Visual Information Processing in the Ventral Division of the Mouse Lateral Geniculate Nucleus of the Thalamus.

Ciftcioglu, Ulas M.; Suresh, Vandana; Ding, Kimberly R.; Sommer, Friedrich T.; Hirsch, Judith A.

Even though the lateral geniculate nucleus of the thalamus (LGN) is associated with form vision, that is not its sole role. Only the dorsal portion of LGN (dLGN) projects to VI. The ventral division (vLGN) connects subcortically, sending inhibitory projections to sensorimotor structures, including the superior colliculus (SC) and regions associated with certain behavioral states, such as fear (Monavarfeshani et ah, 2017; Salay et ah, 2018). We combined computational, physiological, and anatomical approaches to explore visual processing in vLGN of mice of both sexes, making comparisons to dLGN and SC for perspective. Compatible with past, qualitative descriptions, the receptive fields we quantified in vLGN were larger than those in dLGN, and most cells preferred bright versus dark stimuli (Harrington, 1997). Dendritic arbors spanned the length and/or width of vLGN and were often asymmetric, positioned to collect input from large but discrete territories. By contrast, arbors in dLGN are compact (Krahe et ah, 2011). Consistent with spatially coarse receptive fields in vLGN, visually evoked changes in spike timing were less precise than for dLGN and SC. Notably, however, the membrane currents and spikes of some cells in vLGN displayed gamma oscillations whose phase and strength varied with stimulus pattern, as for SC (Stitt et ah, 2013). Thus, vLGN can engage its targets using oscillation-based and conventional rate codes. Finally, dark shadows activate SC and drive escape responses, whereas vLGN prefers bright stimuli. Thus, one function of long-range inhibitory projections from vLGN might be to enable movement by releasing motor targets, such as SC, from suppression.

LATERAL geniculate body; OPTICAL information processing; SUPERIOR colliculus; THALAMUS; STARTLE reaction; MICE

Journal of Neuroscience, 2020, Vol 40, Issue 26, p5019

0270-6474

Academic Journal

10.1523/JNEUROSCI.2602-19.2020