Lesson 14 - The Neurobiology of Anxiety Disorders

What are the main brain imaging techniques used to study anxiety disorders?

• PET (Positron Emission Tomography): Measures blood flow or glucose metabolism.

• SPEC (Single Photon Emission Photography): Measures blood flow.

• fMRI (Functional Magnetic Resonance Imaging): Measures BOLD (blood oxygenation level-dependent) signal changes.

What are the key PET scan findings in PTSD patients?

• Increased amygdala response when reminded of past trauma.

• Smaller responses in the medial frontal cortex (impaired emotion regulation).

• Exaggerated deactivation in some frontal cortical areas (dysregulated fear response).

What does fMRI reveal about PTSD patients in masked face studies?

PTSD patients show hyperactivity of the amygdala even when viewing neutral faces.

How does Social Anxiety Disorder (SAD) affect brain activity?

• Amygdala hyper-responsiveness to neutral human faces.

• Study: SAD patients exposed to aversive odors and neutral faces still showed increased amygdala activation

What is the "False Suffocation Alarm" theory in panic disorder?

• Panic attacks may result from aberrant responsivity to CO2 at the brainstem level.

• The body misinterprets normal respiratory signals as a suffocation threat.

What is CCK-4, and how is it linked to panic attacks?

Cholecystokinin-tetrapeptide (CCK-4) is a neuropeptide that induces panic attacks in susceptible individuals.

What brain region is linked to anticipatory anxiety?

Cingulate Cortex plays a key role in anticipation of anxiety and fear of future panic attacks.

How is GABA dysfunction related to panic disorder and what are the affected regions?

Panic disorder patients show decreased GABAA-benzodiazepine receptor binding in the brain.

• Affected regions include:

  • Thalamus

  • Caudate nucleus

  • Frontal cortex

  • Temporal cortex

  • Insula