Investigation of the neural correlates underlying action observation in multiple sclerosis patients

• Published in: Experimental neurology Vol. 217; no. 2; pp. 252 - 257
• Main Authors: Pierno, Andrea C., Turella, Luca, Grossi, Paola, Tubaldi, Federico, Calabrese, Massimiliano, Perini, Paola, Barachino, Luigi, Morra, Aldo, Gallo, Paolo, Castiello, Umberto
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.06.2009; Elsevier
• Subjects: Adult; Biological and medical sciences; Brain Mapping; Cerebral Cortex - anatomy & histology; Cerebral Cortex - physiology; Cerebrovascular Circulation; Female; Functional Laterality - physiology; Hand - innervation; Hand - physiology; Hand Strength - physiology; Humans; Imitative Behavior - physiology; Magnetic Resonance Imaging; Male; Medical sciences; Movement - physiology; Movement Disorders - complications; Movement Disorders - physiopathology; Movement Disorders - psychology; Multiple Sclerosis - complications; Multiple Sclerosis - physiopathology; Multiple Sclerosis - psychology; Multiple sclerosis and variants. Guillain barré syndrome and other inflammatory polyneuropathies. Leukoencephalitis; Nerve Net - anatomy & histology; Nerve Net - physiology; Neurology; Neuronal Plasticity - physiology; Neuropsychological Tests; Photic Stimulation; Psychomotor Performance - physiology; Young Adult; Human; Nervous system diseases; Multiple sclerosis; Central nervous system disease; Inflammatory disease
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1016/j.expneurol.2009.02.016

Recent fMRI evidence indicates that both the execution and the observation of hand actions in multiple sclerosis (MS) patients increase recruitment of a portion of the so-called mirror neuron system. However, it remains unclear whether this is the expression of a compensatory mechanism for the coding of observed action or whether such a mechanism represents a rather unspecific functional adaptation process. Here we used fMRI on early relapsing remitting MS (RRMS) patients to clarify this issue. Functional images of 15 right-handed early RRMS patients and of 15 sex- and age-matched right-handed healthy controls were acquired using a 1.5 T scanner. During scanning, participants simply observed images depicting a human hand either grasping an object or resting alongside an object. As shown by a between-group analysis, when compared to controls, RRMS patients revealed a robust increase of activation in an extensive network of brain regions including frontal, parietal, temporal and visual areas usually activated during action observation. However, this pattern of hemodynamic activity was completely independent of the type of observed hand–object interaction as revealed by the lack of any significant between-group interaction. Our findings are in line with previous fMRI evidence demonstrating cortical reorganization in MS patients during action observation. However, based on our findings we go one step further and suggest that such functional cortical changes may be the expression of a generalized and unspecific compensatory mechanism, that is not necessarily involved in action understanding.