Encephalization in <i>Chiroptera</i>

Pirlot, Paul; Stephan, Heinz

doi:10.1139/z70-075

Cited by 84 publications

(39 citation statements)

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“…Measurements of total brain volume, cerebellar volume, and body mass for 14 orders of extant mammals were assembled from the literature, including Monotremata (16), Marsupalia (16,17), Insectivora, Macroscelidae and Scandentia (18), Chiroptera (19), Rodentia (17), Edentata (20), Lagomorpha (21), Cetacea (22,23), Proboscidea (24), Sirenia (25), Rodentia (17), Artiodactyla (26), Carnivora (17,21), and Primates (12-14, 18, 21, 27).…”

Section: Methodsmentioning

confidence: 99%

Reciprocal evolution of the cerebellum and neocortex in fossil humans

Weaver

2005

Proc. Natl. Acad. Sci. U.S.A.

177

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Human brain evolution involved both neurological reorganization and an increase in overall brain volume relative to body mass. It is generally difficult to draw functional inferences about the timing and nature of brain reorganization, given that superficial brain morphology recorded on fossil endocasts is functionally ambiguous. However, the cerebellum, housed in the clearly delineated posterior cranial fossa, is functionally and ontologically discrete. The cerebellum is reciprocally connected to each of 14 neocortical regions important to human cognitive evolution. Cerebellar volume varies significantly relative to overall brain volume among mammalian orders, as well as within the primate order. There is also significant diachronic variation among fossil human taxa. In the australopithecines and early members of the genus Homo, the cerebral hemispheres were large in proportion to the cerebellum, compared with other hominoids. This trend continued in Middle and Late Pleistocene humans, including Neandertals and CroMagnon 1, who have the largest cerebral hemispheres relative to cerebellum volume of any primates, including earlier and Holocene humans. In recent humans, however, the pattern is reversed; the cerebellum is larger with respect to the rest of the brain (and, conversely, the cerebral hemispheres are smaller with respect to the cerebellum) than in Late Pleistocene humans. The cerebellum and cerebral hemispheres appear to have evolved reciprocally. Cerebellar development in Holocene humans may have provided greater computational efficiency for coping with an increasingly complex cultural and conceptual environment.human evolution ͉ Plio-Pleistocene hominins ͉ Upper Paleolithic transition P aleoneurologists agree that increased encephalization is an important dynamic of human brain evolution. However, brain evolution involved more than brain expansion. It also involved reorganization to support specific, uniquely human cognitive tasks, including those involved in linguistic processing and a highly developed facility for manufacturing and manipulating tools. Nevertheless, despite more than a century of effort, there is little consensus about how and when such reorganization occurred.One approach to exploring functional reorganization of the brain in humans has been the analysis of impressions of the brain's surface convolutions (sulci and gyri) on the inner table of the endocranium. However, endocranial markings are notoriously difficult to identify reliably (1, 2). Even where the impressions are fairly clear, taphonomic processes may distort the evidence. In addition, the functional correlates of the brain's surface convolutions, especially in fossils, are literally superficial. Cognitive functions occur through internal connections among brain regions, as well as through the distribution of neuroreceptors that cannot be detected by examining the surface of the brain, let alone from endocranial markings. Therefore, functional inferences based on sulcal patterns are problematic.Another approach to endocran...

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Section: Methodsmentioning

confidence: 99%

Reciprocal evolution of the cerebellum and neocortex in fossil humans

Weaver

2005

Proc. Natl. Acad. Sci. U.S.A.

177

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“…The procedure was repeated after emptying out the original shot. Larger specimens were treated in the Pirlot and Stephan (1970) (see Table 1). Since the brain nearly fills the cranial cavity and the specific gravity of the brain nearly equals the specific gravity of water, cranial volumes in cm' should approximate the brain weight in grams.…”

Section: Methodsmentioning

confidence: 99%

Relative Brain Size and Feeding Strategies in the Chiroptera

Eisenberg¹,

Wilson²

1978

Evolution

132

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“…The accuracy of the method was tested by comparing the calculated volume of the cranial capacity with known brain weights, as published by Pirlot and Stephan (1970) (see Table 1). Since the brain nearly fills the cranial cavity and the specific gravity of the brain nearly equals the specific gravity of water, cranial volumes in ern" should approximate the brain weight in grams.…”

Section: Methodsmentioning

confidence: 99%