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Giannicola G.,Centro Clinico Per la Neurostimolazione | Marceglia S.,Centro Clinico Per la Neurostimolazione | Rossi L.,Centro Clinico Per la Neurostimolazione | Mrakic-Sposta S.,Centro Clinico Per la Neurostimolazione | And 6 more authors.
Experimental Neurology | Year: 2010

Local field potentials (LFPs) recorded through electrodes implanted in the subthalamic nucleus (STN) for deep brain stimulation (DBS) in patients with Parkinson's disease (PD) show that oscillations in the beta frequency range (8-20. Hz) decrease after levodopa intake. Whether and how DBS influences the beta oscillations and whether levodopa- and DBS-induced changes interact remains unclear. We examined the combined effect of levodopa and DBS on subthalamic beta LFP oscillations, recorded in nine patients with PD under four experimental conditions: without levodopa with DBS turned off; without levodopa with DBS turned on; with levodopa with DBS turned on; and with levodopa with DBS turned off. The analysis of STN-LFP oscillations showed that whereas levodopa abolished beta STN oscillations in all the patients (p= 0.026), DBS significantly decreased the beta oscillation only in five of the nine patients studied (p= 0.043). Another difference was that whereas levodopa completely suppressed beta oscillations, DBS merely decreased them. When we combined levodopa and DBS, the levodopa-induced beta disruption prevailed and combining levodopa and DBS induced no significant additive effect (p=0.500). Our observations suggest that levodopa and DBS both modulate LFP beta oscillations. © 2010 Elsevier Inc. Source

Rosa M.,Centro Clinico Per la Neurostimolazione | Giannicola G.,Centro Clinico Per la Neurostimolazione | Marceglia S.,Centro Clinico Per la Neurostimolazione | Marceglia S.,Polytechnic of Milan | And 4 more authors.
International Review of Neurobiology | Year: 2012

We review the data concerning the neurophysiology of deep brain stimulation (DBS) in humans, especially in reference to Parkinson's disease. The electric field generated by DBS interacts with the brain in complex ways, and several variables could influence the DBS-induced biophysical and clinical effects. The neurophysiology of DBS comprises the DBS-induced effects per se as well as neurophysiological studies designed to record electrical activity directly from the basal ganglia (single-unit or local field potential) through the electrodes implanted for DBS. In the subthalamic nucleus, DBS locally excites and concurrently inhibits at single-unit level, synchronizes low-frequency activity, and desynchronizes beta activity and also induces neurochemical changes in cyclic guanosine monophosphate (cGMP) and GABA concentrations. DBS-induced effects at system level can be studied through evoked potentials, autonomic tests, spinal cord segmental system, motor cortical and brainstem excitability, gait, and decision-making tasks. All these variables are influenced by DBS, suggesting also distant effects on nonmotor structures of the brain. Last, advances in understanding the neurophysiological mechanisms underlying DBS led researchers to develop a new adaptive DBS technology designed to adapt stimulation settings to the individual patient's clinical condition through a closed-loop system controlled by signals from the basal ganglia. © 2012 Elsevier Inc. Source

Boggio P.S.,Mackenzie Presbyterian University | Ferrucci R.,Centro Clinico Per la Neurostimolazione | Ferrucci R.,University of Milan | Mameli F.,Centro Clinico Per la Neurostimolazione | And 8 more authors.
Brain Stimulation | Year: 2012

Background: Immediately after patients with Alzheimer's disease (AD) receive a single anodal transcranial direct current stimulation (tDCS) session their memory performance improves. Whether multiple tDCS sessions improve memory performance in the longer term remains unclear. Objective: In this study we aimed to assess memory changes after five consecutive sessions of anodal tDCS applied over the temporal cortex in patients with AD. Methods: A total of 15 patients were enrolled in two centers. Cognitive functions were evaluated before and after therapeutic tDCS. tDCS was delivered bilaterally through two scalp anodal electrodes placed over the temporal regions and a reference electrode over the right deltoid muscle. The stimulating current was set at 2 mA intensity and was delivered for 30 minutes per day for 5 consecutive days. Results: After patients received tDCS, their performance in a visual recognition memory test significantly improved. We found a main effect of tDCS on memory performance, i.e., anodal stimulation improved it by 8.99% from baseline, whereas sham stimulation decreased it by 2.62%. tDCS failed to influence differentially general cognitive performance measures or a visual attention measure. Conclusions: Our findings show that after patients with AD receive anodal tDCS over the temporal cerebral cortex in five consecutive daily sessions their visual recognition memory improves and the improvement persists for at least 4 weeks after therapy. These encouraging results provide additional support for continuing to investigate anodal tDCS as an adjuvant treatment for patients with AD. © 2012 Elsevier Inc. All rights reserved. Source

Monti A.,University of Trento | Ferrucci R.,Centro Clinico Per la Neurostimolazione | Ferrucci R.,University of Milan | Fumagalli M.,Centro Clinico Per la Neurostimolazione | And 6 more authors.
Journal of Neurology, Neurosurgery and Psychiatry | Year: 2013

Transcranial direct current stimulation (tDCS), a non-invasive neuromodulation technique inducing prolonged brain excitability changes and promoting cerebral plasticity, is a promising option for neurorehabilitation. Here, we review progress in research on tDCS and language functions and on the potential role of tDCS in the treatment of post-stroke aphasia. Currently available data suggest that tDCS over language-related brain areas can modulate linguistic abilities in healthy individuals and can improve language performance in patients with aphasia. Whether the results obtained in experimental conditions are functionally important for the quality of life of patients and their caregivers remains unclear. Despite the fact that important variables are yet to be determined, tDCS combined with rehabilitation techniques seems a promising therapeutic option for aphasia. Source

Ferrucci R.,Centro Clinico Per la Neurostimolazione | Brunoni A.R.,University of Sao Paulo | Parazzini M.,CNR Institute of Biomedical Engineering | Vergari M.,U.O. Neurofisiopatologia | And 8 more authors.
Cerebellum | Year: 2013

Neuroimaging studies suggest that the cerebellum contributes to human cognitive processing, particularly procedural learning. This type of learning is often described as implicit learning and involves automatic, associative, and unintentional learning processes. Our aim was to investigate whether cerebellar transcranial direct current stimulation (tDCS) influences procedural learning as measured by the serial reaction time task (SRTT), in which subjects make speeded key press responses to visual cues. A preliminary modeling study demonstrated that our electrode montage (active electrode over the cerebellum with an extra-cephalic reference) generated the maximum electric field amplitude in the cerebellum. We enrolled 21 healthy subjects (aged 20-49 years). Participants did the SRTT, a visual analogue scale and a visual attention task, before and 35 min after receiving 20-min anodal and sham cerebellar tDCS in a randomized order. To avoid carry-over effects, experimental sessions were held at least 1 week apart. For our primary outcome measure (difference in RTs for random and repeated blocks) anodal versus sham tDCS, RTs were significantly slower for sham tDCS than for anodal cerebellar tDCS (p=0.04), demonstrating that anodal tDCS influenced implicit learning processes. When we assessed RTs for procedural learning across the one to eight blocks, we found that RTs changed significantly after anodal stimulation (interaction time×blocks 1/8: anodal, p=0.006), but after sham tDCS, they remained unchanged (p=0.094). No significant changes were found in the other variables assessed. Our finding that anodal cerebellar tDCS improves an implicit learning type essential to the development of several motor skills or cognitive activity suggests that the cerebellum has a critical role in procedural learning. tDCS could be a new tool for improving procedural learning in daily life in healthy subjects and for correcting abnormal learning in neuropsychiatric disorders. Source

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