TY - JOUR
T1 - Immediate responses to ambient light in vivo reveal distinct subpopulations of suprachiasmatic VIP neurons
AU - Kahan, Anat
AU - Mahe, Karan
AU - Dutta, Sayan
AU - Kassraian, Pegah
AU - Wang, Alexander
AU - Gradinaru, Viviana
N1 - Publisher Copyright:
© 2023 The Authors
PY - 2023/10/20
Y1 - 2023/10/20
N2 - The circadian rhythm pacemaker, the suprachiasmatic nucleus (SCN), mediates light entrainment via vasoactive intestinal peptide (VIP) neurons (SCNVIP). Yet, how these neurons uniquely respond and connect to intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing melanopsin (Opn4) has not been determined functionally in freely behaving animals. To address this, we first used monosynaptic tracing from SCNVIP neurons in mice and identified two SCNVIP subpopulations. Second, we recorded calcium changes in response to ambient light, at both bulk and single-cell levels, and found two unique activity patterns in response to high- and low-intensity blue light. The activity patterns of both subpopulations could be manipulated by application of an Opn4 antagonist. These results suggest that the two SCNVIP subpopulations connect to two types of Opn4-expressing ipRGCs, likely M1 and M2, but only one is responsive to red light. These findings have important implications for our basic understanding of non–image-forming circadian light processing.
AB - The circadian rhythm pacemaker, the suprachiasmatic nucleus (SCN), mediates light entrainment via vasoactive intestinal peptide (VIP) neurons (SCNVIP). Yet, how these neurons uniquely respond and connect to intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing melanopsin (Opn4) has not been determined functionally in freely behaving animals. To address this, we first used monosynaptic tracing from SCNVIP neurons in mice and identified two SCNVIP subpopulations. Second, we recorded calcium changes in response to ambient light, at both bulk and single-cell levels, and found two unique activity patterns in response to high- and low-intensity blue light. The activity patterns of both subpopulations could be manipulated by application of an Opn4 antagonist. These results suggest that the two SCNVIP subpopulations connect to two types of Opn4-expressing ipRGCs, likely M1 and M2, but only one is responsive to red light. These findings have important implications for our basic understanding of non–image-forming circadian light processing.
KW - Behavioral neuroscience
KW - Biological sciences
KW - Neuroscience
UR - http://www.scopus.com/inward/record.url?scp=85171982840&partnerID=8YFLogxK
U2 - 10.1016/j.isci.2023.107865
DO - 10.1016/j.isci.2023.107865
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AN - SCOPUS:85171982840
SN - 2589-0042
VL - 26
JO - iScience
JF - iScience
IS - 10
M1 - 107865
ER -