Abstract
Chronic pain is debilitating disorder in which the underlying pathophysiology is still unknown. Impaired cortical inhibition is one mechanism that is associated with chronic pain. Cortical inhibition refers to a neurophysiological process in which gamma-aminobutyric acid (GABA) inhibitory interneurons selectively attenuate the activity of pyramidal neurons in the cortex. Previous studies have capitalized on the ability of transcranial magnetic stimulation (TMS) to index cortical inhibition by stimulating the motor cortex and measuring the resulting peripheral motor evoked potentials with electromyography. Chronic pain has been shown to induce changes in cortical inhibition within the motor cortex using TMS. Electroencephalography (EEG) studies also demonstrate that gamma (30–50 Hz) oscillations in the prefrontal and somatosensory cortex are associated with the experience of pain. As gamma oscillations are mediated by GABA, the combination of TMS with EEG allows for the examination of the relationship between cortical inhibition, gamma and chronic pain. In this paper, we summarize the evidence of impaired GABAergic and gamma oscillations in chronic pain patients. We then demonstrate TMS-EEG as a reliable method in which to record cortical inhibition directly from the prefrontal cortex to examine the modulatory effect of GABAB receptor inhibition on cortical oscillations. Finally, the modulation of GABA and gamma oscillations with repetitive TMS will be suggested as the possible mechanism through which rTMS exerts its therapeutic effects in the treatment of pain. The aim of this paper, therefore, is to present the TMS-EEG as a potential method through which to better classify, diagnose and treat chronic pain.
Similar content being viewed by others
References
Akbarian S, Kim JJ, Potkin SG, Hagman JO, Tafazzoli A, Bunney WE Jr, Jones EG (1995) Gene expression for glutamic acid decarboxylase is reduced without loss of neurons in prefrontal cortex of schizophrenics [see comments]. Arch Gen Psychiatry 52(4):258–266, discussion 267-278
Backonja MM (2003) Defining neuropathic pain. Anesth Analg 97(3):785–790
Baron R (2006) Mechanisms of disease: neuropathic pain–a clinical perspective. Nat Clin Pract Neurol 2(2):95–106. doi:10.1038/ncpneuro0113
Barr MS, Farzan F, Arenovich T, Chen R, Fitzgerald PB, Daskalakis ZJ (2011) The effect of repetitive transcranial magnetic stimulation on gamma oscillatory activity in schizophrenia. PLoS One 6(7):e22627. doi:10.1371/journal.pone.0022627
Barr MS, Farzan F, Rusjan PM, Chen R, Fitzgerald PB, Daskalakis ZJ (2009) Potentiation of gamma oscillatory activity through repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex. Neuropsychopharmacology 34(11):2359–2367. doi:10.1038/npp.2009.79
Bartos M, Vida I, Jonas P (2007) Synaptic mechanisms of synchronized gamma oscillations in inhibitory interneuron networks. Nat Rev Neurosci 8(1):45–56
Basar-Eroglu C, Brand A, Hildebrandt H, Karolina Kedzior K, Mathes B, Schmiedt C (2007) Working memory related gamma oscillations in schizophrenia patients. Int J Psychophysiol 64(1):39–45
Benes FM, McSparren J, Bird ED, SanGiovanni JP, Vincent SL (1991) Deficits in small interneurons in prefrontal and cingulate cortices of schizophrenic and schizoaffective patients. Arch Gen Psychiatry 48(11):996–1001
Bonica JJ (1977) Basic principles in managing chronic pain. Arch Surg 112(6):783–788
Bouhassira D, Attal N, Alchaar H, Boureau F, Brochet B, Bruxelle J, Cunin G, Fermanian J, Ginies P, Grun-Overdyking A, Jafari-Schluep H, Lanteri-Minet M, Laurent B, Mick G, Serrie A, Valade D, Vicaut E (2005) Comparison of pain syndromes associated with nervous or somatic lesions and development of a new neuropathic pain diagnostic questionnaire (DN4). Pain 114(1–2):29–36. doi:10.1016/j.pain.2004.12.010
Bouhassira D, Attal N, Fermanian J, Alchaar H, Gautron M, Masquelier E, Rostaing S, Lanteri-Minet M, Collin E, Grisart J, Boureau F (2004) Development and validation of the neuropathic pain symptom inventory. Pain 108(3):248–257. doi:10.1016/j.pain.2003.12.024
Bragin A, Jando G, Nadasdy Z, Hetke J, Wise K, Buzsaki G (1995) Gamma (40–100 Hz) oscillation in the hippocampus of the behaving rat. J Neurosci 15(1 Pt 1):47–60
Brown JT, Davies CH, Randall AD (2007) Synaptic activation of GABA(B) receptors regulates neuronal network activity and entrainment. Eur J Neurosci 25(10):2982–2990
Burt T, Lisanby SH, Sackeim HA (2002) Neuropsychiatric applications of transcranial magnetic stimulation: a meta analysis. Int J Neuropsychopharmacol 5(1):73–103. doi:10.1017/S1461145702002791
Buzsáki G (2006) Rhythms of the brain. Oxford University Press, New York
Casali AG, Casarotto S, Rosanova M, Mariotti M, Massimini M (2010) General indices to characterize the electrical response of the cerebral cortex to TMS. NeuroImage 49(2):1459–1468. doi:10.1016/j.neuroimage.2009.09.026
Casarotto S, Romero Lauro LJ, Bellina V, Casali AG, Rosanova M, Pigorini A, Defendi S, Mariotti M, Massimini M (2010) EEG responses to TMS are sensitive to changes in the perturbation parameters and repeatable over time. PLoS One 5(4):e10281. doi:10.1371/journal.pone.0010281
Chen R (2004) Interactions between inhibitory and excitatory circuits in the human motor cortex. Exp Brain Res 154(1):1–10
Cho RY, Konecky RO, Carter CS (2006) Impairments in frontal cortical gamma synchrony and cognitive control in schizophrenia. Proc Natl Acad Sci U S A 103(52):19878–19883
Cooper MS, Przebinda AS (2011) Synaptic conversion of chloride-dependent synapses in spinal nociceptive circuits: roles in neuropathic pain. Pain Res Treat 2011:738645. doi:10.1155/2011/738645
Coull JA, Beggs S, Boudreau D, Boivin D, Tsuda M, Inoue K, Gravel C, Salter MW, De Koninck Y (2005) BDNF from microglia causes the shift in neuronal anion gradient underlying neuropathic pain. Nature 438(7070):1017–1021. doi:10.1038/nature04223
Crick F, Koch C (1990) Some reflections on visual awareness. Cold Spring Harb Symp Quant Biol 55:953–962
Croft RJ, Williams JD, Haenschel C, Gruzelier JH (2002) Pain perception, hypnosis and 40 Hz oscillations. Int J Psychophysiol 46(2):101–108
Cruccu G, Anand P, Attal N, Garcia-Larrea L, Haanpaa M, Jorum E, Serra J, Jensen TS (2004) EFNS guidelines on neuropathic pain assessment. Eur J Neurol 11(3):153–162
Daskalakis ZJ, Farzan F, Barr MS, Maller JJ, Chen R, Fitzgerald PB (2008) Long-interval cortical inhibition from the dorsolateral prefrontal cortex: a TMS-EEG study. Neuropsychopharmacology 33(12):2860–2869
Daskalakis ZJ, Moller B, Christensen BK, Fitzgerald PB, Gunraj C, Chen R (2006) The effects of repetitive transcranial magnetic stimulation on cortical inhibition in healthy human subjects. Exp Brain Res 174(3):403–412
De Pascalis V, Cacace I (2005) Pain perception, obstructive imagery and phase-ordered gamma oscillations. Int J Psychophysiol 56(2):157–169. doi:10.1016/j.ijpsycho.2004.11.004
Di Lazzaro V, Oliviero A, Mazzone P, Pilato F, Saturno E, Insola A, Visocchi M, Colosimo C, Tonali PA, Rothwell JC (2002) Direct demonstration of long latency cortico-cortical inhibition in normal subjects and in a patient with vascular parkinsonism. Clin Neurophysiol 113(11):1673–1679
Di Lazzaro V, Oliviero A, Meglio M, Cioni B, Tamburrini G, Tonali P, Rothwell JC (2000) Direct demonstration of the effect of lorazepam on the excitability of the human motor cortex. Clin Neurophysiol 111(5):794–799
Diamond A (1991) The future development of chronic pain relief. Anaesthesia 46(2):83–84
Dworkin RH, Backonja M, Rowbotham MC, Allen RR, Argoff CR, Bennett GJ, Bushnell MC, Farrar JT, Galer BS, Haythornthwaite JA, Hewitt DJ, Loeser JD, Max MB, Saltarelli M, Schmader KE, Stein C, Thompson D, Turk DC, Wallace MS, Watkins LR, Weinstein SM (2003) Advances in neuropathic pain: diagnosis, mechanisms, and treatment recommendations. Arch Neurol 60(11):1524–1534. doi:10.1001/archneur.60.11.1524
Eisenberg E, Chistyakov AV, Yudashkin M, Kaplan B, Hafner H, Feinsod M (2005) Evidence for cortical hyperexcitability of the affected limb representation area in CRPS: a psychophysical and transcranial magnetic stimulation study. Pain 113(1–2):99–105. doi:10.1016/j.pain.2004.09.030
Engel AK, Singer W (2001) Temporal binding and the neural correlates of sensory awareness. Trends Cogn Sci 5(1):16–25
Farina S, Tinazzi M, Le Pera D, Valeriani M (2003) Pain-related modulation of the human motor cortex. Neurol Res 25(2):130–142
Farzan F, Barr MS, Levinson AJ, Chen R, Wong W, Fitzgerald PB, Daskalakis ZJ (2010a) Evidence for gamma inhibition deficits in the dorsolateral prefrontal cortex of patients with schizophrenia. Brain 133(Pt 5):1505–1514. doi:10.1093/brain/awq046
Farzan F, Barr MS, Levinson AJ, Chen R, Wong W, Fitzgerald PB, Daskalakis ZJ (2010b) Reliability of long-interval cortical inhibition in healthy human subjects: a TMS-EEG study. J Neurophysiol 104(3):1339–1346. doi:10.1152/jn.00279.2010
Farzan F, Barr MS, Levinson AJ, Chen R, Wong W, Fitzgerald PB, Daskalakis ZJ (2010c) Reliability of long interval cortical inhibition in healthy human subjects: a TMS-EEG study. J Neurophysiol. doi:10.1152/jn.00279.2010
Farzan F, Barr MS, Wong W, Chen R, Fitzgerald PB, Daskalakis ZJ (2009) Suppression of gamma-oscillations in the dorsolateral prefrontal cortex following long interval cortical inhibition: a TMS-EEG study. Neuropsychopharmacology 34(6):1543–1551. doi:10.1038/npp.2008.211
Ferreri F, Pasqualetti P, Maatta S, Ponzo D, Ferrarelli F, Tononi G, Mervaala E, Miniussi C, Rossini PM (2011) Human brain connectivity during single and paired pulse transcranial magnetic stimulation. NeuroImage 54(1):90–102. doi:10.1016/j.neuroimage.2010.07.056
Fisahn A, Pike FG, Buhl EH, Paulsen O (1998) Cholinergic induction of network oscillations at 40 Hz in the hippocampus in vitro. Nature 394(6689):186–189. doi:10.1038/28179
Fitzgerald PB, Maller JJ, Hoy K, Farzan F, Daskalakis ZJ (2009) GABA and cortical inhibition in motor and non-motor regions using combined TMS-EEG: a time analysis. Clin Neurophysiol 120(9):1706–1710. doi:10.1016/j.clinph.2009.06.019
Fries P, Reynolds JH, Rorie AE, Desimone R (2001) Modulation of oscillatory neuronal synchronization by selective visual attention. Science 291(5508):1560–1563. doi:10.1126/science.291.5508.1560
Gross J, Schnitzler A, Timmermann L, Ploner M (2007) Gamma oscillations in human primary somatosensory cortex reflect pain perception. PLoS Biol 5(5):e133. doi:10.1371/journal.pbio.0050133
Gupta A, Wang Y, Markram H (2000) Organizing principles for a diversity of GABAergic interneurons and synapses in the neocortex. Science 287(5451):273–278
Hansson P (2002) Neuropathic pain: clinical characteristics and diagnostic workup. Eur J Pain 6(Suppl A):47–50. doi:10.1053/eujp.2001.0322
Hansson PT, Dickenson AH (2005) Pharmacological treatment of peripheral neuropathic pain conditions based on shared commonalities despite multiple etiologies. Pain 113(3):251–254. doi:10.1016/j.pain.2004.10.007
Hasenstaub A, Shu Y, Haider B, Kraushaar U, Duque A, McCormick DA (2005) Inhibitory postsynaptic potentials carry synchronized frequency information in active cortical networks. Neuron 47(3):423–435
Hauck M, Lorenz J, Engel AK (2007) Attention to painful stimulation enhances gamma-band activity and synchronization in human sensorimotor cortex. J Neurosci 27(35):9270–9277. doi:10.1523/JNEUROSCI.2283-07.2007
Herrmann CS, Munk MH, Engel AK (2004) Cognitive functions of gamma-band activity: memory match and utilization. Trends Cogn Sci 8(8):347–355. doi:10.1016/j.tics.2004.06.006
Hershman KM, Freedman R, Bickford PC (1995) GABAB antagonists diminish the inhibitory gating of auditory response in the rat hippocampus. Neurosci Lett 190(2):133–136
Hewitt SA, Wamsteeker JI, Kurz EU, Bains JS (2009) Altered chloride homeostasis removes synaptic inhibitory constraint of the stress axis. Nat Neurosci 12(4):438–443. doi:10.1038/nn.2274
Howard MW, Rizzuto DS, Caplan JB, Madsen JR, Lisman J, Aschenbrenner-Scheibe R, Schulze-Bonhage A, Kahana MJ (2003) Gamma oscillations correlate with working memory load in humans. Cereb Cortex 13(12):1369–1374
IASP (2011) Classification of chronic pain. In: Merskey H, Bogduk N (eds) Descriptions of chronic pain syndromes and definitions of pain terms. 2nd ed. Seattle: ISAP Press
Janssen SP, Truin M, Van Kleef M, Joosten EA (2011) Differential GABAergic disinhibition during the development of painful peripheral neuropathy. Neuroscience 184:183–194. doi:10.1016/j.neuroscience.2011.03.060
Ji G, Neugebauer V (2011) Pain-related deactivation of medial prefrontal cortical neurons involves mGluR1 and GABA(A) receptors. J Neurophysiol 106(5):2642–2652. doi:10.1152/jn.00461.2011
Jones EG (1993) GABAergic neurons and their role in cortical plasticity in primates. Cereb Cortex 3(5):361–372
Kahle KT, Staley KJ, Nahed BV, Gamba G, Hebert SC, Lifton RP, Mount DB (2008) Roles of the cation-chloride cotransporters in neurological disease. Nat Clin Pract Neurol 4(9):490–503. doi:10.1038/ncpneuro0883
Kujirai T, Caramia MD, Rothwell JC, Day BL, Thompson PD, Ferbert A, Wroe S, Asselman P, Marsden CD (1993) Corticocortical inhibition in human motor cortex. J Physiol 471:501–519
Lee J, Back SK, Lim EJ, Cho GC, Kim MA, Kim HJ, Lee MH, Na HS (2010) Are spinal GABAergic elements related to the manifestation of neuropathic pain in rat? Korean J Physiol Pharmacol 14(2):59–69. doi:10.4196/kjpp.2010.14.2.59
Lefaucheur JP (2006) The use of repetitive transcranial magnetic stimulation (rTMS) in chronic neuropathic pain. Neurophysiol Clin 36(3):117–124. doi:10.1016/j.neucli.2006.08.002
Lefaucheur JP, Drouot X, Menard-Lefaucheur I, Keravel Y, Nguyen JP (2006) Motor cortex rTMS restores defective intracortical inhibition in chronic neuropathic pain. Neurology 67(9):1568–1574. doi:10.1212/01.wnl.0000242731.10074.3c
Leung LS, Shen B (2007) GABAB receptor blockade enhances theta and gamma rhythms in the hippocampus of behaving rats. Hippocampus 17(4):281–291
Lewis DA, Pierri JN, Volk DW, Melchitzky DS, Woo TU (1999) Altered GABA neurotransmission and prefrontal cortical dysfunction in schizophrenia. Biol Psychiatry 46(5):616–626
Lioumis P, Kicic D, Savolainen P, Makela JP, Kahkonen S (2009) Reproducibility of TMS-Evoked EEG responses. Hum Brain Mapp 30(4):1387–1396. doi:10.1002/hbm.20608
Llinas RR, Ribary U, Jeanmonod D, Kronberg E, Mitra PP (1999) Thalamocortical dysrhythmia: a neurological and neuropsychiatric syndrome characterized by magnetoencephalography. Proc Natl Acad Sci U S A 96(26):15222–15227
Malan TP, Mata HP, Porreca F (2002) Spinal GABA(A) and GABA(B) receptor pharmacology in a rat model of neuropathic pain. Anesthesiology 96(5):1161–1167
Mann EO, Radcliffe CA, Paulsen O (2005) Hippocampal gamma-frequency oscillations: from interneurones to pyramidal cells, and back. J Physiol 562(Pt 1):55–63
Mannaioni G, Marino MJ, Valenti O, Traynelis SF, Conn PJ (2001) Metabotropic glutamate receptors 1 and 5 differentially regulate CA1 pyramidal cell function. J Neurosci 21(16):5925–5934
Markram H, Toledo-Rodriguez M, Wang Y, Gupta A, Silberberg G, Wu C (2004) Interneurons of the neocortical inhibitory system. Nat Rev Neurosci 5(10):793–807. doi:10.1038/nrn1519
Max MB (2002) Clarifying the definition of neuropathic pain. Pain 96(3):406–407, author reply 407–408
McCormick DA (1989) GABA as an inhibitory neurotransmitter in human cerebral cortex. J Neurophysiol 62(5):1018–1027
McDonnell MN, Orekhov Y, Ziemann U (2006) The role of GABA(B) receptors in intracortical inhibition in the human motor cortex. Exp Brain Res 173(1):86–93
Metz AE, Yau HJ, Centeno MV, Apkarian AV, Martina M (2009) Morphological and functional reorganization of rat medial prefrontal cortex in neuropathic pain. Proc Natl Acad Sci U S A 106(7):2423–2428. doi:10.1073/pnas.0809897106
Mhalla A, de Andrade DC, Baudic S, Perrot S, Bouhassira D (2010) Alteration of cortical excitability in patients with fibromyalgia. Pain 149(3):495–500. doi:10.1016/j.pain.2010.03.009
Moore KA, Kohno T, Karchewski LA, Scholz J, Baba H, Woolf CJ (2002) Partial peripheral nerve injury promotes a selective loss of GABAergic inhibition in the superficial dorsal horn of the spinal cord. J Neurosci 22(15):6724–6731
Niebur E, Koch C (1994) A model for the neuronal implementation of selective visual attention based on temporal correlation among neurons. J Comput Neurosci 1(1–2):141–158
Oren I, Hajos N, Paulsen O (2010) Identification of the current generator underlying cholinergically induced gamma frequency field potential oscillations in the hippocampal CA3 region. J Physiol 588(Pt 5):785–797. doi:10.1113/jphysiol.2009.180851
Paus T, Sipila PK, Strafella AP (2001) Synchronization of neuronal activity in the human primary motor cortex by transcranial magnetic stimulation: an EEG study. J Neurophysiol 86(4):1983–1990
Picarelli H, Teixeira MJ, de Andrade DC, Myczkowski ML, Luvisotto TB, Yeng LT, Fonoff ET, Pridmore S, Marcolin MA (2010) Repetitive transcranial magnetic stimulation is efficacious as an add-on to pharmacological therapy in complex regional pain syndrome (CRPS) type I. J Pain 11(11):1203–1210. doi:10.1016/j.jpain.2010.02.006
Pleger B, Janssen F, Schwenkreis P, Volker B, Maier C, Tegenthoff M (2004) Repetitive transcranial magnetic stimulation of the motor cortex attenuates pain perception in complex regional pain syndrome type I. Neurosci Lett 356(2):87–90
Rogasch NC, Fitzgerald PB (2012) Assessing cortical network properties using TMS-EEG. Hum Brain Mapp. doi:10.1002/hbm.22016
Rosanova M, Casali A, Bellina V, Resta F, Mariotti M, Massimini M (2009) Natural frequencies of human corticothalamic circuits. J Neurosci 29(24):7679–7685. doi:10.1523/JNEUROSCI.0445-09.2009
Sailer A, Molnar GF, Paradiso G, Gunraj CA, Lang AE, Chen R (2003) Short and long latency afferent inhibition in Parkinson’s disease. Brain 126(Pt 8):1883–1894. doi:10.1093/brain/awg183
Sanger TD, Garg RR, Chen R (2001) Interactions between two different inhibitory systems in the human motor cortex. J Physiol 530(Pt 2):307–317
Schwenkreis P, Janssen F, Rommel O, Pleger B, Volker B, Hosbach I, Dertwinkel R, Maier C, Tegenthoff M (2003) Bilateral motor cortex disinhibition in complex regional pain syndrome (CRPS) type I of the hand. Neurology 61(4):515–519
Schwenkreis P, Scherens A, Ronnau AK, Hoffken O, Tegenthoff M, Maier C (2010) Cortical disinhibition occurs in chronic neuropathic, but not in chronic nociceptive pain. BMC Neurosci 11:73. doi:10.1186/1471-2202-11-73
Siebner HR, Dressnandt J, Auer C, Conrad B (1998) Continuous intrathecal baclofen infusions induced a marked increase of the transcranially evoked silent period in a patient with generalized dystonia. Muscle Nerve 21(9):1209–1212
Singer W (1999) Neuronal synchrony: a versatile code for the definition of relations? Neuron 24(1):49–65, 111-125
Sohal VS, Zhang F, Yizhar O, Deisseroth K (2009) Parvalbumin neurons and gamma rhythms enhance cortical circuit performance. Nature 459(7247):698–702. doi:10.1038/nature07991
Steinmetz PN, Roy A, Fitzgerald PJ, Hsiao SS, Johnson KO, Niebur E (2000) Attention modulates synchronized neuronal firing in primate somatosensory cortex. Nature 404(6774):187–190. doi:10.1038/35004588
Tallon-Baudry C, Bertrand O, Henaff MA, Isnard J, Fischer C (2005) Attention modulates gamma-band oscillations differently in the human lateral occipital cortex and fusiform gyrus. Cereb Cortex 15(5):654–662. doi:10.1093/cercor/bhh167
Thomson AM (2000) Neurotransmission: chemical and electrical interneuron coupling. Curr Biol 10(3):R110–R112
Treede RD, Jensen TS, Campbell JN, Cruccu G, Dostrovsky JO, Griffin JW, Hansson P, Hughes R, Nurmikko T, Serra J (2008) Neuropathic pain: redefinition and a grading system for clinical and research purposes. Neurology 70(18):1630–1635. doi:10.1212/01.wnl.0000282763.29778.59
Tsubokawa T, Katayama Y, Yamamoto T, Hirayama T, Koyama S (1991) Chronic motor cortex stimulation for the treatment of central pain. Acta Neurochir Suppl (Wien) 52:137–139
Turgut N, Altun BU (2009) Cortical disinhibition in diabetic patients with neuropathic pain. Acta Neurol Scand 120(6):383–388. doi:10.1111/j.1600-0404.2009.01235.x
Turton AJ, McCabe CS, Harris N, Filipovic SR (2007) Sensorimotor integration in Complex Regional Pain Syndrome: a transcranial magnetic stimulation study. Pain 127(3):270–275. doi:10.1016/j.pain.2006.08.021
Valls-Sole J, Pascual-Leone A, Wassermann EM, Hallett M (1992) Human motor evoked responses to paired transcranial magnetic stimuli. Electroencephalogr Clin Neurophysiol 85(6):355–364
Volk DW, Pierri JN, Fritschy JM, Auh S, Sampson AR, Lewis DA (2002) Reciprocal alterations in pre- and postsynaptic inhibitory markers at chandelier cell inputs to pyramidal neurons in schizophrenia. Cereb Cortex 12(10):1063–1070
Wang XJ, Buzsaki G (1996) Gamma oscillation by synaptic inhibition in a hippocampal interneuronal network model. J Neurosci 16(20):6402–6413
Werhahn KJ, Kunesch E, Noachtar S, Benecke R, Classen J (1999) Differential effects on motorcortical inhibition induced by blockade of GABA uptake in humans. J Physiol (Lond) 517(Pt 2):591–597
Whittington MA, Traub RD, Jefferys JG (1995) Synchronized oscillations in interneuron networks driven by metabotropic glutamate receptor activation. Nature 373(6515):612–615
Woolf CJ (2004) Dissecting out mechanisms responsible for peripheral neuropathic pain: implications for diagnosis and therapy. Life Sci 74(21):2605–2610. doi:10.1016/j.lfs.2004.01.003
Yaksh TL (1989) Behavioral and autonomic correlates of the tactile evoked allodynia produced by spinal glycine inhibition: effects of modulatory receptor systems and excitatory amino acid antagonists. Pain 37(1):111–123
Ziemann U, Lonnecker S, Steinhoff BJ, Paulus W (1996) The effect of lorazepam on the motor cortical excitability in man. Exp Brain Res 109(1):127–135
Acknowledgments
The authors gratefully acknowledge Anosha Zanjani for her creation of Figure One for this review paper.
The authors alone are responsible for the content and the writing of the paper. PBF is supported by a NHMRC Practitioner Fellowship and has received equipment for research from Medtronic, MagVenture A/S and Brainsway Ltd and research funding from Cervil Neurotech. ZJD has received research funding from Aspect Medical Inc, Brainsway Inc and Neuronetics Inc; he has also received a travel allowance from Pfizer and Merck. This work was funded, in part, by the Ontario Mental Health Foundation (OMHF, ZFD, MB), Canadian Institutes of Health Research (CIHR) doctoral award (FF), Clinician Scientist Award (ZJD), and by a National Health and Medical Research Council (NHMRC) Practitioner Fellowship (PBF) and by Constance and Stephen Lieber through a National Alliance for Research on Schizophrenia and Depression (NARSAD) Lieber Young Investigator award (ZJD). The authors report no conflicts of interest.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Barr, M.S., Farzan, F., Davis, K.D. et al. Measuring GABAergic Inhibitory Activity with TMS-EEG and Its Potential Clinical Application for Chronic Pain. J Neuroimmune Pharmacol 8, 535–546 (2013). https://doi.org/10.1007/s11481-012-9383-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11481-012-9383-y