Biological explanation of OCD Brain Activity

Changes in brain activity Brain scans have shown that people with OCD seem to show more activity in three brain areas: Basal Ganglia Prefrontal Orbital Cortex Cingulate Gryus Explain what function the three parts of the brain have.

Using Page 81: Outline the differences in brain activity in those with OCD: Basal Ganglia Prefrontal Orbital Cortex Cingulate Gryus

Loop of Circuit

This circuit regulates primitive aspects of our behaviour such as aggression, sexuality, and bodily excretions. When this circuit is activated, these impulses are brought to your attention and cause you to perform a particular behaviour that appropriately addresses the impulse. For example, after a visit to the bathroom, you may begin to wash your hands to remove any harmful germs you may have encountered. Once you have performed the appropriate behaviour — in this case, washing your hands — the impulse from this brain circuit diminishes and you stop washing your hands and go about your day. It has been suggested that if you have OCD, your brain has difficulty turning off or ignoring impulses from this circuit. This, in turn means the obsessions and compulsions continue, leading you to wash your hands again and again

Serotonin Abnormalities, or an imbalance in the neurotransmitter, or brain chemical, serotonin, may also help explain OCD. Serotonin is the chemical in the brain that sends messages between brain cells and it is thought to be involved in regulating everything from anxiety, to memory, to sleep. Medications known as Selective Serotonin Re-uptake Inhibitors (SSRIs) are often used to treat OCD Studies have shown that OCD patients tend to have lower levels of this neurotransmitter (NT). Because serotonin is essential for nerve cell communication, it has been proposed that the dysfunction of the “worry circuit/loop” may be caused by the imbalance of serotonin. Baxter et al. (1992) proposed that the 3 brain parts involved in the "worry circuit" can become unlinked with Prozac (SSRI). Evidence for the breakup of the "worry circuit" comes from PET scans which show less activity in the right caudate nucleus after effective pharmacological or psychological therapy.

Diagram to consolidate your understanding Biological explanation of OCD

Describe the biological explanation of OCD (6 marks)

Evaluation – two groups SODAR Group one 1 2 3 Group two 5 6 7 One group : strengths Second group: limitations Using resources on the learning space complete the table. Be prepared to feedback to the class to ensure everyone has notes on all points. (can be added to a shared doc)

Mini class debate Two groups 1: The cognitive explanation is a more appropriate explanation for OCD 2: The biological explanation is a more appropriate explanation for OCD Using the table provide evidence to back up the idea you have been assigned

H/W Revise for class test on OCD characteristics and explanations of OCD