Biopsychology Flashcards
Fight or flight response
THE TEND AND ‘BEFRIEND’ RESPONSE: Taylor et al (2000) suggests that, for females, behavioural responses to stress are more characterised by a pattern of tends and befriend than fight or flight. This involves protecting themselves and their young through nurturing behaviours (tending) and forming protective alliances with other women (befriending). Women have a different system for coping with stress because their responses evolved in the context of being a primary caregiver of their children. This finding, explained in terms of the higher levels of the hormone oxytocin in females, suggests that previous research has obscured patterns of stress response in females
NEGATIVE CONSEQUENCES: the physiological responses associated with fight or flight may be adaptive for a stress response that requires energetic behavioural responses. However, the stressors of modern life rarely require such levels if physical activity. The increased blood pressure that is characteristic of SNS activation can lead to physical damage in blood vessels and eventually to heart disease. As a consequence, although cortisol may assist the body in fighting a viral infection, too much cortisol suppresses the immune response, shutting down the very process that fights infection and increasing the likelihood of stress-related illness.
FIGHT OR FLIGHT DOES NOT TELL THE WHOLE STORY: Gray (1988) argues that the first phase of a reaction to a threat is not to fight or flee, but to avoid confrontation. He suggests prior to responding with attacking or running away, most animals and humans typically display the ‘freeze response’. The adaptive advantages of this response for humans are that ‘freezing’ focuses attention and makes them look for new information in order to make the best response for that particular threat.
GENETIC BASIS TO SEX DIFFERENCES: Lee and Harley (2012) have found evidence of a genetic basis for gender differences. The SRY gene, found exclusively on the male Y chromosome, directs male development, promoting aggression and resulting in the fight or flight response to stress. The SRY gene may prime males to respond to stress in this way by the release of stress hormones such as adrenaline and increased blood flow to organs in fight or flight. In contrast, the absence of the SRY gene in females (who do not have a Y chromosome) may prevent this response to stress, leading instead to ‘tend and befriend’ behaviours.
Localisation of function
CHALLENGES TO LOCALISATION: EQUIPOTENTIALLY: not all researchers agree with the view that cognitive functions are localised in the brain, a conflicting view is the equipotentially theory (Lashley 1930), Lashley believed that basic motor and sensory functions were localised, but thy any higher mental functions were not. He claimed intact areas of the cortex could take over responsibility for specific cognitive functions following injury to the area normally responsible for that function. According to this point of view, the effects of damage to the brain would be determined by the extent rather than the location of the damage. Humans were able to regain some of their cognitive abilities following damage to specific areas of the brain.
COMMUNICATION MAY BE MORE IMPORTANT THAN LOCALISATION: research that what might be more important is how brain areas communicate with each other, rather than which specific brain regions control a particular cognitive process. Wemicke claimed that although different regions of the brain had different specialist functions they are independent in the sense that in order to work they must interact with each other. This suggests complex behaviours such as language, reading and movement are built up gradually as a stimulus enters the brain, them moves through different structures before a response is produced. Damage to the connection between any two points in this process results in impairments that resemble damage to the localised brain region associated with a specific function.
SUPPORT FOR LANGUAGE CENTRES FROM APHASIA STUDIES: Evidence for the different functions of Broca’s and Wernicke’s areas in language production and understanding comes from the discovery that damage to these different areas a results in different types of aphasia. Expressive aphasia or (Broca’s aphasia) is an impaired ability to produce language. In most cases, this is caused by brain damage in Broca’s area. Receptive aphasia (also known as Wernicke’s aphasia) is an impaired ability to understand language, an inability to extract meaning from a spoken or written words. This form of aphasia is usually the result of damage line a stoke. This demonstrates the important role played by these brain regions in different aspects of language.
INDIVIDUAL DIFFERENCES IN LANGUAGE AREAS: the pattern of activation observed in response to various language actives can vary from individual to individual. Bavelier et a; (1997) found considerable variability in patterns of activation across different individuals when reading. They observed activity in the right temporal lobe as well as in the left frontal, temporal and occipital lobes. Other studies have found significant gender differences in the size of the brain areas associated with language. For example, Harasty et al (1997) found that women have proportionality larger Broca’s and Wernicke;s areas than men. These anatomical differences may well explain the superior language skills often found in females.
LANGUAGE PRODUCTION MAY NOT BE CONFINED TO BROCA’S AREA ALONE: Dronker’s et al (2007) re-examined the preserved brains of the two of Broca’s patients, Louis Leborgne and Lazare Lelong. They used modern high-resolution brain MRI imaging in order to identify the extent of any lesions in more detail. The MRI findings revealed that other areas besides Broca’s area could also have contributed to the patient’ reduced speech abilities. This finding is significant because although lesions to Broca’s area alone can cause temporary speech disruption, they do not usually result in severe disruption of spoken language. This study suggests that language and cognition are far more complicated than once thought and involve networks of brain regions rather than being localised to specific areas.
Lateralisation and split brain research
LATERALISATION: INCREASED NEUTRAL CAPACITY: the main strength of the hempispheric lateralisation appears to be that it increases neural processing capacity. By using only one hemisphere to engage in a particular task this would leave the other hemisphere free to engage in another function. Despite this assumption, very little empirical evidence has been provided to show that lateralisation confers any advantage to the functioning of the brain in humans. Roger et al (2004) found that, in the domestic chicken, brain lateralisation is associated with an enhanced ability to perform two tasks simultaneously- finding food and being vigilant for predators. This finding provides some evidence that brain lateralisation enhances brain efficiency in cognitive tasks that demand the simultaneous but different use of both hemispheres.
LATERALISATION AND IMMUNE SYSTEM FUNCTIONING: there are a number of disadvantages associated with hemispheric lateralisation, e.g architects and mathematically gifted tend to have superior right-hemispheric skills but are also so much more likely to be left-handed and to suffer higher rates of allergies and problem with the immune stystem. Tennessean et al (1993) found a small but significant relationship between handedness and immune system disorders, suggesting that the same genetic processes that lead to lateralisation may also affect the development of the immune system. Morift and Weekes (2001) lent support to this suggests finding that left-handlers had a higher incidence of immune system disorders in their immediate families than did right-handlers.
LATERALISATION CHANGES AGE: lateralisation of function appears not to stay exactly the same throughout an indivual’s lifetime, but changes with normal ageing. Lateralised patterns found in younger individuals tend to switch to bilateral patterns in healthy older adults. Szarflarski et al (2006) found language became more lateralised to the left hemisphere with increasing age in children and adolescents, but after the age of 25, lateralisation decreased with each decade of life. It is difficult to know why this is the case but one possibility is that using the extra processing resources of the other hemisphere may in some way compensate for age-related declines in function.
LANGUAGE MAY NOT BE RESTRICTED TO LEFT HEMISPHERE: Gazzangia (1998) suggests that some of the early discoveries from split-brain research have been disconfirmed by more recent discoveries. Damage to the left hemisphere was found to be far more detrimental to language function than was damage to the right. However, case studies have demonstrated that this was not necessarily the case. One patient, known as JW developed the capacity to speak out of the right hemisphere, with the result that he can now speak about information presented to the left or to the right brain (Turk et al 2002). This challenges the claim that the right hemisphere is unable to handle even the most rudimentary language.
LIMITATIONS OF SPLIT-BRAIN RESEARCH: the split-brain procedure is rarely carried out nowadays and Andrewes (2001) points out that many studies are presented with as few as three participants or even just the one single participant. Andrewes claims that, in some cases, conclusions have been drawn from individuals who either have a confounding physical disorder that made the split-brain procedure necessary, or have had a less complete sectioning of the two hemispheres than was originally believed. As a result, patients who have had this procedure without these confounding factors are rarely encountered in sufficient numbers to be useful for research.
Plasticity and functional recovery
Plasticity: RESEARCH SUPPORT FROM ANIMAL STUDIES: Kempermann et al (1998) suggested that an enriched environment could alter the number of neutrons in the brain. They found evidence of an increased number of new neurons in the brain of rats housed in complex environments compared to rats housed in laboratory cages. In particular, the rats housed in the complex environment showed an increase in neurons in the hippocampus, a part of the brain associated with the formation of new memories and the ability to navigate from one location to another. This shows clear evidence of the brains ability to change as a result of experience, e.g it demonstrates plasticity.
Plasticity: RESEARCH SUPPORT FROM HUMAN STUDIES: Maguire et al (2000) in a study of London taxi drivers, discovered that changes in the brain could be detected as a result of their extensive experience of spatial navigation. Using an MRI scanner, the researchers calculated the amount of grey matter in the brains taxi drivers and a set of control participants. The posterior hippocampi of taxi drivers were significantly larger relative to those of control participants and posterior hippocampal volume was positively correlated with the amount of time they had spent as a taxi driver. This not only shows that hippocampal volume was greater in those individuals with job related experience of spatial navigation but also that the highest levels of plasticity were evident in those with more extensive experience.
Functional recovery: RESEARCH SUPPORT FROM ANIMAL STUDIES: Taijiri et al (2013) provided evidence for the role of stem cells in recovery from brain injury. They randomly assigned rats with traumatic brain injury to one of two groups. One group received transplants of stem cells into the region of the brain affected by traumatic injury. The control group received a solution infused into the brain containing no stem cells. Three months later, the brains of the stem cell rats showered clear development of neuron-like cells in an area of injury. This was accompanied by a solid stream of stem cells migrating to the brains site of injury. This development of new neuronal cells was not evident in the control group, supporting the important role played by stem cells in recovery from brain injury.
AGE DIFFERENCES IN FUNCTIONAL RECOVERY: It is commonly accepted that functional plasticity reduces with age (Huttenlocher, 2002). According to this view, the only option following traumatic brain injury beyond childhood is to develop compensatory behavioural strategies to work around the deficit (such as seeking social support or developing strategies to deal with cognitive deficit). However, studies have suggested that even abilities commonly thought to be fixed in childhood can still be modified in adults with intense retraining. Despite these indications of adult plasticity, Elbert et al (2001) conclude that the capacity for neural reorganisation is much greater in children than in adults, as demonstrated by the extended practice that adults require in order to produce changes.
EDUCATIONAL ATTAINMENT AND FUNCTIONAL RECOVERY: Schneider et al (2014) found that patients with the equivalent of a college education are seven times mor likely than those who didn’t finish high school to be disability-free one year after a moderate to severe traumatic brain injury. They carried out a retrospective study based on data from the US traumatic brain injury systems database. Of the 769 patients studied, 214 had achieved disability-free recovery (DFR) after one year. Of these, 39.2% of patients with 16 or more years of education had achieved DFR, as had 30.8% of those with 12-15 years of education and just 9.7% of those with less than 12 years of education achieved DFR after one year. The researchers concluded that ‘cognitive reserve’ (associated with greater educational attainment) was an important factor in neural adaption during recovery from traumatic brain injury.
Ways of studying the brain (strengths)
FMRI- it is noninvasive, nor does it potentially expose the brain to potentially harmful radiation as is the case with some other scanning techniques used in the study of the brain.
FMRI offers a more objective and reliable measure of psychological processes than is possible with verbal reports. It is useful as a way of investigating psychological phenomena that people would not be capable of
proving in verbal reports.
EEG- one strength of the EEG technique is that it provides a recording of the brains activity in real time rather than a still image of the passive brain. This means that the researcher can accurately measure a particular task or activity with the brain activity associated with it.
An EEG is useful in clinical diagnosis, e.g by recording the abnormal neural activity associated with epilepsy. Epileptic seizures are caused by disturbed brain activity, which means that the normal EEG reading suddenly changes. This helps diagnose wether someone experiencing seizures has epilepsy.
ERP- Because ERPs provide a continuous measure of processing in response to a particular stimulus, it makes it possible to determine how processing is affected by a specific experimental manipulation, for example during presentation of visual stimuli.
An ERP can measure the processing of stimuli even in the absence of a behavioural response. ERP recordings make it possible to monitor ‘covertly’ the processing of a particular stimulus without requiring the person to respond to them.
PM- post-moterm studies allow for a more detailed examination of anatomical and neurochemical aspects of the brain that would be possible with the sole use of non-invasive scanning techniques such as FMRI and EEG. For example, it enables researchers to examine deeper regions of the brain such as hypothalamus and hippocampus.
Harrison (2000) claims that post-moterm studies have played a central part in our understanding of the origins of schizophrenia. He suggests that as a direct result of post-moterm examinations, researchers have discovered structural abnormalities of the brain and found evidence of changes in neurotransmitter systems, both of which are associated with the disorder.
Ways of studying the brain (weaknesses)
FMRI- because FMRI measures changes in blood flow in the brain, then it is not a direct measure of neural activity in particular brain areas. This means it is not a truly quantitative measure of mental activity in these brain areas.
Critics argue that FMRI overlooks the networked nature of brain activity, as it focuses only on localised activity in the brain. They claim that it is communication among the different regions that is most critical to mental function.
EEG- because an EEG can only detect the activity in superficial regions of the brain, it cannot reveal what is going on in the deeper regions such as the hypothalamus or hippocampus. Electrodes can be implanted in non-humans to achieve this, but it is not ethically permissible to do this with humans because this would be too invasive.
Electrical activity can be picked up by several neighbouring electrodes, therefore the EEG signal is not useful for pinpointing the exact source of an activity. As a result, it does not allow researchers to distinguish between activities originating in different but closely adjacent locations in the brain.
ERPS- because ERPS are so small and difficult to pick out from other electrical activity in the brain, it requires a large number of trials to gain meaningful data. This places limitations on the types of question that ERP readings can realistically answer.
A limitation of the ERP technique is that only sufficiently strong voltage changes generated across the scalp are recordable. Important electrical activities occurring deep in the brain are not recorded, meaning that the generation of ERPs rends to be restricted to the neocortex.
PM- because people die in a variety of circumstances and at varying stages of disease, these factors can influence the post-northern brain. Similarly, the length of time between death and the post-morterm (delay ), drug treatments and age at death are possible confounding influences of any difference between cases and controls.
This approach is limited because it is retrospective as the person is already dead. As a result, the researcher is unable to follow up on anything that arises from the post-mortem concerning a possible relationship between brain abnormalities and cognitive functioning.
Circadian rhythms
RESEARCH SUPPORT FOR IMPORTANCE OF LIGHT- HUGHES (1997): tested circadian hormone release in 4 participants stationed at British Antarctic station. In feb (end of Antarctic summer) cortisol levels reached highest when participants awoke and lowest when went to bed. However, after 3 months of continuous darkness this pattern changed, with peak levels of cortisol being at noon instead. This suggests daylight in polar regions of the world may be responsible for circadian hormone release. However, other studies in arctic with prolonged winter darkness found no disruption of cortisol release patterns.
INDIVIDUAL DIFFERENCES: CZEISLER ET AL (1999): circadian rhythm cycles can vary in different people from 13 hours to 65 hours and individuals are innately different in terms of when their circadian rhythms reach their peal. DUFFY ET AL (2000): morning people (larks) prefer to rise early and go to bed early (6am and 10pm), whereas evening people (owls) prefer to wake and go to bed later (1am and 10am)
CHRONOTHERAPEUTIC: one real world application is how timing affects drug treatments. Specific time patients take their medication is important as it can have an impact on treatment success, it is essential the right concentration of drug is released in the target area of the body at the time the drug is most needed. E.g the risk of heart attack is greatest during early morning hours after weakening. EVANS AND MARAIN (1996): developed a drug delivery system. These medications can be administered before the person goes to sleep at 10pm but actual drug is not released until vulnerable period of 6am to noon.
Research methodology: lots of early research suffered an important flaw as most participants were isolated from variables such as clocks, radios, daylight and this may affect circadian rhythm. However, they were not isolated from artifical light because it was believed that dim artifical light, in contrast to daylight would not affect it. However, Czeisler altered participants circadian rhythms down to 22 hours and up to 28 hours using dim artifical light alone, therefore early studies may have been confounded by presence of artifical light.
Endogenous pacemakers and exogenous zeitgebers
KLIEN AND WEGMANN (1974): circadian rhythms of air travellers adjusted more quickly if they went outside more. This is thought to be because they picked up on social cues from people in their new time zone.
ENDOGENOUS: ROLE OF SCN- Morgan (1995) bred a strain of hamsters so that they had abnormal circadian rhythms of 20 hours rather than 24 hours. SCN neurons from these abnormal hamsters were then transported into the brains of normal hamsters, the normal hamsters then displayed the same abnormal circadian rhythm of 20 hours. Then transplanted SCN neurons from normal hamsters into the brains of abnormal hamsters, they then changed to a circadian pattern of 24 hours. This confirms the importance of the SCN in setting circadian rhythms.
EXOGENOUS: SUPPORT FOR THE ROLE OF MELANOPSIN- Skene and Arendt (2007) estimate that the vast majority of blind subjects who still have some light perception have normally entrained circadian rhythms. This suggests that the pathway from retinal cells containing melanopsin to the SCN is still intact. As further evidence for the importance of this pathway in setting the biological clock, people without light perception show abnormal circadian entrainment.
USING LIGHT EXPOSURE TO AVOID JET LAG (exogenous) Burgess et al (2003), who found that exposure to bright light prior to an east-west flight decreased the time needed to readjust to local time on arrival. Group One: continuous bright light, shifted circadian rhythms back 2.1 hours. Group 2: intermittent bright light, shifted circadian rhythms back 1.5 hours. Group 3: dim light, shifted circadian rhythms back 0,6 hours. As a result, participants in the first treatment group felt sleepier 2 hours earlier in the evening and woke 2 hours earlier in the morning. This suggests light exposure prior to a flight would allow travellers to arrive with their circadian rhythms already partially re-entrained to a local time.
THE ROLE OF ARTIFICIAL LIGHT AS A ZEITGEBER: Vetter et al (2011) demonstrated the importance of light in the regulation of the sleep-wake and activity- rest patterns of two groups of volunteers participant over a five-week study period. Group One: remained in normal ‘warm’ artificial light over the five weeks, circadian rhythms were affected by sunlight (dawn advanced 42 during experiment). Group 2: blue enriched light with spectral composition close to daylight, circadian rhythms were synchronised to office hours, not daylight. The results confirm that light is the dominant zeitgeber for the SCN and that its effectiveness depends on its spectral composition.
DANGERS OF DISRUPTED RHYTHMS (endogenous): Touitou et al (2017) argue that exposure to artificial light at night results in a disruption of the circadian system, which has adverse effects on health. Touitou’s research has shown that teenagers spend increasing amounts of time on electronic media at night. The LED bulbs of these devices are enriched with a blue light component very active on the circadian clock, which leads to suppression of melatonin secretion and circadian disruption. As a result, adolescent sleep becomes irregular, shortened and delayed. Long term, this combination of sleep deprivation and circadian disruption is detrimental to health, as shown by many studies that have found increase rates of cardiovascular disorders and mood disorders such as depression.
Ultradian and infradian rhythms
INDIVIDUAL DIFFERENCES IN SLEEP STAGES: Differences in sleep patterns of individuals are usually attributed to differences in non-biological factors (e.g sleep hygiene). Tucker et al (2007) suggests these differences are in large part biologically determined and may even be genetic in origin. Participants were studied over 11 consecutive days and nights in a strictly controlled lab environment. The researchers assessed sleep duration, time to fall asleep and amount of time in each sleep stage. They found ID in each of these characteristics across the 8 nights, for deep sleep (stages 3 and 4) the differences were particularly significant. This meant that differences between participants were not driven by circumstance but were at least partially biologically determined.
RESEARCH SUPPORT FOR BRAC: Ericsson et al (2006) provide research support for BRAC study of elite performers, they studied a group of elite violinists and found that, among this group, practice sessions were usually limited to a duration of no more than 90 mins at a time,with practice systematically distributed during the day in these 90 minute segments. This supported Kleitman’s claims that fatigue was a characteristic of the end of the BRAC cycle. Ericsson’s analysis also indicated that the violinists frequently napped to recover from practice, with the very best violinists napping more than their teachers. Consistent with the predictions of the BRAC, Ericsson discovered the same pattern among other musicians, athletes, chess players and writers.
MENSTRUAL CYCLE- ROLE OF EXOGENOUS CUES: menstrual cycle is normally governed by an endogenous system- the release of hormones by the pituitary gland, however it can also be controlled by exogenous cues. When several women of childbearing age live together and do not take oral contraceptives, their menstruated cycles tend to synchronise. In one study, daily samples of sweat were collected from one group of women and rubbed onto upper lips of women in a second group. The groups were kept separate yet their menstrual cycles became synchronised with their ‘odour donor’ (Russell et al 1980). This suggests that the synchronisation of menstrual cycles can be affected by pheromones, which act in a similar way to hormones, but have an effect on the bodies of people close by rather than the body of the person producing them.
THE MENSTRUAL CYCLE INFLUENCES MATE CHOICE: Penton-Voak et al (1999) suggests that human mate choice varies across the menstrual cycle, an infradian rhythm, with different preferences at different stages of the cycle. They found that women generally expressed a preference for ‘slightly feminised’ male faces when picking a partner for a long-term relationship. However, when in the ovulatory phase of their menstrual cycle, women showed a preference for more masculinised faces. This study appears to demonstrate a preference for kindness and co-operation in long term mates, but a preference for males with ‘good genes’ for short liaisons so that these genes might be passed onto their offspring.
BELIEF IN LUNAR RHYTHMS: deposit empirical evidence to the contrary, the belief in an infradian rhythm based on the phases of the moon remains strong. For example, many midwifes still believe that more babies are born during a full moon than during a new moon, but the statistics show that this is a purely subjective association (Arliss et al 2005). Likewise, surveys of workers in the mental health professions have shown a persistent belief that the full moon can alter behaviour (Vance 1995), yet study after study has failed to find any consistent association between the moon and human psychopathology. Occasional studies have found correlations between the phase of the moon and various aspects of human behaviour, there is no evidence of a casual relationship (Foster and Roenneberg, 2008).
