Attentional alterations in migraine: a behavioral and M/EEG study

ABSTRACT Migraine is characterized by a hypersensitivity to environmental stimulation which climaxes during attacks but persists interictally. This multisensory disturbance may arise from a dysfunction of top-down and/or bottom-up attention which would lead to the inability to filter out irrelevant information and a state of sensory overload. We used a recent paradigm to evaluate jointly top-down and bottom-up attention among migraineurs and healthy controls using visually-cued target sounds and unexpected task-irrelevant distracting sounds. Behavioral responses and MEG/EEG were recorded. At the behavioral level, neither top-down nor bottom-up attentional processes appeared to be altered in migraine. However, migraineurs presented heightened evoked responses following distracting sounds (orienting component of the N1 and Re-Orienting Negativity, RON) and following target sounds (orienting component of the N1), concomitant to an increased recruitment of the right temporo-parietal junction. They also displayed an increased effect of the cue informational value on target processing resulting in the elicitation of a negative difference (Nd). Based on these results, migraineurs appear to present an increased bottom-up orienting response to all incoming sounds, and an enhanced recruitment of top-down attention. We propose that the interictal state in migraine is characterized by a dysfunction of bottom-up attention and that the hyperfunction of top-down attention acts as a compensatory mechanism enabling them to maintain adequate task-efficiency. These attentional alterations might participate to the disruptions of sensory processing in migraine.