Dynamic Cognitive Networks in the Human Brain
Even simple ognitive behaviors involve a complex spatiotemporal sequence of coordinated processes in many neural regions. Evoked potentials (EPs) have the subsecond temporal resolution needed to track the flow of information through the brain while subjects perform cognitive tasks. To take full advantage of the information provided by the EPs, both the spatial topography and the temporal relationships of responses measured at different scalp sites must be considered. Toward this end, we have been developing methods for statistically characterizing coordinated processing in distributed cortical networks by analyzing the spatial covariance of EPs recorded from multiple scalp locations. This method is called Evoked Potential Covariance (EPC) analysis.
This paper describes the results of a series of experiments in which sub-second EPC patterns were measured during simple but complete cognitive behaviors—from stimulus expectancy, through stimulus evaluation and decision processes, to response execution and evaluation of feedback, in situations that required responses to the current stimulus, or responses to previous stimuli (thus requiring working memory). Differences in the EPC patterns across the 4- to 6-second intervals spanning the trials demonstrated that different cortical areas form functional associations during each subsequent stage of processing. Subdural electrical recordings suggest that the EPC measure is a physiologically meaningful method of characterizing the association between different brain areas. We speculate that the EPC patterns associated with prestimulus preparation and feedback-evoked updating are manifestations of the internal models created by the brain which provide the context within which stimuli are interpreted.
KeywordsAttenuation Covariance Coherence Tral Deblurring
Unable to display preview. Download preview PDF.
- Bastian HC (1898) Aphasia and other speech defects. London, LewisGoogle Scholar
- Fuster JM (1989) The prefrontal cortex: anatomy, physiology, and neuropsychology of the frontal lobe. Raven Press, New YorkGoogle Scholar
- Gaillard A (1978) Slow brain potentials preceding task performance. Academic Press, AmsterdamGoogle Scholar
- Gersch W (1987) Non-stationary multichannel time series analysis. In: Gevins AS, Remond A (eds) Handbook of electroencephalography and clinical neurophysiology. Vol. 1. Methods of analysis of brain electrical and magnetic signals. Elsevier, Amsterdam, pp 171–193Google Scholar
- Gevins AS (1987) Correlation Analysis. In: Gevins As, Remond A (eds) Handbook of electroencephalography and clinical neurophysiology. Vol. 1. Methods of analysis of brain electrical and magnetic signals. Elsevier, Amsterdam, pp 171–193Google Scholar
- Gevins AS Bressler SL (1988) Functional topography of the human brain. In: Pfurt-scheller G (ed) Functional brain imaging. Hans Huber Publishers, Bern, pp 99–116Google Scholar
- Gevins AS, Cutillo BA, Bressler SL, Morgan NH, White RM, Illes J, Greer D (1989 b) Event-related covariances during a bimanual visuomotor task. Part II: Preparation and feedback. Electroencephal. Clin. Neurophysiol 74:147–160Google Scholar
- Gevins A, Cutillo B, Desmond JE, Ward M, Bressler S (1994) Subdural grid recordings of distributed neocortical networks involved with somatosensory discrimination. Electroenceph Clin Neurophysiol, in pressGoogle Scholar
- Livanov MN (1977) Spatial organization of cerebral processes. Wiley, New YorkGoogle Scholar
- Mars NJ Lopes da Silva FH (1987) EEG analysis methods based on information theory. In: Gevins AS, Remond A (eds) Handbook of electroencephalography and clinical neurophysiology. Vol. 1: Methods of analysis of brain electrical and magnetic signals. Elsevier, Amsterdam, pp 297–307Google Scholar
- Posner MI, Snyder CR (1975) Facilitation and inhibition in the processing of signals. In: Rabbit PM, Domic S (eds) Attention and performance. V. Academic Press, New York, pp 669–682Google Scholar
- Saito Y, Harashima H (1981) Tracking of information within multichannel EEG record-causal analysis in EEG. In: Yamaguchi N, Fujisawa K (eds) Recent advances in EEG and EMG data processing. Elsevier, Amsterdam, pp 133–177Google Scholar
- Stuss D, Benson DF (1986) The frontal lobes. Raven Press, New YorkGoogle Scholar
- Teuber HL (1964) The riddle of frontal lobe function in man. In: Warren J, Akert K (eds) The frontal granular cortex and behavior, McGraw-Hill, New York, pp 410–477Google Scholar
- Weiskrantz L (1987) Neuroanatomy of memory and amnesia: A case for multiple memory systems. Human Neurobiol 6:93–105Google Scholar