FOLLOWING THE BLUES THROUGH THE BRAIN
Chris Tailby, Brett A. Szmajda, Péter Buzás, Barry B. Lee and Paul R. Martin
The retina contains three different classes of colour-sensitive photoreceptor cells (cones), one of which is most sensitive to short wavelengths: 'blue'-cones. Blue-cones comprise less than 10% of all cone photoreceptors and little is known about how they transmit information to the brain.
We recorded from neurons in the lateral geniculate nucleus (LGN) - an important part of the visual pathway. Two classes of LGN neuron receive strong blue-cone input: 'blue-ON' and 'blue-OFF' cells. We found that relative to blue-ON cells, blue-OFF cells have larger receptive-fields and show more low-pass spatial frequency tuning.
Figure: Surround suppression in different classes of LGN neuron. Responses of a blue-on cell to optimum spatial frequency gratings as a function of aperture radius. Filled symbols show responses to S-cone selective gratings; open symbols show responses to ML selective gratings.
Reference: Tailby C, Szmajda BA, Buzas P, Lee BB, Martin PR (2008). Transmission of blue (S) cone signals through the primate lateral geniculate nucleus. Journal of Physiology 585: 5947-5967.