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Simple imaginary movements activate similar cortical and subcortical areas to actual movements, chiefly in the sensory-motor network. However, only a few studies also examined the imagery of more skilful movements such as reaching. Ten volunteers performed reaching movements or imagined the same movements. EEG was simultaneously recorded and analysed with sLORETA, which compared the preparation for actual and imagined reaching with respect to their baseline and between tasks. Major differences between them were found at three time intervals after target presentation, always in favour of the actual reaching condition. The first one was from 160 to 220 msec in the frontal and parietal regions. The second difference was evident from 220 to 320 msec in the premotor cortex. The third difference was evident from 320 msec, mainly in the perirolandic region. Also, the anterior and posterior cingulate cortices were widely involved, in both tasks. We suggest the existence of two separate systems which may work together during actual reaching programming. The first one involves structures such as the premotor cortex, supplementary motor area and primary motor cortex, together with the parietal and occipital cortex. This system may integrate extrinsic target coordinates with proprioceptive information from the reaching arm and pre-stored programs in the associative motor cortex. It is activated strongly and involves more cortical areas in actual than imagined reaching. The second system, common to both tasks, involves anterior and posterior cingulate cortices, with the possible role of contributing awareness and focusing the various components of the process.

Unlabelled: Rett syndrome (RTT) is a frequent neurodevelopmental disorder confirmed by clinical criteria and supported by the methyl-CpG-binding protein 2 gene (MECP2) mutation. A short central motor conduction time (CMCT) was reported in transcranial magnetic stimulation (TMS) studies performed in RTT. This was attributed to hyperexcitability of the motor cortex and/or spinal motor neurons, but was not studied further., Aim: We performed TMS in RTT to evaluate motor cortex excitability by determining the cortical motor threshold (CMT) and motor cortex inhibition by the cortical silent period (CSP) besides measuring CMCT., Methods: Single-pulse TMS was performed in 17 Rett patients, diagnosed by clinical criteria and MECP2 mutation testing, and the same number of healthy controls. The outcome measures were compared between RTT groups with different antiepileptic drugs (AED) and those with and without the MECP2 mutation., Results: CMCT was shorter, but we found elevated CMT and shorter CSP, which suggests decreased excitatory and inhibitory motor cortical function. The outcome was independent of AED and the presence or absence of the MECP2 mutation., Interpretation: Decreased excitatory and inhibitory motor cortical function could explain the short CMCT, with higher stimulus intensities needed to excite pyramidal neurons., (Copyright © 2016 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)

Objective: This study explored event-related desynchronization (ERD) and synchronization (ERS) in amyotrophic lateral sclerosis (ALS) to quantify cortical sensorimotor processes during volitional movements. We furthermore compared ERD/ERS measures with clinical scores and movement-related cortical potential (MRCP) amplitudes., Methods: Electroencephalograms were recorded while 21 ALS patients and 19 controls performed two self-paced motor tasks: sniffing and right index finger flexion. Based on Wavelet analysis the alpha and beta frequency bands were selected for subsequent evaluation., Results: Patients generated significantly smaller resting alpha spectral power density (SPD) and smaller beta ERD compared to controls. Additionally patients exhibited merely unilateral post-movement ERS (beta rebound) whereas this phenomenon was bilateral in controls. ERD/ERS amplitudes did not correlate with corresponding MRCPs for either patients or controls., Conclusions: The smaller resting alpha SPD and beta ERD and asymmetrical appearance of beta ERS in patients compared to controls could be the result of pyramidal cell degeneration and/or corpus callosum involvement in ALS., Significance: These results support the notion of reduced movement preparation in ALS involving also areas outside the motor cortex. Furthermore post-movement cortical inhibition seems to be impaired in ALS. ERD/ERS and MRCP are found to be independent measures of cortical motor functions in ALS., (Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Our aim was to investigate changes in movement-related cortical potentials (MRCPs) in ALS patients with different degrees of upper motor neuron (UMN) involvement. Since respiratory failure is the main cause of death in ALS, changes in inspiratory-related (sniffing) potentials were studied in addition to finger-flexion-related potentials. Subjects (21 ALS, 19 controls) performed two self-paced motor tasks while their EEGs were recorded. The first task required flexions of the right index finger and the second, brisk nasal inspirations. The early (BP1), late (BP2) and motor potential (MP) components of MRCPs were evaluated. Results showed that patients generated higher MRCPs than controls. However, this effect was most significant in the subgroup of patients with low UMN burden (LUB). The high UMN burden (HUB) subgroup did not differ from controls, but had significantly lower MP amplitudes than the LUB subgroup. Progressive UMN deterioration was associated with an initial increase, followed by a later decrease, in MP amplitudes in ALS. In conclusion, the increased MRCPs in LUB compared to HUB patients indicate different processes of ALS pathophysiology that force opposing changes in MRCP amplitudes.

This study estimated the whole-scalp topography and possible generators of the cortical potential associated with volitional self-paced inspirations (sniffs). In 17 healthy subjects we recorded a 32-channel electroencephalogram (EEG) during sniffing, for comparison during finger flexions. We averaged the EEG with respect to movement onset, and performed current source density and principal component analysis on the grand averaged data. We identified an early negative sniffing-related cortical potential starting ∼1.5s before movement at the vertex, which, in its time-course and dipole orientation, closely resembled Bereitshaftspotential preceding finger flexions. Around the movement onset, its topography became unique with three negative current sources: one at the vertex, and two bilaterally over the fronto-temporal derivations. We conclude that sequential cortical activation in preparation for sniffing is similar to other volitional movements. The current sources at sniff onset at the vertex likely reflect somatotopic motor representation of the diaphragm, neck and intercostal muscles, whereas current sources over fronto-temporal derivations likely reflect the somatotopic representation of the orofacial muscles., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Objective: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by degeneration of the upper and lower motor neurons. Each voluntary movement, including inspiration, is preceded by movement-related cortical potential (MRCP) that can be recorded from the scalp. MRCPs of ALS patients with severe upper motor neuron involvement are smaller. Our aim was to explore whether the inspiratory-(sniffing)-related cortical potentials (SRCPs) and index-finger-flexion MRCPs (FFRCPs) can be used as markers of cortical involvement in ALS., Methods: Thirteen ALS patients and 15 healthy volunteers were assessed for their hand dexterity and strength, respiratory function, speech capacity, spasticity, electromyographic parameters and functional rating scales. EEG was recorded during self-paced sniffing and the right index finger flexion. The MRCP amplitudes were assessed at the relevant electrode positions., Results: No statistically significant difference was found between the MRCP amplitudes of the ALS patients and the control subjects. However, patients with more severely affected upper limb functions generated smaller FFRCPs and those with more affected respiratory functions generated smaller SRCPs. Excessively high FFRCPs were associated with better while excessively low FFRCPs with worse scores on some of the clinical measures of the upper limb function., Conclusion: Our preliminary results demonstrate that it is feasible to record SRCP in ALS patients, which combined with FFRCP, may be useful to determine the spectrum of motor control changes in this population., (Copyright © 2012 Elsevier B.V. All rights reserved.)