Selectivity of Canary HVC Neurons for the Bird's Own Song: Modulation by Photoperiodic Conditions

Abstract

To what extent seasonal factors modify the neuronal functional properties within the nuclei of the avian song system remains an open question. In adult songbirds, neurons of the song premotor nucleus HVC (used as a proper name) exhibit selective responses for the bird's own song (BOS). Here we examine whether, outside the breeding season, when songs are less stereotyped, HVC neurons of male canaries still respond selectively to the BOS produced during this period. In an initial experiment, single-unit recordings (n ϭ 114) revealed that the neuronal selectivity for the current BOS was attenuated in males exposed to a short-day photoperiod (typical of the nonbreeding season) compared with that found in males exposed to a long-day photoperiod. In long-day conditions, 35% of the cells responded to the BOS, whereas only 12% did in short-day conditions; there were four times more selective cells (d Ͼ 1) in long-day than in short-day conditions.To determine whether these effects were the consequence of differences in acoustic features between breeding and nonbreeding songs, neurons (n ϭ 72) recorded in short-day conditions were tested with both a short-day BOS and a long-day BOS. A low percentage of neurons exhibited responses to short-day or to long-day BOS (11% for each song). Responses of putative interneurons (spike duration Ͻ0.4 ms) and of putative relay cells were similarly attenuated by the short-day conditions. These results strongly suggest that, in canary, rather than being a fixed property, the selectivity for the BOS moves along a continuum and peaks when the day length mimics the breeding conditions.

Brain estrogen signaling effects acute modulation of acoustic communication behaviors: A working hypothesis

“…These findings resonate with studies in canaries, in which the HVC selectivity for the bird's own vocalizations were enhanced during the long-day (breeding) season relative to short-days [78]. Though not explicitly measured in that study, their finding suggests a role for seasonal changes in plasma- or brain-derived steroids such as estrogens in modulating HVC neuronal selectivity in a more protracted, seasonal timescale.…”

Estrogenic modulation of auditory processing: A vertebrate comparison

“…For example, extracellular single- and multi-unit recordings have shown that in the sensorimotor nucleus HVC of the canary ( Serinus canaria ), long-day photoperiods significantly increase spontaneous activity, increase the proportion of putative interneurons, and enhance neural selectivity (in males) for BOS (Del Negro and Edeline, 2002; Del Negro et al, 2005, 2000). On some level, these results are similar to those reported by Remage-Healey and Joshi (2012) for HVC neurons after manipulation of local E 2 levels in NCM of the non-seasonally breeding zebra finch (see section 3.4.1 above).…”

Neural codes in the thalamocortical auditory system: From artificial stimuli to communication sounds

“…Tian et al, 2001) or for the animal's own vocalization in the high vocal center (HVC) of songbirds (e.g. Lewicki and Konishi, 1995;Margoliash, 1983;Mooney, 2000;Theunissen and Doupe, 1998;Del Negro et al, 2005).…”