Optical imaging of cortical networks via intracortical microstimulation

Andrea A. Brock, Robert M. Friedman, Reuben H. Fan, Anna W. Roe

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Understanding cortical organization is key to understanding brain function. Distinct neural networks underlie the functional organization of the cerebral cortex; however, little is known about how different nodes in the cortical network interact during perceptual processing and motor behavior. To study cortical network function we examined whether the optical imaging of intrinsic signals (OIS) reveals the functional patterns of activity evoked by electrical cortical microstimulation. We examined the effects of current amplitude, train duration, and depth of cortical stimulation on the hemodynamic response to electrical microstimulation (250-Hz train, 0.4-ms pulse duration) in anesthetized New World monkey somatosensory cortex. Electrical stimulation elicited a restricted cortical response that varied according to stimulation parameters and electrode depth. Higher currents of stimulation recruited more areas of cortex than smaller currents. The largest cortical responses were seen when stimulation was delivered around cortical layer 4. Distinct local patches of activation, highly suggestive of local projections, around the site of stimulation were observed at different depths of stimulation. Thus we find that specific electrical stimulation parameters can elicit activation of single cortical columns and their associated columnar networks, reminiscent of anatomically labeled networks. This novel functional tract tracing method will open new avenues for investigating relationships of local cortical organization.

Original languageEnglish (US)
Pages (from-to)2670-2678
Number of pages9
JournalJournal of neurophysiology
Issue number11
StatePublished - Dec 1 2013
Externally publishedYes


  • Electrical microstimulation
  • Intrinsic signal optical imaging

ASJC Scopus subject areas

  • General Neuroscience
  • Physiology


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