Biological Explanation- Neuroanatomical Factors Flashcards
What does neuroanatomical factors mean in schizophrenia?
Research has shown that people with schizophrenia may have abnormalities in the structure of their brain
Frontal lobes:
-play a role in higher intellectual functioning and fluent expression and are smaller in schizophrenics than in control groups.
Also fits with symptoms of schizophrenics such as altered gait and posture which are known to arise from frontal lobe dysfunction.
Ventricles:
- fluid filled cavities in the brain
- they’re larger in schizophrenics, particularly on the left side.
- if there is damage to the brain and parts of it die then the ventricles will enlarge to fill the space
Andreasen conducted a well controlled CT scan study and found significant enlargement of ventricles in schizophrenia patients compared to controls
Auditory system in our brains:
Our brains auditory system allows for the interpretation of speech and areas like Wernicke’s area play an important role in speech comprehension
We also have two separate speech recognition systems, where one is wat system and determines content of speech and the others is the where system and is involved in distinguishing internal speech from external speech.
What does Plaze suggest about auditory hallucinations?
He suggested that disruption to this ‘where’ system in the auditory system could lead to a person perceiving their own internal speech as coming from an outside person.
Where else have abnormalities been found in the brain?
- in the limbic system, which has a role in the regulation of emotion
- corpus callosum which connects the two hemispheres of the brain
Evaluation of neuroanatomical features:
- Although these abnormalities have been found in schizophrenia, much of the research is difficult to interpret and there have been many contradictory findings.
- can also be difficult to disentangle cause and effect because individuals may have had symptoms for years and been taking long term medication.
What does neural correlates mean?
Neural correlates are measurements of the structure or function of the brain that correlates with schizophrenia
Juckel et al. Study of neural correlates in the ventral striatum:
(Functions as part of the reward system)
He measures activity levels in the ventral striatum in schizophrenics and found lower levels of activity than those of controls; they observed a negative correlation between activity levels in the ventral striatum and the severity of overall negative symptoms.
Therefore activity in the ventral striatum is a neural correlate of negative symptoms in schizophrenia.
Allen et al. study of neural correlates of positive symptoms:
Allen scanned the brains of patients experiencing auditory hallucinations and compared them to a control group while they identified pre-recorded speech as theirs or others.
Results: lower activation levels in the superior temporal gyrus (contains the primary auditory cortex, which is responsible for processing sounds) were found in the hallucination group who also made more errors than the control group.
Therefore, reduced activity in these areas of the brain are neural correlates of auditory hallucinations.
Evaluation of neural correlates:
-useful for flagging up particular brain systems that may not be working normally
-leaves a lot of questions unanswered: eg. Correlation between levels of activity in the ventral striatum and negative symptoms of schizophrenia;
It may be that something wrong in the striatum is causing negative symptoms, however it can also be that negative symptoms themselves means less information passes through the striatum, resulting in the reduced activity.
-A third possibility is that another factor influences both the negative symptoms and the ventral striatum activity.
-therefore neural correlates in schizophrenia tells us very little in itself.
