxytocin strengthens communities and enables them to act cooperatively against threats

psychoactive drugs

chemicals that alter the brain, producing changes in perceptions and moods

the 3 major categories of psychoactive drugs:

1. depressants

2. stimulants

3. hallucinogens

depressants

are drugs that calm neural activity and slow body functions; (ex) alcohol, barbiturates (tranquilizers), and opioids

alcohol

an equal-opportunity drug: it increases (disinhibits) helpful tendencies, as when tipsy restaurant patrons leave extravagant tips and social drinkers bond in groups; the urges you would feel if sober are the ones you will be more likely to act upon when intoxicated

opioids

also depress neural functioning; (ex) heroin

stimulants

excite neural activity and speed up body functions; pupils dilate, heart and breathing rates increase, and blood sugar levels rise, reducing appetite and energy and self-confidence also rise; (ex) caffeine and cocaine

cocaine

powerfully addictive stimulant derived from the coca plant

hallucinogens

distort perceptions and evoke sensory images in the absence of sensory input; (psychedelics, meaning “mind-manifesting”); (ex) marijuana, ecstasy, lsd

marijuana

leaves and flowers contain THC and amplifies sensitivity to colors, sounds, tastes, and smells

tolerance

your brains get used to these chemicals so you need more to get the same effects

addiction

constance use to drugs and body starts relying on it; substance abuse disorder

withdrawal

because your body relies on the drugs, your body will go through changes once off it

(neuro)plasticity

brain is constantly changing, building new pathways as it adjust to little mishap and new experience; greatest in childhood, but persists through life

lesion and its purpose

scientist selectively lesion (destroy) tiny clusters of normal or defective braincells, observing any effect on brain function

EEG

amplified readout of electrical waves

fMRI

reveal the brain’s functioning as well as its structure

brainstem

brains innermost region

medulla

the base of the brainstem; controls the heartbeat and breathing

pons

coordinate movement and sleep

contralateral hemispheric organization

most nerves to and from each side of the brain connect with body’s opposite side

thalamus

brain sensory and control center

reticular activating system

governs the reticular formation which controls arousal (fight-or-flight)

cerebellum

coordinate voluntary movement and enables nonverbal (motor) and all skill (procedure) learning; “little brain”; alcohol affects it

limbic system

associated with emotions, drives, and memory formation; contains amygdala, hypothalamus, hippocampus, and pituitary gland

amygdala

enables aggression and fear

hypothalamus

influence hunger, thirst, body temperature, reward system, and sexual behavior; they help maintain a steady (homeostatic) internal state

hippocampus

process conscience and explicit memories (decrease as we age)

pituary gland

controlled by the hypothalamus; among the hormones released by the pituitary, is a growth hormone that stimulates physical development

what is known as the mastermind of the endocrine system?

pituary gland

cerebral cortex

the body’s ultimate control and information-processing center

the location of lobes

frontal lobe

located at front of brain; enables linguistic processing, muscle movement, high-order thinking, and executive functioning (such as making plans and judgement)

parietal lobe

located at the top and to the rear; receives sensory input for touch and body position

temporal lobe

located above the ears; includes auditory areas and enable language processing

occipital lobe

located at the back of brain; includes areas that receive information from visual fields

hemisphere specialization

somatosensory and motor hemisphere serves differing function; each hemisphere control the opposite of the body

motor cortex

output; right hemisphere control the left side of the body such as voluntary movements

somatosensory cortex

input; left hemisphere control the right side of the body such a as the 5 senses

association area

neurons are busy with higher mental functions

prefrontal cortex

enables judgment, planning, social interactions, and processing of new memories

corpus callosum

wide band of axon fiber connecting the two hemisphere and carrying messages between them

split-brain research: how can we treat severe epilepsy?

by surgically severing the corpus callosum

split-brain research: what is the left hemisphere specialized in?

dominant for language and logic

split-brain research: what is the right hemisphere specialized in?

excels at visual-spatial tasks and facial recognition

consciousness

our subjective awareness of ourselves and our environment; helps us make sense of our life through cognition or mental process

blindsight

people can respond to visual stimuli without consciousness awareness of seeing them after damage to the primary visual cortex

circadian rhythm

our internal 24-hour cycle of day and night; affects us when we pull all-nighters or international travels, etc

NREM stage 1

may experience images resembling hallucinations; hypnagogic sensations occurs