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Cognitive impairment (CI) is a common and disabling symptom of Multiple Sclerosis (MS) with a negative impact on daily living. In this pilot study, we applied magnetoencephalography (MEG) and high density (hd) electroencephalography (EEG) study to evaluate acoustic P300 features in a cohort of early MS. Sixteen MS patients (pwMS) and 19 healthy controls (HCs) matched for age and gender underwent an MEG-/(hd)-EEG-co-recording, using 306-channel Vectorview and 64 scalp electrodes. CI was assessed using Rao's Brief Repeatable Battery (BRB). Moreover, we performed psychometric tests to assess depression and fatigue. In pwMS, we observed a slight latency prolongation of P300 peak compared to HCs, while P300 amplitude and scalp distribution were similar in the two groups. pwMS did not show an amplitude reduction and different scalp distribution of Event-Related Potentials (ERPs) and Event Related Fields (ERFs) related to an acoustic oddball paradigm. We found an inverse correlation between P300 amplitude and fatigue (r Spearman = −0.4; p = 0.019). In pwMS, phenomena of cortical adaptation to early dysfunction could preserve the cognitive performance of the P300 acoustic task, while the development of fatigue could prospectively lead to amplitude decline of P300, suggesting its possible role as a biomarker. [ABSTRACT FROM AUTHOR]

A consistent finding in migraine is reduced cortical habituation to repetitive sensory stimuli. This study investigated brain dynamics underlying the atypical habituation to painful stimuli in interictal migraine. We investigated modulations in effective connectivity between the sources of laser evoked potentials (LEPs) from a first to final block of trigeminal LEPs using dynamic causal modelling (DCM) in a group of 23 migraine patients and 20 controls. Additionally, we looked whether the strength of dynamical connections in the migrainous brain is initially different. The examined network consisted of the secondary somatosensory areas (lS2, rS2), insulae (lIns, rIns), anterior cingulate cortex (ACC), contralateral primary somatosensory cortex (lS1), and a hidden source assumed to represent the thalamus. Results suggest that migraine patients show initially heightened communication between lS1 and the thalamus, in both directions. After repetitive stimulations, connection strengths from the thalamus to all somatosensory areas habituated in controls whereas this was not apparent in migraine. Together with further abnormalities in initial connectivity strengths and modulations between the thalamus and the insulae, these results are in line with altered thalamo-cortical network dynamics in migraine. Group differences in connectivity from and to the insulae including interhemispheric connections, suggests an important role of the insulae. [ABSTRACT FROM AUTHOR]

• Central gamma-band oscillations (GBOs) seem to be related to pain perception in controls but not in migraine. • No differences were found in nociceptive-related GBOs between interictal migraine patients and controls. • We suggest the midcingulate cortex to be a source of nociceptive-related GBOs. Gamma-band oscillations (GBOs) induced by nociceptive stimuli were compared between migraine patients and controls in order to further characterize interictal pain processing in the brain of migraineurs. GBOs were related to subjective pain intensity, years of migraine history and migraine attack frequency and the sources of GBOs were investigated. Twenty-three migraine patients without aura and 23 controls received a series of laser stimulations on their right forehead and right hand while recording electroencephalographic data (61 electrodes). After each series they indicated the perceived pain. A multitaper time-frequency method was used on artifact-cleaned scalp data and frequency domain beamforming was used to localize the GBOs. In both groups we observed increases in GBOs around central electrodes, which were not significantly different between groups. The central GBOs were positively associated with the subjective pain ratings in the control group, in accordance with previous studies, but not in the migraine group. Increases in gamma power were observed in the midcingulate cortex. No evidence was found that GBOs differ between interictal migraine and controls nor that central GBOs represent a neurophysiological correlate of subjective pain in migraine. We shed light on observations of GBOs during pain processing in interictal migraine. [ABSTRACT FROM AUTHOR]