A new brain imaging study from
the Institute of Psychiatry shows for the first time that the thalamus, the
brain's main sensory filter or 'hub', is smaller than normal from the earliest
stages of schizophrenia. The findings, published in the American Journal of
Psychiatry in January, may explain why people with schizophrenia experience
confusion during their illness.
The thalamus is the area where information is received and relayed to
other areas of the brain. It is of particular interest in schizophrenia
because of the role it plays in processing information. The thalamus receives
information via the senses, which is then filtered and passed to the correct
regions of the brain for processing. People with schizophrenia often have
difficulties in processing information properly and as a result may end up
with an information overload in some areas of the brain.
This study, led by Dr. Tonmoy Sharma, involved 67 participants: 38 were
experiencing their first episode of psychosis and 29 were healthy volunteers.
In contrast to other studies, thirteen of the people with schizophrenia had no
or little experience of antipsychotic medication.
Magnetic resonance imaging (MRI) scans identified differences in the
thalamus between the two groups. Previous MRI studies have identified several
brain regions affected by schizophrenia, but the results in the thalamus have
been inconclusive. This study finds that even in the earliest stages of
schizophrenia the thalamus is smaller than in healthy people.
Dr. Tonmoy Sharma said: "This study reveals that there is a fundamental
problem in the hub of the brain. If you think of the brain in terms of
networks, it is like making a phone call when the line is not connected
properly, the call can't be made, or you may get through to the wrong person.
It is the same in the brain. If there are problems with the connections,
information will not be passed to the correct regions. The ability to filter
and process information is vital for leading a normal life."
These findings, along with a recent study from Dr. Sharma's team that
showed people with schizophrenia have decreased grey matter at the earliest
stages of the illness suggest a role for brain imaging in pinpointing warning
signs of the illness and even preventing its development.
Reference: U.Ettinger et al. Magnetic resonance imaging of the Thalamus
in first episode psychosis. American Journal of Psychiatry 2001; 158 (1)