A motor theory of speech perception, initially proposed to account for results of early experiments with synthetic speech, is now extensively revised to accommodate recent findings, and to relate the assumptions of the theory to those that might be made about other perceptual modes. According to the revised theory, phonetic information is perceived in a biologically distinct system, a ‘module ’ specialized to detect the intended gestures of the speaker that are the basis for phonetic categories. Built into the structure of this module is the unique but lawful relationship between the gestures and the acoustic patterns in which they are variously overlapped. In consequence, the module causes perception of phonetic structure without translation from preliminary auditory impressions. Thus, it is comparable to such other modules as the one that enables an animal to localize sound. Peculiar to the phonetic module are the relation between perception and production it incorporates and the fact that it must compete with other modules for the same stimulus variations.

Song learning shapes the response properties of auditory neurons in the song system to become highly selective for the individual bird’s own (“autogenous”) song. The auditory representation of autogenous song is achieved in part by neurons that exhibit facilitated responses to combinations of components of song. To understand the circuits that un-derlie these complex properties, the combination sensitivity of single units in the hyperstriatum ventrale, pars caudale (HVc) of urethane-anesthetized zebra finches was studied. Some neurons exhibited nonlinear temporal summation, spectral summation, or both. The majority of these neurons exhibited low spontaneous rates and phasic responses. Most combination-sensitive neurons required highly accurate copies of sounds derived from the autogenous song and responded weakly to tone bursts, combinations of simple

Neuronal activity in the hyperstriatum ventrale, pars caudale (HVc) is associated with and necessary for the production of song by songbirds. HVc neurons also respond to acoustic stim-uli. The present investigation assessed the auditory response properties of neurons in HVc by testing with the individual bird’s own (autogenous) song and the songs of conspecific birds. Throughout HVc, multiunit clusters preferentially responded to autogenous song. Selectivity for autogenous song was apparent even when compared to similar intradialect songs, and neuronal clusters preferred autogenous song over the (tutor) song model that birds heard during the impressionable phase early in life. The responses to autogenous song were stable in the adult. HVc neurons were sensitive to the acoustic parameters of autogenous song and consistently exhibited a diminished response to mod-ified song. In Contras & field L neurons, which are presumed to

More than 50 years after the appearance of the motor theory of speech perception, it is timely to evaluate its three main claims that (1) speech processing is special, (2) perceiving speech is perceiving gestures, and (3) the motor system is recruited for perceiving speech. We argue that to the extent that it can be evaluated, the first claim is likely false. As for the second claim, we review findings that support it and argue that although each of these findings may be explained by alternative accounts, the claim provides a single coherent account. As for the third claim, we review findings in the literature that support it at different levels of generality and argue that the claim anticipated a theme that has become widespread in cognitive science.

Sebastian Seung. Temporal sparseness of the premotor drive is important for rapid learning in a neural network model of birdsong. J Neurophysiol 92: 2274–2282, 2004. First published April 7, 2004; 10.1152/jn.01133.2003. Sparse neural codes have been widely observed in cortical sensory and motor areas. A striking example of sparse temporal coding is in the song-related premotor area high vocal center (HVC) of songbirds: The motor neurons innervating avian vocal muscles are driven by premotor nucleus robustus archistriatalis (RA), which is in turn driven by nucleus HVC. Recent experiments reveal that RA-projecting HVC neurons fire just one burst per song motif. However, the function of this remarkable temporal sparseness has remained unclear. Because birdsong is a clear example of a learned complex motor behavior, we explore in a neural network model with the help of numerical and analytical techniques the possible role of sparse premotor neural codes in song-related motor

Songbirds learn to sing in a two stage process. First, the bird forms a sensory To appear in Computational Neuroscience (Proceedings of the Fourth Annual Computation and Neural Systems Conference) J.M. Bower, Ed.; A Supplement to International Review of Neurobiology (Academic Press), 1996. template by listening to and memorizing its father's song. Second, the bird practices singing and learns to match its song to the memorized template. Two experimentally well-supported hypotheses locate song sequence generation in nucleus HVc, and the sensory template in the anterior forebrain pathway (AFP). However, there is no known connection from the AFP to HVc. Furthermore, due to auditory feedback delay, reinforcement signals from vocalization are likely to reach the motor pathway after the burst of motor activity responsible for the vocalization. Thus, it is unclear how template information and auditory feedback could be used to guide learning of song. A model of sensorimotor learning of sylla...

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ABSTRACT: The zebra finch acquires its song by first memorizing a model song from a tutor and then matching its own vocalizations to the memory trace of the tutor song, called a template. Neural mechanisms underlying this process require a link between the neural memory trace and the premotor song circuitry, which drives singing. We now report that a premotor song nucleus responds more to the tutor song model than to every other stimulus examined, including the bird’s own song (BOS). Neural tuning to the song model occurred only during waking and peaked during the Birds and humans learn vocal signals in two phases: a perceptual phase during which sounds are memorized and a production phase during which vocalizations are matched to the learned sounds (Konishi, 1965, 1985; Doupe and Kuhl, 1999). In zebra finches, the perceptual, or sensory, phase occurs from fledging (�18 days) to 65 days posthatching (Immelmann, 1969; Eales, 1985; Böhner, 1990). During this phase, the tutor song template is formed. The production or These data were previously presented in abstract form (Nick,

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Auditory neurons of the anterior forebrain (AF) in adult zebra finches are highly selective for the bird’s own song (BOS): they respond more to BOS than to songs of other zebra finches (conspecifics) and to BOS played in reverse. In contrast, juvenile AF neurons are not selective at 30 d of age, responding equally well to all song stimuli. Both BOS and tutor song experience are required by juveniles for normal song learning and may produce the selective properties of adult neurons. Because such selectivity could subserve song learning, it is important to determine when it arises. Birds were therefore studied at an intermediate stage of learning, after substantial experience of both tutor song and their own developing (plastic) song. Extracellular single neuron recordings in 60-d-old zebra finches revealed that AF neurons had significant song and order