Biological explation for Schizophrenia : Neural Correlates

Question 1

Neural Correlates

Answer 1

Measurments of the strucutre of the brain that correlate with an experiences, in this case schizophrenia.

Question 2

Neural correlates of negative symptoms

Answer 2

Avolution = loss of motivation
- Motivation involves anticipation of reward and certain regions of the brain, including the ventral straium, are believed to be particulary involved in this anticipation

Question 3

Neural correlates of negative symptoms

Juckle (2006) - Negative correlation between levels of activity + negative symptoms

Answer 3

Found lower leveel of activity compared to a control group in the ventral straitum of schizophrenic paitents compared to controls.

Question 4

Neural correlates of positive symptoms

Answer 4

Allen et al (2007) found lower activation levels in their superior temporal gyrus and the anterior cingulate gyrus in those experirncing auditory hallucinations.

Question 5

Anterior cingulate cortex (ACC)

Answer 5

The frontal part of the cingulate cortex. It is also involved in certain high-level functions, such as reward anticipation, decision-making impulse control,and emotion

Question 6

Ventral striatum

Answer 6

The front part of the striatum, which is a major portion of the basal ganglia and functions as part of the reward system

Question 7

The superior temporal gyrus

Answer 7

Involved in the perception of emotions in facial stimuli. Furthermore,
- an essential structure involved in auditory processing, as well as in the function of language in individuals who may have an impaired vocabulary, or are developing a sense of language.

Question 8

Neural Correlates - The Prefrontal Cortex

Answer 8

• Involved in executive control

- Research has shown that this impaired in sz paitents (Weinberger and Gallhofer, 1997)

Question 9

Neural correlates - The hippocampus

Answer 9

• Several studies have reported changes in the hippocampus in SZ paitents
  (Conrad et al.,1991).
• Deficits in the nerve connections memory

Question 10

Neural correlates - The hippocampus(Mukai et al.2015)

Answer 10

Deficits in the nerve connections memory impairments a central cogitve impairemny in SZ

Question 11

Goto and Grace (2008) Neural correlates - The hippocampus

Answer 11

Suggest that hippocampal dysfunction might influence level of dopamine release in the basal ganlia, indirectly affecting the processing of information in the prefrontal cortex.

Question 12

Neural correlates - Grey Matter

Answer 12

• Individuals with SZ have a reduced volume of grey matter.
• Researcher have also found that many people have SZ, particulary those
  displaying negative symptoms have enlarged ventricles. (Hartberg et al. 2011)

Question 13

Cannon et al. (2014)

Answer 13

Found that individuals at high clinical risk who converted to SZ showed a steeper rate of grey matter loss and greater rate of expansion of brain ventricles compared to those who did not convert to SZ.

Question 14

Neural correlates - White Matter

Answer 14

Found in the brain and spinal cord and is made up of nerve fibres covered in myelin.

Question 15

Du et al. 2013 Neural correlates - White Matter

Answer 15

Found reduced myelination of white matter pathways in SZ paitents, compared to healthy controls.

Question 16

AO3 Neural correlates - Support for the influence of grey matter deficits
Vita et al. (2012)

Answer 16

Analysed the results of 19 stufies. Paitents with schziophrenia, compared with healthy controls, showed higher reudction is cortical grey matter over time.
- Pattern of grey matter reduction was specific to discrete cortical areas in frontal, temporal and partial lobes.

Question 17

Link sentence Grey deficits AO3 Neural correlates - Support for the influence of grey matter deficits
Vita et al. (2012)

Answer 17

The loss of grey matter was especially active in the first stage of the disease consistent with the relatively early onset of SZ.

Question 18

Challenges to dopamine hypothesis - Noll (2009)

Answer 18

Argues that antipsychotic drugs do not alleviate hallucinations and delusions in about 1/3 of people experiencing these symptoms.

Question 19

Challenges to dopamine hypothesis - Noll (2009) - Link sentence

Answer 19

dopamine being the sole of postive symptoms other neurotransmitter systems, acting independently of the dopaminergic system, may also roduce the + symptoms associated with SZ

Question 20

The dopamine hypothesis: Evidence from treatment (Support)

Leucht et al. (2013)

Answer 20

Carried out a meta analysis of 212 studies. They conducted that all the antipsychotic drug tested in these studies were significantly more effective than placebo in the treatment of + symptoms, acheieved by reducing the effects of dopamine.

Question 21

Challenges to dopamine hypothesis - Noll (2009) - Link sentence

Answer 21

Findings also challenge the classfication of antipsychotic into typical and atypica groupings as differences in their effectiveness were only small.

Question 22

Genetic Factors - AO1

Question 23

Familiy studies

Answer 23

Have established that schizophrenia is more common among biological relatices of a person with SZ.

Question 24

Twin studies

Answer 24

If MZ twins are more concordant than DZ twins this suggests that the greater similary is due to genetic factors.

Question 25

Joeseph 2004

Answer 25

MZ - 40.4%, DZ = 7.4%

Question 26

Adoption studies

Answer 26

As of the difficulties disentagling genetic and enviromental influences for individuals who share genes and enviroment, studies of genetically related individuals who have ben reared apart are used.

Question 27

Adoption studies Tienari et al. 2000

Answer 27

Of 164 adoptees whose other had been diagnosed with SZ.

- 6.7% also recieved a diagnosis compared to only 2% of controls.

Question 28

AO3 Adoption studies
Joeseph (2004) MZ Twins
AO3

Answer 28

Twin studies assume that the enviroment of MZ and DZ are equivalent.
- it is widley accepted that MZ twins are treated more similairy.

Question 29

AO3 Adoption studies
Joeseph (2004) MZ Twins
AO3
Importance of this

Answer 29

It allows us to see that there is great similarity in genetic factor and concordance rate of MZ twins could be more similar enviroment rather than genetic factors

Question 30

More specific genetic explanation

Answer 30

Point = SZ is a polygenetic - it requires a number of factors work in combination.

Explain = As there is no ‘SZ gene’ but severa; this increases an individuals overal vulnerability to developing SZ.

Evidence = Ripke et al (2014)

Question 31

Ripke et al. (2014)

Answer 31

Carried out a huge study combinding all previous data from genome-wide studies.

• The genetic make-up of 37,000 paitents was compared to that on 112,00 controls
• 108 separate genetic variations were associated with increased risk of SZ.

Question 32

The Dopamine Hypothesis - Support

Curran et al 2004

Answer 32

Amphetamines that increase the levels of dopamine make SZ worse and can produce SZ like symptoms in non-suffers.

Question 33

The Dopamine Hypothesis - Support

Leucht et al 2013

Answer 33

• Carried out a meta-analysis of 212 studies
• Analysed the effectiveness of different antipsychotic drugs compared to placebo
• Findings = That all drugs tested were significantly more effective than placebo in the treatment of +ve and -ve symptoms