Aberrant functional connectivity of resting state networks related to misperceptions and intra-individual variability in Parkinson's disease.

Patients with Parkinson's disease (PD) frequently suffer from visual misperceptions and hallucinations, which are difficult to objectify and quantify. We aimed to develop an image recognition task to objectify misperceptions and to assess performance fluctuations in PD patients with and without self-reported hallucinations. Thirty-two non-demented patients with Parkinson's disease (16 with and 16 without self-reported visual hallucinations) and 25 age-matched healthy controls (HC) were tested.

Simultaneous Transcranial Alternating Current Stimulation and Functional Magnetic Resonance Imaging.

Transcranial alternating current stimulation (tACS) is a promising tool for noninvasive investigation of brain oscillations. TACS employs frequency-specific stimulation of the human brain through current applied to the scalp with surface electrodes. Most current knowledge of the technique is based on behavioral studies; thus, combining the method with brain imaging holds potential to better understand the mechanisms of tACS.

Transcranial alternating current stimulation affects the BOLD signal in a frequency and task-dependent manner.

Transcranial alternating current stimulation (tACS) has emerged as a promising tool for manipulating ongoing brain oscillations. While previous studies demonstrated frequency-specific effects of tACS on diverse cognitive functions, its effect on neural activity remains poorly understood. Here we asked how tACS modulates regional fMRI blood oxygenation level dependent (BOLD) signal as a function of frequency, current strength, and task condition.