Zafiris J. Daskalakis

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Transcranial magnetic stimulation can be used to non-invasively study inhibitory processes in the human motor cortex. Interhemispheric inhibition can be measured by applying a conditioning stimulus to the motor cortex resulting in inhibition of the contralateral motor cortex. Transcranial magnetic stimulation can also be used to demonstrate ipsilateral(More)
Animal studies have shown that cerebellar projections influence both excitatory and inhibitory neurones in the motor cortex but this connectivity has yet to be demonstrated in human subjects. In human subjects, magnetic or electrical stimulation of the cerebellum 5-7 ms before transcranial magnetic stimulation (TMS) of the motor cortex decreases the(More)
BACKGROUND Transcranial direct current stimulation (tDCS), applied to the left dorsolateral prefrontal cortex (DLPFC) has been found to improve working memory (WM) performance in both healthy and clinical participants. However, whether this effect can be enhanced by cognitive activity undertaken during tDCS has not yet been explored. OBJECTIVE This study(More)
Repetitive transcranial magnetic stimulation (rTMS) procedures are being widely applied in therapeutic and investigative studies. Numerous studies have investigated the effects of rTMS on cortical excitability and inhibition, yielding somewhat contradictory results. The purpose of this study was to comprehensively review this literature to guide the(More)
OBJECTIVES This study explored whether the effects of repetitive transcranial magnetic stimulation (rTMS) on corticospinal excitability are dependent on the stimulation intensity and examined the effect of rTMS on inhibitory function. METHODS Nine normal volunteers received 15min of 1Hz rTMS at 85 and 115% of the resting motor threshold (RMT). Cortical(More)
Several studies have demonstrated that cortical inhibition (CI) can be recorded by paired transcranial magnetic stimulation (TMS) of the motor cortex and recorded by surface electromyography (EMG). However, recording CI from other cortical regions that are more closely associated with the pathophysiology of some neurological and psychiatric disorders (eg,(More)
BACKGROUND Meta-analyses have shown that high-frequency (HF) repetitive transcranial magnetic stimulation (rTMS) has antidepressant properties when compared with sham rTMS. However, its overall response and remission rates in major depression (MD) remain unclear. Thus, we have systematically and quantitatively assessed the efficacy of HF-rTMS for MD based(More)
Gamma (gamma) oscillations (30-50 Hz) elicited during working memory (WM) are altered in schizophrenia (SCZ). However, the nature of the relationship between evoked frontal oscillatory activity, WM performance and symptom severity has yet to be ascertained. This study had two objectives. First, to extend previous studies by examining delta, theta, alpha,(More)
BACKGROUND Cortical inhibition (CI) deficits have been proposed as a pathophysiologic mechanism in schizophrenia. This study employed 3 transcranial magnetic stimulation (TMS) paradigms to assess CI in patients with schizophrenia. Paired-pulse TMS involves stimulating with a lower-intensity pulse a few milliseconds before a higher-intensity pulse, thereby(More)
Transcranial direct current stimulation (tDCS) is a brain stimulation technique that has the potential to improve working memory (WM) deficits in many clinical disorders. The aim of this study was to investigate the role of current strength on the ability of anodal tDCS to improve WM, and secondly to investigate the time course of effects. Twelve healthy(More)