Brain Stimulation and Cognition

Brain Stimulation and Cognition

This topic covers the overarching themes in our research group. See for other research topics the tabs on the right.

Human cognition

This research focuses on the neurobiological and psychological principles underlying attention, memory and cognitive control - combining various brain research techniques, ranging from psychophysics and eye-tracking to functional Magnetic Resonance Imaging (fMRI), Electroencephalography (EEG), and Noninvasive Brain Stimulation (NIBS), especially Transcranial Magnetic (TMS) and Transcranial Electric Brain Stimulation (TES, including TDCS and TACS). 

In this research line, we investigate the neural network dynamics underlying human cognition, aim to experimentally establish functional brain-cognition relationships, unmask and guide the highly dynamic network properties and enormous capacity, adaptivity, and flexibility of the human brain to compensate for any malfunction and to reorganize neural networks to maintain or regain functionality of cognition, as well as to use personalized, oscillatory- and network-based neuromodulation technologies to enhance cognitive performances in the healthy and diseased human brain.

Multimodal Cognitive Brain Stimulation

This research line simultaneously combines noninvasive brain stimulation and neuroimaging techniques, including concurrent TMS – fMRI, concurrent TMS – EEG, concurrent TES – fMRI, concurrent TES – EEG, and concurrent TMS – EEG – fMRI. Sack’s group in Maastricht pioneered the development of simultaneously implemented TMS-fMRI-EEG during cognitive behavior, allowing to apply brain-stimulation while recording the individual brain network (fMRI) and oscillation (EEG) states of cognitively engaged participants. These multimodal brain stimulation approaches enable the direct and non-invasive in-vivo probing of brain-state dependent signal propagation within specific brain-wide cortico-subcortical networks and to study how temporal (oscillations) and spatial (brain-wide networks) coding dynamics interrelate. The noninvasive investigation of such oscillation-network coupling principles allows for subject-specific network research into dynamic cognitive circuits and their dysfunction. 

State-dependence of noninvasive brain stimulation

This research line capitalizes on the combination of brain stimulation and neuroimaging to systematically assess the brain state dependence of transcranial magnetic and transcranial electric brain stimulation technologies. The neurophysiological and cognitive effects of various rTMS and TES protocols are empirically assessed using fMRI and EEG in the context of either different experimentally induced brain states (e.g. cognitive states), and/or EEG-indexed spontaneous fluctuations of endogenous oscillatory resting brain states (e.g. phase-dependent network effects of TMS), and/or the neural state history (e.g. priming or preconditioning). The state-dependence of brain stimulation is also relevant for optimizing protocols aimed at inducing neuroplasticity in the brain.

Brain Plasticity

This research line develops and tests new brain stimulation protocols capable of inducing longer lasting neuroplastic changes. Although repetitive TMS is capable of inducing such longer lasting changes in cortical excitability, the frequency-dependence, state-dependence, and inter-subject variability remain poorly understood. We aim to contribute to a better understating of the mechanisms of neuroplasticity as induced by neuromodulation and brain stimulation technologies, hoping to reduce the currently still unsolved problem of intra-subject reliability and inter-subjkect variability.  This will not only inform us about the fundamental mechanism of brain plasticity in the context of human cognition, but also guide the development of innovative and optimized clinical protocols for treating various psychiatric and neurological disorders.   

Clinical Applications of Noninvasive Brain Stimulation

All research lines described above have direct and indirect implications also for the clinical applications of TMS and TES. Our group constantly aims to promote scientific research and collaboration in the field of applied noninvasive brain stimulation and its translation to clinical practice. As part of a large international network of academic hospitals and clinical practitioners, we are actively involved in bringing the gap between scientific research and clinical practice in the field of brain stimulation. These research lines include clinical research for using TMS and TES for the drug-free treatment of Depression, OCD, Neuropathic Pain, Stroke rehabilitation, Parkinson’s Disease, and Alzheimer’s Disease. We are always open for other clinical cooperation partners interested in expanding, optimizing, and evaluating the indications for noninvasive brain stimulation. Please see also our External PhD Program. 

PI: Alexander Sack

Clinical Brain Stimulation

Non-invasive brain stimulation (NIBS) can modulate neural activity and network excitability during and beyond the stimulation period. These sustained neuroplastic changes make NIBS a good treatment option in a variety of psychiatric, neurological and rehabilitation settings. Neglect rehabilitation after stroke is one of our key clinical applications of NIBS. Patients’ spontaneous functional brain reorganisation is often maladaptive, and we use TMS and tDCS to interchangeably suppress or activate hyper- or hypo-active parts of the network, restoring a healthy hemispheric symmetry and improving the recovery of function. Another clinical application of NIBS is in the treatment of neuropsychiatric disorders such as depression and OCD, where we focus on quantifying sustained neuroplastic improvements and on optimising existing treatment protocols. In these settings, we often work closely with the patient population and collaborate with local clinicians at the MUMC+ and Mondriaan hospitals. 

PI: Teresa Schuhmann

TMS Methodology

Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation technique that is widely used in research to gain insights into brain function and in clinical practice to treat brain-based disorders. Successful TMS application critically depends on the use of adequate stimulation parameters and experimental designs. In many cases, this requires a personalised approach where TMS intensity and localization are tailored to the individual brain region of interest. This research line aims to advance TMS methodology by optimising stimulation parameters, developing robust procedures suitable for specific settings (clinic vs. lab), and implementing multimodal approaches that combine brain stimulation and neuroimaging to explore and validate the effects of TMS on the brain. This also requires awareness and careful implementation of experimental control conditions to prevent confounding (e.g. sensory effects of TMS).

PI: Felix Duecker

Fine-tuning the brain’s brakes

Inhibitory control over unwanted thoughts, emotions and movements is essential for effective interaction with our environment. This becomes particularly evident when there is too little inhibition, as in obsessive-compulsive disorder or Tourette’s syndrome, or too much, as in Parkinson’s disease. Recent evidence links successful inhibition to the power of neural oscillations in the beta band (15-30Hz) in a circuit involving parts of the frontal cortex and the subthalamic nucleus. While this is an important step forward, it is not yet sufficient to develop effective neuromodulatory treatments for inhibitory control disorders. For that, we need to understand how the beta oscillations mediate neuronal communication within the fronto-subthalamic circuit. In this project, we address this challenging question through novel applications of transcranial alternating current stimulation (tACS). This non-invasive brain stimulation technique aligns neuronal oscillations to an oscillating low intensity electrical current applied to the brain. This external control over oscillatory power and phase allows us to investigate: the functional relevance of beta oscillatory phase, the causal role of interactions between beta oscillations and other frequency bands (‘cross-frequency coupling’) and the importance of synchrony within the network. In parallel, we are developing an innovative, non-invasive, treatment strategy for patients with inhibitory control deficits, by recording and modulating abnormal circuit activity in a closed-loop.

PI: Inge Leunissen

Linking temporal dynamics inside and outside the brain

Rhythm and temporal information can be used to optimally predict when something is going to happen. However, temporal information also provides information about the exact content of information, that is temporal information does not only provide cues for when, but also for what. For both operations (tracking and coding temporal information) the same temporal brain dynamics are important, namely brain oscillations. How can the brain track continuously incoming information and simultaneously use the temporal dimension to code information? To do this the brain needs to compute in time as well as with time. This research line investigates how our brain can track temporal structure and how temporal dynamics in the brain are relevant for various cognitive functions such as memory, speech, and attention. We use EEG, MEG, ECoG, brain stimulation, and computational modelling. More information about this research line can be found here: https://tedyum.github.io/

PI: Sanne ten Oever