Oxytocin Circuit Mechanisms for Pair Bonding
Lizi Zhang, Yishan Qu, Lu Li, Yahan Sun, Wei Qian et al.
(see article e2061242025)
In this issue, Zhang and colleagues shed light on oxytocin circuit mechanisms that influence pair bonding between male and female mandarin voles. The authors explored how oxytocin shapes the activity of a circuit from the paraventricular nucleus (PVN) through the nucleus accumbens to the ventral pallidum. Zhang et al. used whole-cell patch-clamp electrophysiology to discover that bonding with females increased neurotransmission from PVN oxytocin neurons onto medium spiny neurons (MSNs) in the male nucleus accumbens. However, using optogenetics to artificially stimulate PVN oxytocin neurons reduced dopamine 2 (D2) MSN activity while increasing dopamine 1 (D1) MSN activity. Probing what happens downstream of nucleus accumbens activation in this circuit, the researchers manipulated the activity of oxytocin receptor-expressing D1 and D2 MSNs projecting to the ventral pallidum. Stimulating these MSNs promoted pair bonding, while MSN inhibition hindered pair bonding. Lastly, disrupting dopamine signaling through D2, but not D1, receptors blocked pair bond formation. According to the authors, these findings suggest that PVN oxytocin may influence how D1 and D2 MSNs target the ventral pallidum to support pair bonding. Future work may continue to probe these complex circuit mechanisms and how they influence pair bonding in voles.
Overlay of two fluorescent photomicrographs showing retrogradely transported fast blue neurons (blue) and tyrosine hydroxylase-positive neurons (green) in the LC. The white arrowheads point to double labeled neurons. See Tran et al. for more details.
Distinct Roles of Noradrenergic Projections in Memory
Stephanie Tran, Gareth R. I. Barker, Mathias L. Mathiasen, John Aggleton, and Elizabeth Clea Warburton
(see article e2408242025)
Tran et al. used a combined optogenetic and pharmacological approach to examine how different locus ceruleus (LC) projections support recognizing the rearrangement of familiar objects. This process requires updating the memory of a previous object–place association with new information. The authors discovered that retrieval of object–place memories may be mediated by a direct projection from LC to the nucleus reuniens of the thalamus via noradrenaline activation of alpha 1 and 2 adrenoreceptors. Updating memories with new information was encoded by an LC projection to the hippocampus via noradrenaline activation of adrenergic beta and alpha 2 receptors. Thus, distinct LC projections may drive different components of associative memory. According to the authors, this work may provide targets in memory processing to support treatment development for memory deficits.
Footnotes
This Week in The Journal was written by Paige McKeon
