Reduction of somatosensory evoked fields in the primary somatosensory cortex in a one-back task

In the present study, responses of the somatosensory cortex to sensory input of ten human volunteers were investigated during a one-back task with different conditions of attention. During an condition of attention subjects were requested to detect a predefined sequence of tactile stimuli applied to two different fingers of the dominant hand while a series of visual stimuli was presented simultaneously with an asynchronous stimulus-onset to the tactile stimuli. During an condition of distraction subjects received the identical series of visual and tactile stimuli like in the condition of attention but were now requested to detect a predefined stimulus sequence within the visual stimulus domain. In both conditions, somatosensory evoked magnetic fields (SEFs) to the tactile stimuli were recorded by means of a 31-channel magnetoencephalograph (MEG) from subjects‘ contralateral primary somatosensory cortex. The mean global field power, the dipole strength, the maximum current density, and the first component of the singular value decomposition (SVD) of magnetic fields were used to compare early components of the SEF in the conditions of attention versus distraction. Surprisingly, results revealed significant decreases of measures of all four parameters during the condition of attention as compared to the condition of distraction indicating that early responses of the primary somatosensory cortex became significantly reduced in the condition of attention. We hypothesize that changes in the centre-periphery-relationship of receptive fields in the primary somatosensory cortex may account for this unexpected result.

[1]  J. Driver,et al.  Preparatory states in crossmodal spatial attention: spatial specificity and possible control mechanisms , 2003, Experimental Brain Research.

[2]  R. Parasuraman.  The attentive brain , 1998 .

[3]  F. Bloom,et al.  Magnetoencephalographic recordings demonstrate attentional modulation of mismatch-related neural activity in human auditory cortex. , 1998, Psychophysiology.

[4]  F Mauguière,et al.  Activation of a distributed somatosensory cortical network in the human brain: a dipole modelling study of magnetic fields evoked by median nerve stimulation. Part II: Effects of stimulus rate, attention and stimulus detection. , 1997, Electroencephalography and clinical neurophysiology.

[5]  W. McIlroy,et al.  Task‐relevant selective modulation of somatosensory afferent paths from the lower limb , 2000, Neuroreport.

[6]  M. Posner.  Attention in cognitive neuroscience: An overview. , 1995 .

[7]  Hiroshi Shibasaki,et al.  Attention modulates both primary and second somatosensory cortical activities in humans: a magnetoencephalographic study. , 1998, Journal of neurophysiology.

[8]  M. Mesulam,et al.  From sensation to cognition. , 1998, Brain : a journal of neurology.

[9]  Christoph Braun,et al.  Habituation of subjective ratings and event-related potentials to painful intracutaneous electrical stimulation of the skin , 1987 .

[10]  R. Hari,et al.  Activation of the human posterior parietal cortex by median nerve stimulation , 2004, Experimental Brain Research.

[11]  D Robertson,et al.  Differential enhancement of early and late components of the cerebral somatosensory evoked potentials during forced‐paced cognitive tasks in man , 1977, The Journal of physiology.

[12]  C. Shagass,et al.  Somatosensory evoked potential changes with a selective attention task. , 1982, Psychophysiology.

[13]  F. Rösler,et al.  Crossmodal and intermodal attention modulate event-related brain potentials to tactile and auditory stimuli , 2002, Experimental Brain Research.

[14]  C Tomberg,et al.  Mapping early somatosensory evoked potentials in selective attention: critical evaluation of control conditions used for titrating by difference the cognitive P30, P40, P100 and N140. , 1989, Electroencephalography and clinical neurophysiology.

[15]  I..  THE ATTENTION SYSTEM OF THE HUMAN BRAIN , 2002 .

[16]  Leslie G. Ungerleider,et al.  Selective attention to face identity and color studied with f MRI , 1997, Human brain mapping.

[17]  J E Desmedt,et al.  The cognitive P40, N60 and P100 components of somatosensory evoked potentials and the earliest electrical signs of sensory processing in man. , 1983, Electroencephalography and clinical neurophysiology.

[18]  Claudio Babiloni,et al.  “Gating” of human short-latency somatosensory evoked cortical responses during execution of movement. A high resolution electroencephalography study , 1999, Brain Research.

[19]  W. McIlroy,et al.  Generalisability of sensory gating during passive movement of the legs , 1998, Brain Research.

[20]  Karl J. Friston,et al.  Human Brain Function , 1997 .

[21]  Marisa Carrasco,et al.  Attention improves or impairs visual performance by enhancing spatial resolution , 1998, Nature.

[22]  Uta Noppeney,et al.  Sustained attention modulates the immediate effect of de-afferentation on the cortical representation of the digits: source localization of somatosensory evoked potentials in humans , 1999, Neuroscience Letters.

[23]  V. Jousmäki,et al.  Activation of a distributed somatosensory cortical network in the human brain. A dipole modelling study of magnetic fields evoked by median nerve stimulation. Part I: Location and activation timing of SEF sources. , 1997, Electroencephalography and clinical neurophysiology.

[24]  S. Hillyard,et al.  Mechanisms of early selective attention in auditory and visual modalities. , 1987, Electroencephalography and clinical neurophysiology. Supplement.

[25]  K Willmes,et al.  Differential effects of pain and spatial attention on digit representation in the human primary somatosensory cortex , 2000, Neuroreport.

[26]  Christoph Braun,et al.  Auditory and somatosensory event-related potentials: I. Effects of attention , 1991 .

[27]  C Braun,et al.  Differential Activation in Somatosensory Cortex for Different Discrimination Tasks , 2000, The Journal of Neuroscience.

[28]  J. Rothwell,et al.  Gating of somatosensory evoked potentials during different kinds of movement in man. , 1981, Brain : a journal of neurology.

[29]  J. Duncan.  Attention, intelligence, and the frontal lobes. , 1995 .

[30]  Nicolas J. Kerscher,et al.  State-dependent receptive-field restructuring in the visual cortex , 1998, Nature.

[31]  Risto Näätänen,et al.  Selective Attention and Evoked Potentials , 1970 .

[32]  L. Cohen,et al.  Localization, timing and specificity of gating of somatosensory evoked potentials during active movement in man. , 1987, Brain : a journal of neurology.

[33]  T. Robbins,et al.  Arousal systems and attention. , 1995 .

[34]  M. H. Goldstein,et al.  Evoked unit activity in auditory cortex of monkeys performing a selective attention task , 1976, Brain Research.

[35]  S. Luck,et al.  Spatio‐temporal dynamics of attention to color: Evidence from human electrophysiology , 1998, Human brain mapping.

[36]  Larry E. Roberts,et al.  Functional Organization of Primary Somatosensory Cortex Depends on the Focus of Attention , 2002, NeuroImage.

[37]  C. Braun,et al.  Dynamic organization of the somatosensory cortex induced by motor activity. , 2001, Brain : a journal of neurology.

[38]  J. Coull.  Neural correlates of attention and arousal: insights from electrophysiology, functional neuroimaging and psychopharmacology , 1998, Progress in Neurobiology.

[39]  Brain "plasticity" in humans: transient finger representation changes in sensory corter somatotopy , 1995 .

[40]  R. Hari,et al.  Separate finger representations at the human second somatosensory cortex , 1990, Neuroscience.

[41]  M. Posner,et al.  Images of mind , 1994 .

[42]  Riitta Hari,et al.  Interaction between afferent input from fingers in human somatosensory cortex , 1995, Brain Research.

[43]  G. Mangun,et al.  Covariations in ERP and PET measures of spatial selective attention in human extrastriate visual cortex , 1997, Human brain mapping.

[44]  F. Bloom,et al.  Modulation of early sensory processing in human auditory cortex during auditory selective attention. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[45]  Matthias M. Müller,et al.  The time course of cortical facilitation during cued shifts of spatial attention , 1998, Nature Neuroscience.

[46]  L. Cohen,et al.  Selectivity of attenuation (i.e., gating) of somatosensory potentials during voluntary movement in humans. , 1987, Electroencephalography and clinical neurophysiology.

[47]  W. Ritter,et al.  Attention affects the organization of auditory input associated with the mismatch negativity system , 1998, Brain Research.

[48]  Claudio Babiloni,et al.  Comparison between SI and SII responses as a function of stimulus intensity , 2002, Neuroreport.

[49]  Ralph Huonker,et al.  Rapid functional plasticity of the somatosensory cortex after finger amputation , 2000, Experimental Brain Research.

[50]  S. Luck,et al.  Chapter 5: Electrophysiological approaches to the study of selective attention in the human brain. , 1998 .

[51]  E. Bizzi,et al.  The Cognitive Neurosciences , 1996 .

[52]  F. Mauguière,et al.  Mapping study of somatosensory evoked potentials during selective spatial attention. , 1991, Electroencephalography and clinical neurophysiology.

[53]  P. Fox,et al.  Retinotopic organization of early visual spatial attention effects as revealed by PET and ERPs , 1997, Human brain mapping.

[54]  H. Nowak,et al.  Combined 3D neuromagnetic source imaging and MRI-scans. , 1996, Electroencephalography and clinical neurophysiology. Supplement.