Brain space for learned song in birds develops independently of song learning

Brenowitz, Eliot A.; Lent, Karin; Kroodsma, Donald E.

doi:10.1523/jneurosci.15-09-06281.1995

Cited by 100 publications

(75 citation statements)

References 11 publications

(28 reference statements)

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“…Burek et al (1991) showed that the total number of HVC neurons in zebra finches deafened early in ontogeny was no different from that seen in intact controls. In line with this, Brenowitz et al (1995) showed that marsh wrens (Cistothorus palustris) induced to learn large song repertoires had no more HVC neurons than those that, because of limited tutoring, had small repertoires. Our observations indicate that the number of HVC neurons present in adulthood is much the same in intact zebra finches that mastered a model as in those that, because of early deafness or syringeal denervation, were unable to imitate a model.…”

Section: Discussionmentioning

confidence: 55%

Experience Affects Recruitment of New Neurons But Not Adult Neuron Number

2002

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It is not known whether the addition of new neurons to the high vocal center (HVC) of juvenile zebra finches permits vocal learning or is the consequence of it. To tease apart these two, we performed surgery on 26-d-old juveniles. The operations were removal of both cochleae and unilateral or bilateral denervation of the syrinx. Ability to imitate a tutor song was little affected by unilateral syringeal denervation but was severely hindered by bilateral denervation or deafening. Recruitment of new HVC neurons was studied by injecting BrdU, a cell birth marker, on post-hatching days 61-65 and killing the animals 30 d later. Deafening or bilateral denervation did not alter the number of BrdU-labeled neurons in HVC, but unilateral denervation nearly doubled this number in the intact side. This doubling was transient, was blocked by deafening, and was not seen in birds that received BrdU injections earlier or later in vocal ontogeny. The adult number of HVC neurons was not affected by any of our surgical procedures. Apparently experience does not affect the total number of neurons in adult HVC, but some kinds of experience can, during narrowly defined times, influence the recruitment of new HVC neurons.

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Section: Discussionmentioning

confidence: 55%

Experience Affects Recruitment of New Neurons But Not Adult Neuron Number

2002

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“…There are very few comparable experimental studies, except those on the American marsh wren Cistothorus palustris (Kroodsma & Canady 1985;Brenowitz et al 1995). These used a slightly different technique of tutoring males with tapes of varying song complexity.…”

Section: Discussionmentioning

confidence: 99%

Song and the song control pathway in the brain can develop independently of exposure to song in the sedge warbler

Leitner

Nicholson

Leisler

et al. 2002

Proc. R. Soc. Lond. B

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Previous studies have shown that female sedge warblers choose to mate with males that have more complex songs, and sexual selection has driven the evolution of both song complexity and the size of the major song control area (HVc) in the brain. In songbirds, learning from conspeci cs plays a major role in song development and this study investigates the effects of isolation and exposure to song on song structure and the underlying song control system. Sibling pairs of hand-reared nestling sedge warblers were reared to sexual maturity under two conditions. Siblings in one group were reared individually in acoustic isolation in separate soundproof chambers. In the other group, siblings were reared together in an aviary with playback of recorded songs. The following spring, analysis of songs revealed that siblings reared in acoustic isolation produced normal song structures, including larger syllable repertoires than those exposed to song. We found no signi cant differences in the volumes of HVc, nucleus robustus archistnatalis, the lateral portion of the magnocellular nucleus and the density of dendritic spines between the two groups. Males exceeded females in all these measures, and also had a larger telencephalon. Our experiments show that complex song, sexual dimorphism in brain structure, and the size of song nuclei can all develop independently of exposure to song. These ndings have important implications for how sexual selection can operate upon a complex male trait such as song and how it may also shape the more general evolution of brain structure in songbirds.

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“…Following previous work with brown-headed cowbirds, we measured the Tel from the first slice in which Hp appeared to the last slice in which we measured Hp (Sherry et al, 1993). On sections in which the telencephalic hemispheres were joined with the diencephalon, prominent markers such as the occipito-mesencephalic tract and the anterior commissure were used to determine telencephalic boundaries (Brenowitz, Lent, & Kroodsma, 1995). The NRot boundaries are particularly clear in Nissl-stained sections ( Figure 1B).…”

Section: Histology and Morphometricsmentioning

confidence: 99%

Sex differences in the effects of captivity on hippocampus size in brown-headed cowbirds (Molothrus ater obscurus).

Day

Guerra²,

Schlinger³

et al. 2008

Behavioral Neuroscience

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In brood parasitic cowbirds, hippocampus (Hp) size is correlated with environmental spatial memory demands. Searching for host nests is the presumed causal factor influencing cowbird Hp size, because Hp volumes vary across species, sexes, and seasons according to nest-searching participation. Brownheaded cowbirds have female-only nest searching and, at least in the eastern subspecies, a larger Hp in females than in males, suggesting that nest searching influences cowbird Hp size. We predicted that female brown-headed cowbirds housed in aviaries lacking host nests would have a smaller Hp than wild-caught females whereas males would be unaffected. We found that the Hp was smaller in captive females, but not males, compared to their wild-caught counterparts. This did not appear to be due to general effects of an impoverished environment on all brain regions. Our results imply that interruption of nest searching in cowbirds prevents seasonal increase in Hp size in females. Future studies should isolate which behavioral differences between wild and captive birds contributed to captivity-induced changes in Hp volume in females while not affecting males. Keywordscowbird; hippocampus; sex differences; brain plasticity; brood parasitism Variation in environmental spatial demands is related to variation in hippocampus (Hp) size among closely related species, between sexes, and across seasons in mammalian, avian, and reptilian species. For example, food-storing behaviors in birds (Clayton, 1995a;Hampton, Sherry, Shettleworth, Kurgel, & Ivy, 1995;Hampton & Shettleworth, 1996;Healy & Krebs, 1992;Krebs, Sherry, Healy, Perry, & Vaccarion, 1989;Sherry, Vaccarino, Buckenham, & Herz, 1989;Volman, Grubb, & Schuett, 1997) and rodents (Jacobs, 1992;Jacobs & Spencer, 1994), foraging-related rate of movement in lacertid lizards (Day, Crews, & Wilczynski, 1999), home-range size in voles (Gaulin, 1992;Jacobs, Gaulin, Sherry, & Hoffman, 1990 Sherry, Jacobs, & Gaulin, 1992), and breeding-habitat complexity in petrels (Abbott, Walsh, Storey, Stenhause, & Harley, 1999) are all associated with enlarged Hp size, presumably due to the demands of spatial memory. In addition, seasonal variation in food-storing demands is associated with seasonal changes in Hp volume (Smulders, Sasson, & DeVoogd, 1995) in black-capped chickadees and rodents (Jacobs, 1996). Males have a larger Hp than females in a vole species in which males have larger home ranges but not in vole species that do not have sex differences in home range (Gaulin, 1992). These results provide evidence that environmental or experiential seasonal changes can alter Hp volume and that natural and sexual selection on a variety of spatial-related skills has produced a larger Hp in some species or sexes than in others.Although correlations of Hp volume with ecological demands for spatial ability are numerous, the specific mechanisms that contribute to such adult variation in the volume of the Hp are not well understood. We do know that species-specific reactions to spatial experience...

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Brain space for learned song in birds develops independently of song learning

Cited by 100 publications

References 11 publications

Experience Affects Recruitment of New Neurons But Not Adult Neuron Number

Experience Affects Recruitment of New Neurons But Not Adult Neuron Number

Song and the song control pathway in the brain can develop independently of exposure to song in the sedge warbler

Sex differences in the effects of captivity on hippocampus size in brown-headed cowbirds (Molothrus ater obscurus).

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