Abstract
Freeman and Baird [5; Freeman WJ, Baird B. Behav Neurosci 1987;101:393–408] recorded from the surface of the brain in waking rabbits and found spatial patterns of voltage that covaried with sensory experience. We simulate mathematically the electric fields produced by radial dipoles in cortical gyri and show that patterns with the spatial frequencies observed by Freeman and Baird could be produced by cortical dipoles spaced 3 mm apart. We further calculate that to resolve the patterns produced by such dipole arrays, it is necessary to record less than 2.5 mm above the surface of the cortex. High-pass spatial filters increase this distance to 4.5 mm. Since the human scalp is 15–16 mm above the brain, we conclude that spatial patterns of voltage covarying with sensation are unlikely to be detectable in scalp records. If such patterns do exist in humans, dural or sub-dural electrode arrays, with an inter-electrode spacing of 1 mm or less, will be necessary to record them.
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Bold GEJ, Pockett S, Diprose B, Hay A. An inexpensive, DC-capable EEG recording system. Proc. 12th Electronics New Zealand Conf. ENZCON05; 2005. p. 201–204.
Engel AK, Moll CKE, Fried I, Ojemann GA. Invasive recordings from the human brain: clinical insights and beyond. Nat Rev Neurosci 2005;6:35–47.
Freeman WJ. Neurodynamics: an exploration in mesoscopic brain dynamics. Springer-Verlag; 2000.
Freeman WJ, Viana di Prisco G. Relation of olfactory EEG to behavior: time series analysis. Behav Neurosci 1986;100:753–63.
Freeman WJ, Baird B. Relation of olfactory EEG to behavior: spatial analysis. Behav Neurosci 1987;101:393–408.
Freeman WJ, Grajski KA. Relation of olfactory EEG to behavior: factor analysis. Behav Neurosci 1987;101:766–77.
Freeman WJ, van Dijk BW. Spatial patterns of visual cortical fast EEG during condition reflex in a rhesus monkey. Brain Res 1987;422:267–76.
Horton JC, Adams DL. The cortical column: a structure without a function. Phil Trans Roy Soc Lond B 2005; DOI: 10.1098/rstb.2005.1623.
Horton JC, Hedley-Whyte T. Mapping of cytochrome oxidase patches and ocular dominance columns in human visual cortex. Phil Trans Roy Soc Lond B 1984;304:255–72.
Kandel ER, Schwartz JH, Jessell TM. Principles of neural science. 3rd ed. Prentice-Hall International; 1991.
McConnell KA, Nahas Z, Shastri A, Lorberbaum JP, Kozel FA, Bohning D, et al. The transcranial magnetic stimulation motor threshold depends on the distance from coil to underlying cortex: a replication in healthy adults comparing two methods of assessing the distance to cortex. Biol Psychiat 2001;49:454–9.
Menon V, Freeman WJ, Cutillo BA, Desmond JE, Ward MF, Bressler SL, et al. Spatio-temporal correlations in human gamma band electrocorticograms. Electroenceph Clin Neurophysiol 1996;98:89–102.
Pockett S. The nature of consciousness: a hypothesis. Lincoln Nebraska: Iuniverse Inc.; 2000.
Quian Quiroga R, Reddy L, Kreiman G, Koch C, Fried I. Invariant visual representation by single neurons in the human brain. Nature 2005;435:1102–7.
Rees G, Kreiman G, Koch C. Neural correlates of consciousness in humans. Nat Rev Neurosci 2002;3:261–70.
Szentagothai J. The Ferrier lecture, 1977: the neuron network of the cerebral cortex: a functional interpretation. Proc Roy Soc Lond B 1977;201:219–48.
Tononi G, Srinivasan R, Russell DP, Edelman GM. Investigating the neural correlates of conscious perception by frequency-tagged neuromagnetic responses. Proc Natl Acad Sci USA 1998;95:3198–203.
Geddes LA, Baker LE. The specific resistance of biological material—a compendium of data for the biomedical engineer and physiologist. Med Biol Eng 1967;5(3):271–93.
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Thanks are due to Steve Warrington for technical assistance and the Department of Anatomy at the University of Auckland for allowing access to their collection of calvaria.
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Pockett, S., Zhou, Z.Z., Brennan, B.J. et al. Spatial Resolution and the Neural Correlates of Sensory Experience. Brain Topogr 20, 1–6 (2007). https://doi.org/10.1007/s10548-007-0023-4
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DOI: https://doi.org/10.1007/s10548-007-0023-4