title: Theta-burst transcranial magnetic stimulation alters cortical inhibition.
abstract: Human cortical excitability can be modified by repetitive transcranial magnetic stimulation (rTMS), but the cellular mechanisms are largely unknown. Here, we show that the pattern of delivery of theta-burst stimulation (TBS) (continuous versus intermittent) differently modifies electric activity and protein expression in the rat neocortex. Intermittent TBS (iTBS), but not continuous TBS (cTBS), enhanced spontaneous neuronal firing and EEG gamma band power. Sensory evoked cortical inhibition increased only after iTBS, although both TBS protocols increased the first sensory response arising from the resting cortical state. Changes in the cortical expression of the calcium-binding proteins parvalbumin (PV) and calbindin D-28k (CB) indicate that changes in spontaneous and evoked cortical activity following rTMS are in part related to altered activity of inhibitory systems. By reducing PV expression in the fast-spiking interneurons, iTBS primarily affected the inhibitory control of pyramidal cell output activity, while cTBS, by reducing CB expression, more likely affected the dendritic integration of synaptic inputs controlled by other classes of inhibitory interneurons. Calretinin, the third major calcium-binding protein expressed by another class of interneurons was not affected at all. We conclude that different patterns of TBS modulate the activity of inhibitory cell classes differently, probably depending on the synaptic connectivity and the preferred discharge pattern of these inhibitory neurons.
authors.affiliation: Department of Neurophysiology, Ruhr-University Bochum, 44780 Bochum, Germany.
authors.forename: Alia
authors.initials: A
authors.lastname: Benali
authors.forename: Jörn
authors.initials: J
authors.lastname: Trippe
authors.forename: Elke
authors.initials: E
authors.lastname: Weiler
authors.forename: Annika
authors.initials: A
authors.lastname: Mix
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Petrasch-Parwez
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Girzalsky
authors.forename: Ulf T
authors.initials: UT
authors.lastname: Eysel
authors.forename: Ralf
authors.initials: R
authors.lastname: Erdmann
authors.forename: Klaus
authors.initials: K
authors.lastname: Funke
mesh_terms: D000200:Action Potentials; D000818:Animals; D064032:Calbindin 2; D064026:Calbindins; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory; D007395:Interneurons / Q000502:physiology; D008297:Male; D009433:Neural Inhibition; D010320:Parvalbumins / Q000096:biosynthesis; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D064030:S100 Calcium Binding Protein G / Q000096:biosynthesis; D050781:Transcranial Magnetic Stimulation
chemical_list: C576764:CALB2 protein, human; C576512:Calb2 protein, rat; D064032:Calbindin 2; D064026:Calbindins; D010320:Parvalbumins; D064030:S100 Calcium Binding Protein G