Schizophrenia; Structural Abnormalities

Question 1

Enlarged ventricles

Answer 1

• ventricles are cavities that produce and transport cerebrospinal fluid.
• cerebrospinal fluid is important as it provides protection, buoyancy and chemical stability to the brain and spine. there are four ventricles in the brain;
  the left and right lateral ventricles (situated in the frontal, occipital and temporal lobes of their respective hemisphere).
  The third ventricle situated between the left and right thalamus.
  The fourth ventricle which lies between the pons and pedulla oblongata.
• Nancy Andreasan (1988) studied MRI scans of individuals with and without schizophrenia, and found that those with schizophrenia had ventricles which were 20% to 50% larger than in controls.

Question 2

Cortical Atrophy

Answer 2

• Cortical atrophy means the loss of neurons in the cerebral cortex. cortical atrophy can occur all over the brain (making it look like it has shrunk) or atrophy can be focused in a limited area.
• In the latter case the atrophy obviously affects the cognitive functions of that area of the cerebral cortex. The atrophy results in the widening of the grooves (called sulci) covering the cerebral cortex. This type of damage appears to characterise the brains of 20% to 35% of people with chronic schizophrenia.
• Antonio Vita et al (1988) used to CAT scans to assess 124 individuals with schizophrenia and 45 control group participants. They found that 33% of the individuals with schizophrenia showed moderate to severe atrophy.
• Atrophy was not found to be related to many individual differences such as age, age of onset or family history, but it was found to be related to sex (specifically male) and if there was also ventricular enlargement.

Question 3

Reversed Cerebral asymmetry

Answer 3

• in most individuals without schizophrenia the left hemisphere is slightly larger than the right hemisphere (cerebral asymmetry). However, in so,e individuals with schizophrenia the right hemisphere is notably larger than the left (reversed cerebral asymmetry). This is relevant when considering that language function is normally found in the left hemisphere, so damage and deterioration in the left hemisphere could lead to the poverty of language (alogia) which is often seen in schizophrenia.
• Daniel Luchins et al. (1979) compared, using CAT scans, 80 right handed people without schizophrenia to 57 left handed people without schizophrenia. They found that there was an increase in the frequency of reversals in both the frontal and occipital lobes of those of those with schizophrenia, but only in those who had no other form of atrophy.
• Those individuals with schizophrenia who had evidence of atrophy had no higher level of reversals than the control group.