ocd bio exp: brain struc and functioning

Question 1

what does the thalamus do

Answer 1

primitive checking and cleaning behaviours- if overactive it triggers a compulsion

Question 2

what is the orbitofrontal cortex

Answer 2

alerts the brains to worries in the environment if overactive the person may have anxiety

Question 3

what is the cingulate gyrus

Answer 3

connects thalamus and orbitofrontal cortex

Question 4

what is the basal ganglia nuclei doing

Answer 4

strongly interconnected with cerebral cortex and thalamus - its meant to inhibit the thalamus so if not working it cannot do this and causes thalamus to be overactive and therefore cause compulsions
globus pallidus braking system for thalamus
Caudate nucleus to calm globus pallidus- if this doesnt hapen then globus cant calm thalamus –> compulsion

Question 5

strengths of bio exp- supporting evidence of ocd

Answer 5

brain scans show differences in brain structure and controls eg menzies 2007 found ppl suffering from OCD different amount of grey matter in orbitofrontal cortex to those w/o and studies with OCD smaller caudate nucleus

show functioning difference- whiteside et al 2005 found cingulate gyrus,basal ganglia, and oc more active when OCD symp stimulated- no longer after DRUG THERAPY AND CBT

salloway and duffy 2002 PET scans of OCD patients had more activity in pfc
because brain scans are scientific way of investigating OCD and other explanations have similar findings

surgical lesioning of cingulate gyrus- good treatment
and alternative explanations- ocd 87% in MZ twins for pos and features

Question 6

limitations of bio exp- ocd

Answer 6

surgery doesnt always work and ocd is more complexkireev et al functions perfomed by cingulate gyrus can be taken over by other areas of the brain so reductionist

brain activity and thoughts are related so it’s difficult to say if brain acitiyt altered thoughts or vice vesa- so they cannot be seperated so it it’s hard to measure cause and effect

against genetic link- they may show higher concordance in MZ but may diagnosed with OCD had no family history

Question 7

what is the cognitive explanation

Answer 7

thoughts ead to emotions which trigger behaviours. thought processes of people who have ocd are better explanation. people with ocd misinterept their thoughts due to false beliefs in earlier life-

if people interpret intrusive thoughts as catastrophic and if they believe their thinking holds truth continue to be distressed and practice avoidance/ritual behaviour- attach exaggerated danger to thoughts because of false beliefs learnt earlier in life salkovkis beliefs important in dev and maintaining obsession eg overestimate danger

Question 8

2 other explanations of cognitive explanations

Answer 8

memory problems sher et al people with OCD had poor memories using standardised rating scales for checking behaviour and woods et al found ocd worse memories for recalling

hypervigilant williams et al attention bias so over sensitive for feel anxious to threats and compulsions
rachman case study of patient w fear of diseases and catastrophic thoughts on AIDs etc and over-estimated and rapid scanned environment

Question 9

strengths of cog exp

Answer 9

supporting evidence eg sher et al ppl w ocd had poor memories- scientific cred
therapy based on cog exp has been sucessful eg van balkom et al fund it was effective as drug treatment
accounts for individual differences

Question 10

weaknesses of cog exp

Answer 10

doesn’t prove cause and effect link- faulty cognitions can be a symp of OCD
reductionist ignores bio and learning in the dev of cognitions