title: Retinal oscillations carry visual information to cortex.
abstract: Thalamic relay cells fire action potentials that transmit information from retina to cortex. The amount of information that spike trains encode is usually estimated from the precision of spike timing with respect to the stimulus. Sensory input, however, is only one factor that influences neural activity. For example, intrinsic dynamics, such as oscillations of networks of neurons, also modulate firing pattern. Here, we asked if retinal oscillations might help to convey information to neurons downstream. Specifically, we made whole-cell recordings from relay cells to reveal retinal inputs (EPSPs) and thalamic outputs (spikes) and then analyzed these events with information theory. Our results show that thalamic spike trains operate as two multiplexed channels. One channel, which occupies a low frequency band (<30 Hz), is encoded by average firing rate with respect to the stimulus and carries information about local changes in the visual field over time. The other operates in the gamma frequency band (40-80 Hz) and is encoded by spike timing relative to retinal oscillations. At times, the second channel conveyed even more information than the first. Because retinal oscillations involve extensive networks of ganglion cells, it is likely that the second channel transmits information about global features of the visual scene.
authors.affiliation: Redwood Center for Theoretical Neuroscience, University of California Berkeley CA, USA.
authors.forename: Kilian
authors.initials: K
authors.lastname: Koepsell
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Vishal
authors.initials: V
authors.lastname: Vaingankar
authors.forename: Yichun
authors.initials: Y
authors.lastname: Wei
authors.forename: Qingbo
authors.initials: Q
authors.lastname: Wang
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Rathbun
authors.forename: W Martin
authors.initials: WM
authors.lastname: Usrey
authors.forename: Judith A
authors.initials: JA
authors.lastname: Hirsch
authors.forename: Friedrich T
authors.initials: FT
authors.lastname: Sommer