Effects of captivity and testosterone on the volumes of four brain regions in the dark‐eyed junco (
            <i>Junco hyemalis</i>
            )

Smulders, Tom V.; Casto, Joseph M.; Nolan, Val; Ketterson, Ellen D.; DeVoogd, Timothy J.

doi:10.1002/(sici)1097-4695(20000605)43:3<244::aid-neu3>3.0.co;2-#

Cited by 53 publications

(19 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A two-fold increase in baseline corticosterone does not alter telencephalon volume, hippocampal volume, cell proliferation, or cell survival in lab-housed mountain chickadees implanted with continuous time-release corticosterone pellets (Pravosudov and Omanska, 2005b). In male dark-eyed juncos ( Junco hyemalis ), a non-caching species, captivity during the breeding season (a time when the birds are normally actively navigating and defending a territory) is associated with reduced hippocampal volume (Smulders et al, 2000a). Adult black-capped chickadees ( Poecile atricapillus ) housed on short days cache more, but do not have a larger hippocampus or more hippocampal neurogenesis than birds on long days (Hoshooley et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Captivity reduces hippocampal volume but not survival of new cells in a food‐storing bird

Tarr

Rabinowitz

Imtiaz

et al. 2009

Developmental Neurobiology

View full text Add to dashboard Cite

In many naturalistic studies of the hippocampus wild animals are held in captivity. To see if captivity itself affects hippocampal structure, adult black-capped chickadees (Poecile atricapilla) were caught in the fall, injected with bromodeoxyuridine to mark neurogenesis and alternately released back to the wild or held in captivity for 4–6 weeks. Wild birds were recaptured and perfused simultaneously with their captive counterparts. The hippocampus of the captive birds was 23% smaller than the wild birds, with no hemispheric differences in volume within groups. There was no statistically significant difference in the size of the telencephalon between groups, or in the number and density of surviving new cells. Proximate causes of the hippocampal volume change could include stress, lack of exercise, diminished social interaction or limited caching opportunity; a hippocampal-dependent activity. The results suggest the avian hippocampus - a structure essential for rapid, complex relational and spatial learning - is both plastic and sensitive, much as is the case in mammals, including humans.

show abstract

Section: Discussionmentioning

confidence: 99%

Captivity reduces hippocampal volume but not survival of new cells in a food‐storing bird

Tarr

Rabinowitz

Imtiaz

et al. 2009

Developmental Neurobiology

View full text Add to dashboard Cite

show abstract

“…Fourteen migratory Z. l. gambelii (seven adults and seven juveniles) were also trapped for behavioural experiments during 12-20 October 2005 near Davis, California. Thus, different groups of birds were used for brain and behavioural analyses to avoid potential effects of captivity on hippocampal structure (Smulders et al 2000). All birds used in behavioural experiments were later released at the sites of capture in mid March 2005.…”

Section: Methodsmentioning

confidence: 99%

The relationship between migratory behaviour, memory and the hippocampus: an intraspecific comparison

2006

View full text Add to dashboard Cite

It has been hypothesized that memory-demanding ecological conditions might result in enhanced memory and an enlarged hippocampus, an area of the brain involved in memory processing, either via extensive memory experience or through evolutionary changes. Avian migration appears to represent one of such memory-demanding ecological conditions. We compared two subspecies of the white-crowned sparrow: migratory Zonotrichia leucophrys gambelii and non-migratory Z. l. nuttalli. Compared to non-migratory Z. l. nuttalli, migratory Z. l. gambelii showed better memory performance on spatial one-trial associative learning tasks and had more hippocampal neurons. Migratory subspecies also had larger hippocampi relative to the remainder of the telencephalon but not relative to body mass. In adults, the differences between migratory and non-migratory sparrows were especially pronounced in the right hippocampus. Juvenile migratory Z. l. gambelii had relatively larger hippocampal volume compared to juvenile non-migratory Z. l. nuttalli. Adult migratory Z. l. gambelii had more neurons in their right hippocampus compared to juveniles but such differences were not found in non-migratory Z. l. nuttalli. Our results suggest that migratory behaviour might be related to enhanced spatial memory and an enlarged hippocampus with more neurons, and that differences in the hippocampus between migratory and non-migratory sparrows might be experience-dependent. Furthermore, for the first time our results suggest that the right hippocampus, which encodes global spatial information, might be involved in migratory behaviour.

show abstract

“…Virtually no consideration has been given to the constraints on overall brain size, and resultant trade-offs among brain functions. Besides the negative effects of domestication and captivity (Rehka¨mper et al 1991(Rehka¨mper et al , 2000Smulders et al 2000), the only natural factor so far discovered to give rise to such constraints seems to be migration (Winkler and Leisler, 2004). The ability to become migratory may be a key feature in the evolution not only of birds ( Berthold 1999;Winker 2000), but also in other organisms (Dingle 1996).…”

Section: Introductionmentioning

confidence: 96%

Ecological constraints on the evolution of avian brains

2004

View full text Add to dashboard Cite

Birds have brains that are comparable in size to those of mammals. However, variation in relative avian brain size is greater in birds. Thus, birds are ideal subjects for comparative studies on the ecological and behavioral influences on the evolution of the brain and its components. Previous studies of ecological or behavioral correlates in relative brain size were mainly based on gross comparisons between higher taxa or focussed on the relationships between the sizes of specific brain structures and the complexity of different tasks.Here we examine variation in dimensions of the braincase, relative overall brain size and size of its components, in reference to one general ecological and behavioral task: migration. We used data from three lineages of closely related species (14 Acrocephalines, 17 Sylvia and 49 parulid warblers). Within each group, species vary in their migratory tendencies. We found that species migrating long distances have lower skulls and smaller forebrains than resident species. We discuss four hypotheses that could explain smaller forebrain sizes, and suggest relevant taxa to use in comparative analyses to examine each of these hypotheses: -Brain size is energetically constrained. Contrasts can be made not only between migrants and residents, but also between birds in habitats with high and low levels of available food. -Brain size is developmentally constrained; birds with short growing periods should have smaller forebrains. Comparisons need to be made between birds living in habitats with long and short breeding seasons. -Bill adaptations for foraging constrain braincase dimensions. Further analyses would need to be done on groups with high variation in bill dimensions and foraging modes. -Birds with small brains have to migrate to compensate for low behavioral flexibility. Contrasts between members of families containing tropical residents and migrants need to be made.We also raise the question of whether only those parts of the brain are reduced that are most dispensable and whether brain size reduction limits foraging skills and social competence.

show abstract

Effects of captivity and testosterone on the volumes of four brain regions in the dark‐eyed junco ( Junco hyemalis )

Cited by 53 publications

References 53 publications

Captivity reduces hippocampal volume but not survival of new cells in a food‐storing bird

Captivity reduces hippocampal volume but not survival of new cells in a food‐storing bird

The relationship between migratory behaviour, memory and the hippocampus: an intraspecific comparison

Ecological constraints on the evolution of avian brains

Contact Info

Product

Resources

About