Evoked potential correlates of semantic meaning--A brain mapping study.

According to the 'semantic differential technique' the affective meaning of words can be quantified in statistically defined, independent dimensions where every word is uniquely located on the three dimensions evaluation ('good-bad'), potency ('strong-weak'), and activity ('active-passive'). Two experiments were performed on a total of 52 adults: first, 162 nouns were rated by 30 subjects. All words had a comparable number of letters and frequency of occurrence in the German language. A factor analysis followed by varimax rotation on the ratings yielded three semantic dimensions, and for each dimension up to 20 words were selected which scored highly positive or highly negative on one of the three dimensions, and had small scores on the others. This resulted in six semantic word classes which were then used in electrophysiological experiments performed on another group of 22 healthy right-handed adults. Stimuli were presented sequentially on a computer monitor in a randomized order, and the EEG was recorded in 30 channels and continuously stored on hard disk. A checkerboard reversal stimulus was used in a control condition. Evoked potentials were computed off-line for each semantic class. Comparison of the factor structure revealed highly similar semantic dimensions and classification of all words used. In the electrophysiological data, specific brain activity occurred that was related to semantic processing. These components, however, showed distinctive differences to brain activity elicited by contrast reversing checkerboard patterns as was evident from significant differences in component latency, amplitude, and scalp topography. Significant differences in scalp topography, latency and field strength between semantic word classes were not restricted to late 'cognitive' components, but brain activity at small latencies was affected by semantic meaning of the stimuli. Our data show how visually evoked brain activity is modulated by the meaning of the stimuli at early processing stages without reflecting hemispheric differences.

[1]  M. Pratarelli,et al.  Semantic Processing of Pictures and Spoken Words: Evidence from Event-Related Brain Potentials , 1994, Brain and Cognition.

[2]  K. Abt.  Descriptive Data Analysis: A Concept between Confirmatory and Exploratory Data Analysis , 1987, Methods of Information in Medicine.

[3]  D. Lehmann,et al.  Verb and Noun Meaning of Homophone Words Activate Different Cortical Generators: A Topographical Study of Evoked Potential Fields , 1979 .

[4]  C. N. Guy,et al.  The parallel visual motion inputs into areas V1 and V5 of human cerebral cortex. , 1995, Brain : a journal of neurology.

[5]  G. Ojemann.  Cortical Organization of Language and Verbal Memory Based on Intraoperative Investigations , 1991 .

[6]  J. T. Marsh,et al.  Contextual meaning effects on speech-evoked potentials. , 1973, Behavioral biology.

[7]  Richard S. J. Frackowiak,et al.  Differential activation of right and left posterior sylvian regions by semantic and phonological tasks: a positron-emission tomography study in normal human subjects , 1994, Neuroscience Letters.

[8]  J. T. Marsh,et al.  Principal component analysis of ERP differences related to the meaning of an ambiguous word. , 1979, Electroencephalography and clinical neurophysiology.

[9]  C. C. Wood,et al.  Event-related potentials, lexical decision and semantic priming. , 1985, Electroencephalography and clinical neurophysiology.

[10]  Richard S. J. Frackowiak,et al.  The anatomy of phonological and semantic processing in normal subjects. , 1992, Brain : a journal of neurology.

[11]  Shigeko Takahashi,et al.  Aesthetic properties of pictorial perception. , 1995, Psychological review.

[12]  W Skrandies,et al.  Distribution of Latent Components Related to Information Processing a , 1984, Annals of the New York Academy of Sciences.

[13]  Susan M. Garnsey,et al.  Evoked potentials and the study of sentence comprehension , 1989, Journal of psycholinguistic research.

[14]  W Skrandies,et al.  Sensory thresholds and neurophysiological correlates of human perceptual learning. , 1996, Spatial vision.

[15]  D. Molfese,et al.  Electrophysiological correlates of semantic features , 1985, Journal of psycholinguistic research.

[16]  Dietrich Lehmann,et al.  Microstates in Language-Related Brain Potential Maps Show Noun–Verb Differences , 1996, Brain and Language.

[17]  John W. Tukey,et al.  Exploratory Data Analysis. , 1979 .

[18]  D. Molfese,et al.  Right-hemisphere responses from preschool children to temporal cues to speech and nonspeech materials: Electrophysiological correlates , 1988, Brain and Language.

[19]  M. Puel,et al.  Brain Functional Profiles in Formal and Semantic Fluency Tasks: A SPECT Study in Normals , 1996, Brain and Language.

[20]  Pierre Goulet,et al.  Impaired word naming in right-brain-damaged right-handers: Error types and time-course analyses , 1988, Brain and Language.

[21]  S E Petersen,et al.  The processing of single words studied with positron emission tomography. , 1993, Annual review of neuroscience.

[22]  H A Whitaker,et al.  Language Production: Electroencephalographic Localization in the Normal Human Brain , 1971, Science.

[23]  Gary S. Rubin,et al.  Reading without saccadic eye movements , 1992, Vision Research.

[24]  C. Osgood,et al.  The Measurement of Meaning , 1958 .

[25]  Dietrich Lehmann,et al.  Spatial analysis of evoked potentials in man—a review , 1984, Progress in Neurobiology.

[26]  J. Russell,et al.  Evidence for a three-factor theory of emotions , 1977 .

[27]  A. Ducati,et al.  Neuronal generators of the visual evoked potentials: intracerebral recording in awake humans. , 1988, Electroencephalography and clinical neurophysiology.

[28]  W Skrandies,et al.  Contrast and stereoscopic visual stimuli yield lateralized scalp potential fields associated with different neural generators. , 1991, Electroencephalography and clinical neurophysiology.

[29]  P. Fox,et al.  Functional Imaging and Language: Evidence from Positron Emission Tomography , 1994, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[30]  H. Neville,et al.  Fractionating language: different neural subsystems with different sensitive periods. , 1992, Cerebral cortex.

[31]  James R. Booth,et al.  Reading unspaced text: Implications for theories of reading eye movements , 1994, Vision Research.

[32]  Michael C. Doyle,et al.  Modulation of event-related brain potentials by word repetition: effects of local context. , 1994, Psychophysiology.

[33]  H. Goodglass,et al.  Auditory Evoked Response: Meaningfulness of Stimuli and Interhemispheric Asymmetry , 1972, Science.

[34]  N. Birbaumer,et al.  Electrocortical distinction of vocabulary types. , 1995, Electroencephalography and clinical neurophysiology.

[35]  H Begleiter,et al.  Cortical evoked potentials to semantic stimuli. , 1969, Psychophysiology.

[36]  D. Regan,et al.  Human brain electrophysiology , 1989 .

[37]  Murray S. Miron,et al.  Cross-Cultural Universals of Affective Meaning , 1975 .

[38]  D. Lehmann,et al.  Reference-free identification of components of checkerboard-evoked multichannel potential fields. , 1980, Electroencephalography and clinical neurophysiology.

[39]  Eran Zaidel,et al.  Auditory Vocabulary of the Right Hemisphere Following Brain Bisection or Hemidecortication , 1976, Cortex.

[40]  W. Skrandies.  Visual information processing: topography of brain electrical activity , 1995, Biological Psychology.

[41]  John W McCrary,et al.  Behavioral and neural analyses of connotative meaning: Word classes and rating scales , 1980, Brain and Language.

[42]  R. C. Oldfield.  The assessment and analysis of handedness: the Edinburgh inventory. , 1971, Neuropsychologia.

[43]  M. Garrett,et al.  Syntactically Based Sentence Processing Classes: Evidence from Event-Related Brain Potentials , 1991, Journal of Cognitive Neuroscience.

[44]  M. Kutas,et al.  Reading senseless sentences: brain potentials reflect semantic incongruity. , 1980, Science.

[45]  M. Bradley,et al.  Measuring emotion: the Self-Assessment Manikin and the Semantic Differential. , 1994, Journal of behavior therapy and experimental psychiatry.

[46]  Colin M. Brown,et al.  Lexical-semantic event-related potential effects in patients with left hemisphere lesions and aphasia, and patients with right hemisphere lesions without aphasia. , 1996, Brain : a journal of neurology.

[47]  W. Skrandies.  Depth perception and evoked brain activity: The influence of horizontal disparity and visual field location , 1997, Visual Neuroscience.

[48]  W. Skrandies.  The Upper and Lower Visual Field of Man: Electrophysiological and Functional Differences , 1987 .

[49]  C. C. Wood,et al.  Auditory Evoked Potentials during Speech Perception , 1971, Science.