Neural explanations of OCD

Question 1

How does abnormal levels of neurotransmitter act as an explanation of OCD?

Answer 1

Dopamine levels are thought to be abnormally high in people with OCD
Lower levels of serotonin are found in people with OCD as well ( based on the conclusion that antidepressant drugs that increase serotonin reduce OCD symptoms)

Question 2

How do abnormal brain circuits link to OCD?

Answer 2

• Serotonin and dopamine are linked to these regions of the frontal lobes
• Comer in 1998 reports that serotonin plays a key role in the operation of the OFC
• it appears that abnormal levels of serotonin plays a key role in the operation in the OFC and the caudate nuclei it may cause these areas to malfunction
• Dopamine is also linked to this system as it is the main neurotransmitter of the basal ganglia.
• high levels of dopamine lead to over activity of this region (Sukel 2007)

Question 3

What did Comer in 1998 find out?

Answer 3

that serotonin plays a key role in the operation of the OFC and the caudate nuclei
this means that abnormal levels of serotonin may cause these areas to malfunction.

Question 4

Discuss abnormal brain circuits

Answer 4

• areas in the frontal lobe are thought to be abnormal in people with OCD
• the caudate nucleus (located in the basal ganglia) normally suppresses signals from the orbitiofrontal cortex
• in turn the OFC sends signals to the thalamus about things that are worrying such as a potential germ hazard
• when the caudate nucleus is damaged, it fails to suppress minor worry signals and the thalamus is alerted
• this in turn sends signals back to the OFC acting as a worry circuit
• this is supported by brain scans (PET) which show high levels of activity in the OFC