Project: Research project

Project Details


This research seeks to increase the information obtained from
noninvasive evoked potential (EP) studies by developing
(1) techniques which separate the contributions of temporally
overlapping generators from the surface-recorded data, and (2)
improved models for the volume conduction mechanisms which
relate generator location to surface topography. These
techniques will be applied to analysis of human short-latency
auditory EPs and subcortical and cortical somatosensory EPs to
median and peroneal nerve stimulation. Human EPs recorded
intracranially during neurosurgery will be used for verification
and optimization of the models and techniques.

Estimated generator waveforms will be defined by principal
component analysis of surface topographic mappings with rotation
of the factors, and examined in normal subjects and in patients
with neurologic disease. In the patient group, the sensitivity of
the test and its ability to localize areas of dysfunction will be
compared to those of conventionally interpreted EPs.

The volume conduction processes by which the surface potentials
are derived from activity in distant generators will be examined
through a numeric or finite-differences computer model. Such a
model takes into account the anatomy of conductance
inhomogeneities within the head, and should more accurately
represent volume conduction of human EPs than models assuming
spherical symmetry. The "forward" volume conduction model
defines the surface distribution produced by a hypothetical array
of generators; the "inverse" problem will be approached by
heurisitically modifying the generator hypotheses to obtain the
best fit between the predicted surface topography and the
empirical data.

The techniques developed in the course of these studies of
specific EPs are also applicable to the analysis of surface-
recorded event-related potentials produced by various other
stimuli and by cognitive and motor tasks. Thus, they will increase
both clinical accuracy and experimental utility of many types of
event-related potentials.
Effective start/end date7/1/886/30/89


  • National Institute of Neurological Disorders and Stroke


  • Computers in Earth Sciences
  • Sensory Systems
  • Geophysics
  • Cognitive Neuroscience
  • Human Factors and Ergonomics

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