NR2B downregulation in a forebrain region required for avian vocal learning is not sufficient to close the sensitive period for song learning

2003 ◽  
Vol 79 (1) ◽  
pp. 99-108 ◽  
Author(s):  
J.E Heinrich ◽  
T.D Singh ◽  
K.W Nordeen ◽  
E.J Nordeen
2005 ◽  
Vol 94 (6) ◽  
pp. 3698-3707 ◽  
Author(s):  
Sarah W. Bottjer

Developmental changes in synaptic properties may act to limit neural and behavioral plasticity associated with sensitive periods. This study characterized synaptic maturation in a glutamatergic thalamo-cortical pathway that is necessary for vocal learning in songbirds. Lesions of the projection from medial dorsolateral nucleus of the thalamus (DLM) to the cortical nucleus lateral magnocellular nucleus of the anterior nidopallium (LMAN) greatly disrupt song behavior in juvenile birds during early stages of vocal learning. However, such lesions lose the ability to disrupt vocal behavior in normal birds at 60–70 days of age, around the time that selective auditory tuning for each bird’s own song (BOS) emerges in LMAN neurons. This pattern has suggested that LMAN is involved in processing song-related information and evaluating the degree to which vocal motor output matches the tutor song to be learned. Analysis of reversed excitatory postsynaptic currents at DLM→LMAN synapses in in vitro slice preparations revealed a pronounced N-methyl-d-aspartate receptor (NMDAR)-mediated component in both juvenile and adult cells with no developmental decrease in the relative contribution of NMDARs to synaptic transmission. However, the synaptic failure rate at DLM→LMAN synapses in juvenile males during the sensitive period for song learning was significantly lower at depolarized potentials than at hyperpolarized potentials. In contrast, the failure rate at DLM→LMAN synapses did not differ at hyper- versus depolarized holding potentials in adult males that had completed the acquisition of a stereotyped song. This pattern indicates that juvenile cells have a higher incidence of silent (NMDAR-only) synapses, which are postsynaptically silent at hyperpolarized potentials due to the voltage-dependent gating of NMDARs. Thus the decreased involvement of the LMAN pathway in vocal behavior is mirrored by a decline in the incidence of silent synapses but not by changes in the relative number of NMDA and AMPA receptors at DLM→LMAN synapses. These findings suggest that a developmental decrease in silent synapses within LMAN may represent a neural correlate of behavioral plasticity during song learning.


2021 ◽  
Author(s):  
Carlos A. Rodriguez-Saltos ◽  
Aditya Bhise ◽  
Prasanna Karur ◽  
Ramsha Nabihah Khan ◽  
Sumin Lee ◽  
...  

In songbirds, learning to sing is a highly social process that likely involves social reward. Here, we hypothesized that the degree to which a juvenile songbird learns a song depends on the degree to which it finds that song rewarding to hear during vocal development. We tested this hypothesis by measuring song preferences in young birds during song learning and then analyzing their adult songs. Song preferences were measured in an operant key-pressing assay. Juvenile male zebra finches (Taeniopygia guttata) had access to two keys, each of which was associated with a higher likelihood of playing the song of their father or that of another familiar adult ("neighbor"). To minimize the effects of exposure on learning, we implemented a reinforcement schedule that allowed us to detect preferences while balancing exposure to each song. On average, the juveniles significantly preferred the father's song early during song learning, before they were themselves singing. At around post-hatch day 60, their preference shifted to the neighbor's song. At the end of the song learning period, we recorded the juveniles' songs and compared them to the father's and the neighbor's song. All of the birds copied father's song. The accuracy with which the father's song was imitated was positively correlated with the peak strength of the preference for the father's song during the sensitive period. Our results show that preference for a social stimulus, in this case a vocalization, predicted social learning during development.


2012 ◽  
Vol 107 (4) ◽  
pp. 1142-1156 ◽  
Author(s):  
Vanessa C. Miller-Sims ◽  
Sarah W. Bottjer

Experience-dependent changes in neural connectivity underlie developmental learning and result in life-long changes in behavior. In songbirds axons from the cortical region LMANcore (core region of lateral magnocellular nucleus of anterior nidopallium) convey the output of a basal ganglia circuit necessary for song learning to vocal motor cortex [robust nucleus of the arcopallium (RA)]. This axonal projection undergoes remodeling during the sensitive period for learning to achieve topographic organization. To examine how auditory experience instructs the development of connectivity in this pathway, we compared the morphology of individual LMANcore→RA axon arbors in normal juvenile songbirds to those raised in white noise. The spatial extent of axon arbors decreased during the first week of vocal learning, even in the absence of normal auditory experience. During the second week of vocal learning axon arbors of normal birds showed a loss of branches and varicosities; in contrast, experience-deprived birds showed no reduction in branches or varicosities and maintained some arbors in the wrong topographic location. Thus both experience-independent and experience-dependent processes are necessary to establish topographic organization in juvenile birds, which may allow birds to modify their vocal output in a directed manner and match their vocalizations to a tutor song. Many LMANcore axons of juvenile birds, but not adults, extended branches into dorsal arcopallium (Ad), a region adjacent to RA that is part of a parallel basal ganglia pathway also necessary for vocal learning. This transient projection provides a point of integration between the two basal ganglia pathways, suggesting that these branches convey corollary discharge signals as birds are actively engaged in learning.


2013 ◽  
Vol 9 (5) ◽  
pp. 20130625 ◽  
Author(s):  
Marcelo Araya-Salas ◽  
Timothy Wright

Vocal learning in birds is typically restricted to a sensitive period early in life, with the few exceptions reported in songbirds and parrots. Here, we present evidence of open-ended vocal learning in a hummingbird, the third avian group with vocal learning. We studied vocalizations at four leks of the long-billed hermit Phaethornis longirostris during a four-year period. Individuals produce a single song repertoire, although several song-types can coexist at a single lek. We found that nine of 49 birds recorded on multiple days (18%) changed their song-type between consecutive recordings. Three of these birds replaced song-types twice. Moreover, the earliest estimated age when song replacement occurred ranged from 186 to 547 days (mean = 307 days) and all nine birds who replaced song-types produced a crystallized song before replacement. The findings indicate that song-type replacement is distinct from an initial early learning sensitive period. As half of lekking males do not survive past the first year of life in this species, song learning may well extend throughout the lifespan. This behaviour would be convergent to vocal learning programmes found in parrots and songbirds.


2011 ◽  
Vol 12 (2) ◽  
pp. 324-350 ◽  
Author(s):  
Sébastien Derégnaucourt

Vocal imitation in songbirds exhibits interesting parallels to infant speech development and is currently the model system of choice for exploring the behavioural, molecular and electrophysiological substrates of vocal learning. Among songbirds, the Zebra Finch (Taeniopygia guttata) is currently used as the ‘flying mouse’ of birdsong research. Only males sing and they develop their song primarily during a short sensitive period in early life. They learn their speciesspecific song patterns by memorizing and imitating the songs of conspecifics, mainly adults. Since Immelmann's pioneering work, thousands of zebra finches have been raised in strictly controlled auditory environments to examine how their experience affected their songs. In this article, I review the different experimental procedures that have been used in the laboratory to study the social influences on song learning in the Zebra Finch. Poor song learning was observed using passive playback of taped songs, whereas self-eliciting exposure using operant tutoring techniques induced significant learning, but with a high interindividual variability. The success of the training paradigm is often measured by the quality of imitation of the songs to which the young bird is exposed. Using empirical evidence from the field and the laboratory, I will also discuss this issue, by summarizing possible advantages and disadvantages of producing a perfect imitation. So far, the best method to get a close copy of a song model in the Zebra Finch is to place a single young bird with an adult male. This situation, which is rather unnatural, does not meet the criteria for precise control necessary in experimental conditions. Optimizing the methods used to train a zebra finch to learn a song, in order to be able to predict the imitation success, will improve our understanding of the dynamics of vocal production learning. It would also consolidate this species as a research model of relevance to human speech development and disorders. Keywords: Zebra Finch; birdsong; learning; development; memory; social influences


2021 ◽  
Author(s):  
Judith M. Varkevisser ◽  
Ralph Simon ◽  
Ezequiel Mendoza ◽  
Martin How ◽  
Idse van Hijlkema ◽  
...  

AbstractBird song and human speech are learned early in life and for both cases engagement with live social tutors generally leads to better learning outcomes than passive audio-only exposure. Real-world tutor–tutee relations are normally not uni- but multimodal and observations suggest that visual cues related to sound production might enhance vocal learning. We tested this hypothesis by pairing appropriate, colour-realistic, high frame-rate videos of a singing adult male zebra finch tutor with song playbacks and presenting these stimuli to juvenile zebra finches (Taeniopygia guttata). Juveniles exposed to song playbacks combined with video presentation of a singing bird approached the stimulus more often and spent more time close to it than juveniles exposed to audio playback only or audio playback combined with pixelated and time-reversed videos. However, higher engagement with the realistic audio–visual stimuli was not predictive of better song learning. Thus, although multimodality increased stimulus engagement and biologically relevant video content was more salient than colour and movement equivalent videos, the higher engagement with the realistic audio–visual stimuli did not lead to enhanced vocal learning. Whether the lack of three-dimensionality of a video tutor and/or the lack of meaningful social interaction make them less suitable for facilitating song learning than audio–visual exposure to a live tutor remains to be tested.


Behaviour ◽  
1999 ◽  
Vol 136 (5) ◽  
pp. 567-594 ◽  
Author(s):  
Howard Russock

AbstractThe mother - fry relationship in the maternal mouthbrooding species of tilapia has become a model of social bond formation in fish because of the relatively extensive care given to the young. This relationship has been extensively studied in Oreochromis mossambicus. In order to determine if the response pattern observed in O. mossambicus fry has broader applications, the critical experiments of these studies were replicated in two closely related species of maternal mouthbrooding tilapia, O. niloticus and O. esculentus. All fry used in the study were removed from their mother's mouth as eggs and hatched artificially in groups. The fry were also exposed to maternal models in groups, but all fry in the study were tested for their responsiveness or preferential behaviour to maternal models individually. Experiment I determined the responsiveness of fry naive to maternal models in order to establish a baseline for future comparisons. O. niloticus fry exhibited a significant decline in responsiveness to models between days 11 and 12 post-hatching while O. esculentus fry exhibited a significant decline between days 16 and 18, suggesting the possible existence of a sensitive period in these two species. In order to obtain evidence for the existence of a sensitive period, naive fry of both species in Experiment II were exposed to maternal models at their peak of responsiveness and then tested at a later age at which responsiveness in naive fry had fallen significantly. In 15 of the 18 comparisons involving the two species, exposure to a maternal model at the peak of responsiveness for naive fry prevented the later decline in responsiveness. Experiment III examined whether experience with maternal models effected how exclusively fry responded to such models in the future. It was predicted that, like O. mossambicus fry, experienced fry of both species would exhibit a decline in responsiveness to models that formed at least a partial mismatch with the fry's initial schema for maternal stimuli. This prediction was not supported. Experiment IV examined preferential behaviour. It was predicted that fry exposed to a maternal model would later behave preferentially toward whichever model of a pair formed a closer match with their schema, and not necessarily toward the model to which they had been previously exposed. Maternally naive fry were not expected to behave preferentially. These predictions were generally supported, although the effect was less vigorous or consistent than in O. mossambicus. Filial social bond formation in these species of maternal mouthbrooding tilapia appears to be characterized by strong predispositions for maternally relevant visual stimuli which require appropriate experience for their maintenance and for the induction of preferences. Since a similar developmental pattern in seen in (e.g.) song learning in passerine birds, imprinting in precocial birds and filial following in substrate spawning cichlid fish, the phenomenon appears to be of broad significance.


Sign in / Sign up

Export Citation Format

Share Document