Biopsychology

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  • Biopsychology
    • The Nervous System
      • THE NS - specialised network of cells in the human body and is our primary internal communication system.
        • CENTRAL NERVOUS SYSTEM - made up of the brain and spinal cord
          • SPINAL CORD - transfers messages to and from the brain and the rest of the body - also responsible for simple reflex actions
          • THE BRAIN - provides conscious awareness and is involved in all psychological processes - brain stem connects brain and spinal cord and control involuntary processes
        • PERIPHERAL NERVOUS SYSTEM - PNS transmits messages via millions of neurons to and from the CNS.The PNS is further divided into the autonomic nervous system and the somatic nervous system
          • SOMATIC NERVOUS SYSTEM - maintains communication between central nervous system abd outside world. Consists of: 1. Sensory pathways: carry info to spinal cord and brain  2. Motor Pathways: allow brain to control movement
          • AUTONOMIC NERVOUS SYSTEM - plays an important role in homeostatis - it only consists of motor pathways
            • SYMPATHETIC NERVOUS SYSTEM - prepares body for fight/flight response Eg. increases blood pressure, heart rate, dilates pupils etc
            • PARASYMPATHETIC NERVOUS SYSTEM - returns body to normal resting state - opposite actions to sympathetic nervous system
    • The Endocrine System
      • HYPOTHALAMUS - control release of hormones in pituitary gland and regulates endocrine system
      • PITUITARY GLAND - control release of hormones from other glands
        • ACTH - released by anterior lobe - stimulates the adrenal cortex and release of cortisol
        • OXYTOCIN - released by posterior lobe - responsible for uterus contractions in child birth
      • PINEAL GLAND
        • MELATONIN - responsible for important biological rhythms including sleep/wake cycle.
      • THYROID GLAND
        • THYROXINE- responsible for the regulation of metabolism
      • ADRENAL GLANDS - helps trigger the fight/flight response
        • ADRENALINE AND NORADRENALINE - released by adrenal medulla - plays key role in fight/flight response
        • CORTISOL - released by adrenal cortex - stimulates release of glucose whilst suppressing the immune system
      • OVARIES
        • OESTROGEN - controls regulation of female reproductive system including menstrual cycle and pregnancy
      • TESTES
        • ANDROGENS - eg. testosterone - responsible for development of male characteristics during puberty/ muscle growth
    • Structure and Function of neurons
      • CELL BODY - includes nucleus which contains genetic material
      • DENTRITES - branch off nerve cell to connect whith other neurons - carry impulses towards cell body
      • AXON TERMINAL - send impulse to next neuron across synapse - contain tiny sacs called neurotransmitters
      • THE AXON - carries nerve impulses away from cell body
      • NODES OF RANVIER - gaps in myelin sheath - increase speed of electrical impulase
      • THE MYELIN SHEATH - Insulates and protects the axon and helps speed up electrical transmission
    • FIGHT/FLIGHT Evaluation
      • 1 - Human behaviour is not limited to only 2 responses
        • Gray - suggests first response to danger is to avoid it all together ("Freeze" response)
          • Humans are hypervigilant while they assess a situation - suggest that fight/flight response explanation of behaviour is limited - doesn't fuly explain complex cognitive and biological factors
      • 2 - doesn't fully explain stress response in females
        • Taylor et al - suggests females adopt a tend and befriend response in stressful situations - women are more likely to protect their offspring and form alliances with other women
          • Highlights a beta-bias in this area of psychology because psychologists assumed that females responded in the same way as males - limited application in females
      • 3 - can have negative / detrimental effect on health
        • modern life rarely requires such an intense biological response  - this matters because the activation of this response can increase blood pressure, cause damage to blood vessels and contribute to heart disease - maladaptive to everyday life
    • Lateralisation of function - the idea that 2 hemispheres have different functions
      • Left - dominant for language, logical and analytical thought and complex movements
      • Right - dominant for non-linguistic functions eg. face recognition, music, emotion and intuition
      • Split-brain research  - Sperry - to demonstrate that hemispheres have different functions and each hemisphere has its own conscious awareness and memory
        • NATURAL EXPERIMENT - 11 male participants (epileptics who had all undergone commisectory
          • VISUAL STIMULI TESTS - slides projected either side of a fixation point at rate of one picture per 1/10 second - participants say/write what they have seen
            • Results and objects only recognised when presented to same eye (evidence for 2 sperate memories
      • Evaluation
        • Evidence - Sperry's pioneering work has produced and impressive and sizable body of research findings - support Sperrys conclusion of functions of left and right hemispheres
        • Methodological strengths - highly specialised and standardised procedures - short amount of time looking as pictures meant that pp couldn't ajust visual field so only one hemisphere was receiving info at one time
        • Theoretical basiss - prompted philosophical debate about degree of communication between 2 hemispheres in everyday functioning - some think two hemispheres behave independently whereas others believe they act together
    • Synaptic transmission
      • Nerve impulse travels down axon and arrives at presynaptic terminal
        • vesicles release their neurotransmitter across the synapse
          • this chemical then locks into special recptor sites of the adjacent neuron (post synaptic recptor sites)
            • Enzymes are released to break down excess neurotransmitter
              • OR excess neurotransmitter is reabsorbed by synaptic terminals where it was released
                • vesicles are replenished with new and reused neurotransmitters ready for the next impulse
    • Localisation of function
      • the idea that different parts of the brain perform different tass and are involved with different parts of the body
        • Right hemisphere mostly responsible for left side of the body
        • left hemisphere mostly responsible for right side
      • VISUAL - occipital lobe
        • AUDITORY - Temporal lobe
          • SOMATO SENSORY - Parietal lobe
            • integrates info to and from different senses and important role in spatial navigation - causes lack of skin sensation if damaged
            • Speech production - Brocas area (left frontal lobe) - converting memories and thoughts into words - damage = Broca's aphasia - speech is slow and lacking in fluency
              • Speech comprehension - Wernicke's area (left temporal lobe) - comprehension or recognition of spoken words - damage = Wernicke's aphasia - difficulty understanding what others say
          • Processes sound - causes partial and total deafness if damaged
        • MOTOR - frontal lobe
          • controls body movement - damages causes impaired movement
      • EVIDENCE FOR LOCALISATION OF FUNCTION
        • Many lab studies using brain scans show how blood flow is concentrated in regions where tasks are performed
          • eg. Dougherty et al - reported on 44 OCD patients who had undergone a cingulotomy (procedure that involves lessoning of the cingulate gyrus)P - at post surgical follow up after 32 weeks one third met the criteria for successful response to the surgery and 14% for partial response - suggest behaviours associated with disorders alike are localised
      • EVIDENCE AGAINST LOCALISATION OF FUNCTION
        • HOLISTIC FUNCTIONING - although some functions are located in certain areas of the brain, most functions involves many interconnected areas of the brain
        • people with damage to a specific area often recover functioning over time because another area of the brain takes over - referred to as brain plasticity
    • Brain plasticity - refers to the brains ability to change and adapt as a result of experience
      • Research into brain plasticity: MAGUIRE ET AL
        • the role of the hippocampus is to facilitate spatial memory in the form of navigation
          • Taxi drivers undergo extensive training known as "The knowledge" and therefore make an ideal group for study of spatial navigation
            • Aim: to examine whether structural changes could be detected in the brains of people with extensive experience of spatial navigation
              • Method: Structural MRI scans were obtained - 16 right-handed London taxi drivers - all had been driving for more than 1.5 years - scans of healthy, right handed males who did not drive taxis as control group
                • Findings - significantly more grey matter posterior hippocampus of taxi drivers than control group
      • Evaluation
        • Practical application - has contributed to field of neurorehabilitation - although the brain may have capacity to fix itself to a point, this process requires further intervention to be completely successful
        • Negative plasticity - maladaptive behavioural consequences - eg. prolonged drug use results in poorer cognitive function and increased risk of dementia later in life
        • Age and plasticity - plasticity tends to reduce with age - in childhood its constantly adapting due to many new experiences and learning
    • Functional recovery - unaffected areas of the brain are often able to adapt and compensate for areas that are damaged
      • Brain is able to rewire and reorganise itself by forming new synaptic connections close to the are of damage
        • Secondary neural pathways would not be used typically to carry out certain functions are activated enable functioning to continue
          • Supported by a number of structural changes in  brain:
            • Axonal sprouting : growth of new nerve endings which connect the undamaged nerve cells to form new neuronal pathways
            • Reformation of blood vessels
            • Recruitment of homologous (similar) areas ont he opposite side of the brain to perform specific tasks  - eg. Broca's area damaged on left side of brain , right side equivalent would carry out its functions
    • Ways of studying the brain
      • POST-MORTEMS - analysis of persons brin after death
        • + = vital in providing a foundation for early understanding of key processes  - allow examinations of deep regions of the brain - allow for a more detailed examination of the anatomical and neurochemical areas of the brain
        • - = causation - ethical issues, may not be able to give informed consent eg. HM
      • FUNCTIONAL MAGNETIC RESONANCE IMAGINING (fMRI) - method used to measure persons brain activity whilst doing a task - detects blood oxygenation
        • + = no radiation needed - risk free - non-invasive - straightforward to use - high spatial resolution
        • - = expensive - need to be perfectly still - poor temporal resolution
      • EVENT-RELATED POTENTIALS (ERPs) - brains electrophysiological response to a specific, cognitive or motor event can be isolated through analysis of EEG data
        • + = much more specificity than EEG - excellent temporal resolution
        • - = lack of standardisation in ERP methodology between different research studies - elimination of background noise and extraneous data is not always easy to achieve
    • Biological Rhythms
      • INFRADIAN - last longer than 24 hours - female menstrual cycle
        • Female reproductive system regulated by hormones - ovulations occurs roughly halfway through cycle when oestrogen levels are highest - usually lasts for 16-32 hrs - after ovulation progesterone levels increase ready for possible embryo implantation - cycle approx 28 days
          • SAD - seasonal affective disorder - changes in eating habits , lowered moods - related to changing patterns of light - affect circadian rhythms which changes mood - serotonin levels low due to less light - treated with light therapy an, SSRI's and psychotherapy - melatonin released affects production of serotonin
        • Advantageous for mothers cycles to be synced and fall pregnant at the same time as babies could be cared for collectively so increases child's chance of survival
          • Methodological issues  such as many factors that influence women's menstrual cycle
      • ULTRADIAN - last less than 24 hours eg. human sleep - this cycle alternated between REM (rapid eye movement) and NREM (non-rapid movement) - five stages
        • eg. sleep cycle
          • Evidence from Dement and kleitman who monitored sleep patterns of 6 pp in sleep lab - brainwave patterns recorded on EEG and caffeine and alcohol were controlled  - REM activity was highly correlated with experience of dreaming
            • - = sample size
      • Endogenous pacemakers - internal mechanisms that govern biological rhythms - eg. circadian seep/wake cycle
      • Exogenous zeitgebers - influence biological rhythms - environmental events that are responsible to resetting the body clock of an organism eg. light, exercise, meal times, social activities
      • CIRCADIAN - 24 - hour eg. sleep/wake cycle and body temperature
        • SIFFRE - absence of external cues significantly affect the circadian rhythm - when he retured for an underground cave where there was no light he believed the date to be a month earlier than it was - suggests that his 24hr sleep/wake cycle was increased by lack of external cues - making him think one day was loner than it was
        • ASHOFF AND WEVER - WW2 bunker - 4 weeks - deprived of natural light - majority of pp displayed circadian rhythms between 24-25 hrs
        • Practical application in shift work - diseases resulted from stress of adjusting different sleep patterns
        • Practical application to drug treatments drug work better at different time of the day

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