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The forkhead domain FOXP2 and FOXP1 transcription factors are implicated in several cognitive disorders with language deficits, notably autism, and thus play a central role in learned vocal motor behavior in humans. Although a similar role for FoxP2 and FoxP1 is proposed for other vertebrate species, including songbirds, the neurodevelopmental expression of these genes are unknown in a species with lifelong vocal learning abilities. Like humans, budgerigars (Melopsittacus undulatus) learn new vocalizations throughout their entire lifetime. Like songbirds, budgerigars have distinct brain nuclei for vocal learning, which include the magnocellular nucleus of the medial striatum (MMSt), a basal ganglia region that is considered developmentally and functionally analogous to Area X in songbirds. Here, we used in situ hybridization and immunohistochemistry to investigate FoxP2 and FoxP1 expression in the MMSt of juvenile and adult budgerigars. We found FoxP2 mRNA and protein expression levels in the MMSt that were lower than the surrounding striatum throughout development and adulthood. In contrast, FoxP1 mRNA and protein had an elevated MMSt/striatum expression ratio as birds matured, regardless of their sex. These results show that life-long vocal plasticity in budgerigars is associated with persistent low-level FoxP2 expression in the budgerigar MMSt, and suggests the possibility that FoxP1 plays an organizational role in the neurodevelopment of vocal motor circuitry. Thus, developmental regulation of the FoxP2 and FoxP1 genes in the basal ganglia appears essential for vocal mimicry in a range of species that possess this relatively rare trait.

International audience; Lateralised function has been observed in a number of animal species. Most studies on the lateralisation of visually guided behaviour indicate a preferential use of the right eye/left hemisphere in food discrimination in chicks, pigeons and zebra finches. One study reported a right eye/left hemisphere dominance in courtship behaviour of male zebra finches, but this result was later disputed. Here we provide clear evidence of lateralised visual function in zebra finch courtship singing, and initial evidence for neural lateralisation. Behavioural experiments using the temporary occlusion of one eye showed that, when presented with a female, male birds tended to start singing later and sang significantly less in both monocular conditions than in binocular condition. Most importantly, birds sang 1.2 times more when using their right than left eye, and they especially sang significantly more motifs. At the central level, the evaluation of the density of ZENK- or Fos-positive cells in the optic tectum showed that the expression of these immediate early genes was significantly higher in several layers of the left than the right optic tectum. The fact that birds sang significantly more motifs when using their right than left eye suggests that there is a preference for visual processing by the right eye during courtship singing. A functional predominance of the left hemisphere processing is further supported by the significantly higher level of expression of immediate early genes in the left optic tectum. Both of these results are consistent with the proposed specialization of the avian left hemisphere in sustaining attention on stimuli, in this context the female zebra finch, to which a motor response is planned. In the future, simultaneous recordings of neuronal activity from both hemispheres will allow us to further characterize such hemispheric specialization.

International audience; Previous studies have described lateralization of sensory and motor aspects of birdsong. We have begun to examine the possibility that communicative function of singing also is lateralized. As the optic nerves in birds decussate nearly completely, one way to show lateralization is to test the birds monocularly. An analysis of visual behavior showed that male birds had a preference for using the right eye (RE) during courtship singing. Birds sang significantly more when using their RE than when using their left eye (LE), and singing began more quickly when birds could use their RE than their LE. This suggests that processing by the left hemisphere is important in courtship singing, consistent with previous suggestions that it is involved in maintaining attention on stimuli to which a motor response is planned. In order to examine possible central results of such behavioral lateralization, we are comparing the levels of ZENK expression and singing-related neural activity from both hemispheres when birds sing while alone and to a female bird.

International audience; [No abstract]

International audience; Birdsong may have several functions as a communicative signal. Zebra finches?produce acoustically similar songs while alone (undirected) and to female birds (directed). Recent studies have shown that the level of neural activity and of expression of the immediate early gene egr-1 in the anterior forebrain (AF) nuclei LMAN and Area X are much higher during undirected than directed singing. To investigate possible sources of this modulation, we examined singing-related gene expression in the medial Habenula (Hb) and interpeduncular (IPN) nuclei. Consistently there is an opposite pattern of expression in these nuclei, compared to AF nuclei; a high level of egr-1 expression is seen only after directed singing. Furthermore, expression is stronger in limited subregions of IPN, in a pattern suggesting that the synaptic inputs from MHb to IPN may be lateralized. We are combining anterograde tracer injection into left and right MHb with egr-1 expression after courtship singing to test this possiblility. As a possible behavioral source of such lateralization, in initial behavioral results 4 of 5 birds tested viewed the female during initial courtship preferentially with the right eye.