Memory-specific correlated neuronal activity in higher-order auditory regions of a parrot.

Funder: Kayamori Foundation for Informational Science AdvancementFunder: the Netherlands Organization for Scientific ResearchFunder: Multi-Career Path Support Model for Female Researchers project of Japan’s Women UniversityFunder: Japan Society for the Promotion of Science (JSPS) Grant-in-AidFunder: ALW Open Competition and GW Horizon ProgrammeMale budgerigars (Melopsittacus undulatus) are open-ended learners that can learn to produce new vocalisations as adults. We investigated neuronal activation in male budgerigars using the expression of the protein products of the immediate early genes zenk and c-fos in response to exposure to conspecific contact calls (CCs: that of the mate or an unfamiliar female) in three subregions (CMM, dNCM and vNCM) of the caudomedial pallium, a higher order auditory region. Significant positive correlations of Zenk expression were found between these subregions after exposure to mate CCs. In contrast, exposure to CCs of unfamiliar females produced no such correlations. These results suggest the presence of a CC-specific association among the subregions involved in auditory memory. The caudomedial pallium of the male budgerigar may have functional subdivisions that cooperate in the neuronal representation of auditory memory

Localized Brain Activation Related to the Strength of Auditory Learning in a Parrot

Parrots and songbirds learn their vocalizations from a conspecific tutor, much like human infants acquire spoken language. Parrots can learn human words and it has been suggested that they can use them to communicate with humans. The caudomedial pallium in the parrot brain is homologous with that of songbirds, and analogous to the human auditory association cortex, involved in speech processing. Here we investigated neuronal activation, measured as expression of the protein product of the immediate early gene ZENK, in relation to auditory learning in the budgerigar (Melopsittacus undulatus), a parrot. Budgerigar males successfully learned to discriminate two Japanese words spoken by another male conspecific. Re-exposure to the two discriminanda led to increased neuronal activation in the caudomedial pallium, but not in the hippocampus, compared to untrained birds that were exposed to the same words, or were not exposed to words. Neuronal activation in the caudomedial pallium of the experimental birds was correlated significantly and positively with the percentage of correct responses in the discrimination task. These results suggest that in a parrot, the caudomedial pallium is involved in auditory learning. Thus, in parrots, songbirds and humans, analogous brain regions may contain the neural substrate for auditory learning and memory

Birdsong and the brain : The syntax of memory

In this issue, Kato et al. use expression of immediate early genes to show that the caudomedial pallium of female Bengalese finches is particularly responsive to the phonology of male song and not to the sequence of its elements. We discuss the significance of these findings in the wider framework of birdsong in songbirds and parrots, which has become a prominent model system for the neurobiology of learning, memory and perception. Male song is an important signal in songbird sexual selection, and females show behavioural and neural preferences for particular songs or song elements. In addition, birdsong learning is increasingly seen as the closest animal equivalent to the acquisition of speech and language in humans

Birdsong and the brain : The syntax of memory

In this issue, Kato et al. use expression of immediate early genes to show that the caudomedial pallium of female Bengalese finches is particularly responsive to the phonology of male song and not to the sequence of its elements. We discuss the significance of these findings in the wider framework of birdsong in songbirds and parrots, which has become a prominent model system for the neurobiology of learning, memory and perception. Male song is an important signal in songbird sexual selection, and females show behavioural and neural preferences for particular songs or song elements. In addition, birdsong learning is increasingly seen as the closest animal equivalent to the acquisition of speech and language in humans

Sex differences in behavioural and neural responsiveness to mate calls in a parrot

Vocalisation in songbirds and parrots has become a prominent model system for speech and language in humans. We investigated possible sex differences in behavioural and neural responsiveness to mate calls in the budgerigar, a vocally-learning parrot. Males and females were paired for 5 weeks and then separated, after which we measured vocal responsiveness to playback calls (a call of their mate versus a call of an unfamiliar conspecific). Both sexes learned to recognise mate calls during the pairing period. In males, but not females, mate calls evoked significantly fewer vocal responses than unfamiliar calls at one month after separation. Furthermore, in females, there was significantly greater molecular neuronal activation in response to mate calls compared to silence in the caudomedial mesopallium (CMM), a higher-order auditory region, in both brain hemispheres. In males, we found right-sided dominance of molecular neuronal activation in response to mate calls in the CMM. This is the first evidence suggesting sex differences in functional asymmetry of brain regions related to recognition of learned vocalisation in birds. Thus, sex differences related to recognition of learned vocalisations may be found at the behavioural and neural levels in avian vocal learners as it is in humans

Sex differences in behavioural and neural responsiveness to mate calls in a parrot

Vocalisation in songbirds and parrots has become a prominent model system for speech and language in humans. We investigated possible sex differences in behavioural and neural responsiveness to mate calls in the budgerigar, a vocally-learning parrot. Males and females were paired for 5 weeks and then separated, after which we measured vocal responsiveness to playback calls (a call of their mate versus a call of an unfamiliar conspecific). Both sexes learned to recognise mate calls during the pairing period. In males, but not females, mate calls evoked significantly fewer vocal responses than unfamiliar calls at one month after separation. Furthermore, in females, there was significantly greater molecular neuronal activation in response to mate calls compared to silence in the caudomedial mesopallium (CMM), a higher-order auditory region, in both brain hemispheres. In males, we found right-sided dominance of molecular neuronal activation in response to mate calls in the CMM. This is the first evidence suggesting sex differences in functional asymmetry of brain regions related to recognition of learned vocalisation in birds. Thus, sex differences related to recognition of learned vocalisations may be found at the behavioural and neural levels in avian vocal learners as it is in humans

Budgerigars can discriminate Japanese words.

<p><b>A</b> A schematic representation of the inside of the Skinner box. <b>B</b> Protocol of the go/no-go auditory discrimination task. <b>C</b> Sonagrams of the two Japanese words, spoken by a male budgerigar, used in the discrimination task. The top word means ‘hello’, and the bottom word means ‘have a nice day.’ <b>D</b> Mean proportion of correct responses in the go/no-go auditory discriminations. The mean (+ s.e.m.) percentage of correct responses for all of the trained birds over the first 5 sessions of training (100 trials per session) was not significantly above chance, but that over the last 5 sessions before stimulus re-exposure was significantly above chance (<i>n</i> = 7; ***<i>p</i><0.005).</p