FIGURE 5.6. Evoked-response potential (ERP) and optical signal averaged across all pixels of the imager (OPTICAL) in a CCD experiment show a response to single-whisker stimulation.

FIGURE 5.6

Evoked-response potential (ERP) and optical signal averaged across all pixels of the imager (OPTICAL) in a CCD experiment show a response to single-whisker stimulation. The optical trace has been inverted to show similarity in temporal structure. An average of 25 baseline images (before stimulation), subtracted from an average of 25 images collected during the early peak response shows a discrete region that corresponds to the cortical column associated with the stimulated whisker. Each image was collected from a 3 mm by 3 mm region of somatosensory cortex over the whisker barrels. A later epoch reveals a spreading of the optical response across space that changes polarity after 500 ms and covers a large portion of the imaged area. In pseudocolor images, warm colors represent decreases in scattered light and cool colors represent scattered light increases. In the lower 5 images, stimulating particular whiskers produced early response images, with discrete regions that localize to the expected map of cortical columns. Each of the five images (3 mm × 3 mm) was collected after stimulating the whisker indicated below the image. For spatial comparison, circles were drawn on all images, showing the activated regions. (Modified from Rector et al., NeuroImage, 26[2], 619–627, 2005. With permission.)

From: Chapter 5, In Vivo Observations of Rapid Scattered Light Changes Associated with Neurophysiological Activity

Cover of In Vivo Optical Imaging of Brain Function
In Vivo Optical Imaging of Brain Function. 2nd edition.
Frostig RD, editor.
Boca Raton (FL): CRC Press/Taylor & Francis; 2009.
Copyright © 2009, Taylor & Francis Group, LLC.

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