RT Journal Article
SR Electronic
T1 Effects of arousal and movement on secondary somatosensory and visual thalamus
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.03.04.977348
DO 10.1101/2020.03.04.977348
A1 Gordon H. Petty
A1 Amanda K. Kinnischtzke
A1 Y. Kate Hong
A1 Randy M. Bruno
YR 2020
UL http://biorxiv.org/content/early/2020/03/05/2020.03.04.977348.abstract
AB All neocortical sensory areas have an associated primary and secondary thalamic nucleus. While the primary nuclei encode sensory information and relay it to cortex, the drivers of activity in secondary nuclei are poorly understood. We recorded juxtasomally from neurons in secondary somatosensory (POm) and visual (LP) thalamic nuclei of awake head-fixed mice with simultaneous whisker tracking and pupilometry. POm activity correlated with the slow components of whisker movement but not fast precise kinematics. This movement modulation was not due to sensory reafference, persisting after unilateral paralysis of the whisker pad. POm tracked whisking even more strongly after optogenetic silencing of primary somatosensory and motor cortex, indicating that cortical motor efference copy cannot explain movement modulation. We observed that whisking and pupil dilation were strongly correlated, raising the possibility that POm tracks arousal rather than whisker movement. LP, being part of the visual system, is not expected to encode whisker movement. However, we discovered that LP and POm track whisking equally well, suggesting a global arousal effect on both nuclei. Our results suggest that motor signals are largely absent in POm. We conclude that global arousal may be a prominent modulator of secondary thalamic nuclei.