Sustained increase of somatosensory cortex excitability by tactile coactivation studied by paired median nerve stimulation in humans correlates with perceptual gain.
Cortical excitability can be reliably assessed by means of paired-pulse stimulation techniques. Recent studies demonstrated particularly for motor and visual cortex that cortical excitability is systematically altered following the induction of learning processes or during the development of pathological symptoms. A recent tactile coactivation protocol developed by Godde and coworkers showed that improvement of tactile performance in humans can be achieved also without training through passive stimulation on a time scale of a few hours. Tactile coactivation evokes plastic changes in somatosensory cortical areas as measured by blood oxygenation level-dependent (BOLD) activation in fMRI or SEP-dipole localization, which correlated with the individual gain in performance. To demonstrate changes in excitability of somatosensory cortex after tactile coactivation, we combined assessment of tactile performance with recordings of paired-pulse SEPs after electrical median nerve stimulation of both the right coactivated and left control hand at ISIs of 30 and 100 ms before, 3 h after and 24 h after tactile coactivation. Amplitudes and latencies of the first and second cortical N20/P25 response components were calculated. For the coactivated hand, we found significantly lowered discrimination thresholds and significantly reduced paired-pulse ratios (second N20/P25 response/first N20/P25 response) at an ISI of 30 ms after tactile coactivation indicating enhanced cortical excitability. No changes in paired-pulse behaviour were observed for ISIs of 100 ms. Both psychophysical and cortical effects recovered to baseline 24 h after tactile coactivation. The individual increase of excitability correlated with the individual gain in discrimination performance. For the left control hand we found no effects of tactile coactivation on paired-pulse behaviour and discrimination threshold. Our results indicate that changes in cortical excitability are modified by tactile coactivation and were scaled with the degree of improvement of the individual perceptual learning. Conceivably, changes of cortical excitability seem to constitute an additional important marker and mechanism underlying plastic reorganization.
Höffken
Oliver
O
Department of Neurology, BG-Kliniken Bergmannsheil, Buerkle-de-la-Camp-Platz 1, 44789 Bochum, Germany.
Veit
Mathias
M
Knossalla
Frauke
F
Lissek
Silke
S
Bliem
Barbara
B
Ragert
Patrick
P
Dinse
Hubert R
HR
Tegenthoff
Martin
M
D000328:Adult; D001931:Brain Mapping / Q000379:methods; D004558:Electric Stimulation / Q000379:methods; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008475:Median Nerve / Q000502:physiology*; D009473:Neuronal Plasticity; D010465:Perception; D011930:Reaction Time; D012684:Sensory Thresholds; D013003:Somatosensory Cortex / Q000502:physiology*; D013997:Time Factors; D014110:Touch
J Neurosci. 2000 Feb 15;20(4):1597-604
10662849
Proc Natl Acad Sci U S A. 1996 Feb 6;93(3):1335-9
8577765
Neuroreport. 2000 Apr 27;11(6):1295-9
10817610
Annu Rev Neurosci. 2000;23:393-415
10845069
Annu Rev Neurosci. 2001;24:139-66
11283308
Exp Brain Res. 2001 Feb;136(4):431-8
11291723
Clin Neurophysiol. 2001 May;112(5):793-9
11336894
Brain. 2001 Jun;124(Pt 6):1171-81
11353733
Clin Neurophysiol. 2001 Jul;112(7):1334-42
11516746
Proc Natl Acad Sci U S A. 2001 Oct 9;98(21):12255-60
11593042
Neuron. 2001 Dec 20;32(6):1149-64
11754844
Annu Rev Physiol. 2002;64:355-405
11826273
Nature. 2002 Feb 7;415(6872):640-4
11807497
Neuroreport. 2003 Mar 24;14(4):543-6
12657881
J Neurophysiol. 2003 May;89(5):2339-45
12612033
Philos Trans R Soc Lond B Biol Sci. 2003 Apr 29;358(1432):735-44
12740120
Electroencephalogr Clin Neurophysiol. 1996 Jan;100(1):62-7
8964265
J Neurophysiol. 1996 May;75(5):1765-78
8734579
J Physiol. 1996 Nov 1;496 ( Pt 3):873-81
8930851
Adv Neurol. 1997;73:159-78
8959213
Neuroreport. 1996 Dec 20;8(1):281-5
9051796
Neuron. 1997 Jun;18(6):995-1008
9208866
J Neurosci. 1998 Feb 1;18(3):1115-23
9437031
Exp Brain Res. 1998 Feb;118(3):421-6
9497149
Annu Rev Neurosci. 1998;21:149-86
9530495
J Physiol. 1998 Jun 1;509 ( Pt 2):607-18
9575308
Ann N Y Acad Sci. 1964 May 8;112:510-25
14188112
Electroencephalogr Clin Neurophysiol. 1964 Aug;17:126-35
14204922
Electroencephalogr Clin Neurophysiol. 1962 Jun;14:331-43
13860632
Neurosci Lett. 2005 Jul 15;382(3):312-6
15925110
PLoS Biol. 2005 Nov;3(11):e362
16218766
Headache. 2005 Nov-Dec;45(10):1394-9
16324172
Ann Neurol. 2006 Jul;60(1):88-94
16685697
Trends Neurosci. 2007 Apr;30(4):167-75
17292975
Curr Opin Neurobiol. 2007 Apr;17(2):148-53
17317151
Exp Brain Res. 2007 Jul;181(1):131-7
17345071
BMC Neurosci. 2007;8:58
17663778
J Clin Neurophysiol. 1998 Jul;15(4):305-24
9736465
Neuron. 1999 May;23(1):159-70
10402202
Science. 2003 Jul 4;301(5629):91-4
12843392
Neurosci Lett. 2003 Sep 11;348(2):105-8
12902029
Neuroreport. 2003 Sep 15;14(13):1747-51
14512850
Clin Neurophysiol. 2003 Dec;114(12):2251-7
14652084
Neuron. 2003 Oct 30;40(3):643-53
14642286
J Neurosci. 2004 Jan 14;24(2):442-6
14724242
Neurosci Lett. 2004 Feb 12;356(2):91-4
14746871
J Neurophysiol. 2004 Apr;91(4):1570-8
14627660
Annu Rev Neurosci. 1989;12:13-31
2648947
J Neurophysiol. 1992 May;67(5):1031-56
1597696
J Neurol Sci. 1992 Mar;108(1):24-31
1624948
J Physiol. 1993 Nov;471:501-19
8120818
J Clin Neurophysiol. 1994 Jan;11(1):111-3
8195414
Annu Rev Neurosci. 1995;18:129-58
7605058
Electroencephalogr Clin Neurophysiol. 1995 Sep;96(5):475-8
7555921
Clin Neurophysiol. 2000 Apr;111(4):671-6
10727918