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D Margoliash

Publications and source records attributed to D Margoliash.

At least 19 recordsLinked to original sources
PubMed2002

Evaluating theories of bird song learning: implications for future directions.

Studies of birdsong learning have stimulated extensive hypotheses at all levels of behavioral and physiological organization. This hypothesis building is valuable for the field and is consistent with the remarkable range of issues that can be rigorously addressed in this system. The traditional instructional (template) theory of song learning has been challenged on multiple fronts, especially at a behavioral level by evidence consistent with selectional hypotheses. In this review I highlight the caveats associated with these theories to better define the limits of our knowledge and identify important experiments for the future. The sites and representational forms of the various conceptual entities posited by the template theory are unknown. The distinction between instruction and selection in vocal learning is not well established at a mechanistic level. There is as yet insufficient neurophysiological data to choose between competing mechanisms of error-driven learning and reinforcement learning. Both may obtain for vocal learning. The possible role of sleep in acoustic or procedural memory consolidation, while supported by some physiological observations, does not yet have support in the behavioral literature. The remarkable expansion of knowledge in the past 20 years and the recent development of new technologies for physiological and behavioral experiments should permit direct tests of these theories in the coming decade.

Animal Communication↗
PubMed2001

Temporal precision and temporal drift in brain and behavior of zebra finch song.

In the zebra finch forebrain nucleus robustus archistriatalis (RA), neurons burst during singing. We showed that the internal structure of spike bursts was regulated with a precision of circa 0.2 ms, and yielded alignment of acoustic features of song with a precision of circa 1 ms. In addition, interburst intervals and corresponding syllable durations displayed systematic variation within song (average elongation 0.3 ms/s song), and slower "drift" across songs. Systematic variation on even a coarser time scale might be difficult to detect in other systems, but could affect the analysis of temporal patterning. The close relationship between precise timing of individual spikes and stereotypic behavior suggests that song is represented in RA by a temporal code.

Action Potentials↗
PubMed2000

Song replay during sleep and computational rules for sensorimotor vocal learning.

Songbirds learn a correspondence between vocal-motor output and auditory feedback during development. For neurons in a motor cortex analog of adult zebra finches, we show that the timing and structure of activity elicited by the playback of song during sleep matches activity during daytime singing. The motor activity leads syllables, and the matching sensory response depends on a sequence of typically up to three of the preceding syllables. Thus, sensorimotor correspondence is reflected in temporally precise activity patterns of single neurons that use long sensory memories to predict syllable sequences. Additionally, "spontaneous" activity of these neurons during sleep matches their sensorimotor activity, a form of song "replay." These data suggest a model whereby sensorimotor correspondences are stored during singing but do not modify behavior, and off-line comparison (e.g., during sleep) of rehearsed motor output and predicted sensory feedback is used to adaptively shape motor output.

Acoustic Stimulation↗
PubMed1999

Gradual emergence of song selectivity in sensorimotor structures of the male zebra finch song system.

Birdsong is a model system for understanding how motor and sensory information interact to coordinate behavior. Neurons in one potential site of sensorimotor integration, the forebrain nucleus HVc, have premotor activity during singing and auditory activity during playback of the bird's own song. It is not known whether the high degree of selectivity for learned features of song observed during playback arises in HVc or also in structures afferent to HVc. We recorded in anesthetized adult zebra finches from two structures afferent to HVc: either the nucleus interfacialis (NIf) or the L1 subdivision of the field L complex, and simultaneously from a second electrode in HVc. Correlations in the bursting pattern of ongoing activity of HVc and NIf recordings were observed; these helped to localize the first electrode to NIf recording sites. Most NIf neurons exhibited song-selective responses, but as a population, they were less selective than were HVc neurons. Most L1 neurons were not song-selective. NIf neurons have also been reported to have premotor activity during singing; thus, NIf is another potential site of auditory-motor interactions in the song system. Evidence gathered to date suggests that those brain areas in the passerine forebrain that are recruited during song production also display the most selective learned auditory responses.

Acoustic Stimulation↗
PubMed1998

Behavioral state modulation of auditory activity in a vocal motor system.

Neurons of the song motor control nucleus robustus archistriatalis (RA) exhibited far weaker auditory responses in awake than in anesthetized zebra finches. Remarkably, sleep induced complex patterns of bursts in ongoing activity and uncovered vigorous auditory responses of RA neurons. Local injections of norepinephrine suggested that the changes in response strength occur through neuromodulatory control of the sensorimotor nucleus HVc, which projects to RA. Thus, motor access to auditory feedback, which zebra finches require for song learning and maintenance, may be regulated through neuromodulation. During sleep, the descending motor system may gain access to sensorimotor song memories represented as bursting patterns of activity.

Acoustic Stimulation↗
PubMed1998

Automated recognition of bird song elements from continuous recordings using dynamic time warping and hidden Markov models: a comparative study.

The performance of two techniques is compared for automated recognition of bird song units from continuous recordings. The advantages and limitations of dynamic time warping (DTW) and hidden Markov models (HMMs) are evaluated on a large database of male songs of zebra finches (Taeniopygia guttata) and indigo buntings (Passerina cyanea), which have different types of vocalizations and have been recorded under different laboratory conditions. Depending on the quality of recordings and complexity of song, the DTW-based technique gives excellent to satisfactory performance. Under challenging conditions such as noisy recordings or presence of confusing short-duration calls, good performance of the DTW-based technique requires careful selection of templates that may demand expert knowledge. Because HMMs are trained, equivalent or even better performance of HMMs can be achieved based only on segmentation and labeling of constituent vocalizations, albeit with many more training examples than DTW templates. One weakness in HMM performance is the misclassification of short-duration vocalizations or song units with more variable structure (e.g., some calls, and syllables of plastic songs). To address these and other limitations, new approaches for analyzing bird vocalizations are discussed.

Animals↗
PubMed1997

Functional organization of forebrain pathways for song production and perception.

This article reviews the organization of the forebrain nuclei of the avian song system. Particular emphasis is placed on recent physiologic recordings from awake behaving adult birds while they sing, call, and listen to broadcasts of acoustic stimuli. The neurons in the descending motor pathway (HVc and RA) are organized in a hierarchical arrangement of temporal units of song production, with HVc neurons representing syllables and RA neurons representing notes. The nuclei Uva and NIf, which are afferent to HVc, may help organize syllables into larger units of vocalization. HVc and RA are also active during production of all calls. The patterns of activity associated with calls differ between learned calls and those that are innately specified, and give insight into the interactions between the forebrain and midbrain during calling, as well as into the evolutionary origins of the song system. Neurons in Area X, the first part of the anterior forebrain pathway leading from HVc to RA, are also active during singing. Many HVc neurons are also auditory, exhibiting selectivity for learned acoustic parameters of the individual bird's own song (BOS). Similar auditory responses are also observed in RA and Area X in anesthetized birds. In contrast to HVc, however, auditory responses in RA are very weak or absent in awake birds under our experimental paradigm, but are uncovered when birds are anesthetized. Thus, the roles of both pathways beyond HVc in adult birds is under review. In particular, theories hypothesizing a role for the descending motor pathway (RA and below) in adult song perception do not appear to obtain. The data also suggest that the anterior forebrain pathway has a greater motor role than previously considered. We suggest that a major role of the anterior forebrain pathway is to resolve the timing mismatch between motor program readout and sensory feedback, thereby facilitating motor programming during birdsong learning. Pathways afferent to HVc may participate more in sensory acquisition and sensorimotor learning during song development than is commonly assumed.

Animals↗
PubMed1996

Temporal hierarchical control of singing in birds.

Songs of birds comprise hierarchical sets of vocal gestures. In zebra finches, songs include notes and syllables (groups of notes) delivered in fixed sequences. During singing, premotor neurons in the forebrain nucleus HVc exhibited reliable changes in activity rates whose patterns were uniquely associated with syllable identity. Neurons in the forebrain nucleus robustus archistriatalis, which receives input from the HVc, exhibited precisely timed and structured bursts of activity that were uniquely associated with note identity. Hence, units of vocal behavior are represented hierarchically in the avian forebrain. The representation of temporal sequences at each level of the hierarchy may be established by means of a decoding process involving interactions of higher level input with intrinsic local circuitry. Behavior is apparently represented by precise temporal patterning of spike trains at lower levels of the hierarchy.

Action Potentials↗
PubMed1996

Template-based automatic recognition of birdsong syllables from continuous recordings.

The application of dynamic time warping (DTW) to the automated analysis of continuous recordings of animal vocalizations is evaluated. The DTW algorithm compares an input signal with a set of predefined templates representative of categories chosen by the investigator. It directly compares signal spectrograms, and identifies constituents and constituent boundaries, thus permitting the identification of a broad range of signals and signal components. When applied to vocalizations of an indigo bunting (Passerina cyanea) and a zebra finch (Taeniopygia guttata) collected from a low-clutter, low-noise environment, the recognizer identifies syllables in stereotyped songs and calls with greater than 97% accuracy. Syllables of the more variable and lower amplitude indigo bunting plastic song are identified with approximately 84% accuracy. Under restricted recordings conditions, this technique apparently has general applicability to analysis of a variety of animal vocalizations and can dramatically decrease the amount of time spent on manual identification of vocalizations.

Animals↗
PubMed1995

Parallel pathways and convergence onto HVc and adjacent neostriatum of adult zebra finches (Taeniopygia guttata).

The structure and connectivity of the forebrain nucleus HVc, a site of sensorimotor integration in the song control system of oscine birds, were investigated in adult zebra finches. HVc in males comprises three cytoarchitectonic subdivisions: the commonly recognized central region with large and medium-sized darkly staining cells, a ventral caudomedial region with densely packed small and medium-sized cells, and a dorsolateral region with oblong cells and rows of cells. All three subdivisions project to area X and the robust nucleus of the archistriatum, with more complexity in the classes and distribution of cells than previously reported. In females, HVc is very small and has a cytoarchitecture distinct from that of the three male subdivisions. The structure of HVc in females treated with estradiol at 15 days of age is similar to male HVc. Tracer studies in males with fluorescent and biotinylated dextrans demonstrate non-topographic projections onto HVc that may carry auditory information, including type 1 and type 2 neurons in subdivisions L1 and L3 of the field L complex, a class of neurons in nucleus interface, nucleus uvaeformis, the caudal neostriatum ventral to HVc, and intrinsic HVc connections. These data are interpreted in terms of HVc's functional properties. Additionally, the neostriatum immediately ventral to HVc receives projections from field L, ventral hyperstriatum, and caudal neostriatum, and projects to a region surrounding RA and near to or into area X. The similarity of the connectivity of HVc and adjacent neostriatum suggests the possibility that they share a common origin.

Afferent Pathways↗
PubMed1994

Global synchronous response to autogenous song in zebra finch HVc.

1. The spatial distribution of neuronal responses to autogenous song (AS) was investigated in the HVc of urethan-anesthetized adult male zebra finches (Taeniopygia guttata). In seven birds, penetrations covered the entire mediolateral, rostrocaudal, or dorsoventral extents of HVc. In an eighth, control birth penetrations were made near to but outside of HVc. Reconstruction of recording sites from histological material indicated a good correspondence between sites that exhibited stronger responses to AS than to tone or noise bursts, and sites that were within HVc. 2. Within each experimental bird but not in the control, multiple-unit responses to AS were similar across the entire spatial extent of HVc (up to 1.3 mm). For each experimental bird, the strongest responses occurred within a narrow range of times. The middle of this range of times is called the time of maximum synchronization (TMS). Across birds, 34-75% of recording sites exhibited the same TMS. With the use of a criterion of > 33% of sites exhibiting their strongest responses at the TMS, the temporal scatter around the TMS varied between 6 and 138 ms across individuals. In six of the seven experimental birds, the position of the TMS was not affected by changing the window of integration from 10 to 150 ms. In two experimental birds, short windows of integration tended to emphasize beginning portions of the song. In one case this effect was sufficiently strong to change the TMS for short windows of integration. 3. Each TMS was associated with a syllable of maximum synchronization (SMS). The positions of the SMS varied considerably across birds. In four birds the SMS was one of the syllables of the first motif (a motif is a temporal sequence of syllables that can be repeated > or = 1 times to form a song), in two birds the SMS was the introductory note of song, and in one bird the SMS was the second syllable of the last (3rd) motif. Syllables of the same type as the SMS but occurring in other motifs typically elicited much weaker responses, in many cases weaker than other syllables in those motifs. Syllables that elicited strong responses in non-SMS motifs did not necessarily elicit strong responses in the SMS motif, even if they preceded the SMS. There were no apparent acoustical features of the SMS or the preceding syllable that could account for the global synchronous response to song.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Distributed representation in the song system of oscines: evolutionary implications and functional consequences.

This paper reviews the organizational principles and implications that have emerged from the analysis of HVc, a forebrain nucleus that is a major site of sensory, motor, and sensorimotor integration in the song control system of oscine passerine birds (songbirds). Anatomical, physiological, and behavioral data support the conclusion that HVc exists within a hierarchically organized system with parallel pathways that converge onto HVc. The organization of HVc is distributed and redundant, and its outputs exhibit broad divergence. A similar pattern of connectivity exists for neostriatum adjacent to HVc. This and other data support the hypothesis that the song system arose from an elaboration or duplication of pathways generally present in all birds. Spontaneous and auditory response activity is strongly correlated throughout HVc, with auditory responses exhibiting strong temporal modulation in a synchronized fashion throughout the nucleus. This suggests that the auditory representation of song is encoded in the synchronized temporal patterns of activation, and that the predominant selectivity for the individual's own song that is observed for HVc neurons results from interactions of auditory input with central pattern generators for song. Most, or all HVc neurons are recruited during singing. The auditory response and motor recruitment properties of individual HVc neurons have no simple relationship, and the spontaneous activity in HVc may build up in the seconds preceding a song. To the extent HVc participates in perceptual phenomena associated with song, production and perception are not tightly linked in adults but may be linked by shared developmental processes during periods of sensorimotor learning.

Animals↗
PubMed1993

Parametric modeling of the temporal dynamics of neuronal responses using connectionist architectures.

1. We describe an exploratory approach to the parametric modeling of dynamical (time-varying) neurophysiological data. The models use stimulus data from a window of time to predict the neuronal firing rate at the end of that window. The most successful models were feedforward three-layered networks of input, hidden, and output "nodes" connected by weights that were adjusted during a training phase by the backpropagation algorithm. The memory in these models was represented by delay lines of varying length propagating activation between the layers. Connectionist models with no memory (1 sequential node per layer) as well as zero-memory nonlinear nonconnectionist models were also tested. 2. Models were tested with recordings of neuronal activity from the auditory thalamic nucleus ovoidalis of urethane-anesthetized zebra finches (Taeniopygia guttata). All cells reported here showed phasic/tonic responses. Extensive modeling of one neuron (cell 1) defined a "canonical" architecture, which was most successful in modeling this cell. The canonical model had a zero-memory input layer, a hidden layer with 29 bins representing 185.6 ms, and a single output node whose value as a function of sequential bin position represented the output of the neuron as a function of time. The canonical model achieved convergence on the entire data set for cell 1, including responses to single tone bursts and zebra finch songs. The "frequency" weights of the canonical model matched well excitatory and inhibitory frequencies for cell 1 as determined by the cell's frequency tuning curve. The "memory" weights of the canonical model were dominated by excitation over the first 25 ms followed by inhibition. 3. When trained with only the dynamical responses to tone bursts, the canonical model also accurately predicted the responses to song (average R2 = 0.823). Thus for this neuron the responses to single tone bursts were sufficient to predict most of the responses to six different songs, each presented at three different amplitudes, although a Monte Carlo procedure indicated the residual variance was not just due to noise (P < 0.001). 4. The model's ability to predict the responses to song was further explored by altering the tone burst (training) data. For cell 1, the responses to songs were most strongly related to the phasic/tonic details of the temporal responses to tone bursts. Changes in the characteristic frequency, frequency tuning curves, and rate/intensity function of the neuron had less effect. These experiments would be difficult or impossible to conduct electrophysiologically.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Cytoarchitectonic organization and morphology of cells of the field L complex in male zebra finches (Taenopygia guttata).

The organization of the field L complex, a thalamorecipient auditory region in the telencephalon of birds, was examined in Nissl and Golgi preparations of male zebra finches (Taenopygia guttata). The field L complex comprises five cytoarchitectonic subdivisions: L1, L2a, L2b, L3, and L, although the border between L and L2b is not distinct. L2a is a plate extending dorsocaudally from the dorsal medullary lamina in the caudal neostriatum. L1 lies on the anterodorsal border and L3 lies on the posteroventral border of L2a. L, the area designated "field L" by Rose (J. Psychol. Neurol., 1914, 2:278-352), forms the medial and posterior borders of the field L complex. L2b is a thick band that forms the dorsal and dorsolateral boundary of the field L complex and is continuous with L medially. Nucleus interface (NIf) is a nucleus that lies between L2a and L1 near the lateral edge of the complex. The four types of Golgi stained neurons that occur in the zebra finch field L complex correspond to those described for the European starling (Sturnus vulgaris). Additionally, type 3 neurons are subdivided into "unoriented" neurons with spherical dendritic fields and "oriented" neurons with bipolar dendritic fields. NIf contains a distinct class of neurons that have large somata with both thick and thin spiny dendrites. The distribution of Golgi cell types between the subdivisions of the field L complex corresponds to the morphology of cells seen in Nissl material. Type 3 oriented cells are found almost exclusively within L2a. L3 has significantly greater numbers of the largest cells (type 1) and significantly smaller numbers of the smallest cells (type 4) than does L1. There are no significant differences in the distribution of Golgi stained cells between L2b and L.

Animals↗