title: Increased short latency afferent inhibition after anodal transcranial direct current stimulation.
abstract: Transcranial direct current stimulation (tDCS), a technique for central neuromodulation, has been recently proposed as possible treatment in several neurological and psychiatric diseases. Although shifts on focal brain excitability have been proposed to explain the clinical effects of tDCS, how tDCS-induced functional changes influence cortical interneurones is still largely unknown. The assessment of short latency afferent inhibition (SLAI) of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS), provides the opportunity to test non-invasively interneuronal cholinergic circuits in the human motor cortex. The aim of the present study was to assess whether anodal tDCS can modulate interneuronal circuits involved in SLAI. Resting motor threshold (RMT), amplitude of unconditioned MEPs and SLAI were assessed in the dominant hemisphere of 12 healthy subjects (aged 21-37) before and after anodal tDCS (primary motor cortex, 13min, 1mA). SLAI was assessed delivering electrical conditioning stimuli to the median nerve at the wrist prior to test TMS given at the interstimulus interval (ISI) of 2ms. Whereas RMT and the amplitude of unconditioned MEPs did not change after anodal tDCS, SLAI significantly increased. In conclusion, anodal tDCS-induced effects depend also on the modulation of cortical interneuronal circuits. The enhancement of cortical cholinergic activity assessed by SLAI could be an important mechanism explaining anodal tDCS action in several pathological conditions.
authors: Centro Clinico per la Neurostimolazione, le Neurotecnologie ed i Disordini del Movimento, Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico, Via F. Sforza 35, Milan, Italy.
authors: Emma
authors: E
authors: Scelzo
authors: Gaia
authors: G
authors: Giannicola
authors: Manuela
authors: M
authors: Rosa
authors: Matteo
authors: M
authors: Ciocca
authors: Gianluca
authors: G
authors: Ardolino
authors: Filippo
authors: F
authors: Cogiamanian
authors: Roberta
authors: R
authors: Ferrucci
authors: Manuela
authors: M
authors: Fumagalli
authors: Francesca
authors: F
authors: Mameli
authors: Sergio
authors: S
authors: Barbieri
authors: Alberto
authors: A
authors: Priori