Aromatase and nonaromatase neurons in the zebra finch secondary auditory forebrain are indistinct in their song‐driven gene induction and intrinsic electrophysiological properties

Abstract

Estrogens support major brain functions including cognition, reproduction, neuroprotection and sensory processing. Neuroestrogens are synthesized within some brain areas by the enzyme aromatase and can rapidly modulate local circuit functions, yet the cellular physiology and sensory-response profiles of aromatase neurons are essentially unknown. In songbirds, social and acoustic stimuli drive neuroestrogen elevations in the auditory forebrain caudomedial nidopallium (NCM). In both males and females, neuroestrogens rapidly enhance NCM auditory processing and auditory learning. Estrogenproducing neurons in NCM may therefore exhibit distinguishing profiles for sensory-activation and intrinsic electrophysiology. Here, we explored these questions using both immunocyctochemistry and electrophysiological recordings. Immunoreactivity for aromatase and the immediate early gene EGR1, a marker of activity and plasticity, were quantified in NCM of song-exposed animals versus silence-exposed controls. Using whole-cell patch clamp recordings from NCM slices, we also documented the intrinsic excitability profiles of aromatase-positive and aromatase-negative neurons. We observed that a subset of aromatase neurons were significantly activated during song playback, in both males and females, and in both hemispheres. A comparable population of non-aromatase-expressing neurons were also similarly driven by song stimulation. Membrane properties (i.e., resting membrane potential, rheobase, input resistance and multiple action potential parameters) were similarly indistinguishable between NCM aromatase and non-aromatase neurons. Together, these findings demonstrate that aromatase and non-aromatase neurons in NCM are indistinct in terms of their intrinsic electrophysiology and responses to song. Nevertheless, such similarities in response properties may

Season-dependent processing of innate conspecific vocalizations in the male and female European starling (Sturnus vulgaris)

“…The copyright holder for this preprint (which this version posted July 22, 2023. ; https://doi.org/10.1101/2023.07.20.549888 doi: bioRxiv preprint songbirds such as the zebra finches (Saldanha et al, 2000;Pinaud et al, 2006;de Bournonville, Mendoza and Remage-Healey, 2021), white-throated sparrows (Apfelbeck et al, 2013) and canaries (Metzdorf, Gahr and Fusani, 1999), creating a versatile environment for spatiotemporal hormone fluctuations subserving estrogen-dependent modulation of auditory perception (De Groof et al, 2017; see review Spool, Bergan and Remage-Healey, 2022).…”

Acute Aromatase Inhibition Impairs Neural and Behavioral Auditory Scene Analysis in Zebra Finches

“…Aromatase neurons in the NCM show induction of immediate early genes after song stimulation (de Bournonville et al, 2021;Krentzel et al, 2020;Macedo-Lima et al, 2021). Social interactions and song playback rapidly stimulate aromatase activity and elevate estradiol levels in the NCM of both sexes (Remage-Healey et al, 2012, 2008.…”