Intensity-dependent effects of repetitive anodal transcranial direct current stimulation on learning and memory in a rat model of Alzheimer's disease.

Single-session anodal transcranial direct current stimulation (tDCS) can improve the learning-memory function of patients with Alzheimer's disease (AD). After-effects of tDCS can be more significant if the stimulation is repeated regularly in a period. Here the behavioral and the histologic effects of the repetitive anodal tDCS on a rat model of AD were investigated. Sprague-Dawley rats were divided into 6 groups, the sham group, the ß-amyloid (Aß) group, the Aß+20µA tDCS group, the Aß+60µA tDCS group, the Aß+100µA tDCS group and the Aß+200µA tDCS group. Bilateral hippocampus of the rats in the Aß group and the Aß+tDCS groups were lesioned by Aß1-40 to produce AD models. One day after drug injection, repetitive anodal tDCS (10 sessions in two weeks, 20min per session) was applied to the frontal cortex of the rats in the tDCS groups, while sham stimulation was applied to the Aß group and the sham group. The spatial learning and memory capability of the rats were tested by Morris water maze. Bielschowsky's silver staining, Nissl's staining, choline acetyltransferase (ChAT) and glial-fibrillary-acidic protein (GFAP) immunohistochemistry of the hippocampus were conducted for histologic analysis. Results show in the Morris water maze task, rats in the Aß+100µA and the Aß+200µA tDCS groups had shorter escape latency and larger number of crossings on the platform. Significant histologic differences were observed in the Aß+100µA and the Aß+200µA tDCS groups compared to the Aß group. The behavioral and the histological experiments indicate that the proposed repetitive anodal tDCS treatment can protect spatial learning and memory dysfunction of Aß1-40-lesioned AD rats.

[Design of low-intermediate frequency electrotherapy and pain assessment system].

Aiming at the single treatment and the design separation between treatment and assessment in electrotherapy equipment, a kind of system including low-intermediate frequency treatment and efficacy evaluation was developed. With C8051F020 single-chip microcomputer as the core and the circuit design and software programming used, the system realized the random switch of therapeutic parameters, the collection, display and data storage of pressure pain threshold in the assessment. Experiment results showed that the stimulus waveform, current intensity, frequency, duty ratio of the system output were adjustable, accurate and reliable. The obtained pressure pain threshold had a higher accuracy (< 0.3 N) and better stability, guiding the parameter choice in the precise electrical stimulation. It, therefore, provides a reliable technical support for the treatment and curative effect assessment.