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  • 1
    ISSN: 1432-1939
    Schlagwort(e): Migration ; Garden warbler ; Zugunruhe ; Activity patterns ; Food shortage
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The present study describes the effects of food-deprivation on migratory restlessness and diurnal activity in the garden warbler, a long-distance migrating passerine. Fourteen first-year birds were held from August through March in individual registration cages and exposed to daylength changes experienced by birds that winter at the equator. With the beginning of the fall migratory season the birds increased their body weights due to fat deposition and showed nocturnal migratory restlessness characteristic for this species. After the birds had deposited more than about 4 g of fat they were food-deprived until their body mass had declined to a value about 1 g above fat free mass. Subsequently they were re-fed. This procedure was repeated through fall and winter, beyond the termination of spontaneous fall migratory restlessness. — Food deprivation consistently caused an increase in duration and intensity of nocturnal activity. After the end of spontaneous migratory restlessness and before the onset of winter molt it led to a reinduction of nocturnal activity. When nocturnal activity increased, the duration of diurnal activity decreased, whereas its intensity increased. With regard to the performance of free-living migrants these results suggest (1) that nocturnal migratory activity is enhanced in birds travelling across areas with unprofitable resting places; (2) that nocturnal migratory activity may be reactivated in birds that have settled for the winter in an area with deteriorating food supply; and (3) that the pattern of diurnal activity may change conspicuously when nocturnal migratory activity is enhanced or resumed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 50 (1983), S. 1-8 
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Association areas ; Thalamus ; Tectum ; Pons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Efferent brain stem projections from area 18 of the albino rat cortex were traced by autoradiography. Since results could have been compromised by spread of injected label to neighboring areas 17 and 29, studies of projections from these areas were used as controls. A hitherto unreported projection from area 18 to the thalamus in the region of its anterior nuclei was found, terminating in a roughly circular area including parts of the anteromedial, ventral, ventromedial and rhomboid nuclei. At this same level, a very light projection was seen in the contralateral anteromedial nucleus. More caudally the projection pattern was similar to that of area 17, with the lateral, lateral posterior, posterior and pretectal nuclei as targets. However, area 18 showed no projections to either division of lateral geniculate nucleus, projections which are commonly seen following injections in area 17. More caudally, the area 18 projection to the superior colliculus was confined to its four deepest laminae, a projection identical to that from areas 29c and 29b. Area 18 also resembled the cingulate cortex in that it sent a small projection to the dorsolateral central gray, although the routes taken to this region were slightly different. It was decided that the projections from this visual association area were, for the most part, unique to that area, although some of them resembled those from either the cingulate cortex or the primary visual area.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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