Data from: Effects of arousal and movement on secondary somatosensory and visual thalamus

Neocortical sensory areas have associated primary and secondary thalamic
nuclei. While primary nuclei transmit sensory information to cortex,
secondary nuclei remain poorly understood. We recorded juxtasomally from
secondary somatosensory (POm) and visual (LP) nuclei of awake mice while
tracking whisking and pupil size. POm activity correlated with whisking,
but not precise whisker kinematics. This coarse movement modulation
persisted after facial paralysis and thus was not due to sensory
reafference. This phenomenon also continued during optogenetic silencing
of somatosensory and motor cortex and after lesion of superior colliculus,
ruling out a motor efference copy mechanism. Whisking and pupil dilation
were strongly correlated, possibly reflecting arousal. Indeed LP, which is
not part of the whisker system, tracked whisking equally well, further
indicating that POm activity does not encode whisker movement per se. The
semblance of movement-related activity is likely instead a global effect
of arousal on both nuclei. We conclude that secondary thalamus monitors
behavioral state, rather than movement, and may exist to alter cortical
activity accordingly.