PSYCHOLOGY - biopsychology

the key assumptions made by biopsychologists

• behaviour and experiences are caused by activity in the nervous system

• the nervous system transmits signals for communication via billions of neurons

what is a neuron

nerve cells in the human nervous system,

80% in the brain

send signals electrically and chemically

used for communication

what are the three types of neurons

sensory

relay

motor

what do these neurons look like

what is the dendrite

branch-like structures that receive the nerve impulses from adjacent neurons.

what is the axon

where the impulses travel along

what is the myelin sheath

protects the axon from external influences - so transmission is not affected.

what are the nodes of ranvier

these speed up the transmission of nerve impulses by forcing them to jump between myelin sheath segments.

what are terminal buttons

send signals to the adjacent cell/neuron

function and structure of motor neuron

• carries messages from the CNS to effectors like muscles or glands

• short dendrites

• long axons

function and structure of relay neuron

• transfers messages from sensory neurons to other relay or motor neurons

• short dendrites

• short axons

function and structure of sensory neuron

• carries messages from the PNS to the brain and spinal chord

• long dendrites

• short axons

what is a knee jerk reaction, as a reflex arc

• stimulus is detected by sense organs in the peripheral nervous system

• this conveys a message along a sensory neuron

• when the message reaches the central nervous system it connects with a relay neuron

• this then transfers the message to a motor neuron

• which triggers a response in the effector muscle, resulting in a quick, involuntary movement.

excitation vs inhibition

excitatory - make neurons more likely to fire

inhibitory - make it less likely that the neuron will fire

what is summation

The process by which multiple signals combine to influence a neuron's likelihood of firing. Summation can be either

spatial, where signals from different neurons are received at the same time

temporal, where signals from the same neuron are received in quick succession.

what are the two different nervous systems

central nervous system (CNS), the brain and spinal cord

peripheral nervous system (PNS), CNS to the rest of the body.

how can the PNS be subdivided

somatic nervous system - controls muscle movement and receives information from sensory receptors

autonomic nervous system - regulates involuntary bodily functions, such as heart rate, digestion, sexual arousal and stress responses.

how can the ANS be divided

into the sympathetic and parasympathetic nervous systems.

what makes up the endocrine system

glands and hormones that regulate various bodily functions such as metabolism, growth, and mood. In addition to the glands, such as the pituitary, thyroid, and adrenal glands, hormones are released into the bloodstream to target organs.

how does the flight or fight reaction occur

1. the stressor is perceived

2. the hypothalamus activates the pituitary gland and triggers activity in the sympathetic branch of the ANS

3. the ANS transfers from the resting state (parasympathetic) to its aroused state (sympathetic)

4. the stress hormone adrenaline is released into the blood stream

5. this stimulates reactions in the body such as an elevated heart rate

this response is immediate and automatic

6. once the threat has passed, the body returns to the parasympathetic state.

what did Broca and Wernicke cause

a paradigm shift from supporting a holistic approach to the mind, to the localisation of function

what is the holistic approach

looking at the body as a whole picture

what is the localisation of function

the idea that specific parts of the brain are responsible for specific functions

what is lateralisation

that body functions are more dominantly controlled by one hemisphere of the brain.

what are the four centres of function in the brain

motor

somatosensory

visual

auditory

what/where is the motor centre

The area of the brain responsible for the planning, control, and execution of voluntary movements.

found at the back of the frontal lobe

what/where is the somatosensory centre

The part of the brain that processes sensory information from the body, such as touch, temperature, and pain.

It is located in the postcentral gyrus of the parietal lobe.

what/where is the visual centre

The region of the brain responsible for processing visual information, including shapes, colours, and motion.

It is primarily located in the occipital lobe.

what/where is the auditory centre

The area of the brain that processes auditory information, including sound frequency and rhythm.

It is mainly located in the temporal lobe.

what/where is the Broca area

The region of the brain responsible for speech production and language processing, crucial for forming coherent sentences.

it is primarily located in the left frontal lobe.

what are the symptoms of Broca’s aphasia

Broca's aphasia is characterized by difficulty in speech production, including halting speech, poor grammar, and trouble forming complete sentences while comprehension remains relatively intact.

what/where is the Wernicke area

The area of the brain involved in understanding and processing spoken and written language.

It is primarily located in the left temporal lobe.

what are the symptoms of Wernicke’s aphasia

Wernicke's aphasia is characterized by fluent but nonsensical speech, lack of meaningful content, and difficulty comprehending language, while speech production is typically preserved.

what are the 4 lobes of each hemisphere

evaluate localisation of function

+ evidence from neurosurgery

+ case study evidence

+ evidence from brain scans -

COUNTERPOINT - karl lashely (1950)

- language localisation questioned 

strengths of localisation of function

P - neurosurgery evidence

E - damage to specific areas of the brain have been linked to mental disorders. Dougherty et al (2002)  found that in 44 OCD patients who underwent cingulotomy, 30% met the criteria for successful response to the procedure.

E - so shows that OCD is linked to the cingulate gyrus, and that separate parts of the brain are used for different functions 

P - brain scan evidence 

E - Petersen et al (1988) used scans to demonstrate how Wernicke’s area was active during a listening task

E - So showing the specific functions and supporting the localisation of function theory. - COUNTERPOINT 

P - case study evidence

E - Phineas Gage (1848) blasting rock for railway, tamping iron used to pack explosives went through his left cheek, passing behind his left eye and exiting from the top of his head - removing a large portion of his temporal lobe. survived, but his personality changed dramatically from calm to quick tempered.

E - this supports localised function as damage/loss of the frontal lobe changed his mood and ability to regulate mood, suggesting that that function is specific to that area.

limitations of localisation of function 

COUNTERPOINT -

P - research

E - Lashley (1950) - removed 10% - 50% of rats cortexes that were learning the way through a maze. No area seemed more useful

E- suggesting a more holistic process

P - language may not be localised

E - Dick and Tremblay (2016) found only 2% of modern researchers think that language is exclusive to Broca’s and Wernicke’s areas. fMRI means that now we can see a holistic representation of brain function when language functions take place. areas such as subcortical regions and the thalamus have been noted.

E - this is a representation of holistic functioning in humans as well, so rejects the idea of purely localised functions in the brain

how are the two hemispheres wired

in a contralateral way - left controls right of the body and vice versa

what connects the two hemispheres

The corpus callosumis a wide band of neural fibers

what are the left brain functions

• reasoning

• number skills

• written language

• spoken language

• scientific skills

• right-hand controls

what are the right brain functions

• insight

• 3D forms

• art awareness

• imagination

• left-hand control

• music awareness

which hemisphere does the LVF send info to

left visual field goes to the RH and vice versa

who pioneered split brain research

Roger Sperry

outline Sperry’s procedure

(1968)

• 11 Ps who had undergone a split brain procedure - had their corpus callosum severed

• focused on a point and stimuli were shown on either side, sending information to each hemisphere separately

outline Sperry’s findings

1. when LVF shown stimuli, RH couldn’t verbalise the information , but with the left hand (controlled by the RH) they could identify associated or matching stimuli.

   also found that Ps would say they didn’t see anything, but sometimes the stimuli would elicit an emotional response

2. when RVF shown stimuli, the LH (where the speech an d language centre is focused) allowed the Ps to verbalise the stimuli they saw.

conclusions from Sperry’s research

• supports hemispheric lateralisation

• LH - speech centre focused

• RH - emotional processes focused

evaluate Sperry’s research

• + research support - Luck et al (1989)

• + high internal validity

• - issues with generalisation

• - ethics

strengths of Sperry’s research

P - research support

E -  luck et al (1989) found that split brain patients perform better in some tasks - as left brain is not watering down the right brain

E - so supports theory that two have separate functions

P - high internal validity

E - as controlled lab setting, and clearly testing what it intended to test

E - so little to confound results

limitations of Sperry’s research

P - generalisation issues

E - the control group used were neurotypical, as all of the split brain patients all have the procedure to cure severe epilepsy this means that the data is difficult to apply to the population as epilepsy is an extraneous variable

E - as it may not represent the general population's brain functionality.

P- ethics

E - trauma from major brain surgery may have influenced their ability to give informed consent, and testing is over many years, so could cause stress or inconvenience.

what is brain plasticity

the brain's ability to reorganize itself by forming new neural connections throughout life.

what is the term for strengthening frequently used connections, and deleting rarely-used connections 

synaptic pruning 

how does brain plasticity change 

more synaptic connections in infancy - peaks at 2-3 with double an adult (15,000)

what studies were done into brain plasticity

Maguire et al (2000)

conducted a study on London taxi drivers, showing larger hippocampi due to spatial navigation experience. she believed that taking the knowledge changed the structure of their brains - and the longer they’d been a taxi driver the more extreme the structural difference

Draganski et al (2006) - imaged students brains 3 months before and after a test. changes were seen in the hippocampus and parietal cortex

what is functional recovery

an example of plasticity

when healthy brain areas take over the functions that the damaged areas were in control of. This can happen very quickly after injury (spontaneous recovery) which eventually slows down and therapies are used to further recovery after a few weeks-months.

what happens to the brain during functional recovery

brain rewires itself by forming new synaptic connections, and secondary neural pathways are activated to take over the damaged function. this happens by three processes

• axonal sprouting - growth of new nerve endings which connect with other undamaged nerve cells - creating new neural pathways

• denervation supersensitivity - when axons the perform similar functions become aroused to a higher level to compensate for the nerves lost- can sometimes lead too pain if aroused too high

• recruitment of homologous areas - areas on the opposite hemisphere of the brain taking over the function of the damaged area, aiding in recovery. - after time this can shift back

evaluate brain plasticity 

P - negative plasticity

E - Medina et al (2007) - brains adaptation to prolonged drug use leads to poorer cognitive functioning in later life, and increases the risk of dementia

E - so can also harm the brain

P - age and plasticity

E - Bezzola et al (2012) - how 40 hours of golf training caused changes in neural representations of movement in Ps aged 40-60 (reduced motor cortex activity - more efficient)

E- so shows that can occur at any age

P - seasonal brain changes

E - animals brains structures shrink during spring and expand in autumn - most experiments on songbirds so not super generalisable

evaluate functional recovery 

P - real world application

E - understanding has contributed to neurorehabilitation. new therapies were developed based on axon growth. e.g constraint-induced movement therapy

P - cognitive reserve

E - Shneider et al (2014) says that the higher a persons cognitive reserve (or level of education) the higher their chance of disability free recovery.

• 40% with DFR had more than 16 years of education

• 10% with DFR had less than 12 years of education

E - so recovery is more likely for people with higher levels of education

what are the techniques for investigating the brain

functional magnetic resonance imaging (fMRI)

electroencephalography (EEG)

event related potential

post-mortem examinations

what is functional magnetic resonance imaging (fMRI)

detects change in the O2 conc. of blood that occur as a result of brain activity.

more active areas require more O2 so blood flow is directed there - called the haemodynamic response 

what is electroencephalography (EEG)

• measures the electrical activity of the brain using electrodes placed on the scalp.

• the scan recording represents the pattern of brainwaves generated by the action of thousands of neurons to give an overall measure of brain activity 

• disorders can be diagnosed by recording unusual arrhythmic patterns (Alzhimers, epilepsy, sleep disorders)

• used for ; sleep studies, determining death, measuring the depth of amnesia=

what does DARE stand for (EEG)

D - detects 

A - amplifies 

R - records 

E - electrical activity 

what is event related potential

(ERP) is a measured brain response that is the direct result of a specific sensory, cognitive, or motor event, typically obtained through EEG. ERPs are used to assess cognitive processes and brain function related to specific tasks.

what are post-mortem examinations

Post-mortem examinations are procedures performed on the deceased to investigate the cause of death or study disease processes and brain structure.

evaluate functional magnetic resonance imaging (fMRI)

P - does not rely on radiation

E - non invasive and risk free if done correctly.

P - high spatial resolution

E - can depict details up to 1mm so localisation can be shown in smaller areas

P - more expensive than others

P - poor temporal resolution

E - has around a 5 second time-lag so actual patterns cannot be recorded in real time

evaluate electroencephalography (EEG)

P - high temporal resolution

E - can detect at resolution of a single millisecond. so useful in conditions diagnosis eg. epilepsy (random bursts of brain activity).

P - generalised data

E - information from thousands of neurons. so cannot pinpoint neural activity exactly. so activity cannot be distinguished from the origin and adjacent locations

evaluate event related potential

P - ERPs are more specific than EEGs.

E - ERPs are are taken from EEG measurements, have excellent temporal resolution (better than fMRI)

E - so is used to measure cognitive functions and deficits

P - lack of standardisation

E - methodology differs between research studies

P - conditions

E - background noise must be removed and extraneous material must be removed - difficult to achieve

evaluate post-mortem examinations

P - provided foundation for research

E - broca and wernicke relied on post mortems before neuroimaging was possible

P - observed damage origin

E - could be due to unrelated trauma or decay

P - ethics

E - consent is difficult as family member would have to - can’t always give informed consent whilst grieving

what are circadian rhythms 

Biological processes that cycle in a 24-hour period, eg, sleep cycle or core body temperature

what are is another name for the bodies internal clock

endogenous pacemakers

what are exogenous zeigebers

external changes that effect biological rhythms, such as light and temperature.

what is an infradian rhythm

A biological rhythm that occurs over a period longer than 24 hours, such as the menstrual cycle or seasonal affective disorder.

what is an ultradian rhythm

A biological rhythm that occurs in less than 24 hours, such as the sleep cycle.

what is meant by a free-running cycle

A biological rhythm that is not influenced by external cues, such as light or temperature, and continues at its natural pace.

outline research studies into exogenous and endogenous studies

1. Siffre (1962) - examined the impact of isolation on circadian rhythms by living in a cave for two months, finding that his biological clock naturally settled to one beyond the 24-hour cycle (roughly 25 hours). But still continued to sleep and wake regularly

2. Aschoff and Wever (1976) - studied participants in a WW2 bunker without natural light, finding that most had circadian rhythms between 24 and 25 hours (bar one - 29 hours) supporting the existence of endogenous clocks.

3. Simon Folkard (1975) - 12 people lived in a dark cave for 3-weeks but went to bed when the clock said 11:45 and woke when it said 7:45. Researches gradually increased the speed of the clock covertly from 24 to 22 hours. only one Ps was able to adapt to the shorter cycle. This shows that exogenous zeitgebers cannot easily override free-running circadian rhythms.

what is the SCN

The suprachiasmatic nucleus (SCN) is a group of cells in the hypothalamus that regulates circadian rhythms by responding to light signals and controlling the release of hormones like melatonin.

evaluate circadian rhythms

• Shift work - COUNTERPOINT - research was correlational

• medical treatment

• individual differences

• shifting the school day

• gender bias

• research not generalisable

limitations of circadian rhythms

P - shift work studies

E - Boivin(1996) found that shift workers have decreased higher risk of cardiovascular disease. E - individual differences, as some people are more adaptable to changes in circadian rhythms than others, leading to varying effects.

strengths of circadian rhythms

outline procedure of Reinberg (1967) study into infradian rhythms

woman who spent 3 months in a cave with a small lamp for light.

outline findings of Reinberg (1967) study into infradian rhythms

her menstrual cycle shortened from 28 days to 25.7 days

So with the lack of light (exogenous zeitgeber) her infradian rhythm changes 

this suggests that external factors have an effect on infradian rhythms 

evaluate Reinberg (1967) study into infradian rhythms

• only one participant 

• menstrual cycle varies naturally 

• research support 

outline procedure of Russell et al (1980) study into infradian rhythms

sweat (pheromones) were taken from one group and applied to the upper lip of a separated second group

outline findings of Russell et al (1980) study into infradian rhythms

the study found that the menstrual cycles of women who were exposed to these pheromones synchronized with the cycles of the donor.

evaluate Russell et al (1980) study into infradian rhythms

• small sample size affected generalizability

• supports the role of pheromones in synchronizing cycles

• questions about ecological validity of laboratory settings

• factors effecting cycle - stress, weight, age, diet

outline Penton-Volk et al (1999)

study into infradian rhythms, where women expressed a preference for feminised faces at the least fertile stages of the cycle, but more masculine faces at fertile points.

so women’s sexual drive/ behaviour is effected by their infradian rhythms

what is SAD

Seasonal Affective Disorder

a depressive disorder triggered by reduced sunlight during winter months.

what are the symptoms of SAD 

• low mood 

• fatigue

• irritability

• social withdrawal

• changes in sleep and appetite

• lack of interest in in life 

what type of circadian rhythm is SAD

SAD is classified as a circannual rhythm (annual cycle)

which hormone contributes to SAD

Melatonin - sleepy hormone, triggered by a lack of light stimuli

this is thought to have a knock-on effect on serotonin levels

what are the four steps 

1. light exposure triggers signal from retina to superchiasmatic nucleus (pacemaker)

2. signal relayed by the pineal gland 

3. pineal gland secretes melatonin

4. too much melatonin may effect serotonin levels  

evaluate SAD 

P -real world application

E - light therapy where a persons body clock is stimulated by artificial light has helped to reduce the SAD symptoms in 80% of Ps - Sanassi (2014)

E - so proves that a lack of light, and melatonin production causes depressive symptoms

COUNTERPOINT 

E - Rohan et al (2009) recorded a relapse rate of 46% the following winter after light therapy, compared to the 23% relapse rate of those who received CBT.

E - so not purely hormone based 

what are the 5 stages of the sleep cycle

what type of rhythm is the sleep cycle

evaluate ultradian rhythms

what is the SCN

outline research into SCN in animals

what is the pineal gland

what is melatonin

evaluate endogenous pacemakers

what are exogenous zeitgebers