Seeing visual hallucinations with functional magnetic resonance imaging

Area of Science:

• Neuroscience
• Medical Imaging

Background:

• Cortical Lewy body dementia (CLBD) is characterized by visual hallucinations.
• The neural basis of these hallucinations remains unclear.
• Understanding the origin of hallucinations is crucial for effective treatment.

Purpose of the Study:

• To investigate the visual cortex response during visual hallucinations in a patient with CLBD.
• To determine if hallucinations affect primary visual cortex activity.
• To explore the role of the primary visual cortex in the generation of visual hallucinations.

Main Methods:

• Utilized blood oxygenation level dependent (BOLD) imaging with functional magnetic resonance imaging (fMRI).
• Assessed brain activity in response to photic stimulation.
• Compared fMRI data during hallucination episodes versus non-hallucination periods.
• Evaluated the effects of risperidone treatment on brain activity and hallucinations.

Main Results:

• Normal bilateral activation in the striate cortex was observed during photic stimulation when the patient was not hallucinating.
• During visual hallucinations, photic stimulation induced very limited activation in the striate cortex.
• Risperidone treatment was associated with reduced hallucinations, though fMRI data during treatment were not detailed.

Conclusions:

• The findings suggest that the primary visual cortex is involved in the experience of visual hallucinations.
• Activity in the primary visual cortex may be suppressed or altered during hallucination episodes.
• This research provides insights into the neurobiological underpinnings of visual hallucinations in CLBD.