Synaptogenesis and changes in synaptic morphology related to acquisition of a new behavior

DeVoogd, Timothy J.; Nixdorf, Barbara E.; Nottebohm, Fernando

doi:10.1016/0006-8993(85)90539-6

Cited by 201 publications

(106 citation statements)

References 24 publications

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“…The muscles of the left syrinx are somewhat larger than those of the right (Luine et al 1980) and the tracheosyringeal portion of the left hypoglossal nucleus is slightly larger than the right (Nottebohm & Arnold 1976; Nottebohm et al 1981;DeVoogd 1991). Despite the dominance of the left syrinx in song production, no anatomical asymmetry is evident in song control nuclei above nXII (DeVoogd & Nottebohm 1981;Nottebohm et al 1981;DeVoogd et al 1985).…”

Section: Lateralization Of Song Production (A) Lateralized Syringeal mentioning

confidence: 86%

The neuromuscular control of birdsong

Suthers

Goller

Pytte

1999

Phil. Trans. R. Soc. Lond. B

185

154

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Birdsong requires complex learned motor skills involving the coordination of respiratory, vocal organ and craniomandibular muscle groups. Recent studies have added to our understanding of how these vocal subsystems function and interact during song production. The respiratory rhythm determines the temporal pattern of song. Sound is produced during expiration and each syllable is typically followed by a small inspiration, except at the highest syllable repetition rates when a pattern of pulsatile expiration is used. Both expiration and inspiration are active processes. The oscine vocal organ, the syrinx, contains two separate sound sources at the cranial end of each bronchus, each with independent motor control. Dorsal syringeal muscles regulate the timing of phonation by adducting the sound-generating labia into the air stream. Ventral syringeal muscles have an important role in determining the fundamental frequency of the sound. Di¡erent species use the two sides of their vocal organ in di¡erent ways to achieve the particular acoustic properties of their song. Reversible paralysis of the vocal organ during song learning in young birds reveals that motor practice is particularly important in late plastic song around the time of song crystallization in order for normal adult song to develop. Even in adult crystallized song, expiratory muscles use sensory feedback to make compensatory adjustments to perturbations of respiratory pressure. The stereotyped beak movements that accompany song appear to have a role in suppressing harmonics, particularly at low frequencies.

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Section: Lateralization Of Song Production (A) Lateralized Syringeal mentioning

confidence: 86%

The neuromuscular control of birdsong

Suthers

Goller

Pytte

1999

Phil. Trans. R. Soc. Lond. B

185

154

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“…The sexual dimorphism of the song system (Nottebohm and Arnold 1976) is a compelling example of how sex steroids affect the structure of song nuclei, including neuronal morphology (DeVoogd and Nottebohm 1981;DeVoogd et al 1985;Gurney 1981). The effects of augmenting early testosterone on LMAN and RA volume, neuron number, and soma size has been examined in adult male zebra finches (Schlinger and Arnold 1991), but no morphological analysis has been FIG.…”

Section: Testosterone Treatment Alters Neuronal Morphology In Lman Bmentioning

confidence: 99%

Androgens Modulate NMDA Receptor–Mediated EPSCs in the Zebra Finch Song System

White

Livingston

Mooney

1999

Journal of Neurophysiology

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Androgens potently regulate the development of learned vocalizations of songbirds. We sought to determine whether one action of androgens is to functionally modulate the development of synaptic transmission in two brain nuclei, the lateral part of the magnocellular nucleus of the anterior neostriatum (LMAN) and the robust nucleus of the archistriatum (RA), that are critical for song learning and production. We focused on N-methyl-D-aspartate-excitatory postsynaptic currents (NMDA-EPSCs), because NMDA receptor activity in LMAN is crucial to song learning, and because the LMAN synapses onto RA neurons are almost entirely mediated by NMDA receptors. Whole cell recordings from in vitro brain slice preparations revealed that the time course of NMDA-EPSCs was developmentally regulated in RA, as had been shown previously for LMAN. Specifically, in both nuclei, NMDA-EPSCs become faster over development. We found that this developmental transition can be modulated by androgens, because testosterone treatment of young animals caused NMDAEPSCs in LMAN and RA to become prematurely fast. These androgen-induced effects were limited to fledgling and juvenile periods and were spatially restricted, in that androgens did not accelerate developmental changes in NMDA-EPSCs recorded in a nonsong area, the Wulst. To determine whether androgens had additional effects on LMAN or RA neurons, we examined several other physiological and morphological parameters. In LMAN, testosterone affected ␣-amino-3-hydroxy-5-methyl-4-isoxazoleproprianate-EPSC (AMPA-EPSC) decay times and the ratio of peak synaptic glutamate to AMPA currents, as well as dendritic length and spine density but did not alter soma size or dendritic complexity. In contrast, testosterone did not affect any of these parameters in RA, which demonstrates that exogenous androgens can have selective actions on different song system neurons. These data are the first evidence for any effect of sex steroids on synaptic transmission within the song system. Our results support the idea that endogenous androgens limit sensitive periods for song learning by functionally altering synaptic transmission in song nuclei.

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“…This treatment induces a 49% increase in the length of the dendrites of type IV neurons (DeVoogd and Nottebohm,198 1 b). The increase in dendritic length is accompanied by a 5 1% increase in the number of synapses present in RA (DeVoogd et al, 1985). Two-yearold female canaries with intact ovaries also respond to testosterone, in this case with a 69% increase in RA volume (Nottebohm, 1980).…”

mentioning

confidence: 92%

“…There is the possibility that synapses with perforated synaptic zones were counted as 2 separate synapses if the discontinuity caused by the perforation was not recognized. The occurrence of perforated synaptic zones was estimated by DeVoogd et al (1985) to be lo-15% in the central RA of female canaries. This estimate was not found to differ between normal and testosterone-treated females in that study.…”

Section: Methodsmentioning

confidence: 99%

Effect of testosterone on input received by an identified neuron type of the canary song system: a Golgi/electron microscopy/degeneration study

et al. 1988

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Combinations of the Golgi stain, anterograde degeneration, and electron microscopy are used to further characterize the hormone-sensitive “type IV” neuron of the forebrain nucleus robustus archistriatalis (RA) of adult female canaries. Anterograde degeneration was used to “stain,” at the electron-microscopic level, the axon terminals of neurons projecting to RA from hyperstriatum ventralis, pars caudalis (HVc) and from the lateral magnocellular nucleus of the anterior neostriatum (L- MAN). The HVc neurons projecting to RA type IV cells form synapses predominantly on the dendritic spines of those cells, while L-MAN neurons that project to RA type IV cells form a 2.5:1 mixture of shaft and spine synapses. There were about 1000 synapses from HVc neurons (about 30% of all spine synapses) on typical type IV cells and about 50 synapses from L-MAN neurons. Earlier work had shown that in female canaries the dendrites of type IV neurons of the avian song control nucleus RA increase in total length after systemic testosterone treatment, and that this increase in dendritic length was accompanied by the development of malelike song. We now show that testosterone treatment also increases the number of dendritic spines present in type IV neurons. Presumably this is accompanied by an increase in the number of synaptic inputs received by type IV cells. Earlier evidence suggested that the testosterone-induced addition of extra dendritic length to type IV cells occurred at existing dendritic tips. We tested the hypothesis that these added peripheral ends received a special subset of inputs, which might then account for the change in behavior, and found it to be false. Mapping and counts of degenerating synapses resulting from lesion of HVc and L-MAN suggest that under the influence of hormone, new synapses are added throughout the dendritic tree, with no special distribution or change in ratio of inputs occurring at the tip of dendrites. Under the influence of testosterone, each type IV cell may receive only “more of the same” inputs it received before onset of treatment. We speculate on how such changes in circuitry may relate to song stability and learning.

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Synaptogenesis and changes in synaptic morphology related to acquisition of a new behavior

Cited by 201 publications

References 24 publications

The neuromuscular control of birdsong

The neuromuscular control of birdsong

Androgens Modulate NMDA Receptor–Mediated EPSCs in the Zebra Finch Song System

Effect of testosterone on input received by an identified neuron type of the canary song system: a Golgi/electron microscopy/degeneration study

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