Biopsychology Flashcards
(22 cards)
Outline AO1 for the Nervous System
nervous system is a specialised network of cells that collect, processes and responds to information from the environment and coordinates the working of different organs and cells
The Main Divisions
CNS:
- consists of the brain and spinal cord
- brain is the centre of all conscious awareness, divided into several specialised areas
- spinal cord is an extension of the brain and responsible for reflex actions and for transmitting messages to and from the brain and PNS
PNS:
- transmits messages to and from the CNS to the rest of the body
- divided into:
- somatic NS: controls voluntary movement of skeletal muscles and receives information from sensory receptors
- autonomic NS: controls involuntary bodily functions such as heart rate
- further divided into:
- sympathetic NS: fight or flight
- parasympathetic NS: returns the body to
normal resting state
Outline AO3 for the Nervous System
+ scientific support
structure and function of the NS is based on empirical biological evidence and makes it scientifically credible
+ RWA
understanding of the ANS has led to the development of medical treatments such as beta blockers for anxiety and high blood pressure which work by reducing sympathetic activity
- ignores individual variation
model doesnt account for how individual differences affect how the NS responds to stimuli - focus on physiological mechanisms
doesnt take psychological or environmental influences in shaping behaviours
Outline AO1 for the Endocrine System and the Flight or Fight Response
The Endocrine System
- a network of glands that secrete hormones directly into the bloodstream to regulate bodily functions
- works alongside the NS but acts more slowly and has widespread, long-lasting effects
hormones: chemical messengers
glands: thyroid, adrenal and pitituary
pituitary gland is the master gland because it controls the release of hormones from all other endocrine glands
- divided into anterior and posterior
Fight or Flight Response
biological reaction to acute stress, coordinated by hypothalamus and the ANS espescially the sympathetic branch
1. perception of stressor
2. hypothalamus activates the sympathetic nervous system
3. adrenal medulla in adrenal glans releases adrenaline and noradrenaline into the
bloodstream
4. physiological changes occur such as:
- increased heart rate
- faster breathing
- pupil dilation
- inhibited digestion and saliva
production
5. after the threat has passed, the parasympathetic branch of the ANS restores the body to its resting state which slows the heart rate and resumes digestion
Outline the AO3 for the Endocrine System and Flight or Fight Response
+ scientific evidence
the FoF system is well-documented in humans and animals and is supported by research into the role of adrenaline and the SNS
+ RWA
understanding endocrine system to stress has led to medical treatments e.g. managing stress-related illnesses
- gender bias
fight or flight is primarily based on male animals
Taylor et al shows that females may respond with the “tend and befriend” response (protect offspring and seek social support) which indicates that gender biases are not accounted for - chronic stress
the fight or flight system evolved for acute physical threats, not modern, long term stressors like exams
prolonged activation can be damaging
Outline AO1 for Neurons and Synaptic Transmission
neurons: specialised cells that transmit electrical and chemical signals throughout the NS:
- cell body: contains nucleus housing cells genetic material
- dendrites: branch-like structures that receive messages from other neurons
- axon: conducts electrical impulses away from the cell body
- myelin sheath: a fatty layer that insulates the axon and therefore facilitates faster transmission of impulses
- nodes of ranvier: gaps in myelin sheath that allow the impulse to jump making the transmission faster
- terminal buttons: located at end of axon and release ntm into synaptic gap
Types of Neurons:
1. sensory neurons carry info from sensory receptors to the cns
2. relay neurons connect sensory and motor neurons within the CNS
3. motor neurons transmit signals from the CNS to effectors such as muscles and glands
Synaptic Transmission
- process by which neurons communicate with eachother
1. electrical impulse travels down the axon of presynaptic neuron
2. upon reaching terminal buttons, ntm release is triggered which are stored in synpatic vesicles
3. ntm cross the synaptic cleft and bind to receptor sites on the post synaptic neuron
4. this binding can result in either excitation or inhibition of the post synaptic neuron, depending on ntm
Excitation and Inhibition
- excitatory ntm: increase the likelihood that the post synaptic neuron will fire an action potential
- inhibitory ntm: decrease the likelihood of the post synaptic neuron firing
Outline AO3 for Neurons and Synaptic Transmission
+ clinical applications
understanding synaptic mechanisms has led to the development of pharmacological treatments for neurological and psychiatric disorders such as antidepressants targeting serotonin pathways
+ biological basis of behaviour
this area provides a foundational understanding of how biological processes underpin behaviour, supporting the biological approach in psychology
- determinism
emphasizing biological determinism may overlook the role of free will
Outline AO1 for Localisation of Function in the Brain
- theory that specific areas of the brain are responsible for specific functions
- cerebral cortex is divided into two hemispheres and each control the opposite side of the body
- its split into 4 main lobes: F,P,O,T
- Frontal Lobe
- motor cortex (back of frontal): controls voluntary movement
- Brocas area: (left frontal lobe): speech production - Parietal Lobe
- somatosensory cortex: processes sensory info - Occipital Lobe
- visual cortex: processes visual info from eyes
- each eye sends info to both hemispheres
- each eye has a R or L visual field.
- RVF sends to the left side of the hemispheres
- LVF sends to the right side of the hemisphere - Temporal Lobe
- auditory cortex: processes hearing and sound
- Wernickes area (left hemisphere): language comprehension
Brocas aphasia: damage to Brocas area results in difficulty producing speech
Wernickes area: damage to Wernickes area leads to fluent but meaningless speech
Outline AO3 for Localisation of Function in the Brain
+ RS for Broca
patient Tan could understand language but couldnt produce coherent speech - post mortem found damage to left frontal lobe which is evidence for this area being responsible for speech production
+ RS for Wernickes
found patients who could produce fluent speech that lacked meaning and had damage to the left temporal lobe
+ Brainscan evidence - Peterson
fMRI showed Brocas area active during speech production and Wernickes area is during comprehension tasks
- CE Lashley
removed 10-50% of cortex in rats trained to run maze and found no specific area being more important than another for learning - Brain plasticity - functional compensation
when brain is damaged, other parts take over the function of the damaged part
this undermines localisation by showing brain is flexible and adaptable and not rigidly fixed in function
Outline AO1 for Hemispheric Lateralisation and Split-Brain Research
hemispheric lateralisation refers to the idea that the two halves of the brain are functionally different and certain functions are mainly controlled by one hemisphere
left: language, logic, analytical tasks
right: spatial ability, facial recognition, creativity
- corpus callosum connects the two hemispheres and allows communication between them
Split-Brain Research - Sperry
- investigating the effects of severing the corpus callosum to understand hemispheric lateralisation
Procedure:
- P naturally existed as split brain patients
- visual stimuli presented to either LVF or RVF
- due to no corpus callosum, the info couldnt transfer between the hemispheres
Findings:
- image in LVF / RH: P couldnt say what they saw but could draw / select it with left hand
- image in RVF / LH: P could verbally describe
- this supports the idea that language is localised to the left hemisphere whilst visual-spatial tasks managed by the right
Outline AO3 for Hemispheric Lateralisation and Split-Brain Research
+ strong empirical evidence
controlled lab experiments with standardised procedures and increases internal V
+ RWA
helps neurosurgeons and neuropsychologists understand effects of brain damage and tailor rehabilitation strategies and informs treatment planning for epilepsy and brain injury
- Sperrys sample
all epileptic patients undergoing rare surgeries so results cant be generalised to the wider population with intact brains - artificial tasks lack ecological V
- oversimplification of hemispheric functions
later research shows that both hemispheres work together in most tasks which challenges the view of strict lateralisation as is too reductionist
Outline AO1 for Brain Plasticity and Functional Recovery after trauma
brain plasticity refers to the brains ability to change and adapt as a result of experience and learning
- during infancy, the brain experiences rapid growth in synaptic connections
- in adulthood, number of synapses is reduced (synaptic pruning) but brain retains ability to form new connections in response to learning and environment
Research into plasticity - Maguire et al
- studied London taxi drivers using MRI scans
- found significantly more grey matter in the posterior hippocampus compared to the control group which is responsible for spatial and navigational skills
- longer the term of driving = more pronounced the structural difference which shows experience-dependant plasticity
Functional Receovery
- brains ability to reorganise itself to recover lost functions after experiencing trauma
- axonal sprouting: new nerve endings grow to reconnect neurones
- reformation of blood vessels
- recruitment of homologous areas: similar areas in the opposite hemisphere take over
Outline AO3 for Brain Plasticity and Functional Recovery
+ RS - Maguire et al
real world, non-invasive brain scanning showed structural changes linked to experience
+ practical applications - neurorehabilitation
led to the development of neurorehabilitation therapies e.g. movement, electrical stimulation which helps patients regain functioning
- maladaptive plasticity
not all plasticity changes are beneficial and some can lead to negative outcomes such as phantom limb syndrome where amputees feel sensations in missing limbs due to reorganisation of somatosensory cortex - individual differences
factors like age, education and lifestyle affect recovery - younger brains are more plastic and functional recovery declines with age
Elbert et al found more plasticity in children than adults
Outline AO1 for Ways of Studying the Brain
- fMRI (functional magnetic resonance imaging)
- detects changes in blood oxygenation and flow when a brain area is active
- 3D images produced showing which areas are involved in specific mental processes
- non-invasive, no radiation - EEG (Electroencephalogram)
- measures electrical activity in the brain via electrodes placed on the scalp
- records brainwave patterns associated with arousal states
- useful for diagnosing neurological disorders like epilepsy - ERPs (event-related potentials)
- uses raw EEG data filtered to isolate brain activity in response to a specific stimulus
- provides temporal resolution for cognitive processes - Post-mortem examinations
- analysis of a persons brain after death
- often used when someone displayed abnormal behaviour during life
- can identify brain abnormalities that may relate to disorders
Outline AO3 for Ways of Studying the Brain
- fMRI
+ high spatial resolution which provides detailed localisation of function
+ non-invasive and safe so suitable for repeat in research
- poor temporal resolution - 5s lag between activity and signal
- only measures blood flow and not direct neuronal activity - EEG
+ excellent temporal resolution - 1ms which is useful for diagnosing epilepsy and studying real time brain activity
+ non-invasive and cost-effective
- poor spatial resolution as electrical activity is measured at scalp level so hard to localise the exact source - ERP
+ combines EEGs temporal resolution with the ability to study the specific cognitive processes such as decision-making or memory
+ makes experimental conditions more controlled
- hard to isolate pure ERP signals as data must be filtered extensively and background noise can reduce reliability - Post-mortem
+ vital for early discoveries
+ can examine deep structures which arent accessible by scanning
- retrospective method
no direct observation of brain activity and causality cant be established
- other factors such as age may confound the findings
Outline AO1 for Circadian Rhythms
biological rhythms: regular changes in the body controlled by endogenous pacemakers (internal body clocks) and exogenous zeitgebers (external cues like light)
circadian rhythms:
last around 24 hours and regulate biological processes such as the sleep-wake cycle and core body temperatures
Sleep-Wake Cycle
- controlled by the suprachiasmatic nucleus (SCN) in the hypothalamus - bodys main endogenous pacemaker
- light is the exogenous zeitgeber which is detected by the retina and sent to the SCN which regulates melatonin release by the pineal gland to promote sleep
- even without external cues, circadian rhythms persist which suggests a strong internal mechanism
Siffre
- spent 6 months in a cave with no natural light or clocks
- his natural circadian rhythm settled at around 25 hours but he maintained a regular sleep/wake cycle
- demonstrates the endogenous clock continues in absence of external cues though it may drift slightly
Outline AO3 for Circadian Rhythms
+ practical applications - shift work
knowledge of circadian rhythms has improved the health and productivity for shift workers
e.g. circadian trough - dip in alertness 2-4AM has helped plan safety critical jobs
+ RS for endogenous pacemakers shows that the rhythms persist without external cues
- case study limitations
Siffres study was on one individual so findings lacks generalisability - individual differences in rhythms
Duffy et al found some people have natural early chronotypes while others are night owls, this suggests circadian rhythms are not universal and vary due to genetics or lifestyle
Outline AO1 for Infradian Rhythms
infradian rhythms last longer than 24 hours occurring weekly, monthly or annually
- Menstrual Cycle
- an infradian rhythm that typically occurs every 28 days regulated by hormones such as oestrogen or progestrogen
- oestrogen promotes egg release (ovulation) whilst progesterone prepares the womb lining
- endogenous factors drive the cycle but can be influenced by exogenous zeitgebers like pheromones
McClintock
- studied 29 women with irregular periods, collected their pheromones from 9 women at different stages of their cycle via cotton pads under their armpits
- these pads were then rubbed on the upper lips of other women
- found that 68% of participants cycles became closer to the donors which suggests synchronisation due to exogenous cues (pheromones)
SAD- Seasonal Affective Disorder
- type of depression with a seasonal pattern usually in winter
- possibly triggered by low-light levels which reduce melatonin breakdown which disrupts sleep-wake cycle
- melatonin may inhibit the production of serotonin which is linked to depression symptoms
Outline AO3 for Infradian Rhythms
+ RS for exogenous influences
McClintocks study shows that biological rhythms can be influenced by social/environmental factors which reinforces the idea of interaction between internal and external factors which increases ecological validity
+ practical applications - SAD
understanding SAD has led to development of light therapy which resets melatonin levels and improves mood, this is effective in 60% of sufferers and shows real-world benefits of infradian rhythm research
- methodological issues in McClintock study
had a small sample size, and other confounding variables may have affected the cycle changes - SAD research could be correlational
light levels and melatonin are correlated with SAD symptoms but the causation isnt proven as other factors like genetics may contribute aswell
Outline AO1 for Ultradian Rhythms
occur more than once in 24 hours e.g. sleep cycle
Sleep Cycle
- has 5 distinct stages, identified with EEG recordings
Stage 1&2 - light sleep
person easily woken, brain waves are high frequency, short amplitude, Stage 2 shows sleep spindles - random changes in patterns from alpha waves
Stage 3&4 - deep sleep / slow wave sleep
delta waves with lower frequency and higher amplitude - difficult to wake someone
Stage 5 - REM sleep
body is paralysed but brain activity closely resembles that of the awake brain, Theta waves produced and eyes occasionally move around, dreams most often experienced in REM sleep but also sometimes in deep sleep
The sleep cycle occurs around 4-6 times per night
Outline AO3 for Ultradian Rhythms
+ objective evidence from EEGs
sleep stages identified using EEG which provides empirical and reliable data, the brain wave patterns are consistent across individuals which supports validity of model
+ practical applications
REM sleep has been linked with memory consolidation, understanding the cycle helps in optimising learning and treating sleep disorders
- individual differences in sleep patterns
Tucker et al found large differences in duration of stages, especially slow wave sleep even in controlled lab settings which suggests other factors like age, biology or lifestyle affects the stages - reduces generalisability - artificial research
Rs is mainly based in labs with electrodes which affects natural sleep behaviour, lowering the ecological validity of findings
Outline AO1 for Endogenous Pacemakers and Exogenous Zeitgebers
biological rhythms are governed by a combination of endogenous pacemakers and exogenous zeitgebers
EP - internal body clocks
EZ - external body clocks
Endogenous Pacemakers - SCN
- bundle of nerve cells located in the hypothalamus in the brain
- primary internal body clock and controls circadian rhythms particularly the sleep- wake cycle
- SCN receives info about light directly from the retina, even when our eyes are closed
- SCN sends signals to pineal gland which increases melatonin production at night to induce sleep
DeCoursey et al
- destroyed the SCN in 30 chipmunks and when they returned to the wild, they were killed by predators and this is likely because their sleep-wake cycle was disrupted so they were awake at dangerous times
Ralph et al
- bred ‘mutant’ hamsters with a 20 hour circadian rhythm transplanted SCN cells from these into normal hamsters who then adopted 20 hour cycle
- this shows that the SCN controls circadian rhythms and is inherently programmed
Exogenous Zeitgebers - Light and Social Cues
- light is the most important EZ as it resets SCN and synchronies body clock with environment
- also influences hormone secretion (melatonin) and activity levels
Campbell and Murphy
- demonstrated light can affect the biological clock even when its not received through the eyes
- P had light shone on the back of their knees which caused deviations in their sleep-wake cycles
- suggests that light receptors exist in the skin
Social Cues like meal times, social activities, alarms also act as EZ
Outline AO3 for Endogenous Pacemakers and Exogenous Zeitgebers
+ RS for SCN as a pacemaker
animal studies provide strong casual evidence that the SCN controls circadian rhythms
biological basis is supported by transplant studies which enhances the ecological V
+ RWA - jet lag and shift work
understanding EZ like light helps with strategies for overcoming jet-lag such as exposure to light at the right time
practical applications also for managing sleep disorders and optimising shift patterns
- ethical issues in animal research
DeCoursey study involved harm to animals which raises ethical concerns and findings may not generalise well to human biological systems
-Oversimplification of the role of pacemakers and zeitgebers
research often seperates internal and external factors but in reality they interact so a holistic view may be more appropriate which suggests the reductionist approach lacks external validity
