Related Experiment Video
Updated: May 21, 2026
07:13
Experience-Dependent Remodeling of Juvenile Brain Olfactory Sensory Neuron Synaptic Connectivity in an Early-Life Critical Period
Published on: March 1, 2024
Changing neuroestrogens within the auditory forebrain rapidly transform stimulus selectivity in a downstream
Luke Remage-Healey1, Narendra R Joshi
1Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts, Amherst, Massachusetts 01003, USA. healey@cns.umass.edu
Summary
Brain-derived estrogens (neuroestrogens) rapidly enhance song selectivity in the HVC nucleus by modulating the NCM. This steroid-dependent modulation influences downstream sensorimotor pathways in songbirds.
Area of Science:
- Neuroscience
- Endocrinology
- Auditory Processing
Background:
- Neuromodulators shape sensory circuit activity and sensorimotor integration.
- Brain-derived estrogens (neuroestrogens) act as local modulators in the songbird auditory forebrain.
- Neuroestrogen levels in the caudomedial nidopallium (NCM) fluctuate with social interactions and song stimuli, impacting neuronal responses.
Purpose of the Study:
- To investigate if fluctuating neuroestrogens in NCM influence stimulus selectivity in the downstream HVC nucleus.
- To determine the specificity and timing of neuroestrogen action within the auditory pathway.
- To explore the developmental and receptor-mediated mechanisms of neuroestrogen effects.
Main Methods:
- Dual extracellular recordings and retrodialysis in adult male songbirds.
- Manipulating neuroestrogen production and delivery in specific brain regions (NCM, mesopallium, HVC).
- Comparing effects in adult and juvenile males, and investigating receptor types.
Main Results:
- Increasing NCM neuroestrogens rapidly enhanced song selectivity in HVC.
- Inhibiting NCM neuroestrogen production rapidly decreased HVC song selectivity.
- Neuroestrogen effects were specific to NCM, with no impact on HVC selectivity when delivered elsewhere or in juveniles.
- Rapid estrogen actions involved membrane-bound receptors in NCM.
Conclusions:
- Neuroestrogen modulation of sensory processing in NCM rapidly influences downstream sensorimotor nucleus HVC.
- This steroid-dependent modulation is transsynaptically transmitted, affecting sensorimotor and premotor targets.
- The findings highlight a non-local steroid-dependent modulation network within the songbird auditory system.
Related Concept Videos
01:15Auditory Pathway
Auditory pathways constitute the complex neural circuits responsible for transmitting and interpreting auditory information from the peripheral auditory system to the brain. Sound waves are initially captured by the outer ear, funneled through the ear canal, and reach the tympanic membrane (eardrum). These vibrations are transmitted via the middle ear's ossicles to the inner ear's cochlea.
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking the...
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking the...
01:31Hearing
When we hear a sound, our nervous system is detecting sound waves—pressure waves of mechanical energy traveling through a medium. The frequency of the wave is perceived as pitch, while the amplitude is perceived as loudness.
01:13The Cochlea
The cochlea is a coiled structure in the inner ear that contains hair cells—the sensory receptors of the auditory system. Sound waves are transmitted to the cochlea by small bones attached to the eardrum called the ossicles, which vibrate the oval window that leads to the inner ear. This causes fluid in the chambers of the cochlea to move, vibrating the basilar membrane.
01:01Neuroplasticity
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01:22Hair Cells
Hair cells are the sensory receptors of the auditory system—they transduce mechanical sound waves into electrical energy that the nervous system can understand. Hair cells are located in the organ of Corti within the cochlea of the inner ear, between the basilar and tectorial membranes. The actual sensory receptors are called inner hair cells. The outer hair cells serve other functions, such as sound amplification in the cochlea, and are not discussed in detail here.