Neural correlates associated with impaired disgust processing in pre-symptomatic Huntington's disease

Area of Science:

• Neuroscience
• Neurology
• Psychology

Background:

• Facial expression recognition, particularly disgust, is impaired in Huntington's disease.
• The insula and basal ganglia are critical for disgust perception.
• Neural substrates of early-stage Huntington's disease (HD) emotion processing are not fully understood.

Purpose of the Study:

• To investigate neural correlates of disgust processing in pre-symptomatic Huntington's disease gene carriers.
• To examine insula and basal ganglia function using functional MRI (fMRI).
• To correlate neural findings with behavioral deficits in disgust recognition.

Main Methods:

• Functional MRI (fMRI) was used to study brain activity in nine pre-symptomatic HD gene carriers and nine matched healthy controls.
• Participants viewed facial expressions of disgust, surprise, and neutral emotions.
• Behavioral tests assessed facial expression recognition accuracy.

Main Results:

• HD gene carriers exhibited reduced activation in the left dorsal anterior insula when processing disgusted facial expressions compared to controls.
• Healthy controls showed significant activation in the left dorsal anterior insula and putamen during disgust processing, which was absent in HD gene carriers.
• Behavioral analysis confirmed a selective impairment in recognizing disgust facial expressions among HD gene carriers.

Conclusions:

• Reduced insula activation in pre-symptomatic HD gene carriers explains deficits in recognizing disgust.
• This finding highlights the insula's crucial role in disgust processing and its vulnerability in early HD.
• The study provides a neural basis for early emotional processing disturbances in Huntington's disease.