Brain responses to emotional stimuli in patients with amyotrophic lateral sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS), a progressive motor neuron disease, affects movement and communication abilities and emotional processing. Subjective ratings of emotional stimuli depicting social interactions and facial expressions differed significantly between ALS patients and healthy controls in a previous study with a reduction of negative emotional valence (pleasantness) and lower subjective arousal (excitement) in ALS patients. In the present study, sixty similar emotional slides were presented to 13 ALS patients, 15 matched healthy controls and six tetraplegic patients. Subjective reports of valence and arousal as well as brain responses to the affective pictures using functional magnetic resonance imaging (fMRI) were measured. The picture series was presented twice with a 6-months interval to investigate effects of disease progression. ALS patients presented an increased brain response in the right supramarginal area and a reduced brain response in extrastriate visual areas at both measurements compared with healthy controls. Within the ALS patients' group a reduction of brain responses in the anterior insula at the follow-up was correlated with the subjective arousal. The reduced response in the anterior insula is tentatively interpreted as indicating reduced arousal during the course of the disease at the neural and behavioural level. The reduction of activity in extrastriate visual areas might be similarly interpreted. The increased brain response in the right supramarginal area of ALS patients might represent an altered sensitivity to social-emotional cues.