Consensus Paper: Probing Homeostatic Plasticity of Human Cortex With Non-invasive Transcranial Brain Stimulation

Abstract

Homeostatic plasticity is thought to stabilize neural activity around a set point within a physiologically reasonable dynamic range. Over the last ten years, a wide range of non-invasive transcranial brain stimulation (NTBS) techniques have been used to probe homeostatic control of cortical plasticity in the intact human brain. Here, we review different NTBS approaches to study homeostatic plasticity on a systems level and relate the findings to both, physiological evidence from in vitro studies and to a theoretical framework of homeostatic function. We highlight differences between homeostatic and other non-homeostatic forms of plasticity and we examine the contribution of sleep in restoring synaptic homeostasis. Finally, we discuss the growing number of studies showing that abnormal homeostatic plasticity may be associated to a range of neuropsychiatric diseases.

Quadri-Pulse Theta Burst Stimulation using Ultra-High Frequency Bursts – A New Protocol to Induce Changes in Cortico-Spinal Excitability in Human Motor Cortex

“…These changes (i.e. increase or decrease in cortico-spinal excitability) can be induced non-invasively in the human cortico-spinal motor system using continuous or patterned repetitive transcranial magnetic stimulation (rTMS) protocols displayed by an increase or decrease in MEP amplitudes [5, 6]. Two patterned rTMS protocols have been established to induce synaptic or cortical plasticity in human primary motor cortex (M1).…”

Cognitive function assessment during 2 mA transcranial direct current stimulation in DLPFC in healthy volunteers

“…Therefore, the potential of tDCS to modulate brain activity and cognitive function remains a matter of controversy and questionable. It is highly likely that tDCS effects are state-dependent with aa time scale ranging from minutes to hours, and is highly dependent on the immediate history of neural circuits activity (Silvanto et al 2008) and occurrence of synaptic plasticity (Karabanov et al 2015;Ziemann and Siebner 2015).…”

Motor Cortex Reorganization and Repetitive Transcranial Magnetic Stimulation for Pain—A Methodological Study

“…This is commonly described as macrosystem-level changes in neuronal excitability and/or shape and size of cortical maps (representational areas of specific motor functions) (28,29). Microsystem-level cellular changes include formation of new neuronal connections as well as altered synaptic efficacy (21,(30)(31)(32)(33). These effects combined may interfere with the ability of rTMS to evoke the necessary changes in neuronal activity and appropriate remote effects.…”

“…Multifaceted cortical neuroplastic changes can be crudely divided into two spatial categories; internal (within-representation) and external (across-representation) (30,34). Their role in symptom formation and recovery are distinct and likely opposite or competitive (34).…”