ABSTRACT
The pain-relieving effect of acupuncture is known to involve primary afferent nerves (PANs) via their roles in signal transmission to the CNS. Using single-unit recording in rats, we characterized the generation and transmission of electrical signals in Aβ and Aδ fibers induced by acupuncture-like stimuli. Acupuncture-like signals were elicited in PANs using three techniques: manual acupuncture (MAc), emulated acupuncture (EAc), and electro-acupuncture (EA)-like peripheral electrical stimulation (PES). The discharges evoked by MAc and EAc were mostly in a burst pattern with average intra-burst and inter-burst firing rates of 90 Hz and 2 Hz, respectively. The frequency of discharges in PANs was correlated with the frequency of PES. The highest discharge frequency was 246 Hz in Aβ fibers and 180 Hz in Aδ fibers. Therefore, EA in a dense-disperse mode (at alternating frequency between 2 Hz and 15 Hz or between 2 Hz and 100 Hz) best mimics MAc. Frequencies of EA output >250 Hz appear to be obsolete for pain relief.
ABSTRACT
Concomitant transcranial direct current stimulation (tDCS) is suggested to enhance the functional effects of other physical rehabilitation methods in individuals with motor impairment stemming from a chronic cerebrovascular disease. Thus, the primary aim of the proposed study is to analyze the electrical activity of the tibialis anterior (TA) muscle of the paretic limb in stroke survivors following an intervention involving the combination of tDCS over the motor cortex and peripheral electrical stimulation (PES) administered over the paretic TA. The secondary objective is to analyze the effect on dynamic balance Methods: Thirty-six adult stroke survivors will be randomized into three groups: 1) Active tDCS+ active PES; 2) Sham tDCS + active PES and 3) Active tDCS + sham PES. TDCSactive will be positioned bilateral over the primary motor cortex of the damaged hemisphere (C1 or C2) and the cathode will be positioned over the primary motor cortex of the undamaged hemisphere (C1 or C2) with a current of 2 mA for 20 minutes. For sham tDCS, will follow the same standarts, however, the equipment will be switched on for only 20 seconds. PES will be administered to the paretic TA at 50 Hz for 30 minutes. Evaluations: the median frequency and root mean square (RMS) of the paretic TA will be analyzed using electromyography (EMG) and dynamic balance will be evaluated using the Mini-Balance Evaluation System (Mini-BESTest) at baseline (pre-intervention), after 10 treatment sessions at a frequency of five times a week for two weeks (post-intervention) and 30 days after the end of the interventions (follow up). Discussion:PES has proven to facilitate the conduction of sensory-motor afferences to the cerebral cortex in stroke survivors. Combining PES with tDCS, which has a direct effect on increasing cortical excitability, could favor motor acquisition and neuronal plasticity in this population
ABSTRACT
Objective To investigate the mechanisms of the inhibitory effects of peripheral electrical stimu- lation(PES)on chronic central pain(CCP)after spinal cord injury(SCI).Methods Twenty-four male Sprague- Dawley rats with CCP following SCI were randomly divided into three groups:a group without stainless steel needles implanted (NSSN group,n=8),a group with a stainless steel needle implanted but no peripheral electrical stimula- tion applied(NPES group,n=8)and a PES group(PES group,n=8).The rats' CCP was evaluated through ob- serving their response to nociceptive stimulation by means of the paw withdrawal pressure threshold(PWPT)and the paw withdrawal latency(PWL).Spontaneous pain behaviors including autophagia and scratching were observed at the same time.PES was applied via stainless steel needles inserted into standard acupoints on the hind limps and the back.The expression of the NMDA receptor 1(NR-1)subunit in the spinal cord horn was measured using immuno- chemical methods.Results Compared with the NSSN and NPES groups,CCP in the PES group was alleviated, PWPT and PWL were dramatically increased(P＜0.01)and the expression of NR-1 was obviously decreased (P＜0.01).Conclusion Peripheral electrical stimulation may alleviate chronic central pain after spinal cord injury in rats.