UNIT 1 PSYCH - Biological Bases Pillar

Evolutionary psych – study how natural selection influences behavior

NERVOUS SYSTEM

CENTRAL NS: Brain and spinal cord

PERIPHERAL NS: Rest of the NS – relays to Central NS

Somatic NS: Voluntary movement, has sensory and motor neurons

Autonomic NS: Involuntary organs (heart, lungs, etc) – contains the:

Sympathetic NS: fight/flight (generally activates – exception digestion)

Parasympathetic NS: rest/digest (generally inhibits - exception digestion)

NEURONS

Dendrites: Receive incoming NTs

Axon: AP travels down this

Myelin Sheath: speeds up AP down axon, protects axon

Synapse: gap w neurons, where APs happen

SENSORY neurons: receive sense signals from environ.–send signal to brain

MOTOR neurons: signals to move – send signals from brain

Interneurons: cells in spinal cord /brain responsible for reflex arc

Reflex arc: important stimuli skips the brain and routes through the spinal cord for immediate reactions (hand on a hot flame)

Glial cells: support cells – give nutrients and clean up around neurons

Neurons Fire w/ an Action Potential: ions move across membrane sends an electrical charge down the axon

Resting potential: neuron maintains a -70mv charge when not doing anything

Depolarization: (+) sodium ions go into cell causing it to be more positive, triggers action potential

Threshold of depolarization: stimulus strength must reach this point to start the AP

Refractory period: time that a neuron must reset before it can fire again

NEUROTRANSMITTERS

• chemicals that are released in synaptic cap, received by neurons

Excitatory: increase action potential

Inhibitory: decrease action potential

GABA: inhibitory, slows down brain activity

Glutamate: excitatory, for normal brain functions

Dopamine: reward and fine movement—in hypothalamus, associated with addiction

Serotonin: moods, emotion, sleep—in amygdala, lack of it is associated w depression

Acetylcholine: Memory and movement—in hippocampus, associated w Alzheimer’s

Norepinephrine: alertness and arousal, sympathetic NS—lack of it is associated w depression

Endorphins: decrease pain

Substance P: pain signals

HORMONES (not in NS)

Oxytocin: love, bonding, childbirth, laxation

Adrenaline: fight or flight

Leptin: makes you full

Ghrelin: makes you hungry

Melatonin: sleepy

Reuptake: unused neurotransmitters taken back up into sending neuron

PSYCHOACTIVE DRUGS

Agonist: drug that mimics neurotransmitter

Antagonist: drug that blocks a neurotransmitter

Depressants: Decrease NS activity, relaxed (alcohol)

Stimulants: increase NS activity, alertness (caffeine, nicotine, amphetamines)

Hallucinogens: hallucinations and altered perceptions (marijuana)

Opioids: relieve pain, increases dopamine levels (endorphin agonists) (heroin)

Tolerance: needing more of a drug to achieve the same effects

Addiction: must have it to avoid withdrawal symptoms

Withdrawal: painful (psychological and physical) symptoms associated with sudden stoppage

BRAIN

Cerebellum: movement, balance, coordination, procedural memory (ability to perform learned skills without conscious effort)

Brainstem/Medulla: vital organs, automatic functions (HR, BP, breathing)

Reticular Activating System: alertness, arousal, sleep, eye movement

Cerebral Cortex: outer portion of brain, higher order thought processes, includes limbic system, lobes, corpus callosum

• Limbic System (think emotions)

  • Amygdala: negative emotions

  • Hippocampus: episodic and semantic memory, creating new memories

  • Hypothalamus: reward center, eating behaviors—like to endocrine system, homeostasis

  • Thalamus: relay center for all senses except smell

  • Pituitary gland: talks w endocrine system and hypothalamus—releases hormones

• Occipital Lobe: vision, in back of brain

• Frontal Lobe: decision making, planning, judgement, movement, personality, language, executive functioning

  • Prefrontal cortex: front of frontal lobe—executive function, decision making, socializing

  • Motor cortex: back of frontal lobe, controls skeletal movements (voluntary body movements)

  • Parietal Lobe: sensations and touch

    • Somatosensory cortex: registers and provides touch sensations

  • Temporal lobe: auditory and face recognition, language

  • Aphasia: damaged speech, comes from damage to left hemisphere

  • Broca’s Area: producing speech

  • Wernicke’s Area: comprehending speech

• Corpus Callosum: connects 2 hemispheres

Split-brain experiments: split the corpus callosum—image shown to right eye is processed in left hemisphere, patient can say what they saw—image shown to left eye processed in right hemisphere, can’t say what was seen

Plasticity: brain changed through damage and experiences

Endocrine System: sends hormones throughout body

• Pituitary gland: controlled by hypothalamus, releases growth hormones

EEG: shows broad brain activity, not specific, electrical output, with electrodes

fMRI: shows brain activity in specific regions, measures oxygen

Lesion: intentional destruction of brain tissue to see effect

DISEASES AND DISORDERS

Multiple Sclerosis: destruction of myelin sheath (pathway in neurons), disrupts action potentials, causes impaired mobility, paralysis, pain

Myasthenia gravis: acetylcholine blocked, disrupts action potentials, causes poor motor control and paralysis

Blindsight: caused by lesions to a primary visual cortex, individuals can still respond to visual stimuli without conscious awareness of seeing them, information from the eye is being processed unconsciously

Prosopagnosia: face blindness, caused by damage to occipital and/or temporal lobe

Broca’s aphasia: broken speech

Wernicke’s aphasia: jumbled speech

Phantom limb pain: pain from an amputated limb, caused by brain plasticity

Epilepsy: seizures, caused by too much/too little glutamate/GABA

Alzheimer’s: memory loss, caused by destruction of acetylcholine

SLEEP

Consciousness: awareness of cognitive processes

Circadian rhythm: biological clock of body

Sleep stages:

• NREM 1: light sleep, hypnagogic sensations (ex. feeling of falling)

• NREM 2: sleep spindles (random bursts of brain activity) and K complexes, light sleep

• NREM 3: deep sleep, delta waves (slow and large)

• REM: dreaming, muscles relaxed but other body systems active, body paralyzed

• REM rebound: after sleep disruptions and/or lack of REM sleep REM becomes more intense

Dream theories:

Activation synthesis: the brain produces random bursts of energy stimulating lodged memories in limbic system and brain stem, brain’s attempt at making sense of random neural activity

Consolidation dream theory: brain is combining and processing memories for storage

Why do we need sleep

Consolidation: storage of memories

Restoration: helps regenerate the immune system and restore energy

Sleep disorders:

Insomnia: inability to fall/stay asleep

Somnambulism: sleep walking, happens during NREM3

Narcolepsy: fall into REM out of nowhere

Sleep apnea: stop breathing while asleep, usually due to obesity

REM behavior disorder: malfunction of mechanism that paralyzes you during REM, physically act out dreams

SENSATION

Transduction: convert stimulus to action potential

Absolute threshold: minimum amount of stimulus to detect sound, 50% of time detected

Just noticeable difference: minimum difference between 2 stimuli required for detection

Weber’s Law: 2 stimuli must differ by a constant minimum proportion, depends on intensity of original stimulus

Sensory Adaptation: diminished sensitivity as a result of constant exposure (ex. getting used to AC blowing), allow us to focus on more important sensations

VISUAL SYSTEM

Lens: focuses light on retina, behind pupil

Retina: light sensitive inner surface of eye, contains receptor rods, cones, neurons, processes visual information

Fovea: area of best vision, cones located there

Rods: black and white, dark adaptation, more rods than cones, along sides of retina

Cones: color, bright light, in fovea

Ganglion cells: creates optic nerve

Blind spot: occurs where optic nerve leaves eye, can’t see there, brain fills in blank

light → retina (rods/cones → bipolar cells → ganglion cells) → fovea → optic nerve → brain

other vocab:

Accomodation: lens changes curvature to focus images on retina

Nearsightedness: better vision near, light focused in front of retina

Farsightedness: better vision far, light focused behind retina

Color vision theories:

Trichromatic: three cones for receiving color, blue-short waves, green-medium waves, red-long waves (ex. when see purple, red and blue cones activated)

Opponent Process: complementary colors are processed in ganglion cells, explains why we see an afterimage

Color deficiency: damage to/missing cones or ganglion cells

• dichromatism: missing 1 cone, trouble distinguishing between two colors

• monochromatism: only have rods, see black and white

AUDITORY SYSTEM

Wavelength: long waves=low pitch, short waves=high pitch

Amplitude: short waves=quiet, tall waves=loud

Theories of hearing (in cochlea):

Place theory: location where hair cells in cochlea bends allow us to perceive pitch

Frequency theory: the rate at which action potentials are sent determines sound

Volley theory: groups of neurons fire action potentials out of sync

Sound localization: which ear gets the waves first tells the location of sound

Conduction deafness: damage to middle ear (bones of ear and eardrums) can cause hearing loss

Sensorineural: damage to cochlea, hairs in cochlea, or nerve—usually due to old age and loud noise

OTHER SENSES

Vestibular: sense of balance, hair cells in ear

Kinesthetic: sense of body position and movement without looking

Pain: gate-control theory—gate that controls how much pain is felt, physical and psychological

Hot: activation of warm and cold receptors

Taste: 6 taste receptors: sweet, salty, bitter, umami, sour, and oleogustus (oily)

• some people have more (supertasters) or less (nontasters)

• connected with smell

Smell (olfaction): only sense that does not route through the thalamus, processed by olfactory bulb in limbic system, pheromones (odor molecules)