The goal of the present studies is to develop and validate novel stimulation protocols for the entrainment of gamma oscillations, which are associated with many cognitive functions and critically involved in cognitive impairment such as Alzheimer's disease. In this proposal, combination of repetitive transcranial magnetic stimulation (rTMS) and transcranial alternating current stimulation (tACS), which has been shown effective for the induction, and stabilisation of alpha and theta frequencies in our forgoing studies, will be adopted to the gamma frequency range and applied on prefrontal regions as well as model-based cortical areas to enhance and stabilize gamma oscillations, thereby facilitating cognition
Neuropsychiatric disorders are a leading cause of global disability-adjusted life years, and treatment solutions are lacking. Recent findings suggest that non-invasive brain stimulation may be a valuable option in conditions such as epilepsy or Alzheimer's disease (AD). Still, a better understanding of mechanisms and patient-specific factors is needed. Personalized hybrid brain models uniting the physics of electromagnetism with physiology - NeuroTwins (NeTs) - are poised to play a fundamental role in understanding and optimizing the effects of stimulation at the individual level. The purpose of this project is to deliver solutions through model-driven, individualized therapy. A computational framework - weaved and validated across scales and levels of detail - will be proposed to represent the mechanisms of interaction of electric fields with brain networks and assimilate neuroimaging data. This will allow us to characterize the dynamical landscape of the individual brain and define strategies to restore healthy dynamics. The work package, which will take place at IfADo, is part of the consortium collaborating with labs across Europe and USA, aiming to validate and optimize the realistic hybrid brain models developed by NeTs. The targeted subject groups of the IfADo project will be healthy young and old participants. Non-invasive brain stimulation including repetitive transcranial magnetic stimulation and transcranial alternating current stimulation will be applied with electroencephalography, and magnetic resonance spectroscopy as outcome measures. The results are to be translated into a technology pipeline for the design of new personalized neuromodulation protocols which will further be tested in a cohort of AD patients by another clinical consortium member, delivering model-driven breakthroughs in basic and clinical neuroscience, with patients ultimately benefiting from safe, individualized therapy solutions.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
30
Transcranial alternating current was delivered utilizing a Starstim 8-channel constant current, battery-powered electric stimulator (Neuroelectrics, Barcelona, Spain). Circular carbon rubber electrodes (2cm radius, 12,57 cm2) were used throughout the stimulation. Before placing the electrodes on the head, the subject's hair was moved to the side
the intermittent theta burst stimulation (iTBS) which is regarded as safe for high-frequency neuromodulation. Compared to classical rTMS, where pulses are applied repeatedly at a fixed frequency, iTBS consists of bursts of pulse triplets. In the classical protocol, the bursts are applied for two seconds in 5Hz intervals followed by an eight-second break, before the next bursts are applied. This pattern is repeated for 190 seconds resulting in 600 pulses per protocol.
In the case of sham TMS, two different sham coils (double 70mm pCool-SHAM coil, Mag\&More GmbH, Munich, Germany) will produce audible clicks at the decibel intensity corresponding to an active coil without the induction of an electromagnetic pulse. Sham tACS will be applied by only ramping the current for 15 seconds up and 15 seconds down at the beginning and end of the stimulation respectively.
Leibniz-Institut für Arbeitsforschung
Dortmund, North Rhine-Westphalia, Germany
Working Memory behavioral performance
Participants view a continuous sequence of alphabet letters, presented as stimuli in Arial font, size 120pt, on a tube screen positioned at 60cm eye distance. The stimuli are shown with a time interval of two seconds between them. The task consisted of six blocks with 70 stimuli, including 12 possible hit trials. Participants were instructed to press the left key on a response box if the presented stimulus matched either the one presented one trial prior (1-Back) or three trials prior (3-Back). In all other cases, participants press the right key. The left button is pressed with the index finger, while the right button is pressed with the middle finger of the right hand, with buttons aligned horizontally. The response condition varied by block, with three blocks for 3-Back and three for 1-Back, and the order was counterbalanced across participants and sessions.
Time frame: During procedure (20 minutes)
electroencephalogram (EEG) oscillatory power
Change in the EEG power in alpha, delta, theta and beta bands
Time frame: up to 2 hours after the intervention
electroencephalogram (EEG) functional connectivity
Change in EEG functional connectivity, specifically global efficiency, coherence, and phase-locking value.
Time frame: up to 2 hours after the intervention
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