Psych Unit 1- Biological Basis of Behavior & States of Consciousness

Natural Selection

organisms with traits that better enable them to survive and reproduce in their environment are more likely to pass those traits on to future

nature vs nurture

nature: heredity, how passed down physical or mental traits affects a person

nurture: environmental factors and how they affect a person

Eugenics

improving genetic quality of human population by selectively breeding for desirable trait and discouraging reproduction among those with traits considered undesirable 

Epigenetics

focuses on how environment and a person’s behavior affect a person’s genes and how they work

• how a persons’s body reads a DNA sequence

  • can help explain how even twins can be completely different ppl despite having the same genes

evolutionary psychology

study of the evolution of behavior and the mind, using principles such as natural selection. (how are ppl alike/different because of out shared biology and natural history?)

behaviour genetics

study of how environment and genetics affects behaviour

Twin studies

• compare identical twins to one another

  • Monozygotic (identical twins) vs dizygotic (fraternal twins) 

Adoption Studies

• compare twins who have been separated and adopted by different families 

Family studies

• researchers assess hereditary influence by examining blood relatives to see how much they resemble each other on a specific trait 

Neurons (know the parts)

• Dendrite

• Cell body/soma

• Axon

• Myelin Sheath

• Axon terminals/terminal buttons

• synapse/synaptic cleft 

glia cells

• form basis of the nervous system and are building block of all behavior and mental processes

• most abundant cell in nervous system

• do not send any messages or signals in the body

• provide structural support and insulation; 1 to 5 million 

reflex arc

• neural pathway that allows body to respond to stimulus without thinking

• includes sensory, inter, and motor neurons   

• receptor activation, sensory neuron transmission, interneuron transmission, motor neuron transmission, and effector response.

• allows body to respond to a threat before processing what’s going on 

sensory neurons (afferent neurons)

send signals from sensory receptors to CNS

motor neurons (efferent neurons)

send signals from CNS to PNS

interneurons

•  connect sensory neurons to motor neurons in CNS

mirror neurons

• fire both when an individual perform and action or observes the same action being performed (when watching smth ur brain processes it as if you’ve done it too) 

dopamine

neurotransmitter

Functions:

• Movement

• Rewards and addiction

• Pleasurable emotions

Condition related to excess/deficit:

• Oversupply: Linked to schizophrenia

• Undersupply: Leads to tremors and decreased mobility in Parkinson’s disease

serotonin

neurotransmitter

Functions:

• Mood regulation

• Hunger/appetite

• Sleep

Condition related to excess/deficit:

• Undersupply: Linked to depression

• Some antidepressants work by raising serotonin levels

norepinephrine

neurotransmitter

Functions:

• “Fight-or-flight” response: increases heart rate, circulation, and respiration

• Slows down appetite and digestion during fight-or-flight

Condition related to excess/deficit:

• Undersupply: Can depress mood

GABA

neurotransmitter

Functions:

• Inhibits excitation and anxiety (calming effect)

• Primary inhibitory neurotransmitter

Condition related to excess/deficit:

• Undersupply: Linked to seizures, tremors, and insomnia

glutamate

neurotransmitter

Functions:

• Primary excitatory neurotransmitter

• Learning and memory

Condition related to excess/deficit:

• Oversupply: Can overstimulate the brain, producing migraines or seizures

substance p

neurotransmitter

Functions:

• Excitatory neurotransmitter responsible for transmitting pain signals

Condition related to excess/deficit:

• Oversupply: Can lead to chronic pain

acetylcholine

neurotransmitter

Functions:

• Voluntary movement

• Memory

• Learning

Condition related to excess/deficit:

• In Alzheimer’s disease, ACh-producing neurons deteriorat

endorphins

neurotransmitter

Functions:

• Pain relief and feelings of pleasure

• Stress reduction

• “Natural opiates”

Condition related to excess/deficit:

• Oversupply: Can overstimulate the brain, producing migraines or seizures

resting potential

• stable, negative charge when the cell is inactive (polarized)

action potential

• rapid, electrical impulse that travels down a neuron's axon to transmit signals

  • all the same size

• send signal down the axon to other neurons. then, neuron goes through process of depolarization which brings neuron back to resting potential  

absolute refractory period

• minimum time which another impulse can not occur (1-2 milliseconds) 

all-or-nothing principle

• a neuron either fires or it doesn’t 

synapse

small pocket of space between axon terminal of one neuron and dendrite of another neuron

chemical synapse: uses neurotransmitters for slower communication

electrical synapse: for messages that need to be send ASAP

inhibitory neurotransmitters

chemical messengers that reduce the likelihood of a neuron firing an action potential

excitatory neurotransmitters

chemical messengers in the nervous system that increase the likelihood of a neuron firing an action potential

reuptake

the process where a cell reabsorbs excess substance left in the synaptic gap, such as a neurotransmitter

synaptic pruning

unnecessary connection between neurons are eliminated in the brain for efficiency 

neuron firing process

1. action potential send a signal down axon of neuron to the presynaptic terminal

2. channel in axon terminal are opened and neurotransmitters are released into synaptic gap

3. neurotransmitters diffuse through synaptic gap, and bind to receptors in postsynaptic terminal

4. neurotransmitters unbind with receptors, some (neurotransmitters) are destroyed and some go through reuptake process

agonist drugs

increases effectiveness of neurotransmitters by mimicking them

• bind to receptors in synapse that are meant for neurotransmitters, 

antagonist drugs

decrease effectiveness of neurotransmitters

• either blocks neurotransmitters from being released, or connects to receptors and blocks neurotransmitters from binding  

central nervous system

• body’s main processing center

• Brain: receives and processes sensory info, initiates responses, stores memories, generates thoughts and emotions 

• Spinal cord: conducts signals to and from the brain control reflex activities 

peripheral nervous system

includes all nerves outside the brain and spinal cord, acting as the body's communication network between the central nervous system and the rest of the body.

autonomic nervous system

controls involuntary responses. makes sure ur heart’s beating, stomach’s digesting, ur breathing, etc

sympathetic division 

mobilizes body and gets it ready for action. pulls dilate, increases breathing, etc '

• fight or flight

parasympathetic division

relaxes body. slows heart rate, increases digestion, helps focus and saving and storing energy

somatic nervous system

responsible for voluntary muscle movements and sensory perception from the skin and muscles. happens consciouslyand voluntarily

fight-flight response

a physiological reaction that occurs in response to perceived stress or danger.

lesioning

• destroying a piece of the brain

  • Insert electrode into a brain structure and pass a high electrical current which burns tissue

brainstem

connects brain to spinal cord, and helps regulate involuntary body functions (breathing, heart rate, etc) 

• medulla, pons, midbrain

hindbrain: medulla, cerebellum

medulla: Lowest part of the brain stem that controls autonomic movements like breathing, heart rate, blood pressure, sneezing, swallowing.

cerebellum: Part of the hindbrain responsible for coordinating voluntary movements, balance, and posture

midbrain: reticular activating system

Network of neurons in the brainstem that regulates wakefulness and alertness

forebrain: cerebrum, cerebral cortex

cerebrum: largest part of brain, controls voluntary actions, responsible for cognitive functions (thinking, learning, reasoning, memory) 

cerebral cortex: wrinkled outermost layer of the brain. center for higher-level functions (memory, language, consciousness). divided into 4 lobes 

limbic system- thalamus, hypothalamus, hippocampus, amygdala

Thalamus: Located right above brain stem and acts as the brain’s “sensory control center” by relaying sensory information to cerebral cortex

hypothalamus: helps regulate autonomic nervous system (endocrine system) by regulating things like thirst, hunger, temperature

hippocampus: Structure in the limbic system critical crucial for memory formation, spatial navigation, and consolidating short-term memories into long-term ones

amygdala: Located in temporal lobe responsible for processing emotions (especially fear and anger). Helps trigger fight-or-flight mode, forming emotional memories, moderating emotional responses.

occipital lobe- visual cortex

Part of the occipital lobe that analyzes basic visual stimuli like orientation and movement, laying the foundation for higher-level processing of visual information from the eyes, enabling us to perceive shapes, colors, and movements.

parietal lobe- somatosensory cortex

Processes sensory input from the skin, muscles, and joints. This area detects and interprets information on touch, temperature, pain, and pressure, and allows us to perceive the size, shape, and texture of an object via touch.

temporal lobe- auditory cortex

Found within the temporal lobe, it is responsible for processing sounds and interpreting auditory stimuli, allowing us to recognize different pitches, tones, and rhythms

frontal lobe- prefrontal & motor cortex

prefrontal cortex: part of the frontal lobes at the very front of the brain. It's involved with executive functions such as self-control, planning, reasoning & abstract thought.

motor cortex: part of the cerebral cortex involved in planning, control, and execution of voluntary movements.

brain plasticity

the brain's ability to change and adapt its structure and function throughout life. It allows the brain to reorganize itself in response to experiences, learning, and even injuries.

neurogenesis

the process of creating new neurons from neural stem cells, which contributes to brain functions like memory, learning, and mood regulation.

broca’s area

Located in the frontal lobe, it is essential for speech production and language processing, enabling us to formulate and articulate spoken language.

wernicke’s area

Located in the temporal lobe, it is critical for language comprehension, allowing us to understand spoken and written language effectively

aphasia

inability (or impaired ability) to understand or produce speech, as a result of brain disease or damage.

left hemisphere

• Analytics thought, logic, language, science and math 

• Controls right side of the body 

right hemisphere

• Holistic thought, intuition, creativity, nonverbal expressions (body language, facial expression, etc), art and music 

• Controls left side of the body 

corpus callosum

a thick bundle of nerve fibers that connects the left and right hemispheres of the brain, allowing them to communicate and share information.

Roger Sperry & Michael Gazzaniga’s split brain research- Contralateral hemispheric organization

demonstrated contralateral hemispheric organization, where each side of the brain controls the opposite side of the body and has specialized functions. Because the corpus callosum was severed in split-brain patients, the hemispheres could not communicate, revealing how each side processes information independently.

adrenaline

hormone

Functions:

• Activates the sympathetic nervous system

• Involved in the fight-or-flight response

Released from:

• Adrenal glands (located on top of the kidneys)

leptin

hormone

Functions:

• Provides information about the body’s fat stores

• High levels: Signal fullness

• Low levels: Increase feelings of hunger

Released from:

• Adipose tissue (body fat) — proportional to amount of body fat

oxytocin

hormone

Functions:

• Social bonding (“love hormone”)

• Childbirth

Released from:

• Produced by the hypothalamus, then stored and released by the pituitary gland

melatonin

hormone

Functions:

• Regulates the sleep-wake cycle

• Increased levels: Cause drowsiness

Released from:

• Pineal gland (small cone-shaped endocrine organ in the center of the brain)

ghrelin

hormone

Functions:

• “Hunger hormone”

• Increased levels: Increase appetite

Released from:

• Stomach

pituitary gland

“The master gland” responsible for producing hormones that regulate body functions such as growth, metabolism, stress, and reproduction

multiple sclerosis

• Potentially disabling disease of the brain and spinal cord

• Immune system attacks protective (myelin sheath) that covers nerve fibers and causes communication problems between brain and rest of body

• Can cause permanent damage or deterioration of nerve fibers 

• May lose ability to walk independently or ambulate at all

myasthenia gravis

• Causes weakness in voluntary muscles, especially those in eyes, mouth, throat, and limbs, double vision and difficulty speaking and chewing 

critical period

• specific developmental window during which neurons are highly sensitive to environmental stimuli 

Consciousness

• state of awareness of our mental activity and external stimuli

EEG

uses electrodes that are placed on an individual’s scalp. allows researcher to record electrical signals from neurons firing. 

• allows to measure brain frequencies

MRI and fMRI

• Brain imaging- MRI: persons head is surrounded by a magnetic field and the brain is exposed to radio waves, which cause hydrogen atoms in the brain to to release energy

  • fMRI: also measures movement of blood molecules (an index of neural activity)

    • Provides both functional and structural information in the same image

Brain waves: beta, alpha, theta, delta

• Beta 15-30 Hz

  • Awake, normal alert consciousness

• Alpha 9-14 Hz

  • Relaxed, calm, meditation, creative visualization

• Theta 4-8 Hz

  • Deep relaxation, and meditation, problem solving

• Delta 1-3 Hz

  • Deep, dreamless sleep 

Sleep stages with EEG patterns

• Awake (beta waves)

• Drowsy, relaxed (alpha) 

• Stage N1 sleep (theta)

• Stage N2 (sleep spindles)

• Stage N3 (delta)

• REM sleep (fast, random)

Circadian rhythms

• 24 hour biological clock

• Our body temps and awareness changes throughout the day

• Best to take a test or study during circadian peaks

Jet lag

tiredness felt by a person after a long flight across different time zones.

NREM stages 1-3 (your textbook also has a stage 4)

• Stage 1

  • Lasts between 1-5 min and occupies approximately 2-5% of normal night sleep 

  • Easily awaken 

  • Consists mostly of theta waves (high amplitude, low frequency (slow))

  • Brief periods of alpha waves 

  • Hypnagogic sensations can occur (ex: feeling of falling) 

• Stage 2

  • 10-20 minutes

  • Follows stage 1 and is the “baseline” of sleep 

  • Theta waves and sleep spindles

  • Occupies approximately 45-60% of sleep 

• Stage 3 (used to be 3 and 4) 

  • Has delta waves, “slow wave” sleep and may last 15-30 minutes

  • Brain activity slows down dramatically and hight of waves increase dramatically

  • Delta sleep is the “deepest” stage of sleep (not REM) and the most restorative

  • Production of growth hormones 

  • It is delta sleep that a sleep deprived person craves the most 

  • In children, delta sleep can occupy 40% of all sleep time 

• Stage 4 (REM sleep) 

  • REM = rapid eye movement

  • Very active stage of sleep  (paradoxical sleep)

  • Composed 20–25% of nights sleep

  • Vivid dreams can occur

  • Body is essentially paralyzed 

  • Breathing, heart rate, brain waves quicken 

hypnagogic sensations (occur in stage1)

vivid, dream-like experiences that occur during the transition from wakefulness to sleep

REM rebound

tendency for rem sleep to increase following REM sleep deprivation

Insomnia

• Recurring problem of falling or staying asleep even when the opportunity is presented 

• 1 in 5 adults have insomnia 

• Nature → some ppl have it genetically 

• Nurture → stress or drinking caffeine can reduce sleep quality and cause insomnia

• Melatonin works in helping regulate it, you can build up a tolerance to it tho. Sleep specialist can help with long term treatments 

• Symptoms: chronic tiredness, increased depression, hypertensions, arthritic and fibromyalgia pain, obesity

Narcolepsy

• Sleep disorder characterized by uncontrollable sleep attacks. Affected person may lapse directly into REM sleep often at inopportune times 

• 1-2000 adults have it 

• Nature AND nurture- there is a gene that causes it, in most cases sporadic and environmental triggers like infections and stress likely play a key role in activating disease in genetically susceptible individuals

• No cure, but medications such as stimulants and changes to lifestyle can be beneficial

• Attacks are usually less than 5 minutes but they tend to happen at the most vulnerable times

Sleep apnea

when an individual has a hard time falling or staying asleep cuz they struggle with breathing

• prevents REM since they keep waking up 

Somnambulism

• (AKA sleepwalk) 

  • Repeated episodes of complex motor behaviour, such as walking while asleep happens in stage theme 

  • most common during stage 3 sleep 

  • 1-15 in 100 have it 

  • Nature 

  • Can be treated with stress management and a consistent sleep schedule and here are medications if serious 

  • Most cannot recall their trip the next morning 

REM sleep behavior disorder

• person acts out their dreams during REM sleep

• normally body is paralyzed during sleep, but this disorder causes this paralysis to be absent or incomplete 

• may be at risk for self injury 

Hobson & McCarley’s Activation-Synthesis theory of dreams

• Our cerebral cortex is trying to interpret random electrical activity while we sleep 

• That is why dreams sometimes make no senes 

• Biological theory 

Consolidation dream theory (memory consolidation)

• Dreaming is a result of memory consolidation that occurs during sleep 

• Suggests that the brain reactivates memories during sleep, which then influences the content of dreams

restoration theory

we sleep bcuz we get tired from daily activities and we sleep to restore our energy & resources

stimulants

excite and promote neural activity

• gives and individual energy, reduces appetite, causes them to be irritable

• Ex: caffeine, nicotine, cocaine

depressants

• reduce neural activity 

• cause drowsiness, muscle relaxation, lowered breathing, and if abused- death

• Ex: alcohol, sleeping pills

hallucinogens

• cause individual to sense things that are not acc there

• can reduce motivation, and cause extreme panic

• Ex: marijuana, peyote, LSD

opioids

• function as a depressant, but have their own category due to addictive nature 

• panic relief

• Ex: morphine, heroin, oxycotine

Addiction

chronic, relapsing condition characterized by a compulsive need for a substance or behavior, despite harmful consequences.

Tolerance

needing more of smth to produce the same effect 

Physical dependence

a condition where a person's body becomes adapted to a substance, and unpleasant physical withdrawal symptoms occur if the substance is suddenly stopped or its dose is reduced.

Psychological dependence

psychological dependancea behavioral and psychological syndrome characterized by loss of control over drug use and compulsive, continuous use despite damage caused to oneself and others.

Withdrawal

physical and mental symptoms that a person has when they suddenly stop or cut back the use of an addictive substance

sensation

process of detecting information from the environment

• when taking in outside stimulus, you activate sensory neurons which create sensation (sensory transduction)

sensory adaptation

stimulus is continuous and doesn’t change

• Ex: lighting a candle and smelling it initially, but you get used to the smell so you don’t smell it anymore