Unit 1B Biological Basis of Behaviour

Consciousness

Def: State of being aware of our self, thoughts, and environment

• has various levels of awareness

• Wakefulness and sleep are two types of consciousness

  • Awake: highly aware

  • Asleep: still conscious but lower level of awareness

Sleep

Def: Natural, periodic, recurring state where consciousness is altered

• Natural loss of consciousness

• undergoes restorative process

even in sleep, brain is active and still has awareness

Circadian Rhythm

Def: Regulates sleep-wake cycle over a 24 hours period

• bodies internal clock

• regulates sleep, wakefulness, and other bodily functions

  • functions such as: hormone release, alertness, and body temp

Altered States of Consciousness

Def: Person’s normal state of awareness is modified

• Any conditions that differ from normal waking state

• Affects awareness and perception

NREM Sleep Stage 1

Def: Lightest stage of sleep, can be awoken easily

• occurs when you first fall asleep

• alpha waves and hypnagogic sensations (aka hypnic jerk, sensations you imagine that are real)

• Lasts 5-10 minutes

Characterized by:

• slowed breathing

• decreased HR

• Mind starts to slow

NREM Sleep Stage 2

Def: Deeper relaxations, largest portion of sleep

• theta waves are present

• lasts 10-20 minutes per cycle

characterized by:

• sleep spindles = bursts of neural activity

• decrease in HR and body temperature

• more synchronized brain activity

roles:

• memory consolidation and blocks external distractions

NREM Sleep Stage 3

Def: Deepest stage of NREM sleep

• slow delta waves

• lasts approximately 30 minutes

characterized by:

• sleep walk/talking

• body repairs tissue, bone, and muscles

• strengthens immune system

role:

• hardest stage to wake

• more restorative part of sleep

  • crucial for physical restoration

REM Sleep (Rapid Eye Movement)

Def: Stage of sleep where dreams occur, the last stage

• aka paradoxical sleep

• Brain is active but body is relaxed

characterized:

• increased brain activity but body is immobilized

• rapid eye movement

• associated with VIVID dream

Role:

• emotion regulation, memory consolidation, and cognitive function

Types of Brain Waves
(used with EEG to visualize the brain waves and patterns)

ALPHA WAVES

• prior to NREM Stage 1

• Brain waves of relaxed, awake state

• Moderate frequency and amplitude

BETA WAVES

• stressful situations, not in sleep

• used in active thinking, problem solving, etc.

• Fastest = high frequency, low amplitude

THETA WAVES

• transition from stage 1 to 2 of NREM

• light sleep or deep relaxation

• lower frequency, higher amplitude

DELTA WAVES

• stage 3 NREM to deep sleep

• lowest frequency, highest amplitude

REM Rebound

Def: Phenomenon when brain is deprived of REM sleep, it will compensate by increasing amount of REM sleep in subsequent nights

• enters REM more quickly and spends more time in the next sleep cycle

• natural respond to sleep deprivation

• suggests that REM serves essential function = brain prioritizes.

Activation Synthesis Theory

Def: dreams are the brains attempt to make sense of random neural activity

• that dreams don’t necessarily have deep meanings, but result from brain trying to make sense of activity by creating dreams

Consolidation Theory

Def: Dreams help process and consolidate memories and strengthen neural connections formed during the day

• especially during REM Sleep

• organized connections between neurons related to recent experiences

• Focus on role of sleep in memory consolidation and learning

Ex: study ap psych notes and during dream, brain organizes the info = helps with recall the next day

Insomnia

Def: Characterized by persistent difficulty falling asleep or staying awake

• leads to fatigue and impaired functioning during the day

• caused by stress and poor sleeping habits

Narcolepsy

Def: chronic neurological disorder that affects brain’s ability to regulate sleep-wake cycles

• causes “sleep attacks” - sudden uncontrollable, episodes of sleep

• disrupts normal REM Sleep cycles

• linked to deficiency in neurotransmitter hypocretin which regulates wakefulness

symptoms:

• muscle weakness, hallucinations, sleep paralysis.

REM Sleep Behaviour disorder

Def: leads to individuals to act out their dream

• due to lack of muscle paralysis during REM sleep

example: smo dreams about fighting in sleep and then actually starts fighting the air lol

Sleep apnea

Def: characterized by repeated interuptions in breathing during sleep

• breathing repeatedly stops and starts

• most common is where airway is blocked

causes:

• high blood pressure, disease, heart failure, and more

Somnambulism

Def: person performs complex behaviours while in deep NREM sleep (stage 3)

• sleep walk or talking

different from REM Sleep behaviour:

• RBD involves dream enactment behavior. The difference between sleepwalking and RBD is subtle, but important: sleepwalking typically takes place in non-REM and transitional stages of sleep, whereas RBD takes place during REM (rapid-eye-movement) sleep.

sensation

def: process which sensory receptors detect physical stimuli from environment and send info to brain for processing

• raw data collected by sensory organs before brain interprets it

Absolute threshold

def: minimum level of stimulus intensity needed for person to detect stimulus 50% of the time

• for you to experience sensation, need to hit this threshold

• aka the second it goes from nothing to something

example:

• hearing → can hear watch ticking 20ft away

Sensory adaptation

Def: reduced sensitivity to stimulus after prolonged exposure to it

• decreased sensitivity to it over time

• allows brain to focus on changed in environment rather than constant stimulus

example: you stop paying attention to feeling of clothing

Just-noticable difference (or difference threshold)

Def: the smallest change between two stimuli that cause people to notice change

• just noticeable difference in smallest change in stimuli

• greater the intensity = LARGER change needed to detect it

example:

• weight of 100 grams → may notice 5g increase

• weight of 1kg → 5g change might not be noticeable

difference between absolute threshold and just noticeable difference (sound example)

The absolute threshold for sound, for example, would be the lowest volume level that a person could detect. The just noticeable difference would be the smallest change in volume that a person could sense

Weber’s Law

Def: degree to which stimuli must be different for the difference to be noticed

• the JND is constant proportion to original stimulus intensity, rather than fixed amount

• related to the JND = calculates for the amount

example:

if notice 1lb increase to 10lb weight, law predicts for 20lb you need 2lb increase to notice difference

sensory interaction

def: principle that one sense can influence another

• brain combines input from multiple sensory things to create cohesiveness

example:

• how smell can affect taste - stinky tofu

Synesthesia

Def: rare condition which stimulation of one sensory pathway involuntarily triggers another

• leads to blended or “crossed” sensory experiences

example:

• see colour when listening to music

• taste words

Priming

Def: psychological phenomenon which exposure to a stimulus influences person subsequent behavior/perception unconsciously

example:

• primed with yellow = more likely to recall yellow objects

Transduction

Def: process which sensory organs convert physical stimuli into neural signals that brain can interpret

• allows body to translate environmental stimuli into language brain can understand

example:

• retina in eye convert light waves into electrical signals that are sent to the brain

• hair in ears transform sounds waves to percieve sound

parts of the eye

Photoreceptors

Def: Specialized cells in retina that respond to light and convert it into electrical signals for the brain to process

• There’s two types: Rods and Cones

• Travels through optic nerve into the brain to become picture of the world

Rods vs Cones

Rods:

• Best in DIM Light = night vision

• Detects light but not colour

• located in periphery of the retina

• ex: see in dark

Cones:

• Best in BRIGHT light = enables colour vision

• detects colour

• concetrated in center of retina (fovea)

• ex: distinguish colours of rainbow

Accomodation

Def: process which eye’s lens changes to focus on objects at different distances

• when altered leads to far/near sight

example:

• book close = lens thicken to focus on near

• book far = lens flatten to bring image to focus

Near vs Farsighted

Near:

• see things clear up close

Far:

• see things clear from far

Trichromatic Theory

def: proposes that retina contains 3 types of cones sensitive to different wavelengths

• combines to produce perception of any colour

• photoreceptors work in teams of three (red, green, and blue)

• able to see colour because combo of three colours

example:

• see purple = red and blue stimulated to create perception

Opponent-Process Theory

def: colour perception controlled by opposing pairs of colours

• when colour in pair is stimulated, other is inhibited

• Explains pheomenon like “afterimage”

  • stare at red image then look at white = might see green afterimage cuz red-green system in fatigued - rebounds with opposing colour

Colour vision deficiencies

def: involves damage or irregularities to one or more cones or ganglion cells (type of neuron that reciepes visual info from receptors)

• when cones in retina don’t function properly

• leads to difficulties distringuishing between colours

• includes dichromatism and monochromatism

  • leads to colour blindness

Prospagnosia

deg: results from occipital and temporal lobes = lose ability to recognize faces

• aka “face blindness”

• neurological disorder

• person can recognize frience by voice, hairstyle instead of face

  • inability to recognize faces even tho other visual processing is still there

Blindsight

def: ability to people who are blind to respond to visual stimuli without percieving them consciously

• due to damage to primary cisual cortex in occipital lobe

example: person with blindsigh might avoid obstacle in path even though they did not see it

Sound

def: occurs throuhg movement of air molecules at different wave legnths and amplitudes

• pitch and loudness

• sound waves vary in wavelengths and amplitude

  • sound is perception of vibrations throuhg a medium

Wavelenght (aka pitch)

def: distance between consecutive peaks of a sound wave

• inversely related to frequancy, which determines pitch

  • shorter length=high frequency=high pitch

• frequency is number of waves that pass given point per second

Amplitude (aka loundess)

def: height of sound wave

• determines loundenss/intesnsity

• measured in decibels

• larger amplitude = louder sound

Sound localization

def: ability to identify the location of sounds in 3d space

• process where brain determines origin of sounds, allowing us to identify direction and distance of sounds

example: car on right honks = more intense sound on right/sooner

Place theory

def: theory stating that different frequency stimulate specific places along the basilar membrane in the cochlea

the idea:

• high frequency = stimulates base of cochlea

• lower frequency = stimulates apex of cochlea

best for explaining HIGHER pitch sounds

Frequency theory

def: theory that frequency of a sound wave is matched by firing rate of auditory nerve

• entire basilar membrane vibrates in unison

example: sound wave at 300Hz causes auditory nerve to fire 300 times per second

• best for explaing LOWER pitch sounds

• struggles to explain high frequency cuz nerons max firing rate is 1000Hz

Volley Theory (extensions of frequency theory)

def: suggests that groups of neurons work together to encode frequency of sound wave

• group of neurons fire in staggered manner, allowing them to collectively match frequency of higher pitch sounds

example:

• 4000hz cant be processed by single neuron fire = multiple neuron fire alternatively to represent frequency

sensorineural deafness

def: hearing loss caused by damage to inner ear or auditory nerve

• decline in clarity of loundess and range of sounds

symptoms:

• difficulties hearing high pitched sounds

• trouble understanding speech in noisy places

causes:

• exposure to loud noise over time

Conduction deafness

def: caused by problems in outer/middle ear, preventing sound waves from reaching inner ear

• prevents sound from travelling efficiently to inner ear

symptoms:

• muffled hearing

• sounds seem quieter than they are

causes:

• earwax :P

Olfactory system

def: sensory system responsible for SMELL

• works by detecting chemical molecules in air and converting them into neural signals

  • process called transduction

• smell bypasses thalumus and go directly to limbic system

  • why certain smells trigger emotional memories

Pheromones

def: chemical signals released that can influence behaviour

• chemical messages for the olfactory system

Gustation

def: sense of taste, which detects chemical compounds in food/drinks

• through taste receptors on the tongue

Taste buds

def: tiny sensory organs located on tongue that contains taste receptors

• sends signals to brain when they detect certain chemicals in food

Types of tastes (primary taste categories)

1. Sweet

2. Sour

3. Salty

4. Bitter

5. Umami

6. Oleogustus

Taste receptors

Def: special cells in taste buds that detect chemicals from food and send signals to the brain

• detects chemical dissolved in saliva

• sends signals to brain via the gustatory pathway

Types of tasters

1. Supertasters

   1. people with more taste buds

2. Medium Tasters

   1. average number of taste buds

3. Nontasters

   1. people with fewer taste buds

   2. especially to bitter flavours

INteraction and coordination of chemical senses

def: refers to the way our sense of smell (olfaction) and taste (gustation) work togtehr to create combined perception of flavour

• taste = combo of taste and smell

• why food taste bland when you can’t smell well

Skin receptors

def: sensory receptors in skin that detects specific types of stimuli

• ex: touch, pressure, temp, and pain

Types of skin receptors

1. Mechanoreceptors

   • detects pressure, texture, and vibrations

2. Thermoreceptors

   • detects changes in temperature

3. Nociceptors

   • detects pain

   • caused by potential/actual tissue damage

structures that process touch

1. somarosensory cortex

   • in parietal lobe of brain = processes touch sensations

   • processes sensory input & maps where it is

2. Thalamus

   • brains sensory relay station that sends touch info from body to somatosensory cortex

Processes and complexities of pain

def: pain is body’s way of signaling potential/actual injury

• processed through physical and emotional pathways

1. Nociceptors (in the skin)

   • detects tissue damage/harmful stimuli → send signal to brain

2. Thalamus

   • relays those signals to somatosensory system and limbic system

Gate control theory

def: explains how pain signals are modulated in spinal coord before reaching brain

• spinal coord has neurological gate the blocks/allows pain signals

• large fibers carrying non-painful stimuli can close gate by inhibiting smaller nerves that contain pain signals

example:

rubbing some spot can reduce pain because non-painful touch signals “close” the gate to the pain signals

Phantom limb sensation

def: perception of sensations in a limb that has been amputed

• brain’s sensory map (in somatosensory cortex) still include missing limb

• brain can misfire and produce sensation

Vestibular sense

def: sense of balance and spatial orientation, allows for posture and coordination movement

• lcoated in inner ear - semicicular canals

• detects changes in position of head and body in relation to gravity

example:

when you spin in circles and stop, vesticular sense causes dizziness as floud in semicircular canals keep moving

Semicircular canals

def: three fluid filled tubes in the inner ear that detects rotational movement of the head

• located in the inner ear

• each canal is oriented in a differnt plane

• detects different type of head movement

vertigo

def: sensation of spinning or dizziness caused by issues in the vestibular syste

• occurs when brain recieves conflicting signals from vestibular system and other senses

• feels like your surrounding are spinning even when you’re standing still

Kinesthetic sense

def: sense of body position and movement, allowing use to be aware of our limbs wihout looking at them

• able to touch nose with eyes closed - relies on this sense