Localization of visually evoked cortical activity in humans.

Transcription

1 Page 1 of 5 Journal List > J Physiol > v.360; Mar 1985 J Physiol March; 360: PMCID: PMC Copyright notice R Srebro This article has been cited by other articles in PMC. Abstract The locations of cortical activity evoked by visual stimuli presented at different positions in the visual field are deduced from the scalp topography of visually evoked potentials in humans. To accomplish this, the Laplacian evoked potential is measured using a multi-electrode array. It is shown that the Laplacian response has the following useful attributes for this purpose. It is reference-free. Its spatial resolution is approximately 2 cm referred to the surface of the cortex. Its spatial sensitivity characteristic is that of a spatial band-pass filter. It is relatively insensitive to source--sink configurations that are oriented tangentially to the surface of the scalp. Only modest assumptions about the source--sink configuration are required to obtain a unique inversion of the scalp topography. Stimuli consisting of checkerboard-filled octant or annular octant segments are presented as appearance-disappearance pulses at sixteen different positions in the visual field in randomized order. The locations of evoked cortical activity in the occipital, parietal and temporal lobes are represented on a Mercator projection map for each octant or octant segment stimulated. Lower hemifield stimuli activate cortex which lies mainly on the convexity of the occipital lobe contralateral to the side of stimulus presentation in the visual field. The more peripheral the stimulus is in the visual field, the more rostral is the location of the active cortex. The rostral-to-caudal location of the evoked activity varies from subject to subject by as much as 3 cm on the surface of the occipital cortex. Furthermore, in any single subject there is a substantial amount of hemispheric asymmetry. Upper hemifield stimuli activate cortex that lies on the extreme caudal pole of the occipital lobe. This activity is relatively weak, and in some subjects it is almost unmeasurable. It is suggested that the representation of the upper hemifield in the cortex lies mostly on the inferior and mesial walls of the occipital lobe and possibly within the calcarine fissures. Those locations are inaccessible to the Laplacian analysis because the current generators therein may be oriented tangentially to the surface of the overlying scalp. Posterior parietal lobe activity and/or inferior temporal lobe activity is frequently evoked. Different subjects have different patterns of evoked activity. Unilateral or bilateral posterior parietal lobe activity is the most common pattern. Unilateral inferior temporal lobe activity is a less common pattern.(abstract TRUNCATED AT 400 WORDS) Full text Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (2.1M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

2 Page 2 of

3 Page 3 of Images in this article Plate 1 on p Click on the image to see a larger version. Selected References These references are in PubMed. This may not be the complete list of references from this article.

4 Page 4 of 5 Blumhardt LD, Barrett G, Kriss A, Halliday AM. The pattern-evoked potential in lesions of the posterior visual pathways. Ann N Y Acad Sci. 1982;388: Brindley GS. The variability of the human striate cortex. J Physiol Sep;225(2):1P 3P. Brindley GS, Lewin WS. The sensations produced by electrical stimulation of the visual cortex. J Physiol May;196 (2): Darcey TM, Ary JP, Fender DH. Spatio-temporal visually evoked scalp potentials in response to partial-field patterned stimulation. Electroencephalogr Clin Neurophysiol Dec;50(5-6): Fuster JM, Jervey JP. Neuronal firing in the inferotemporal cortex of the monkey in a visual memory task. J Neurosci Mar;2(3): Gross CG, Bender DB, Gerstein GL. Activity of inferior temporal neurons in behaving monkeys. Neuropsychologia. 1979;17 (2): Haimovic IC, Pedley TA. Hemi-field pattern reversal visual evoked potentials. II. Lesions of the chiasm and posterior visual pathways. Electroencephalogr Clin Neurophysiol Aug;54(2): Halliday AM, Michael WF. Changes in pattern-evoked responses in man associated with the vertical and horizontal meridians of the visual field. J Physiol Jun;208(2): Henderson CJ, Butler SR, Glass A. The localization of equivalent dipoles of EEG sources by the application of electrical field theory. Electroencephalogr Clin Neurophysiol Aug;39(2): Hosek RS, Sances A, Jr, Jodat RW, Larson SJ. The contributions of intracerebral currents to the EEG and evoked potentials. IEEE Trans Biomed Eng Sep;25(5): Jeffreys DA. Cortical source locations of pattern-related visual evoked potentials recorded from the human scalp. Nature Feb 12;229(5285): Jeffreys DA, Axford JG. Source locations of pattern-specific components of human visual evoked potentials. I. Component of striate cortical origin. Exp Brain Res. 1972;16(1):1 21. Jeffreys DA, Smith AT. The polarity inversion of scalp potentials evoked by upper and lower half-field stimulus patterns: latency or surface distribution differences? Electroencephalogr Clin Neurophysiol Apr;46(4): Kavanagh RN, Darcey TM, Lehmann D, Fender DH. Evaluation of methods for three-dimensional localization of electrical sources in the human brain. IEEE Trans Biomed Eng Sep;25(5): Klee M, Rall W. Computed potentials of cortically arranged populations of neurons. J Neurophysiol May;40(3): Lehman D, Meles HP, Mir Z. Average multichannel EEG potential fields evoked from upper and lower hemi-retina: latency differences. Electroencephalogr Clin Neurophysiol Nov;43(5): Lesevre N, Joseph JP. Modifications of the pattern-evoked potential (PEP) in relation to the stimulated part of the visual field (clues for the most probable origin of each component). Electroencephalogr Clin Neurophysiol Aug;47(2): MacKay DM. Source density analysis of scalp potentials during evaluated action. II. Lateral distributions. Exp Brain Res. 1984;54(1): Marr D, Hildreth E. Theory of edge detection. Proc R Soc Lond B Biol Sci Feb 29;207(1167): Michael WF, Halliday AM. Differences between the occipital distribution of upper and lower field pattern-evoked responses in man. Brain Res Sep 24;32(2):

5 Page 5 of 5 Mikami A, Kubota K. Inferotemporal neuron activities and color discrimination with delay. Brain Res Jan 20;182(1): Motter BC, Mountcastle VB. The functional properties of the light-sensitive neurons of the posterior parietal cortex studied in waking monkeys: foveal sparing and opponent vector organization. J Neurosci Jan;1(1):3 26. Mountcastle VB, Andersen RA, Motter BC. The influence of attentive fixation upon the excitability of the light-sensitive neurons of the posterior parietal cortex. J Neurosci Nov;1(11): Ridley RM, Hester NS, Ettlinger G. Stimulus- and response-dependent units from the occipital and temporal lobes of the unanaesthetized monkey performing learnt visual tasks. Exp Brain Res Apr 21;27(5): Rolls ET, Judge SJ, Sanghera MK. Activity of neurones in the inferotemporal cortex of the alert monkey. Brain Res Jul 15;130(2): Rush S, Driscoll DA. Current distribution in the brain from surface electrodes. Anesth Analg Nov Dec;47(6): Rush S, Driscoll DA. EEG electrode sensitivity--an application of reciprocity. IEEE Trans Biomed Eng Jan;16(1): Wallin G, Stålberg E. Source derivation in clinical routine EEG. Electroencephalogr Clin Neurophysiol Nov;50(3-4): WILSON FN, BAYLEY RH. The electric field of an eccentric dipole in a homogeneous spherical conducting medium. Circulation Jan;1(1): Articles from The Journal of Physiology are provided here courtesy of The Physiological Society