PT  - JOURNAL ARTICLE
AU  - Daniel J. Denman
AU  - Diego Contreras
TI  - Complex Effects on <em>In Vivo</em> Visual Responses by Specific Projections from Mouse Cortical Layer 6 to Dorsal Lateral Geniculate Nucleus
AID  - 10.1523/JNEUROSCI.0027-15.2015
DP  - 2015 Jun 24
TA  - The Journal of Neuroscience
PG  - 9265--9280
VI  - 35
IP  - 25
4099  - http://www.jneurosci.org/content/35/25/9265.short
4100  - http://www.jneurosci.org/content/35/25/9265.full
SO  - J. Neurosci.2015 Jun 24; 35
AB  - Understanding the role of corticothalamic projections in shaping visual response properties in the thalamus has been a longstanding challenge in visual neuroscience. Here, we take advantage of the cell-type specificity of a transgenic mouse line, the GN220-Ntsr1 Cre line, to manipulate selectively the activity of a layer 6 (L6) corticogeniculate population while recording visual responses in the dorsal lateral geniculate nucleus (dLGN). Although driving Ntsr1 projection input resulted in reliable reduction in evoked spike count of dLGN neurons, removing these same projections resulted in both increases and decreases in visually evoked spike count. Both increases and decreases are contrast dependent and the sign is consistent over the full range of contrasts. Tuning properties suggest wide convergence of Ntsr1 cells with similar spatial and temporal frequency tuning onto single dLGN cells and we did not find evidence that Ntsr1 cells sharpen spatiotemporal filtering. These nonspecific changes occur independently of changes in burst frequency, indicating that Ntsr1 corticogeniculate activity can result in both net excitation and net inhibition.