Paper 2 - Biopsyc Flashcards
What does the CNS comprise of?
- the brain and the spinal cord SPINE: Relays info between brain and body, co-ordinates both voluntary and involuntary actions BRAIN: Cerebrum: comprises of 4 lobes Cerebellum: balance, posture, co-ord Brain stem: autonomic reg Diencephalon: thalamus, hypothalamus
What does the CNS do?
Controls behaviour and regulates physiological processes - will receive info from receptors and send impulses through the body
What does the PNS consist of?
Nerves outside of the CNS to relay impulses
Somatic pathway: 12 pairs of cranial nails and 31 pairs of spinal nerves. Relays sensory and motor to and from CNS. Voluntary and reflex
Autonomic pathway: serves as a relay between the brain/spine with the rest of the body - involuntary — splits into sympathetic: flight/fight, increases blood pressure, prep for rapid action
parasympathetic: rest/digest and relax after emergencies
Describe a neurone
Consists of a cell body, nucleus with axon and dendron (or small= dendrites) with myelin sheath
Extra info: sensory - sensory to impulse. relay - communicates between sensory and motor
motor - muscle/ contraction
What is synaptic transmission?
- Action potential travels down nerve to stimulate vesicles in the pre-synaptic knob
- Vesicles containing the neurotransmitter will move towards the membrane and excrete neurotransmitter out of the synapse (due to Ca+)
- Neurotransmitter diffuses across the gap
- It is reabsorbed - longer in the synapse, longer effect
What is the difference between excitatory and inhibitory neurotransmitters and which will be expressed?
Excitatory - fire up (adrenaline)
Inhibitory - calming (serotonin)
the summation of the two; whichever appears greater will be expressed
What does the endocrine system comprise of?
Glands and hormones: hypothalamus/ pituitary gland would be signalled to release hormones to respond to stimuli and target cells to induce physiological reactions; although dysfunction may cause Cushings syndrome/depression
- Pituitary gland regulates basic functions of the body; anterior (ACTH for stress responses and sex hormones like FSH) and posterior (oxytocin contracts uterus and important for bonding between child and mother)
- Regulated by negative feedback - keeps stable by stopping hormone levels from rising to high
- Adrenal gland; cortex - hormones necessary for life, cortisol responses to stress, for immune system and blood pressure. Aldosterone for maintaining blood pressure
- Adrenal gland; medulla - adrenaline and noradrenaline for flight/fight
- ovaries and testes
Outline the fight/flight response (PNS)
- responding to immediate stressors
- detected by amygdala which signals the hypothalamus
- activates the sympathomedullary pathway
- signal send to the adrenal medulla to release adrenaline/noradrenaline
- increases blood pressure, heart rate, digestion will stop (then switches to parasympathetic when stressor passes)
Outline the chronic stress response (HPA axis)
- when exposed to a stressor for a long period of time, it is detected by the hypothalamus to simulate the pituitary gland to produce ACTH
- ACTH stimulates adrenal cortex to release corticosteroids (cortisol) to provide energy to cope
What is localisation of brain function? What was the assumption of brain function prior to this discovery?
discovering that different areas of the brain are specifically responsible different functions
Before: holistic view of the brain but the case of Phineas Gage and psychologists like Wernicke and Broca are responsible for the change
Describe the division of the brain
- divided into two symmetrical halves (hemispheres) which are subdivided into 4 lobes - general rule: actions on the left side of the body are controlled by the right side of the brain
What are the different areas and functions of the brain? (Mums Find Sending People Videos Online Bring Wins)
Motor area (Frontal) = responsible for voluntary movements by sending signals to muscles Somatosensory area (Parietal) = receives incoming sensory info (pressure, pain temp) - more sensitive - more of the somatosensory devoted to it Visual area (Occipital) = receives and processes visual info (different types processed in different areas) Broca's area = left frontal, speech production (discovered through post-mortems) - any damage leads to aphasia (slow, lacking fluency) Wernicke's area = left temporal, language comprehension (meaningless chatter) - aphasia; nonsense words
Give strengths of research into localisation of brain function (but evaluate each strength)
- brain scanning evidence: supports neurological functions are localised - Petersen used brain scans to demonstrate how Wernicke’s area is active during listening but Broca’s active in reading. Shows diff tasks activate diff areas (also evident in Tulving’s research; episodic and semantic reside in different areas of prefrontal cortex) - objective research with mundane realism
Case : Phineas Gage: metal pole exploded through left cheek and damaged frontal lobe. Various changes in personality: aggressive, sexual - damage in specific area altered specific functions
HOWEVER… you cannot use idiographic approaches and apply them nomothetically
Neurosurgical evidence
Freeman ; surgically removing parts of the brain (lobotomy) can control different aspects (removing parts of the frontal lobe to treat aggression).
In OCD, Dougherty used 44 patients who had had a cingulotomy and successful results; suggests mental disorders are localised (33% success , 14% partial)
HOWEVER… very brutal
What are weaknesses into research in localisation of brain function?
- evidence involved in neuroplasticity:
suggests that when the brain is damaged, the rest of the brain attempts to compromise to that which is lost e.g. in stroke victims - this wouldn’t be possible if all areas of the brain are limited to one specific function
What is brain plasticity?
Refers to the brains ability to change and adapt based on experience (e.g. infants begins with a rapid growth of synaptic connections but slowly delete and strengthen those which are most frequently used - pruning - still forms beyond the critical period)
Outline Maguire’s research into neuroplasticity?
- investigated London’s cab drivers who would have extensive experience into spatial navigation (they also had to participate in ‘The Knowledge’ - memorising maps etc)
- compared them to a specifically matched control group
- found an increase in the vol of grey matter in the posterior hippocampus of the cab drivers (memory, spatial)
- correlation found between vol of grey matter and the time spent as a cab driver (growing with experience)
- SUPPORT - research by Mechelli found larger parietal cortex in bilinguals compared with monolinguals
What is functional recovery?
When the brain transfers functions from the damaged areas of the brain to non-damaged areas - begins spontaneous and then slows down (and may require rehabilitation)
How does functional recovery occur?
- rewiring and reorganisation by forming new synaptic connections and activating secondary neural pathways
- axonal sprouting (growth of nerve endings)
- reformation of blood vessels
- recruitment of homologous areas (equivalents)
Doidge
What are strengths of research into plasticity/ functional recovery?
- support from animal studies: Wiesel et al sewed a kitten’s eye shut and analysed for cortical responses. Found that the optical cortex associated with the shut-eye was not idle as it processed info from the other eye
HOWEVER… animals are different , we are potentially more complex - positive app: research contributes to the understanding of neurorehabilitation; forms of physical therapy can be used to improve functional - electrical stimulation can counter deficits in motor/cog functions to fix itself
Weaknesses of research into brain plasticity?
Negative plasticity - Medina :
- a brains ability to repair itself can be maladaptive: 60-80% of amputees have phantom limb syndrome and experience unpleasant sensation whey lost a limb- due to cortical reorganisation in somatosensory cortex
- this research doesn’t dispute plasticity as it is still an effect of it
Individual differences : Schneider; those with higher levels of education had greater disability free recovery
What is hemispheric lateralisation?
Suggests that the two halves of the brain are functionally different & certain behaviours/mental processes are mainly controlled by one half
LEFT: speech productions, analytics, language, knowledge
RIGHT: creative, emotional, visual motor
They communicate through the corpus callosum
What was Sperry’s method?
Aimed to see the extent to which different hemispheres are specialised
Used split-brain patients (undergone surgery which removed their corpus callosum to stop seizures) - this means they had lack of communication between the sides
Carried out several tasks
Explain Sperry’s findings
Describe what you see: picture in the RVF and they could describe it (left hemisphere processed it)
Shown in LVF, could not process/describe (lack of language)
Tactile task: object placed in right hand and they were able to describe and identify against alternatives (left hemisphere). When placed in left hand, couldn’t describe, but could feel and identify against alternatives
Drawing and matching faces: LVF (right hemisphere), consistently draw (still true even for right handed ppts) - visual motor in right. RVF - left hemisphere - never clear drawings but attempts made
What are strengths of research into hemispheric lateralisation?
- Lab experiments: controlled, standardised procedures which can be repeated. Controlled extraneous variable and only flashed images for 1/10th of a second to stop eyes communicating.
Control groups
HOWEVER… lacks mundane realism - Gazzinga and Sperry : Demonstrating a plethora of research which shows the right hemisphere is the synthesiser whereas the left hemisphere is analyser
- Theoretical basis: allowed theorists like Pucetti to suggest that the two hemispheres are functionally different and we have duality and two minds in everyday situation, using split brain patients just emphasises the duality rather than creating. Stimulates need for further research