Functional architecture of cortex revealed by optical imaging of intrinsic signals

Abstract

Optical imaging of cortical activity offers several advantages over conventional electrophysiological and anatomical techniques. One can map a relatively large region, obtain successive maps to different stimuli in the same cortical area and follow variations in response over time. In the intact mammalian brain this imaging has been accomplished with the aid of voltage sensitive dyes. However, it has been known for many years that some intrinsic changes in the optical properties of the tissue are dependent on electrical or metabolic activity. Here we show that these changes can be used to study the functional architecture of cortex. Optical maps of whisker barrels in the rat and the orientation columns in the cat visual cortex, obtained by reflection measurements of the intrinsic signal, were confirmed with voltage sensitive dyes or by electrophysiological recordings. In addition, we describe an intrinsic signal originating from small arteries which can be used to investigate the communication between local neuronal activity and the microvasculature. One advantage of the method is that it is non-invasive and does not require dyes, a clear benefit for clinical applications.

Mesoscale infraslow spontaneous membrane potential fluctuations recapitulate high-frequency activity cortical motifs

“…Given the susceptibility of infraslow frequency fluctuations to be potentially confounded by non-neuronal phenomenon, we examined the mechanistic basis underlying our observed infraslow fluctuations 7,[42][43][44] . Topical treatment of the cortical surface with TTX (10 mM), a voltage-gated sodium channel antagonist, completely abolished whisker sensory stimulation-evoked VSD responses from primary barrel somatosensory cortex associated with the C2 whisker (BCS1), secondary barrel somatosensory cortex associated with the C2 whisker (BCS2) and from motor cortex associated with C2 whisker (mBC) indicating complete and spatially widespread inhibition of sensory-evoked activity in the cortex ( Supplementary Fig.…”

Interpreting fMRI data: maps, modules and dimensions

“…The first demonstrations of more fine-scale functional organization in v1 were maps of ocular dominance 10 and orientation preference 90,91 . Later studies provided evidence of clustering of several other functional-response properties in at least some species, for example, spatial frequency and direction of motion 64 .…”

“…An obvious example is the first-order representation of receptor arrays (such as retinotopic maps) that determine the large-scale However, controversy arises once the clear link to the receptor array is lost and the maps reflect higher-order properties of the stimulus. The first demonstrations of more fine-scale functional organization in v1 were maps of ocular dominance 10 and orientation preference 90,91 . Later studies provided evidence of clustering of several other functional-response properties in at least some species, for example, spatial frequency and direction of motion 64 .…”

Wavelet-based multi-resolution statistics for optical imaging signals: Application to automated detection of odour activated glomeruli in the mouse olfactory bulb

“…Optical imaging of the visual area V1, e.g. allows visualizing territories coding for retinal position (Grinvald et al, 1986;Schuett et al, 2002), orientation (Bonhoeffer and Grinvald, 1991), colour (Landisman and Ts'o, 2002) and left or right eye. These territories overlap but differ in their size and shape.…”