Flashcards in Biopsychology Deck (56):
What is localisation of functioning
What did people believe before this
Refers to the theory that different parts of the brain are responsible for different behaviours or processes.
-prior to this scientist believed that all parts of he brain was involved in the processing of thoughts and action I.e- the holistic theory of the brain
Where did the early research into localisation of the brain come from
How is local of functioning divided
Dr halows research on phineas Gage, he was proved to be correct through macmillians 2002 research.
The cerebral cortex (outer layer of the brain) (3 mm thick) and is subdivided into 4 lobes each associated with different functions.
What is the motor cortex - where is it located
Located in the back of the frontal lobe and controls voluntary movement. Sends messages to the muscles via the brain stem and spinal cord. It is important for complex movement. Both hemispheres have a motor cortex
What areas of the brain are involved in movement
Spinal cord and brain- coordinate movement
Premotor cortex - plans a movement prior to executing it
Prefrontal- stores sensory information prior to a movement and works out the probable outcome of the movement
What is the somatosensory
Located at the front of the parietal lobes, it is separated from the motor cortex by a valley Called the central sulcus.
Somatosensory refers to sensory information from the skin- perceives touch, pressure, pain and temperate.
The amount of neurones needed is dictated by the amount of somatosensory cortex needed for that area of the body.
Touch sensitive areas such as the the face need more somatosensory cortex.
Each hemisphere has a somatosensory with each side of the brain receiving information from the opposite side of the body
What is the visual centre of the brain
Where is this located
How is visual information sent and what does this mean could happen
What happens when light enters the eye
Primary visual cortex
- occipital lobe (back of the brain) - main visual centre
- from the right visual field to the left visual cortex vice versa, so damage to the left hemisphere can produce blindness in the right visual field of both eyes.
-activates the photoreceptors in the retina, nerve impulses are sent via the optic nerve . Most of the impulses are sent to the thalamus which acts as a rely station passing the Information to the visual cortex
What area of the brain is necessary for visual perception
What happens if this area is damaged
Where is the visual image transmitted
- completely blind even In there dreams.
- transmitted along 2 pathways, one containing the components of the visual field and other being involved with the location within he visual field.
What research supports evidence into a damaged v1 (un conscious vision )
Bridgeman and staggs 1982
Occasionally individual with damage to the area V1 will show a blindside - this is a condition we're someone appears qualitatively blind- they report no revision but they can locate objects in the visual field by pointing to them. Suggesting that some of the processing in the visual cortex is not conscious.
Overgaard- 31 year old known as GR. in tests asking to detect a letter shown on a screen she could not identify the letter but did report awareness of something despite seeing nothing (haemorrhage in the left occipital lobe)
How many primary auditory centre does the brain have
How does it receive information
What happens if it is damaged
What did Meyer et al find out about the primary cortex
2 - one in each hemisphere housed in the temporal lobes.
- receives info through both ears via 2 pathways that transmit info about sound and where it's located, information from the right ear goes to the left hemisphere but some is transmitted to the left primary auditory centre too. Vice vesa.
-if damaged you do not go completely death- sound can be heard but some complex processing such as music can't be heard.
-found that it's not just conscious sound. If someone is watching a silent film their primary auditory cortex will active for instance if a door shuts the Bang will be imagined
What are the two language centres in the brain and where are they located
What happens to patients who have damage to brocas and wernicke's area ( give examples )
Broca's and wernicke's area
Located in the left hemisphere
Broca's- in the left frontal lobe.
Broca's - called Broca's aphasia (not all words are effected equally ) nouns and verbs are often u affected. But some classes of words such as prepositions and conjunctions cannot be spoken. Can't read out lout "to be or not to be" but can say "two bee oar knot tow bee" also there speech is slow and lacks in fluency.
Tan- understood spoken language but unable to express his thoughts through writing. Broca stidied tan and other patients and found patients with the same damage in the right hemisphere wasn't affected in the same way - identified a language centre in the frontal lobe in the left hemisphere.
Wernicke's area - those with damage in the left temporal lobe close to the auditory cortex had specific language impairment. - the inability to comprehend language and anomia (struggle to find words they need ) but they do have fluent speech. Access words quickly but what they said was meaningless. People with wernicke's area will often produce nonsense words.
What did fedorenko et al further discover in Broca's area
What is wernicke's area important in
Two regions, one involving language and the other responding to demanding cognitive tasks e.g.- maths problems.
- understanding language and accessing words.
How can the localisation be supported
-Peterson et al-
Brain scan to demonstrate that Broca's area was active during a reading task and wernicke's during a listening task. Suggesting different functions.
-Tulving- semantic and episodic memories reside in different parts of the prefrontal cortex
- neurosurgical evidence suggest that symptoms associated with mental disorders are localised. Dougherty et al 2002 - 44 OCD patients who had undergone cingulotomy after 32 weeks after the surgery 1/3 had met the criteria for success response to surgery and 14% had partial response.
What oils challenge the localisation
-Lashley- rats brains did not find a specific area associated with memory, it appeared to be stored all over the brain. He removed the cortex in rats that was learning a maze. No areas were seen as more important when trying to learn the maze. Suggesting that the learning is too complex to be localised.
Can this be generalised though?
- the fact that's there rehabilitation following brain injury suggests that there in no localisation. If there were task specific areas then there would be no brain plasticity. The law of equipotentability suggests that in fact areas of the cortex can take over the responsibility for specific functions following damage to the area normally responsible.
- Danelli et al -EB had his left hemisphere removed during surgery at 2.5 years old loosing his linguistic abilities- after a rehabilitation programme he began to improve around the age of 5 and by 8 he had regained most of his ability. This would seem like there's no localisation/ lateralisation of functioning. However EB never fully recovered as at the age of 17 he had minor grammatical problems and was slow at naming objects and pictures - this suggests there is some localisation with certain areas of the brain.
How are the two hemisphere in the brain bridged
Define lateralisation and contralateral
By the corpus callosum - a bundle of fibres is effectively a communication pathway so the two hemispheres can exchange information.
- lateralisation: two hens are functioning different with certain mental process mainly controlled by one hem rather than the other
- contralateral: when the right hem deals with the left hand side of the body and vice Versa.
What is the division of functions between the two hemispheres known as
What did toda and Morois find ?
What suggest that the right hemisphere is associated with spatial awareness
- through brain images he found greater activity in the left hemisphere for a visual task and greater activity In the right hemisphere for a spatial task ( working memory model)
- Clarke et al: woman with damage to right hem- she would often get lost if she was not given verbal directions even in familiar places - right hen deals with spatial info.
Along side spatial awareness what else is the right hem associated with
What may suggest that the left hem focus on the detail and the right process overall patterns ?
Recognising emotions.work has soon that if a image is presented that has been split with a happy and a sad face, the emotion of the left side of the picture is more likely to be the most recognised emotions, ( heller and levy)
- if somebody asks you to identify the small detail there will be greater level of activity in the left hem however if someone asks you to look at a image holistically this prompts more activity in the right hem.
What was the aim, procedure and results of sperrys split brain research
Aim: the effects of hemisphere disconnection and show that each hemisphere has different functions
Method : 11 split brain patients( all undergone disconnection of the cerebral hemispheres ) all suffered a history of epilepsy which couldn't be controlled through media. Quasi experiment - IV- a person with hemisphere disconnection or not. DV- how participants performed on tasks. Lab conditions and lab equipment - highly standardised.
Results : when presented with a image to the left visual field they could not respond to the same of the stimulus ( information can't pass to the left where language Is processed)
- participants couldn't give a description of an image presented to the left visual field but could draw it with there left hand.
How can sperrys research be evaluated
-quasi + case study - combine qualitative and quantitive data - statistically reliable info.
- Localisation of functioning
- 11 ps - small sample however there is not many split brain patients ( ore depth)
- ingenious tasks - highly standardised procedures
- the extent to which the split brains were indicative of normal functioning prior to surgery is an issue, especially as the surgery was to treat a problem with the brain
What does diamond say in addition to sperrys's research
The person feels like 2 people in once body. The left hemisphere takes control of situations and suppresses interference from the right hemisphere by Using smaller pathways that connect the hemisphere
What is synaptic pruning
What can be formed as a result of learning and new experiences
Rarely used connections are deleted and frequently used connections are strengthened
- neural connections can change or new neural connections can be formed.
What is the research into plasticity
Kempermann et at - found evidence of an increased number of neurones in the brain of rats housed in complex environments compared to rats housed in lab cages. Rats housed in complex environments showed an increase in neurones in the hippocampus associated with the formation of new memories and the ability to navigate from one direction to the next.
Maguire et al - studied the brain of London taxi drivers and found that they had more volume of grey matters in the hippocampus than in a matched control group. This was the area associated with the development of spatial and navigational skills in humans and other animals. As part of London cabbies training they must take a test called 'the knowledge' which assess their recall of London streets and other possible routes. It appears that the result of this learning experience is to alter the structure of the taxi drivers brain.
What are the 3 main anatomic ways the body can replace axon function in the brain after trauma
Axonal sprouting - growth of new nerve endings with connect with other undamaged nerve cells to form new neuronal pathways.
- reformation of blood cells
- recruitment of homologous areas on the opposite side of the brain eg- damage to the left hem would result in a similar area in the right hem taking over functionality.
What research has been done into functional recovery
Schneider et al - retrospective study. Asked on date from the us traumatic brain injury systems database. Of 769 patients studied 214 had achieved disability free recovery after one year. 39.2% of patients with 16 or more years of education had achieved DFR as 30% of those with 12-15 years of education.
What does FMRI stand for and what are they?
Functional magnetic resonance imaging.
Operate in the same way as standard MRI's but can also show changes in Brian activity as it occurs while a person performs a task.
Measures changes in blood flow in areas which indicate increased neural activity.
Measures the energy realised in haemoglobin - when haemoglobin is oxygenated it reacts differently to when it's deoxygenated. So when an area of the brain is more active it produces more oxygen, the different amount of energy realised. Y the haemoglobin is detected by the scanner and the change measured.
Dynamic moving picture - showing activity one second after it occurs, it is also accurate to within 1-2mm in the brain. This has important indications in understanding of localisation of function.
- moving picture - patterns of activity can be compared rather than just the physiology of the brain.
-it does not rely on radiation like PET scans, this makes it risk free, non invasive and straightforward to use. Produced images that have a very high spatial resolution - providing a c,ear picture of how the brain is localised.
-complexity of the brain activity means that interpreting them can be problematic. It is difficult because of the time delay of the scan- poor temporal resolution because there is around 5 seconds lag time between the image on screen and the initial firing neuronal activity.
-expensive to buy and maintain and they require trained operators - expensive and difficult to organise. Not as many studies as it's difficult to replicate.
- often small sample size in studies due to limited a availability and funding. One captures a clear image if participant is completely still, can't study people with Parkinson's, children- difficult to generalise.
What does EEG stand for
What does it do
- electrodes are placed on the scalp and they record the electrical activity of the Brian. There can be anything for 2-3 to 100. Electrodes measure the brain activity of the cells immediately under the electrodes so using more electrodes gives a fuller picture. The electrodes are fixed to the scalp using a skull cap. It is often used by clinicians as a diagnostic tool as unusual arrhythmic patterns of activity may indicate neurological abnormalities such as epilepsy, tumours or disorders of sleep.
What are the four EEG
Beta waves- found during R.E.M. Sleep. Low amplitude, fast frequency, normal waking state of consciousness- alert, concentration.
Alpha waves - relaxation of light meditation, frequency is reduced
Theta waves - lights sleep or deep meditation
Delta waves -deep sleep, slower frequency and greater amplitude
How can EEG be evaluated
- proved invaluable in the diagnosis of conditions such as epilepsy
- it has contributed much to our understanding of sleep
-unlike FMRI and EEG technology has extremely high temporal resolution of a single millisecond. Brain activity is recorded in real time which means the researcher can measure a particular task with the brain activity associated with it.
-very superficial- can't tell us about the activity of some deeper regions e.g. The hippocampus
- cheaper method than scanning - more widely available
-the info received is of a generalised nature - not useful for pinpointing the exact source of neural activity - it does not allow the researcher to distinguish between activities originating in different but adjacent locations.
What are ERP's
Event related potentials
Same apparatus as EEGs but record when there is activity in response to a stimulus introduced by the researcher.
Using a statistical a averaging technique
Looking for - event related potentials - a type of brain triggered by particular events.
ERPs are linked to cognitive processes e.g. Attention and perception. For example waves occurring in the first 100 millisecond after presentation of a stimulus are termed sensory ERPs as they reflect the initial response to the stimulus. ERPs generated after the first 100 milliseconds are termed cognitive ERPs as they demonstrate information processing and the manner in which the evaluates the stimulus.
What evidence shows that ERPs are more accurate that self report
Costa et at - used this method to record to responded to nude pictures of both sexes in ps 19-29. When asked how they felt men where generally aroused by the female pictures but woman reported neutral feelings to both male and female nude pics. However when costa examined ERPs of both male and female they found a higher response to opposite sex nude pictures than reported.
How can ERPs be evaluated
- limitations of EEGs
-ERPs excellent temporal resolution ( see it as it occurs) especially when comparing to neuroimaging techniques such as FMRI and this has led to their widespread use in the measurements of cognitive functions and deficits
- lack of standardisation in ERP methodology between different research studies which make it difficult to confirm findings.
- background noise and extraneous material must be completely eliminated, this is not always easy to achieve. ERPs are small and difficult to pick out therefore a large number of trails have to be carried out to gain meaningful date - this limits the kind of questions the ERP readings can answer.
What is the difference between EEGs and ERPs
EEG- general wave activity
ERPs- elicited by specific stimuli.
What is a post Morton examination
When a personal body, including the brain is examined after they have died. They can be used to see we're damage has occurred in the brain and how they may explain behaviour exhibited by the individual prior to death.
Areas of damage within the brain are examined after death and are compared with neurotypical brains in order to ascertain the extend of the difference and therefore reveal the possible cause of their behaviour.
Evaluate post mortem
Post mortem evidence was vital to providing a foundation for early understanding of key processes in the brain.
Broca's and wernicke's both relied on post moderate studies in establishing links to language, brain and behaviour decades before neuroimaging ever became a possibility. Improve medical knowledge and help generate hypotheses for further studies.
Detailed examinations of anatomical aspects of the brain than are possible with FMRI or EEGs - deeper areas such as the hippocampus and hypothalamus can be examined
Carried out retrospectively - drug treatment, age of death and stage of disease could all influence the post mortem brain and confound any differences between cases and control.
Ethical issues - consent from patient before death? HM lost his ability to form memory and was no able to form such consent.
Define endogenous peacemakers and exogenous zeitgebers
How are biological rhythms evolved
What is the most important Rhythm?
EP- internal Boyd clock that regulate biological rhythms eg- sleep
EZ- external stimuli- e.g. Light and temperate that influence biological rhythms.
- evolved because of the environment with organisms live has cycle changes - day/ night summer/winter.
- circadian rhythms ( any cycle that lasts 24 hours ) these rhythms optimise an organisms physiology and behaviour to best meet the varying demands of the day/night cycle
How is our boys clock regulated ?
What controls our circadian rhythms ?
What must the pace makers constantly do?
The release of hormones like melatonin, metabolic rate and body temperate.
- driven by our body clock. Found in all cells and synchronised by the master circadian pacemaker; the suprachiasmatic nuclei (SCN) found in Yh hypothalamus.
- must constantly reset so we're in synchrony to the outside world.
Give an example of a circadian rhythm
The sleep wake cycle - light and darkness are the external signals that determine when we need to sleep and wake up. Sleep and wakefulness are under homeostatic control- the homeostatic system tends to make us feel sleepier as time goes on, regardless of day or night.
What is our core Body temp?
During the Normal circadian rhythm when does sleep occur ?
Lowest - at its lowest about 36 decrees at about 4:30 am
Highest 38 decrees about 6pm
- occurs when the core temp begins to drop and body temp starts to rise during the last hours of sleep.
Why encourages sleep ?
Where is this released from?
Melatonin - when it is dark more is produced and when it's light the production of melatonin drops and a person wakes up.
- released from the pineal gland in the brain
What research shows the effect of circadian rhythms which have been allowed to run free ?
Siffre- cage in Texas for 6 months - settled to a sleep / wake cycle of between 25 and 30 hours. He resurfaced from on the 17th of September believing the date was the 20th august.
What research may suggest that circadian rhythms can not be easier altered ?
Folkard - group of 12, lived in a cave for 3 weeks, told to sleep as 11:45 and rose at 7:46, unbeknown to the ps the clock was being sped up to a 22 hour day- none of the ps could comfortable adjust to the new regime.
What is a real world application to circadian rhythms
Chronotherapeutics - the study of how timing effects drug treatment. The specific time patients take their medication is very important as it can have a significant impact on treatment success.
Chronotherapeutics have been developed with a novel drug delivery system - medications should be taken before the person goes to bed but is not released until the vulnerable period of 6am to noon.
What are infradian rhythms
Rhythms that last more than 24 hours eg- menstral cycle which is determined by the endocrine cycle.
What is the menstrual cycle
How may it be influenced by endogenous factors ?
Governed by changes in hormone levels which regulate ovulation. Rising levels of oestrogen cause the ovary to develop an egg and release it after which point progesterone leads to the womb lining growing thicker ready to receive the egg.
- stern and McClintock- may synchronise because of the influence of female pheromones. In a sample of 29 women with irregular periods found the women's menstrual cycle was shortened when receiving odourless compounds from the armpits of 9 other women.
How can infradian rhythms be evaluated
- the effects of hormones can help explain menstrual synchronicity explaining why women who live together become synchronised.
An evolutionary approach would support this as women take care of each other eg- breast feeding another child if a mother dies.
- Wilson challenged menstrual synchrony stating that experimental evidence of it existence was over exaggerated.
What are ultradian rhythms
Having a period of less than one day
Eg- slow wave sleep and rapid eye movement during the night
How long is the slow wave sleep cycle
90 minutes- after several stage of SWS, R.E.M. occurs for 15 mins and the cycle starts again.
4-6 complete cycles in one night.
Explain the different stages of the SWS
One- 5 to 15 mins.
Brain activity - Less than relaxed wakefulness
Physiological effects - heart rates slow and muscles relax, people are still easily woken at this stage.
Two- 5 to 15 minutes.
Brain activity - sleep spindles, short bursts of activity
Physiological - the body continues to relax- easy to wake someone
Three - 5-15 mins
Brain activity - less sleep spindles in this stage, slow delta waves.
Physiological - the body relaxes and it becomes harder for people to wake in this stage
Four- 40 mins
Brian activity- delta waves increase and the level of activity it lower than other stages
Physiological - metabolic rate is low, people are difficult to wake and growth hormones are released
R.E.M.- 15 mins lengthening through the night
Brian activity - more brain activity than in any other stage.
Physiological effects - complete relaxation of the trunk, irregular breathing and heart rate and the probability of dreams
What did research by Dement and Kleitman find about the SWS
- dreams tend to be recalled when woken up in the R.E.M. Stage
- the research woke them up with a bell and the ps spoke into a recoded device stating whether they were dreaming or not and then give details of the dream.
- NREM sleep few dreams were recalled
-ultradian rhythms varied between 70-104 average was 92 mins
- direction of eye movement was associated with dream content eg- vertical - climbing a ladder.
Sleep lab- effects quality of sleep this May effect how long they spend in each stage
They may be less relaxed as they keep getting woken up
What is the basic rest activity cycle
Kleitman - the 90 minute cycle. Suggesting that this 90 mins of ultradian rhythms continues through the day but instead of passing stage of sleep we go from stages of alertness to fatigue every 90 mins. Suggesting that the human brain can only concentrate for period of 90 minutes before a loss of concentration, fatigue or feeling hungry, this may explain for the 10:30 coffee break in work places.
How can the difference in sleep patterns be explained
Some may say non biological factors e.g. Temperature and noise
Tucker- studied participants for 11 days and nights in a strictly controlled lab environment. Assessing sleep duration, time to fall asleep and the amount of time spent in each stage, in deeper sleep stages (3 and 4) the individual differences were significant suggesting that sleeping patterns maybe particularly biological.
Ericsson- supported the importance of the basic rest activity cycle (BRAC) and found that elite violinists practice sessions were limited to no more than 90 mins, most of them napped between practice and the best violinists napped the most.
What is the most important pacemaker
Lies in the hypothalamus and plays an important role in generating the body's circadian rhythms. It acts as the master clock. Neurone within the SCN spontaneously synchronise with each other. The peripheral clocks can maintain a circadian rhythm but not for very long so this Is why there controlled by the SCN.
SCN receives info about light levels via the optic nerve even when our eyes are shut.
What happens if they biological clock is running slow
What else does the suprachiasmatic nucleus regulate ?
The morning light automatically adjusts the clock putting it in rhythm with the outside world.
- regulates the manufacture and secretion of melatonin in the pineal gland via interconnecting neural pathways
What role does the pineal gland play
How does melanin induce sleep?
Despite the endogenous nature of these clocks why must their activity be synchronised with the light dark cycle of the outside world?
The SCN sends signals to the pineal gland, directing it to increase production and secretion of the hormone melatonin at night and to decrease it as light levels increase in the morning.
- by inhabiting the brain mechanisms that promote wakefulness
- because of the sensitivity of the pineal gland and SCN to light and the role of melatonin in controlling sleep and activity
How can endogenous pacemaker be evaluated
The importance of the suprachiasmatic nucleus has been demonstrated through animal studies
Morgan - bred a strain of hamsters so they had abnormal circadian rhythms of 20 hours instead of 24. The SCN from these abnormal hamsters were then transplanted into the brains of normals hamsters who them displayed the circadian rhythm of 20 hours showing that the transplant SCN had imposed it patterns on the recipients of the brain.