Search PubMed⌕ Search

Biomedical subjects

F Nottebohm

Publications and source records attributed to F Nottebohm.

At least 73 records · Page 4Linked to original sources
PubMed1985

Auditory responses in avian vocal motor neurons: a motor theory for song perception in birds.

The hypoglossal motor neurons that innervate the vocal organ (syrinx) of the male zebra finch show a selective, long-latency (50-millisecond) response to sound. This response is eliminated by lesions to forebrain song-control nuclei. Different song syllables elicit a response from different syringeal motor neurons. Conspecific vocalizations may therefore be perceived as members of a set of vocal gestures and thus distinct from other environmental sounds. This hypothesis is an avian parallel to the motor theory of speech perception in humans.

Animals↗
PubMed1985

Synaptogenesis and changes in synaptic morphology related to acquisition of a new behavior.

Systemic testosterone treatment induces adult female canaries to develop male-like song. This same treatment induces a doubling in size of the forebrain nucleus robustus archistriatalis (RA), known to be involved in song control, and a 51% increase in the number of synapses formed on RA neurons. In central RA, the number of synaptic vesicles per synapse increases as do several measures of synaptic size. Housing in spring-like conditions is also associated with larger synapses and more vesicles per synapse than housing in fall-like conditions. We suggest that formation of new synapses on existing neurons leading to or associated with modifications in synaptic morphology is important for acquisition of a new behavior. We also suggest that maximal behavioral and anatomical effects are associated with testosterone given under spring-like conditions.

Animals↗
PubMed1985

Cells born in adult canary forebrain are local interneurons.

Thymidine autoradiography and retrograde transport of horseradish peroxidase (HRP) were combined to determine the connectivity of neurons born in adult canary forebrain. Adult male and female canaries were pretreated with [3H]thymidine to label cells undergoing DNA synthesis prior to mitosis. Thirty or 60 days later, neurons in a forebrain nucleus, hyperstriatium ventralis, pars caudalis (HVc), were labeled by retrograde transport of HRP injected into the only two nuclei known to receive a projection from HVc: robustus archistriatalis (RA) and area X of lobus parolfactorius. The birds were then killed and brain sections were treated to visualize cells containing HRP; these sections were processed for autoradiography to detect [3H]thymidine-labeled cells in the same tissue. More than 9% of all neurons in HVc were thymidine labeled; but of the almost 20,000 HRP-labeled projection neurons examined, fewer than 20 (0.1%) were labeled by the thymidine treatment. Furthermore, the median cell body size for area X-projecting cells was significantly larger than that of thymidine-labeled cells, and the median size of thymidine-labeled cells was significantly larger than that of RA-projecting cells. The simplest interpretation of these results is that the new neurons incorporated into nucleus HVc in adult canary brain are local interneurons, intermediate in size between neurons projecting to RA and area X.

Animals↗
PubMed1984

Population differences in complexity of a learned skill are correlated with the brain space involved.

The song of marsh wrens (Cistothorus palustris) is a learned trait passed on from generation to generation. Male marsh wrens from California and New York learn about 150 and 50 different songs apiece, respectively. The volumes of the hyperstriatum ventralis, pars caudalis and the robust nucleus of the archistriatum, two telencephalic nuclei involved in song control, are larger by an average of 40% and 30%, respectively, in the population with a larger song repertoire.

Animals↗
PubMed1984

Modification of synapses in androgen-sensitive muscle. I. Hormonal regulation of acetylcholine receptor number in the songbird syrinx.

The songbird syrinx is sexually dimorphic and responds to changes in blood testosterone levels with changes in muscle size and in activity of cholinergic enzymes (Luine, V., F. Nottebohm, C. Harding, and B.S. McEwen (1980) Brain Res. 192: 89-107). Here, we demonstrate that there is a sex difference in the number of acetylcholine receptors (AChRs) in the syrinx and that alterations in the levels of circulating testosterone can cause changes in AChR number in syringeal muscles. These results suggest that the size or number of endplates in the syringeal muscles may be increased by circulating testosterone. The time course of these effects was examined after increases in blood testosterone in females and decreases in males. We also examined the effect of increased testosterone in syrinx isolated from neural influences by denervation and found that denervated muscle responded to testosterone with an increase in acetylcholinesterase activity but not with increases in protein content or AChR number.

Acetylcholinesterase↗
PubMed1983

Neuronal production, migration, and differentiation in a vocal control nucleus of the adult female canary brain.

The vocal control nucleus designated HVc (hyperstriatum ventrale, pars caudalis) of adult female canaries expands in response to systemic testosterone administration, which also induces the females to sing in a male-like manner. We became interested in the possibility of neurogenesis as a potential basis for this phenomenon. Intact adult female canaries were injected with [3H]thymidine over a 2-day period. Some birds were given testosterone implants at various times before thymidine. The birds were sacrificed 5 wk after hormone implantation, and their brains were processed for autoradiography. In parallel control experiments, some birds were given implants of cholesterol instead of testosterone. All birds showed considerable numbers of labeled neurons, glia, endothelia, and ventricular zone cells in and around HVc. Ultrastructural analysis confirmed the identity of these labeled neurons. Cholesterol- and testosterone-treated birds had similar neuronal labeling indices, which ranged from 1.8% to 4.0% in HVc. Thus, neurogenesis occurred in these adults independently of exogenous hormone treatment. Conversely, both glial and endothelial proliferation rates were markedly stimulated by exogenous testosterone treatment. We determined the origin of the thymidine-incorporating neurons by sacrificing two thymidine-treated females soon after their thymidine injections, precluding any significant migration of newly labeled cells. Analysis of these brains revealed no cells of neuronal morphology present in HVc but a very heavily labeled ventricular zone overlying HVc. We conclude that neuronal precursors exist in the HVc ventricular zone that incorporate tritiated thymidine during the S phase preceding their mitosis; after division these cells migrate into, and to some extent beyond, HVc. This ventricular zone neurogenesis seems to be a normally occurring phenomenon in intact adult female canaries.

Animals↗
PubMed1982

Connections of vocal control nuclei in the canary telencephalon.

Connections of two telencephalic vocal control nuclei, the hyperstriatum ventrale, pars caudale (HVc), and robust nucleus of the archistriatum (RA), were investigated in adult canaries. Methods used were transport of horseradish peroxidase and 3H-adenosine and silver staining of degenerating axons. Three nuclei project to HVc: medial nucleus magnocellularis of the anterior neostriatum (MAN), nucleus interfacialis (NIf) of midneostriatum, and nucleus uvaeformis (Uva) of the diecephalon. Uva also projects to NIf. NIf and Uva have not been described previously. HVc projects to area X of lobus parolfactorius, to RA, and to field Avalanche of hyperstriatum ventrale. Nucleus RA receives projections from HVc and from lateral MAN. All these projections are ipsilateral. No gross male/female differences were apparent in the projections to and from HVc. Uptake of HRP by cell somata in HVc following localized injections of this substance into RA or HVc suggests that HVc is composed of rostrocaudally organized clusters of cells, with little lateral communication between them.

Afferent Pathways↗
PubMed1982

Relation of medullary motor nuclei to nerves supplying the vocal tract of the budgerigar (Melopsittacus undulatus).

The locations of brainstem motor nuclei supplying efferents to organs of the vocal tract of the budgerigar (Melopsittacus undulatus) were determined as a first step in describing brain pathways for vocal control in this species. We identified four major nerves supplying the muscles of the syrinx, larynx, and tongue, and separately treated each of these with horseradish peroxidase. Nerves supplying efferents to the larynx and tongue arise from ipsilateral cells in the nucleus ambiguus and hypoglossal nucleus, respectively. Each right and left half of the syrinx is supplied by both right and left halves of the hypoglossal nucleus, via axons crossing in the common anastomosis of the tracheosyringeal nerves. This bilateral innervation of the syrinx will allow testing for central asymmetries of dominance for vocal control in the absence of any underlying anatomical laterality in the periphery.

Animals↗
PubMed1981

A brain for all seasons: cyclical anatomical changes in song control nuclei of the canary brain.

Male canaries that have reached sexual maturity can, in subsequent years, learn new song repertoires. Two telencephalic song control nuclei, the hyperstriatum ventrale, pars caudale, and nucleus robustus archistriatalis are, respectively, 99 and 76 percent larger in the spring, when male canaries are producing stable adult song, than in the fall, at the end of the molt and after several months of not singing. It is hypothesized that such fluctuations reflect an increase and then reduction in numbers of synapses and are related to the yearly ability to acquire new motor coordinations.

Animals↗
PubMed1981

Gonadal hormones induce dendritic growth in the adult avian brain.

Ovariectomized adult female canaries were treated with physiological doses of testosterone, dihydrotestosterone, or estradiol. Singing, which is typical of males, occurred in the testosterone-treated birds but not in any of the other birds. The effect of these hormones was assessed on dendrites from a class of neurons in the nucleus robustus archistriatalis (RA), a forebrain nucleus for song control. The RA neurons of the testosterone-treated birds had dendritic trees resembling those of intact males. The RA neurons of the estradiol- and dihydrotesterone-treated birds resembled those of intact females. All hormone-treated groups had dendrites that were significantly longer than those of untreated ovariectomized females. Thus gonadal hormones induce dendritic growth in the adult avian brain.

Animals↗
PubMed1981

Brain space for a learned task.

Forty-six adult male and female canaries were sacrificed, their brains were weighed and the volume of several brain nuclei reconstructed from the cresyl violet-stained material. Two forebrain vocal control nuclei, hyperstriatum ventrale, pars caudale (HVc) and nucleus robustus archistriatalis (RA), were approximately 4 and 3 times larger, respectively, in males than in females, confirming previous findings. There was no consistent right-left asymmetry in the volume of these nuclei in males and females. Twenty-five male birds in this study had their song repertoire recorded during the peak of the singing season. They were sacrificed 3 to 4 months later. The size of the song repertoire, measured as number of different syllable types, showed a positive and significant correlation with the size of HVc and RA. There was no significant correlation between size of the syllable repertoire and age, brain weight or the volume of two brain nuclei not involved in song control. This is the first time that the amount of brain allotted to a specific learned skill has been shown to correlate positively with the amount of that skill that is learned. Interestingly, too, there was a positive and significant correlation between testis weight at the end of the breeding season and the volume of RA at that time, suggesting a hormone-mediated seasonal modulation of part of the brain space occupied by song control pathways. This material seems well suited for studying the relation between space and learning, and the manner in which this relation is influenced by gonadal hormones.

Animals↗
PubMed1981

Sex differences in dendritic morphology of a song control nucleus in the canary: a quantitative Golgi study.

Singing in the canary is a learned male behavior controlled predominantly by nuclei in the left hemisphere (Nottebohm and Nottebohm, '76; Nottebohm et al., '76; Nottebohm, '77). These nuclei are several times larger in males than in females (Nottebohm and Arnold, '76). One of the telencephalic song control nuclei, robustus archistriatalis (RA), was examined in Golgi-stained tissue sections from the left and right hemispheres of male and female canaries. At least four cell classes were present in each sex. One of these cell classes was further studied with a variety of quantitative techniques. No hemispheric differences were seen in either sex. However, dendrites from male cells tend to branch and end further from the cell body than do dendrites from female cells. This difference is seen most clearly when serial sections are used to reconstruct the entire dendritic tree.

Animals↗
PubMed1981

Bilateral organization of the vocal control pathway in the budgerigar, Melopsittacus undulatus.

Anatomical and electrophysiological methods were used to map the vocal control nuclei of the budgerigar, Melopsittacus undulatus. Beginning with the motor nucleus of the syrinx, nuclei were located using antidromic stimulation and then injected with horseradish peroxidase (HRP). Retrogradely transported HRP labeled afferents to the injected nucleus. This procedure was repeated at successively higher levels along the vocal pathway. Connections found using this strategy then were confirmed using anterograde transport of HRP and/or tritiated proline and orthodromic electrical stimulation. We found that the primary vocal control pathway consisted of (1) the motor nucleus innervating the trachea and syrinx, nXIIts; (2) an archistriatal nucleus, RA; and (3) a neostriatal nucleus, "HVc." These nuclei correspond to similar, possibly homologous, nuclei in the vocal control pathway of the canary (Nottebohm, F., T. M. Stokes, and C. M. Leonard (1976) J. Comp. Neurol. 165: 457-486) but, because of differences in gross brain morphology, are displaced considerably in absolute position. Furthermore, the projection from RA to the motor nucleus is bilateral in the budgerigar, whereas the same connection is strictly ipsilateral in the canary. The projection of the motor nucleus to muscles of the vocal organ is also bilateral in the budgerigar (Manogue, K. R., and F. Nottebohm (1981) J. Compl. Neurol., in press) but ipsilateral in the canary. the possible significance of these species differences for lateralization of motor control is discussed.

Afferent Pathways↗
PubMed1980

Androgen affects cholinergic enzymes in syringeal motor neurons and muscle.

We examined the role of testosterone (T) in regulating the weight of the songbird syrinx and the activity of two cholinergic enzymes, choline acetyltransferase (CAT) and acetylcholinesterase (AChE). Castration of adult male zebra finches or neonatal canaries results in a lowering of syringeal weight and CAT and AChE activity. Administration of T for 1-4 weeks restores syringeal weight and AChE to intact levels in male zebra finches. Activity of CAT in muscle is not fully restored. Ovariectomy of female zebra finches and canaries does not affect these syringeal parameters, but T administration to ovariectomized females for 1 month increases syringeal weight and AChE activity. In the zebra finch tracheosyringealis nerve, activity of CAT and AChE is decreased one month after castration. T administration to castrates maintains nerve AChE activity but not CAT. In contrast to changes in the syrinx, tongue muscles do not change in weight or enzyme activity when circulating T levels are altered. Effects of muscle use and disuse were found on syringeal weight and AChE activity, but an androgenic effect also operates in addition. Results suggest that one mechanism for T regulation of singing in passerine birds is through induction of specific enzymatic proteins in androgen target neurons and muscles.

Acetylcholinesterase↗
PubMed1980

Testosterone triggers growth of brain vocal control nuclei in adult female canaries.

Two vocal control nuclei of the canary telencephalon, hyperstriatum ventrale, pars caudale (HVc) and nucleus robustus archistriatalis (RA), are larger in males, that learn complex songs, than in females, that normally do not sing. HVc and RA can be induced to grow by 90% and 53%, respectively, in adult gonadectomized females under the influence of testosterone, as these birds acquire male-like song. The magnitude of this effect is comparable, though of reversed sign, to that following early castration in males. This system is unique in the extent to which gross neural plasticity normally associated with early development can be induced in adulthood.

Animals↗
PubMed1979

Projections of a telencephalic auditory nucleus-field L-in the canary.

Anterograde projections of a telencephalic auditory area - field L of the neostriatum - were traced in canaries, Serinus canarius. Field L was defined as the neostriatal projection of nucleus ovoidalis of the thalamus. Using amino acid autoradiography, two efferent projections of field L and adjacent neostriatum were observed: (1) a projection to the medial and ventral borders of nucleus hyperstriatum ventrale, pars caudale (HVc) and (2) a smaller projection to medial paleostriatum augmentatum (PA). When autoradiographic injection sites included neostriatum postero-ventral to field L, a projection to archistriatum outlining the anterior and ventral borders of the nucleus robustus archistriatalis (RA) resulted. Injection sites that included neostriatum antero-lateral to "L" gave rise to projections to the interior of HVc proper. Above background numbers of silver grains were consistently observed over caudal dorso-lateral portions of nucleus ovoidalis. Following lesion of field L and adjacent neostriatum, argyrophilic degeneration was traced to medial PA and to a shelf of neostriatum underlying HVc. All observed anterograde projections were ipsilateral. Two of the nuclei outlined by neostriatal projections in this study, HVc and RA, have important roles in the motor control of canary song (Nottebohm et al., '76). The development of song is dependent on auditory information. Auditory-vocal neural connections described here may be involved in song learning.

Animals↗