biopsychology Flashcards
Name the 4 lobes of the brain and their basic functions and their location
Frontal lobe (behind the forehead, front of brain
-functions - problem-solving, intelligence, attention
- contains premotor cortex, motor cortex, prefrontal cortex, Broca’s area (language production)
-Temporal lobe (both sides, by the temples)
Min functions - language, understanding, perception
Left temporal lobe (dominant in most people)- language, learning, memorizing, forming words. Contains Wernicke’s area - language comprehension
Right temporal lobe - processes non-verbal info e.g. facial expressions
Parietal lobe( top of brain)
-Somatosensory info (e,g, touch, pressure, temp
-contains somatosensory cortex. processes sensory info and integrates this into a representational map of the body.
Occipital lobe- (back of brain)
-receive sensory info from eyes’ retinas, which is then encoded into visual data - associated with depth awareness, colour, spatial awareness etc
what do the amygdala, hypothalamus, hippocampus and cerebellum do?
amygdala - processes emotions and fear
hypothalamus - regulates autonomic processes e,g, hunger, thirst, temp
hippocampus - formation of memories
cerebellum - balance + coordination
What are the parts of the nervous system?
central nervous system (CNS) (centre of body) and the peripheral nervous system (PNS)(outer parts)
CNS made of brain and spinal cord
PNS made of autonomic nervous system (unconscious actions e.g. breathing) and the somatic nervous system (awareness and voluntary movements)
autonomic nervous system made of 2 parts:
-sympathetic nervous system (fight or flight response)
-parasympathetic (rest and digest response)
What is a neurone?
cells specialised to carry neural info.
Consist of:
-cell body
-dendrites (branched connections allowing cells to communicate with eachother)
-an axon (where impulse is carried along)
-axon terminal (where impulse terminates)
-myelin sheath (insulating layer allows impulses to travel more rapidly)
What are the 3 types of neurons?
Sensory neuron - carry impulses from receptors to CNS
Relay neuron - within the CNS - lie between sensory and motor neurones
Motor neuron - in the CNS that project their axons outside the CNS and directly/indirectly control muscles. When stimulated the neuron releases neurotransmitters that bind to the receptors on the muscles and trigger a response which leads to muscle movement
Explain synaptic transmission
Once the impulse reaches the end of the neuron it must be passed onto the next neuron.
To do this it must cross a gap between the presynaptic neuron and the postsynaptic neuron
The gap between them is known as the synaptic gap
At the end of axon there is synaptic vesicles. These vesicles contain chemical messengers (neurotransmitters) that assist in the transfer of the action potential.
As the action potential reaches the synaptic vesicles it causes them to release their contents - exocytosis
The neurotransmitters diffuse across the gap and bind to receptors on the surface of the next neuron.
What is the endocrine system made up of?
A network of glands that secrete chemical messengers known as hormones to target areas
The endocrine system, unlike the nervous system, produces a slow response - minutes to hours
What is the pituitary gland?
Located at the base of the brain by the hypothalamus
-secretes hormones to other glands telling them to release hormones
Pituitary gland is controlled by the hypothalamus
high levels of hormones produced in other endocrine glands can stop the hypothalamus + pituitary gland producing more of their own hormones = negative feedback
What is the pineal gland?
Located in the brain
Produces melatonin which affects physiological cycles e.g. sleep
What is the thyroid gland?
Located in the throat
Produces thyroxine - controls rate of metabolism and rate that glucose is used in respiration
What does the pancreas produce?
Insulin - converts excess glucose into glycogen for storage in the liver
Glucagon - converts glycogen back to glucose in liver
What do the ovaries produce?
oestrogen - controls ovulation and secondary sexual characteristics
progesterone - prepares uterus lining for receiving an embryo
What do the testes produce?
testosterone - controls sperm production and secondary sexual characteristics
What are the adrenal glands?
located on top of the kidney
-separated into 2 parts:
-adrenal cortex (outer parts)
-adrenal medulla (inner parts)
Adrenal cortex - produces cortisol - regulates cardiovascular and anti-inflammatory functions.
Cortisol is produced as a response to stress. If cortisol levels are low = low blood pressure, poor immune functioning, inability to cope with stress
Adrenal medulla - releases adrenaline and noradrenaline - prepare the body for flight or fight response
Adrenaline - prepares body for stressful situations - increase HR and blood flow to the muscle + the brain + helps conversion of glycogen to glucose to provide energy
Noradrenaline - constricts blood vessels causing BP to increase
Explain how the endocrine system produces a response
- Signal sent from hypothalamus to pituitary gland telling it to release its hormone
- Pituitary gland secretes a stimulating hormone into the blood stream
- Hormone signals to the target gland to secrete its hormones
- Levels of hormones rise in the blood stream
- Hypothalamus then shuts down the secreting hormone
- Pituitary gland shuts down production of the hormone
- Stabilisation for hormones
Explain the fight or flight response
The fight or flight response is a survival response when we are threatened which allows you to fight off the threat, or flee
- Amygdala associates sensory signals with emotions such as fear/anger and sends a distress signal to hypothalamus
- sympathetic nervous system (SNS) prepares body for rapid action
- hypothalamus responds to continued threat and releases CRH into bloodstream
- Pituitary gland releases ACTH into the blood stream, this goes to its target sites
- Adrenal cortex - releases stress hormones inc cortisol
- Adrenal medulla - releases adrenaline into bloodstream - increased HR and release of blood sugar
- Feedback system - cortisol levels monitored so that CRH and ACTH production is inhibited if cortisol is too high
- parasympathetic nervous system (PNS) dampens down the stress response when threat is passed
Explain the response to sudden (acute) stressors
The sympathetic nervous system is triggered, this prepares the body for fight or flight.
SNS sends messages to the adrenal medulla, which responds by releasing adrenaline into the bloodstream
Adrenaline causes HR increase, BP increase, breathing increase to take in as much oxygen as possible, release of glucose and fats into blood to supply more energy to body parts associated with fight or flight
Parasympathetic nervous system - when threat has passed PNS dampens down the stress response - reduces HR and BP and starts digestion off again
Explain the response to chronic stressors
if the brain continues to perceive something as threatening a second system starts.
As the initial wave of adrenaline subsides the hypothalamus activates the HPA axis:
- Hypothalamus - releases CRH into bloodstream
-Pituitary gland - CRH causes pituitary gland to release ACTH which is transported through the bloodstream to its target sites - the adrenal glands
-Adrenal cortex - ACTH causes adrenal cortex to release stress hormones such as cortisol. Gives body energy + lowers pain sensitivity, other side effects can be negative such as lowered immune response and impaired cognitive function
Evaluate the fight or flight response/ responses to stressors
- Taylor et al (00) suggested females have a different stress response, characterised by tend and befriend rather than fight or flight. Involves them protecting themselves and their young (tend) and from alliances with other women (befriend)
- different response due to evolution as caregivers - fleeing would put their offspring at risk - women release oxytocin, inducing relaxation and reducing fearfulness
-low ecological validity - cannot be generalised to explain all humans.
-furthermore, other researchers found genetic difference in men and women - the SRY gene found on the male Y chromosome promotes aggression, priming males with adrenaline. The absence of this gene in women as well as oxytocin & oestrogen prevents this reaction in women
-Other researchers challenges the view that men only respond to stress with fight or flight. Acute stress can lead to greater cooperation & friendly behaviour in men - could be due to humans being social animals and it is the protective nature that allows us to thrive
What is localisation of function?
The idea that specific functions have specific locations in the brain
Explain where the functions for movement and somatosensory processes are located in the brain and how they work
Motor cortex - voluntary movements.
-located in the FRONTAL LOBE, in the precentral gyrus.
-both hemispheres of the brain have a motor cortex, the left side controls the right side of the body. The regions are controlled next to each other; the actions of the foot are next to the region that controls the leg
Somatosensory cortex - directs the sensory events
-located in the PARIETAL LOBE, in the postcentral gyrus, which processes info relating to touch
-using sensory info from the skin, the cortex produces sensations such as touch, pressure, and temperature and then localises body regions
Explain where the functions for visual and auditory info are located in the brain and how they work
visual cortex - visual centre
-located in the OCCIPITAL LOBE
-visual processing begins in the retina where light enters and signals photoreceptors. Nerve impulses from retina are transferred to the brain via the optic nerve, where most info terminates in the thalamus that passes the info to the visual cortex
auditory cortex - auditory centres
-Located in the TEMPORAL L0BE
-auditory pathway begins in the cochlea where sound impulses which travels to the auditory cortex.
-the brain stem decodes the duration and the intensity of the sound, the thalamus carries out further processing.
Explain where the functions for language processing are located the brain
Broca’s area - production of language
-located in the left frontal hemisphere, the POSTERIOR FRONTAL LOBE
-control of mouth, tongue and vocal cords
Wernicke’s area - comprehension of language
-located in the POSTERIOR LEFT TEMPORAL LOBE
Evaluate the idea of localisation of function
Support for language centres from aphasia studies:
-aphasia=inability to understand/produce speech as a result of brain damage
-Expressive aphasia (Broca’s aphasia) - impaired ability to produce language - normally caused by damage to Broca’s area, this shows how important this area is in the production of language. Provides scientific evidence - high ecological validity
Language production might not just be confined to Broca’s area alone:
-researchers stated MRI findings have suggested other areas apart from Broca’s could contribute to impaired speech abilities.
-suggests language and cognitive centres are much more complex than one specific area
-low ecological validity
What is hemispheric lateralisation?
Refers to the idea that both hemispheres of the brain are unalike.
each hemisphere has specialisations e.g. left is dominant for language and speech whereas right is dominant in visual motor tasks.
we have the chance to explore the hemispheres when patients with severe epilepsy have their corpus callosum cut.
Evaluate the idea of hemispheric lateralisation
Advantages of lateralisation:
-lateralisation is thought to increase neural processing activity.
-by using only 1 hemisphere for a task, this would leave the other side free to perform another function
-however very little evidence shows that lateralisation is advantageous to the brain.
-a researcher found that in chicken’s brain lateralisation help when performing 2 tasks at once
-extrapolation - can’t apply to humans
Lateralisation changes with ageing.
-lateralisation in young people appears to turn to bi-lateralisation in later life.
-a researcher found language was found in the left hemisphere but after 25 yrs it decreased with each decade. It is thought this could be due to compensating for ageing
How was split brain research first conducted?
Sperry & Gazzaniga’s were the first to research split brain patients. To test the capabilities, they were able to send visual info to just one hemisphere (hemispheric lateralisation)
Used fact that images to left visual field is processed in the right hemisphere and had no opportunity to pass to right side as the corpus callosum was cut
-PP’s were shown images to left or right visual field.
-were asked to make responses with either their left hand (right hemisphere), right hand (left hemisphere), or verbally (left hemisphere) without being able to see what their hands were doing
e.g. if patient was shown a picture of a dog to the RIGHT visual field they would see a dog. if they were shown a dog to the LEFT visual field they would say they see nothing.
this is because info in left hemisphere is processed in the right hemisphere which can see the image but has no language capabilities. the left side which has language abilities has not received the message about the dog and therefore cannot say it has seen it.
research suggests that the connectivity between the 2 hemispheres is vital and as important as the different parts
Evaluate split brain research
Language may not be constricted to the left hemisphere:
- suggested that some of the early findings are no longer true.
A patient called JW found the capability to speak from his right hemisphere, he can speak information that is presented to both hemispheres
-low historical validity
Limitations of split brain research:
-split brain research rarely carried out now, so there are not enough patients to create conclusions from
-most studies use 1-3 pps so results are generalised from people who severe disorders
-low ecological validity.
What is brain plasticity?
the brains ability to change and adapt as a result of experience - learning takes place throughout life as we make new neural pathways
the brain also appears to show functional recover - moving functions from a damaged area to an undamaged area
What causes plasticity?
life experience:
-new experiences = new neural pathways develop stronger connections whereas neurons that are rarely used die - causing change to the brain
- researcher found evidence for brain plasticity in 60yr olds who were taught a new skill. this increased the grey matter of their visual cortex, when they stopped practicing the changes reversed
video games:
-researchers compared control group with a video training group
-training group trained 30 mins a day for 3 months on SuperMario.
-found a significant increase in grey matter in cortex(movement), hippocampus(memory), and the cerebellum (balance/coordination)
-results not seen in control group
-suggested the game had produced new synaptic connections in the brain.
-low eco validity, high control -lab study
Meditation:
-researchers worked with Tibetan monks demonstrating meditation can change inner working for the brain.
-a researcher compared 8 monks to 10 volunteers with no meditation experience
-both groups fitted with electrical sensors and asked to meditate.
those used to meditating produced more gamma waves - therefore meditation may causes permanent brain changes.
Evaluate brain plasticity
Research support from animals - extrapolation
-researchers investigated if an enriched environment could alter the number of neurons in the brain
-rats who had a stimulating environment had an increased number of neurons in comparison to rats who were kept in basic conditions
-low ecological validity
Support from human studies;
-researchers studied London taxi drivers to see if their spatial navigation altered their brain. The posterior hippocampus was significantly larger in taxi drivers compared to a control group of participants.
How does the brain recover itself after trauma?
Regeneration of the brain arises from the brain’s plasticity. It changes both its structure and function following trauma in 2 ways:
-Neural unmasking - dormant synapses that exist anatomically can have blocked functions. normally these synapses are ineffective as neural inputs are too low for them to fire.
-if an area nearby is damaged there would be an increased rate of firing - can unmask/open these synapses - opens connections that are not normally active, creating a lateral spread
Stem cells - specialised cells that have the ability to carry out specific functions such as characteristics of a nerve cell
-some researchers believe these cells implant in the brain and replace dead cells
-a second possibility is that they secrete growth factors that rescue injured cells
-also a possibility they can link undamaged areas of the brain together
Evaluate functional brain recovery after trauma
research from animal studies:
- a researcher assigned lab rats with brain trauma to 1 of 2 conditions
-1 group injected w/ stem cells to traumatised area
-2nd group received injection w/ no stem cells to traumatised area
-after 3 months rats injected w/ stem cells began to show neural cells in the damaged area
-extrapolation - increases reliability as study can be repeated
-low ecological validity - cannot be generalised to explain human brain trauma
-control group increases internal validity
-supports trauma recovery mechanisms
Age differences in functional recovery :
-plasticity reduces with age
-trauma to brain after childhood is to develop compensatory strategies for recovery
-some studies show plasticity is maybe possible in adults but is nowhere as successful as it is in childhood
-criticises plasticity as a recovery mechanism
-low ecological validity - if it only happens in children how can we use it to explain brain activity in adults?
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What has been found during post-mortem brain examinations?
When patients are alive they exhibit a particular form of brain damage - when they are dead researchers look for abnormalities that might explain the behaviour
-Broca’s patient Tan displayed speech problems when alive, when dead the patient displayed lesions in Broca’s area - speech production area
HM’s post-mortem highlighted lesions in the hippocampus - an inability to store new memories
reduced number of glial cells in the frontal cortex were associated with depression
Evaluate post-mortem examinations
-allow for detailed anatomical and neurochemical research - allows deeper regions of the brain to be studied such as the hypothalamus and hippocampus
-researchers found post mortem studies have revealed a great deal about Schizophrenia, structural abnormalities and found changes in neurotransmitters
-As people die at different stages of illness this can influence a post mortem’s results
-drug treatments, age, length of time between death and post mortem can all impact on findings
Describe how fMRI (Functional Magnetic Resonance Imagine) scanning works
-Measure changes in brain activity whilst person is performing a task
-measures changes in blood flow, this indicates increased neural activity
-when an area becomes more active - increased demand for oxygen
-brain responds to oxygen demand by increasing blood flow
-researchers produce brain maps, which areas are associated with particular tasks
Evaluate fMRI scanning
-non-invasive and no harmful radiation is used - safe
-reliable for neural activity that cannot be demonstrated verbally
-not a direct measurement, only records blood flow - therefore not truly a quantitative method of activity
-method ignores the networked capabilities of the brain and assumes all tasks are localised to specific areas
Describe how EEG (Electroencephalogram) scanning works
-measures electrical activity of the brain
-electrodes are paced on the scalp detect small electrical charges, these are then converted to graphs
-can detect a range of disorders that influence electrical activity e.g. Alzheimer’s - brain damage can slow down electrical activity
Evaluate EEG scanning as a way of studying the brain
-real time reading of the brain - tasks accurately measured
-useful in clinical diagnosis
-cannot investigate deeper regions of brain - electrodes can be implanted into animal’s brains but this is unethical
-impossible to pin point exact locations of electrical activity - impossible to tell if activity is due to the test being carried out or if its due to actual brain activity
Describe ERPs (Event Related Potentials)
-small voltage changes in the brain that are triggered by cognitive processing or tasks
-can be difficult to pick out amongst all other electrical activity
-to establish a response a target requires many presentations of the stimulus and these responses are averaged together to cancel out other neural activity
ERPs divided into 2 categories:
Sensory ERPs -Waves that occur within the first 100 milliseconds after presentation - reflect an initial response to the physical characteristics of the stimulus
Cognitive ERPs - generated after first 100 milliseconds reflect the manner in which you evaluate the stimulus - demonstrate information processing
Evaluate ERPs as a method of studying the brain
-provides continuous method of processing - can see how processing is affected by manipulation
-ERPs can measure behaviour without needing a behavioural response
-ERPs are so small it is difficult to pick them out from other electrical activity - a number of trials are required to get any meaningful data
-electrical activity within brain is not picked up, similar to EEG only the neocortex is registered.
Describe circadian rhythms
Biological rhythms are changed to the biological systems that evolve due to our environment changing
- Circadian rhythms last around 24 hours due to our body clock lasting that long
Sleep-wake cycle
-dictates when we should sleep/wake up
-rhythm peaks and dips, making us feel awake in the morning and tired later on
-rhythm links to homeostatic control - melatonin produced by pineal gland making us feel tired, then decreases to make us feel alert
Endogenous pacemaker (internal cues)
-circadian pacemaker found in suprachiasmatic nucleus (SCN) in hypothalamus which constantly resets to align with the environment. Light receptor cells in eyes send messages to SCN when it is bright.
Exogenous zeitgebers (external cues)
-Light is the primary input in the rhythm. Darkness causes tiredness and light resets the cycle causing us to wake
Evaluate circadian rhythms
Siffre - case study
- lived underground for 61 days then later in life spent another 6 months underground
-had no external cues such as light and ate and slept when he wanted to
-only influence was his internal body clock (SCN)
-found little change to cycle - stayed around 24 hrs
-shows internal cues are more important than external cues.
-Folkard - 12 pps lived in cave for 3 weeks
-went to bed when clock said 11:45 and woke at 7:45
-over time the clock was sped up resulting in a 22 hour day
-None could adjust to this - clocks still set to 24 hours
- tells us external factors are not stronger than endogenous pacemakers
Describe endogenous pacemakers and exogenous zeitgebers
Endogenous Pacemakers:
- Internal body clocks that regulate many biological rhythms e.g. the influence of the SCN on the sleep-wake cycle
Role of SCN:
-nerve cells in hypothalamus, receive light info through optic nerve, allows body clock to adjust to change in light
Pineal gland and melatonin:
-SCN passes info on day length/light
-Night/ pineal gland increases melatonin production - induces sleep
-Morning - melatonin decreases
-Causal factor of seasonal effective disorder (S.A.D)
Exogenous zeitgebers:
-External cues that affect our biological rhythms, e.g. influence of light on the sleep/wake cycle
-Light:
-can reset body’s SCN
-Campbell + Murphy:
- light detected through skin receptors sites when same info is not received through eyes
-15 pps woke up several times and light was shone on the back of their knees
-Managed to change sleep-wake cycle by 3 hours
Social Cues:
-Babies - random sleep/wake cycle
-circadian rhythms start around 6-16 weeks
-routines set by parents (e.g. routines - bedtime, teatime)
-jetlag can be fixed by adapting to local eating/sleeping times
Evaluate endogenous pacemakers/ exogenous zeitgebers
SCN - Animal studies
- Decoursey:
- destroyed SCN of chipmunks who returned to natural habitat + observed for 80 days
-sleep/wake cycle disappeared
-Ralph:
- bred ‘‘mutant’ hamsters with a 20hr sleep/wake cycle
-SCN cells transferred to normal hamsters, the cycle defaulted to 20 hours
-Numerous circadian rhythms found in different organs that can act independently without SCN - suggests there is other influences on the sleep/wake cycle
-Animal studies - cause harm to animals - extrapolation
Exogenous Zeitgebers:
-Influence may be exaggerated
-Blind person with a circadian rhythm of 24.9 hours
-even with exposure to social cues the cycle could not be adjusted
-Indv living in Artic regions, where the sun does not set in summer, have normal sleep/wake rhythms
-suggests they have little influence on the circadian rhythms
