M. D. Zaretsky
Departments of Zoology and Physiology, University of Iowa, USA
(2)
Department of Biology, Princeton University, USA
(3)
Department of Zoology, University of California, 94720 Berkeley, California, USA
Received: 15 September 1977
http://www.springerlink.com/content/xx7x58t5728166v3/
Key Words Songbird - Auditory forebrain area - Hearing and song control
-------------------------------------------------------------
HVC (nidopallial area, formerly known as hyperstriatum ventrale pars caudalis), a key centre for song control in oscines, responds in a selective manner to conspecific songs as indicated by electrophysiology. However, immediate–early gene induction cannot be detected in this nucleus following song stimulation. HVC contains neurons projecting either towards the nucleus robustus archistriatalis (RA; motor pathway) or area X (anterior forebrain pathway). Both RA- and area X-projecting cells show auditory responses. The present study analysed these responses separately in the two types of HVC projection neurons of canaries by a new in vivo approach using manganese as a calcium analogue which can be transported anterogradely and used as a paramagnetic contrast agent for magnetic resonance imaging (MRI). Manganese was stereotaxically injected into HVC and taken up by HVC neurons. The anterograde axonal transport of manganese from HVC to RA and area X was then followed by MRI during ≈ 8 h and changes in signal intensity in these targets were fitted to sigmoid functions. Data comparing birds exposed or not to conspecific songs revealed that song stimulation specifically affected the activity of the two types of HVC projection neurons (increase in the sigmoid slope in RA and in its maximum signal intensity in area X). Dynamic manganese-enhanced MRI thus allows assessment of the functional state of specific neuronal populations in the song system of living canaries in a manner reminiscent of functional MRI (but with higher resolution) or of 2-deoxyglucose autoradiography (but in living subjects).
----------------------------------------------------------------------------------------------
Article
Central control of song in the canary, Serinus canarius
Fernando Nottebohm 1 2, Tegner M. Stokes 1 2, Christiana M. Leonard 1 2
1The Rockefeller University, New York, New York 100212Department of Anatomy, Mount Sinai School of Medicine of the City University of New York, New York 10029
Abstract
We have traced central nervous pathways controlling bird son in the canary using a combination of behavioral and anatomical techniques. Unilateral electrolytic brain lesions were made in adult male canaries whose son had been previously recorded and analysed on a sound spectrograph. After severral days of postoperative recording, the birds were sacrificed and their brains processed histologically for degeneration staining with the Fink-Heimer technique. Although large lesions in the neostriatum and rostral hyperstriatum had no effect on song, severe song deficits followed damage to a discrete large-celled area in the caudal hyperstriatum ventrale (HVc). Degenerating fibers were traced from this region to two other discrete nuclei in the forebrain: one in the parolfactory lobe (area X, a teardrop-shaped small-celled nucleus) and a round large-celled nucleus in the archistriatum (RA). Unilateral lesions of X had no effect on song; lesions of RA, however, caused severe song deficits. Degenerating fibers from RA joined the occipitomesencephalic tract and had widespread ipsilateral projections to the thalamus, nucleus intercollicularis of the midbrain, reticular formation, and medulla. It is of particular interest that direct connections were found onto the cells of the motor nucleus innervating the syrinx, the organ of song production. Unilateral lesions of n. intercollicularis (previously implicated in the control of vocal behavior) had little effect on song.
One bilateral lesion of HVc resulted in permanent (9 months) and complete elimination of the audible components of song, although the bird assumed the posture and movements typical of song. Preliminary data suggest that lesions of the left hemisphere result in greater deficits than lesions of the right one. This finding is consistent with earlier reports that the left syrinx controls the majority of song components. Results reported here suggest a localization of vocal control in the canary brain with an overlying left hemispheric dominance.
http://www3.interscience.wiley.com/cgi-bin/abstract/109685172/ABSTRACT?CRETRY=1&SRETRY=0
----------------------------------------------------------------------------------------------
Auditory Sensitivity and Song Spectrum of the Common Canary (Serinus canarius)
Robert J. Dooling and James A. Mulligan
Department of Biology, St. Louis University, St. Louis, Missouri 63104
James D. Miller
Central Institute for the Deaf, St. Louis, Missouri 63110
(Received 5 March 1971)
The auditory sensitivity of one strain (Belgian Waterschlager) of common canary (Serinus canarius) was measured by behavioral audiometry. Four birds were trained by instrumental avoidance conditioning in a double-grille cage, and their thresholds for pure tones (0.25–9.0 kHz) were measured. Auditory sensitivity is greatest between 2.0 and 4.0 kHz with a possible maximum at 2.8 kHz, declines about 15 dB/oct for frequencies below 2.0 kHz, declines about 25 dB between 4.0 and 8.0 kHz, and 13 dB between 8.0 and 9.0 kHz. The acoustic power in the songs and calls of the Belgian Waterschlager falls primarily in the range 1.8–4.5 kHz as do the critical frequencies of a substantial proportion of the neural units in the cochlear nucleus of the canary. Thus, the auditory sensitivity and the neural machinery of the peripheral auditory system appear to be matched to the long-term-average power spectrum of the songs. In addition, these facts are compared to those for other birds and mammals, and speculations as to some of the selective pressures that influenced the evolution of hearing are presented. Certain relevant problems of the biophysics of hearing are also discussed. ©1971 Acoustical Society of America -http://scitation.aip.org/jasa/
