Hikmat Hadoush

Administration of microRNA-210 promotes spinal cord regeneration in mice.

Study Design. Experimental animal study of treatment of spinal cord injury (SCI). Objective. To investigate the therapeutic effects of administering microRNA-210 (miR-210) to promote angiogenesis in a mouse SCI model. Summary of Background Data. Despite many previous studies regarding SCI, there is no established treatment in clinical practice. miRNAs have attracted immense attention because of their crucial role in human disease, and they have been proposed as potential new therapeutic targets for SCI. Methods. At specific times after administration, mice were analyzed by several methods to examine the distribution of miR-210, histological angiogenesis and neurogenesis, functional recovery from SCI, and the expression levels of target genes of miR-210. Results. After injection of miR-210 into the lesion of the injured spinal cord, expression of endogenous miR-210 increased until 6 days after injection. The administration of miR-210 promoted angiogenesis and astrogliosis, and improved functional recovery after SCI compared with the noninjected controls. Furthermore, the area made up of axons and myelin in the spinal cord tissues caudal to the injury site was larger in mice injected with miR-210 than those of the controls. Apoptotic cell death was lower in mice administered miR-210. After administration of miR-210, the expressions of protein-tyrosine phosphate 1B and ephrin-A3, both gene targets of miR-210, were downregulated at the protein level and protein-tyrosine phosphate 1B expression was also downregulated at the transcriptional level. Conclusion. MiR-210 might contribute to spinal cord repair by promoting angiogenesis via the inhibition of protein-tyrosine phosphate 1B and ephrin-A3. Level of Evidence: N/A

Ipsilateral primary sensorimotor cortical response to mechanical tactile stimuli

We studied somatosensory-evoked fields elicited by mechanical versus electrical stimuli to index finger of healthy participants. Mechanical stimulation was index pulp compression and decompression by using nonmagnetic mechanical stimulator. Electrical stimulation was three times of sensory threshold and delivered to index pulp by using ball-shaped electrodes. Mechanical/electrical stimuli evoked contralateral primary somatosensory cortical responses in all respective participants. Compressive stimuli evoked ipsilateral primary sensorimotor cortical responses in all respective participants, with dipole strengths less than contralateral primary somatosensory cortical responses of compressive stimuli. Mechanical/electrical stimuli evoked secondary somatosensory (SII) cortical responses bilaterally; electrical-stimuli SII dipole strengths were relatively stronger than compressive-stimuli SII responses. It is concluded that the use of mechanical stimulation may improve our understanding of functional sensory cortical responses compared with electrical stimulation.

Monopolar surface electromyography: a better tool to assess motoneuron excitability upon passive muscle stretching

Bipolar and monopolar surface electromyography (sEMG) are known procedures to measure the H-reflex. However, signal cancellation is a potential experimental problem of bipolar sEMG. The results of our study show that monopolar sEMG was the more sensitive procedure to differentiate motoneuron excitability at different passive muscle stretching speeds as it overcame signal cancellation.

Somatosensory mechanical response and digit somatotopy within cortical areas of the postcentral gyrus in humans: an MEG study.

Somatosensory evoked fields in response to compression (termed as Co) and decompression (termed as De) of glabrous skin (D1, thumb; D2, index finger; D5, little finger) were recorded. Although estimated equivalent current dipoles (ECDs) following stimulation of D1 and D5 were larger, but not significantly larger, in decompression than in compression, those of D2 were significantly larger (P = 0.035). The ECDs were located in the postcentral gyrus in the order of D5De, D2De, and D1De medially, posteriorly, and superiorly in decompression but not in compression (z‐value, F = 2.692, P = 0.031). The average distance of ECDs between D1 and D5 was longer in decompression (12.8 ± 1.6 mm) than in compression (9.1 ± 1.6 mm). Our data suggest that the cortical response for the commonly used digit D2 is functionally different from those for other digits (D1 and D5) that the somatotopic variability is greater in compression. Hum Brain Mapp, 2013.

Motor somatotopy of extensor indicis proprius and extensor pollicis longus

After tendon transfer of extensor indicis proprius (EIP) to extensor pollicis longus (EPL), rehabilitation is initiated to enhance motor cortex reorganization. However, patients have been described showing thumb extension immediately after the tendon transfer. At cortical level, no evidence supports either of these assumptions. We noninvasively investigated motor cortical source locations of EIP and EPL muscles. Magnetoencephalography was used to identify motor somatotopic map in healthy right-handed participants, who performed voluntary extension at index metacarpophalangeal joint and thumb interphalangeal joint. Motor cortical representation of EIP was more medial than cortical representation of EPL, with mean Euclidean distance of 15.4±2.7 mm. Motor somatotopic map of EIP/EPL that was obtained by magnetoencephalography supports ‘functional somatotopy’ representation of the finger in primary motor cortex.

Bilateral anodal transcranial direct current stimulation effect on balance and fearing of fall in patient with Parkinson’s disease

BACKGROUND A number of studies have examined the therapeutic effects of transcranial direct current stimulation (tDCS) stimulation in patients with Parkinsons disease (PD) using unilateral anodal stimulation applied either on the left or right brain hemisphere. However, PD involves the dysfunctions of both brain hemispheres. OBJECTIVES This study investigates the therapeutic effects of bilateral anodal tDCS stimulation on balance and fear of fall outcomes in patient with PD. METHODS Eighteen patients with idiopathic PD completed the study. Ten sessions of bilateral anodal tDCS stimulation were applied over the FC1 and FC2 targeting both pre-frontal and motor areas for each patient, 5 sessions per week for 2 weeks. Berg Balance Scale (BBS), Falls Efficacy Scale-International (FES-I), and 10 meters walk test (10mwt) were applied before and after the stimulation therapy. RESULTS Paired t-test showed a significant increase in the BBS scores and decrease in the FES-I scores after the bilateral tDCS compared with those scores before tDCS therapy (P < 0.05), as well improvement in the 10mwt scores. CONCLUSION Our data showed that bilateral anodal tDCS serves as an effective, safe and feasible approach for rehabilitation of patients with PD with the issues related to balance and fear of fall.

Frequency 3D mapping and inter-channel stability of EEG intrinsic function pulsation: Indicators towards autism spectrum diagnosis

Autism spectrum is one of the serious disorders influencing mental capacities and hence behavior. The present work investigates the potential of detecting irregularities of EEG activity and connectivity in Autism Spectrum by studying the inter-channel stability of EEG components point-by-point pulsation as well as by frequency 3D mapping. First, Empirical Mode Decomposition is used to find the Intrinsic Mode Functions of every EEG channel. Second, the Phase derivatives of analytic intrinsic modes are then calculated. Third, each phase derivative function obtained for an intrinsic mode is plotted versus the phase derivative function of the counterpart intrinsic mode in another channel. Finally, the stability loops found out are then analyzed. Furthermore, 3D mapping of EEG frequency bands (Delta, Theta, Alpha and Beta) is conducted and examined.

Dipole orientation of receptive fields in the somatosensory cortex after stimulation of the posterior tibial nerve in humans.

Summary: The origins of the earliest evoked potentials and magnetic fields after tibial nerve electrical stimulation are still controversial. We focused on the initial activity from the gyrus area and analyzed the components for the coronal and sagittal planes. In 12 healthy right-handed subjects, electrical stimuli were delivered to the left posterior tibial nerve at the ankle. The cortical somatosensory evoked fields were recorded, and the equivalent current dipoles were calculated and separated into the sagittal plane (y-components) and coronal plane (x-components) components. In nine subjects, we observed two deflections (y1 and y2) in the y-component waveform and two deflections (x1 and x2) in the x-component waveform over 60 milliseconds; y1 was directed anteriorly, y2 posteriorly, x1 to the left, and x2 to the right. The y1 was originated in the anterior wall of the central sulcus. By focusing on the y-component, we elucidated the existence of the posteroanterior component, which may originate from the area 3b (gyrus) in tibial nerve somatosensory evoked fields and has the same quality as N20m for median nerve somatosensory evoked fields. This is the first report to suggest that the posteroanterior component in the tibial nerve is analogous to N20m in the median nerve using magnetoencephalography.

Somatosensory cortical plasticity after toe-to-index transfer.

We quantified and compared neuroimaging data and behavioral data (cortical plasticity and hand sensibility, respectively) from a patient who underwent toe-to-index transplantation. Magnetoencephalographic (MEG) recordings of somatosensory-evoked fields (SEFs) response to mechanical tactile stimulation of the index and little fingers of both hands were obtained in parallel with a hand sensibility test from the patient at multiple sessions (week 4, 12, and 24 after the operation). Cortical plasticity refers to SEFs’ latency, dipole strength, and primary somatosensory representation, and the Euclidean distance between primary somatosensory representations of the index and the little fingers. Hand sensibility refers to a patient’s conscious perception of tactile stimulation applied to the transplanted index finger and scored by Semmes-Weinstein monofilaments. SEFs recordings from six healthy participants at one session were used for comparative purposes. At week 4, although the patient had no conscious perception in the left transplanted index to tactile stimulation, SEFs were recorded in response to tactile stimulation. At weeks 12 and 24, the Euclidean distance between primary somatosensory representations of the transplanted index and little fingers increased, together with SEFs dipole strength, whereas SEFs latencies decreased. These occurred in parallel to improvement in hand sensibility. Primary somatosensory representations of the index and little fingers of the patient’s intact right hand were similar to those of the healthy participants’ right hand, indicating the consistency of MEG recording during the follow-up sessions. In conclusion, a combination of neuroimaging and behavioral data may be essential for better assessment of functional recovery after a toe-to-digit operation because the cortical recovery observed by MEG preceded that of hand sensibility observed clinically.

7. Sensory neural plasticity after toe-to-thumb transfer

The aim of this study was to examine a sense of agency in schizophrenia patients using somatosensory evoked potentials (SEP) and fields (SEF). The subjects were 15 right-handed schizophrenia patients and 14 healthy controls. SEP and SEF were conducted with electrical stimuli to the left median nerve at intervals of 1–3 s. In ‘auto’ condition, the stimuli were externally induced. In ‘self’ condition, the stimuli were induced by tapping with their own right index finger. Peak to peak amplitude at C4 in SEP and root mean square (RMS) in 10 channels on right primary somatosensory area in SEF were analyzed. In SEP, the amplitude in ‘self’ was decreased with N33-P45, P45-N55, N55-P85 and P85N140 in control, while significant reduction was shown only with N33-P45 in schizophrenia. In SEF, there was no significant difference between ‘auto’ and ‘self’ condition in both groups about the RMS at N20m. However, at P30m, the RMS in ‘self’ was significantly decreased compared with that in ‘auto’ in control group only. Moreover, the RMS at P30m in ‘self’ in schizophrenia group was positively correlated with PANSS positive scale. These results suggest that positive symptom in schizophrenia patents may be caused by a malfunction of sense of agency.