Journal of Neuroscience, Vol 7, 2756-2767, Copyright © 1987 by Society for Neuroscience
Release of cortical catecholamines by visual stimulation requires activity in thalamocortical afferents of monkey and cat
RT Marrocco, RF Lane, JW McClurkin, CD Blaha and MF Alkire
Catecholamine (CA) release was measured in vivo in the monkey and cat
visual cortices electrochemically. Stereate-modified, graphite-paste
electrodes were used to monitor changes in norepinephrine and dopamine
release. Micromolar changes in CA concentration were obtained by
stimulation of the eye with nonspecific (strobe) or specific (oriented
bars, radial gratings) stimuli. CA release depended on which eye was
illuminated. Electrodes passed tangentially through the striate area
recorded release following visual stimulation of one eye or the other in
succession, and the shift in eye dominance occurred at about 500 microns
intervals. The magnitude of CA release was highly correlated with the
ocular dominance of neuronal activity measured with tungsten
microelectrodes. Light-stimulated release was not recorded in monkey area
V2, V4, or somatosensory area 1, but was recorded in cat V2, suggesting
that the presence of LGN afferents is associated with CA release. Results
are discussed in terms of the role of geniculate activity and the specific
role of CAs in cortical information processing.