Summary
In this study we attempted to extend our previous results on regional specialization of frontal cortical function in humans, by means of magnetoencephalography (MEG). We used a verbal task and predicted that some part of the left frontal lobe would be active during engagement in that task, since the left hemisphere is known to be implicated in language. We did not require a motor response because in previous experiments we observed bilateral frontal magnetic activity, and we suspected that it was due to the addition of movement-related fields to our recordings. Six right handed subjects (three males and three females) participated in the study. The task consisted in silently counting the number of word pairs that matched with respect to semantic category. Experimental runs were composed by series of 120 trials or word pairs. All six subjects presented dipolar magnetic field distributions on the left fronto-temporal area of the scalp, but not on the right, during different portions of the trial duration. These fields were successfully modeled as equivalent current dipoles (ECDs). The spatial ECD coordinates were translated onto magnetic resonance image (MRI) coordinates for each subject. The dipole positions were typically near the cortical surface corresponding to areas 6 and 44 of Brodmann. No dipole-like sources were observed in the right frontal lobe.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Basile, L.F.H., Rogers, R.L., Bourbon, W.T. and Papanicolaou, A.C. Slow magnetic fields from human frontal cortex. Electroenceph. clin. Neurophysiol., 1994, 90:157–165.
Basile, L.F.H., Brunder, D.G. and Papanicolaou, A.C. Magnetic fields from human prefrontal cortex differ during two recognition tasks. Int. J. Psychophysiol., (in press 1996).
Cohen, R.M., Semple, W.E., Gross, M., King, A.C. and Nordahl, T.E. Metabolic brain pattern of sustained auditory discrimination. Exp. Brain Res., 1992, 92:165–172.
Courtney, S.N., Ungerlieder, L.G., Keil, K. and Haxby, J.V. Object and spatial visual working memory activate separate neural systems in human cortex. Cerebral Cortex, 1996, 6:39–49.
Eckenstein, F. and Baughman, R.W. Cholinergic innervation in cerebral cortex. In: Cerebral Cortex. Vol 6: Chap 3. Jones, E.G. and Peters, A. (Eds). Plenum Press. New York, 1987.
Fallon, J.H. and Loughlin, S.E. Monoamine innervation of cerebral cortex and a theory of the role of monoamines in cerebral cortex and basal ganglia. In: Cerebral Cortex. Vol 6: Chap 2. Jones, E.G. and Peters, A. (Eds). Plenum Press. New York, 1987.
Frith, C.D., Friston, K., Liddle, P.F. and Frackowiak, R.S. Willed action and the prefrontal cortex in man: a study with PET. Proc. R. Soc. Lond. B, 1991, 244:241–246.
Fuster, J.M. The Prefrontal Cortex (2nd ed). Raven Press. New York, 1989.
Hämäläinen, M., Hari, R., Ilmoniemi, R.J., Knuutila, J. and Lounasmaa, O.V. Magnetoencephalography — theory, instrumentation, and applications to noninvasive studies of the working human brain. Reviews of Modern Physics, 1993, 65:413–497.
Hämäläinen, M.S. and Sarvas, J. Realistic conductivity model of the human head for interpretation of neuromagnetic data. IEEE Trans. Biomed. Eng., 1989, 36:165–171.
Ioannides, A.A., Muratore, R., Balish, M. and Sato, S. In vivo validation of distributed source solutions for the biomagnetic inverse problem. Brain Topography, 1993, 5:263–273.
Kaufman, L., Schwartz, B., Salustri, C. and Williamson, S.J. Modulation of spontaneous brain activity during mental imagery. J. of Cogn. Neurosci., 1990, 2:124–132.
Kaufman, L., Kaufman, J.H. and Wang, J. On cortical folds and neuromagnetic fields. Electroenceph. clin. Neurophysiol., 1991, 79:211–226.
Lewine, J.D. Neuromagnetic techniques for the noninvasive analysis of brain function. In: Noninvasive Techniques in Biology and Medicine. Chap 3. Freeman, S.E.; Fukushima, E. and Greene, E.R. (Eds). San Francisco Press, San Francisco, 1990.
McCarthy, G., Blamire, A.M., Rothman, D.L., Gruetter, R. and Shulman, R.G. Echo-planar magnetic resonance imaging studies of frontal cortex activation during word generation in humans. Proc. Natl. Acad. Sci. USA, 1993, 90:4952–4956.
Petrides, M., Alivisatos, B., Evans, A.C. and Meyer, E. Dissociation of human mid-dorsolateral from posterior dorsolateral frontal cortex in memory processing. Proc. Natl. Acad. Sci. USA, 1993a, 90:873–877.
Petrides, M., Alivisatos, B., Meyer, E. and Evans, A.C. Functional activation of the human frontal cortex during the performance of verbal working memory tasks. Proc. Natl. Acad. Sci. USA, 1993b, 90:878–882.
Rogers, R.L., Baumann, S.B., Papanicolaou, A.C., Bourbon, T.W., Alagarsamy, S. and Eisenberg, H.M. Localization of the P3 sources using magnetoencephalography and magnetic resonance imaging. Electroenceph. clin. Neurophysiol., 1991, 79:308–321.
Rogers, R.L., Papanicolaou, A.C., Baumann, S.B. and Eisenberg, H.M. Late magnetic fields and positive evoked potentials following infrequent and unpredictable omissions of visual stimuli. Electroenceph. clin. Neurophysiol., 1992, 83:146–152.
Rogers, R.L., Basile, L.F.H., Papanicolaou, A.C., Bourbon, T.W. and Eisenberg, H.M. Visual evoked magnetic fields reveal activity in the superior temporal sulcus. Electroenceph. clin. Neurophysiol., 1993a, 86:344–347.
Rogers, R.L., Basile, L.F.H., Papanicolaou, A.C. and Eisenberg, H.M. Magnetoencephalography reveals two distinct sources associated with late positive evoked potentials during visual oddball tasks. Cerebral Cortex, 1993b, 3:163–169.
Roland, P.E. and Friberg, L. Localization of cortical areas activated by thinking. J. Neurophysiol., 1985, 53:1219–1243.
Shallice, T., Fletcher, P., Frith, C.D., Grasby, P., Frackowiak, R.S.J. and Doland, R.J. Brain regions associated with acquisition and retrieval of verbal episodic memory. Nature, 1994, 368:633–635.
Smith, E.E., Jonides, J. and Koeppe, R.A. Dissociating verbal and spatial working memory using PET. Cerebral Cortex, 1996, 6:11–20.
Tanila, H., Carlson, S., Linnankoski, I. and Kahila, H. Regional distribution of functions in dorsolateral cortex of the monkey. Behav. Brain Res., 1993, 53:63–71.
Wang, J., Kaufman, L. and Williamson, S.J. Imaging regional changes in the spontaneous activity of the brain: an extension of the minimum-norm least-squares estimate. Electroenceph. clin. Neurophysiol., 1993, 86:36–50.
Watanabe, M. Prefrontal unit activity during associative learning in the monkey. Exp. Brain Res., 1990, 80:296–309.
Williamson, S.J. and Kaufman, L. Analysis of neuromagnetic signals. In: Handbook of Electroencephalography and Clinical Neurophysiology. Human Event-Related Potentials (revised series vol.1) Gevins, A.S. and Remond, A. (Eds.). Elsevier Science Publishers, 1987, 405–448.
Wilson, F.A.W., Scalaidhe, S.P.O. and Goldman-Rakic, P.S. Dissociations of object and spatial processing domains in primate prefrontal cortex. Science, 1993, 260:1995–1958.
Author information
Authors and Affiliations
Additional information
This research was supported by grant NS 29540-005A1 from the National Institutes of Health, Washington, D.C.
Rights and permissions
About this article
Cite this article
Basile, L.F.H., Simos, P.G., Tarkka, I.M. et al. Task-specific magnetic fields from the left human frontal cortex. Brain Topogr 9, 31–37 (1996). https://doi.org/10.1007/BF01191640
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01191640