bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fine structural correlates of the choroid plexus of the lateral cerebral ventricle of the human fetal brain
Authors: Scott David E. , Bergevin Michael 
Published: October 2004

AbstractThe germinal matrix neuroepithelium and the choroidal fissure of the fetal choroid plexus commonly possess microvessels that are often poorly developed. There may be a reduction of type IV collagen that surrounds these fragile microvessels. During the first and second trimester of neural development, these microvessels are friable and can undergo intraventricular hemorrhage under a number of circumstances. Early subtle changes in the integrity of germinal matrix epithelium are not easily visualized by ultrasound. The current investigation employing scanning electron microscopy clearly defines subtle hemorrhagic events and tearing of the germinal matrix neuroepithelium in the brains of human fetuses. A 23‐week‐old fetus survived for 11 days but died from other causes. The choroid plexus of this fetus was compared with the choroid plexus and germinal matrix epithelium of a 22‐week‐old fetus that was the product of an elective termination due to severe anhydramnios of unknown origin and a 19‐week‐old male fetus from an elective termination. All tissues were autopsy material not requiring institutional review board approval. © 2004 Wiley‐Liss, Inc.
Evolution of the special senses in primates: Past, present, and future
Authors: Dominy Nathaniel J. , Ross Callum F. , Smith Timothy D. 
Published: October 2004

AbstractThe present special issue ofThe Anatomical Recordis the result of a symposium entitled Evolution of the Special Senses in Primates. Considered together, the special senses of primates are remarkable because they constitute a singular and definitive suite of mammalian characteristics. Examining their evolution is pivotal for understanding the origin and present‐day variation of primate behavior and ecology. Accordingly, the 14 articles assembled here consider the different constraints and opportunities associated with the uptake and use of physical and chemical stimuli. The present issue brings together experts on different primate sensory modalities and stresses events at the sensory periphery, where the organism is exposed to and comes into contact with its environment. Key topics include color vision, the genetics of olfaction, the morphological basis and significance of chemical communication, and the neural organization and scaling of primate sensory systems. The result is a special issue that both reflects our current understanding of primate sensory modalities and challenges certain fundamental assumptions concerning their evolution. © 2004 Wiley‐Liss, Inc.
High‐resolution computed tomography study of the cranium of a fossil anthropoid primate, Parapithecus grangeri: New insights into the evolutionary history of primate sensory systems
Authors: Bush Eliot C. , Simons Elwyn L. , Allman John M. 
Published: October 2004

AbstractExtant anthropoids have large brains, small olfactory bulbs, and high‐acuity vision compared with other primates. The relative timing of the evolution of these characteristics may have important implications for brain evolution. Here computed tomography is used to examine the cranium of a fossil anthropoid, Parapithecus grangeri. It is found that P. grangeri had a relatively small brain compared with living primates. In addition, it had an olfactory bulb in the middle of the range for living primates. Methods for relating optic foramen area and other cranial measurements to acuity are discussed. Multiple regression is used to estimate retinal ganglion cell number in P. grangeri. Given currently available comparative data, P. grangeri seems to have had retinal ganglion cell counts intermediate for living primates, overlapping with the upper end of the range for strepsirrhines and possibly with the lower end for anthropoids. © 2004 Wiley‐Liss, Inc.
Three‐dimensional structure and evolution of primate primary visual cortex
Authors: Bush Eliot C. , Allman John M. 
Published: October 2004

AbstractIn this study, three‐dimensional reconstructions of primate primary visual cortex (V1) were used to address questions about its evolution. The three‐dimensional shape of V1 in anthropoids is significantly longer and narrower than in strepsirrhines. This difference is an effect of clade and is not due to differences in activity pattern or V1 size. New measurements of V1 volume were also provided in order to reassess V1 size differences between strepsirrhines and anthropoids. It was found that for a given lateral geniculate nucleus (LGN) volume, anthropoids have a significantly larger V1 than strepsirrhines do. This is important since LGN is the principal source of V1's input. Finally, independent contrasts analysis was used to examine the scaling of V1 relative to LGN, the rest of cortex, and the rest of the brain. It was confirmed that V1 scales with positive allometry relative to LGN. A number of possible explanations for scaling are discussed. V1 scaling may have to do with the tendency of large brains to be more compartmentalized than small brains, or V1 scaling might reflect the geometry of information representation. © 2004 Wiley‐Liss, Inc.
Comparative morphology of the eye in primates
Authors: Kirk E. Christopher 
Published: October 2004

AbstractComparative studies of mammalian eye morphology have shown that relative cornea size is an important correlate of visual ecology. Nocturnal species tend to have large corneas relative to eye size as an adaptation for increasing visual sensitivity. By contrast, diurnal species tend to have smaller corneas relative to eye size because their eye morphology maximizes visual acuity. Although qualitative analyses suggest that activity pattern may have a similar influence on eye morphology in primates, various current hypotheses have proposed that either diurnal anthropoids or diurnal lemurs have visual systems that diverge from those of other diurnal mammals. The goal of this analysis is to quantify the relationship between eye morphology and activity pattern in primates and to determine whether primates exhibit variation in eye morphology comparable to that of other mammals. Data on eye size and cornea size were collected for 147 specimens of 55 primate species. These data reveal that, within primate suborders, diurnal species have significantly smaller relative cornea sizes than nocturnal or cathemeral species. Both haplorhines and strepsirrhines thus exhibit variation in eye morphology that is consistent with functional expectations. However, comparisons between the two primate suborders demonstrate that haplorhines and strepsirrhines differ significantly in eye morphology. Whereas strepsirrhines have relative cornea sizes that are similar to nonprimate mammals of comparable activity pattern, diurnal anthropoids have smaller relative cornea sizes than most nonprimate mammals. This derived eye morphology in anthropoids probably evolved in the anthropoid stem lineage as a result of selection for highly acute diurnal vision. © 2004 Wiley‐Liss, Inc.
On the relationship between orbit orientation and binocular visual field overlap in mammals
Authors: Heesy Christopher P. 
Published: October 2004

AbstractThe orbital apertures of Primates are among the most convergent (i.e., facing in the same direction) among mammals. It is often assumed that orbit convergence is associated with binocular visual field overlap and stereoscopic depth perception in primates. Likewise, it is also assumed that orbit orientation reflects the shape of the visual field across mammals. To date, however, no study has demonstrated that orbit and visual field orientation are correlated, much less comparable, across mammals. In this study, data on orbit convergence were collected for a representative sample of mammals for which data on the extent of the visual field are available. Both standard and phylogenetically controlled comparisons were made. The results demonstrate that orbit convergence and binocular visual field overlap are significantly correlated and display a linear relationship. Based on orbit convergence, Primates as a group have the largest binocular visual fields among mammals. © 2004 Wiley‐Liss, Inc.
Primate hearing from a mammalian perspective
Authors: Heffner Rickye S. 
Published: October 2004

AbstractThis review discusses hearing performance in primates and selective pressures that may influence it. The hearing sensitivity and sound‐localization abilities of primates, as indicated by behavioral tests, are reviewed and compared to hearing and sound localization among mammals in general. Primates fit the mammalian pattern with small species hearing higher frequencies than larger species in order to use spectral/intensity cues for sound localization. In this broader comparative context, the restricted high‐frequency hearing of humans is not unusual. All of the primates tested so far are able to hear frequencies below 125 Hz, placing them among the majority of mammals. Sound‐localization acuity has been determined for only three primates, and here also they have relatively good localization acuity (with a minimum audible angle roughly similar to other mammals such as cats, pigs, and opossums). This is in keeping with the pattern among mammals in general, in which species with narrow fields of best vision, such as a fovea, are better localizers than those with broad fields of best vision. Multiple lines of evidence support the view that sound localization is the selective pressure on smaller primates and on other mammals with short interaural distances for hearing high frequencies. © 2004 Wiley‐Liss, Inc.
Primate auditory diversity and its influence on hearing performance
Authors: Coleman Mark N. , Ross Callum F. 
Published: October 2004

AbstractThe auditory region contains numerous structures that have proven useful for phylogenetic classification at various taxonomic levels. However, little work has been done in primates relating differences in morphology to variations in hearing performance. This study documents anatomical and physiological distinctions within primates and begins to address the functional and evolutionary consequences of these and other auditory features. The dimensions of the outer ear (pinna) were measured in cadaveric specimens representing nearly every primate family and used to calculate a shape ratio (height/width). It was found that nonanthropoids have a significantly higher ratio than anthropoids, although the actual height was not found to differ. This indicates that most nonanthropoids have ears that are tall and narrow, whereas monkeys and apes are characterized by ears with more equal height and width dimensions. Eardrum area, stapedial footplate area, and ossicular lever arm lengths were measured in dried specimens to calculate an impedance transformer ratio. A distinction was found between anthropoids and strepsirrhines, with the latter group having a transformer ratio indicative of a higher percentage of acoustic energy transmission through the middle ear. Audiogram data were gathered from the literature to analyze hearing sensitivity and it was found that platyrrhines illustrate more low‐frequency sensitivity than like‐sized lorisoids. The effects of intraspecific variation on the audiogram results were also examined and were found to produce similar results as the analysis using species mean threshold values. Lastly, correlations between morphological and audiogram variables were examined. Several measures of hearing sensitivity were found to be correlated with pinna shape but correlations with middle ear transmission properties were weaker. In addition to using traditional statistical techniques, phylogenetic corrective methods were applied to address the problem of statistical nonindependence of the data and the results of both analyses are compared. These findings are discussed with respect to how sensory adaptations and phylogenetic history may be related to the current radiation of primates. © 2004 Wiley‐Liss, Inc.
Meissner corpuscles and somatosensory acuity: The prehensile appendages of primates and elephants
Authors: Hoffmann Joscelyn N. , Montag Anthony G. , Dominy Nathaniel J. 
Published: October 2004

AbstractMeissner corpuscles (MCs) are specialized mechanoreceptors located exclusively in the papillae of glabrous skin. They are confined largely to cutaneous pads of the extremities and respond to transient, phasic, or vibratory stimuli. Though absent in most eutherian taxa, MCs are reported in all primates studied, being most developed in modern humans. The location of MCs between the internal ridges of the epidermis indicates they are well situated to detect friction or deformation at the external surface. Accordingly, MCs are hypothesized to provide primates generally with an enhanced tactile perception. However, the selective pressures favoring greater somatosensory acuity in primates are seldom considered. Interestingly, primate digital dexterity varies greatly. In general, dexterity improves with the extent to which foraging requires food manipulation or textural evaluation. This observation implies that MC density could vary accordingly. Here we report on the density of MCs in five anthropoid taxa selected to represent diverse dietary regimes. Results show that greater MC density correlates with the extent to which primates are frugivorous; however, locomotor and/or phylogenetic effects cannot be discounted. © 2004 Wiley‐Liss, Inc.
Evolution of somatosensory and motor cortex in primates
Authors: Kaas Jon H. 
Published: October 2004

AbstractInferences about how the complex somatosensory systems of anthropoid primates evolved are based on comparative studies of such systems in extant mammals. Experimental studies of members of the major clades of extant mammals suggest that somatosensory cortex of early mammals consisted of only a few areas, including a primary area, S1, bordered by strip‐like rostral and caudal somatosensory fields, SR and SC. In addition, the second somatosensory area, S2, and the parietal ventral area, PV, were probably present. S1, S2, and PV were activated independently via parallel projections from the ventroposterior nucleus, VP. Little posterior parietal cortex existed, and it was unlikely that a separate primary motor area, M1, existed until placental mammals evolved. Early primates retained this basic organization and also had a larger posterior parietal region that mediated sensorimotor functions via connections with motor and premotor areas. The frontal cortex included M1, dorsal and ventral premotor areas, supplementary motor area, and cingulate motor fields. Ventroposterior superior and ventroposterior inferior nuclei were distinct from the ventroposterior nucleus in the thalamus. In early anthropoid primates, areas S1, SR, and SC had differentiated into the fields now recognized as areas 3b, 3a, and 1. Areas 3b and 1 contained parallel mirror‐image representations of cutaneous receptors and a parallel representation in area 2 was probable. Serial processing became dominant, so that neurons in areas 1, S2, and PV became dependent on area 3b for activation. Posterior parietal cortex expanded into more areas that related to frontal cortex. Less is known about changes that might have occurred with the emergence of apes and humans, but their brains were larger and posed scaling problems most likely solved by increasing the number of cortical areas and reducing the proportion of long connections. © 2004 Wiley‐Liss, Inc.
Comparative analysis of the role of olfaction and the neocortex in primate intrasexual competition
Authors: Alport Laura J. 
Published: October 2004

AbstractIn strepsirrhine primates, the accessory olfactory system plays an important role in intrasexual competition. However, it does not play the same role in most haplorhines. In these primates, the main olfactory system and neocortex may have evolved to serve similar functions as the accessory olfactory system in strepsirrhines. To test these hypotheses, the relative size of the main olfactory bulb and neocortex were analyzed for associations with male and female competition frequency and intensity (categorized as low or high). Because neocortex size and competition intensity are associated with diet, only frugivorous species were analyzed (catarrhines, n = 7; platyrrhines, n = 8). Neither the size of the main olfactory bulb nor the neocortex was significantly associated with intrasexual competition among males. However, neocortex size was related to the frequency of female competition. Because the main olfactory system and neocortex both serve multiple purposes, there may not be a single behavioral variable that has selected for their size. Furthermore, categorization of male and female competition intensity reflects physically aggressive behavior. Use of the neocortex for social manipulation may allow males to obtain copulations and females to obtain food resources despite poor physical fighting abilities and low dominance rank. © 2004 Wiley‐Liss, Inc.
Expression of neuron‐specific markers by the vomeronasal neuroepithelium in six species of primates
Authors: Dennis John C. , Smith Timothy D. , Bhatnagar Kunwar P. , Bonar Christopher J. , Burrows Anne M. , Morrison Edward E. 
Published: October 2004

AbstractVomeronasal organ (VNO) morphology varies markedly across primate taxa. Old World monkeys display no postnatal VNO. Humans and at least some apes retain a vestigial VNO during postnatal life, whereas the strepsirrhines and New World Monkeys present a morphologically well‐defined VNO that, in many species, is presumed to function as an olfactory organ. Available microanatomical and behavioral studies suggest that VNO function in these species does not precisely duplicate that described in other mammalian taxa. The questions of which species retain a functional VNO and what functions they serve require inquiry along diverse lines but, to be functional, the vomeronasal epithelium must be neuronal and olfactory. We used immunohistochemistry to establish these criteria in six primate species. We compared the expression of two neuronal markers, neuron‐specific β‐tubulin (BT) and protein gene product 9.5, and olfactory marker protein (OMP), a marker of mature olfactory sensory neurons, in paraffin‐embedded VNO sections from two strepsirrhine and four haplorhine species, all of which retain morphologically well‐defined VNOs during postnatal life. The infant Eulemur mongoz, adult Otolemur crassicaudatus, neonatal Leontopithicus rosalia, and adult Callithrix jacchus express all three proteins in their well‐defined vomeronasal neuroepithelia. The infant Tarsius syrichta showed some BT and OMP immunoreactivity. We establish that two strepsirrhine species and at least some New World haplorhines have mature sensory neurons in the VNO. In contrast, at all ages examined, Saguinus geoffroyi VNO expresses these markers in only a few cells. © 2004 Wiley‐Liss, Inc.
Facts, fallacies, fears, and frustrations with human pheromones
Authors: Wysocki Charles J. , Preti George 
Published: October 2004

AbstractAmong primates in general, pheromones are of variable importance to social communication. Data on humans have generated the greatest controversy regarding the existence of pheromonal communication. In this review, the likelihood of pheromonal communication in humans is assessed with a discussion of chemical compounds produced by the axilla that may function as pheromones; the likelihood that the vomeronasal organ (VNO), a putative pheromone receptor organ in many other mammals, is functional in humans; and the possible ways pheromones operate in humans. In the human axilla, the interactions between the cutaneous microflora and axillary secretions render this region analogous to scent glands found in other primates. Both the chemistry of axillary secretions and their effects on conspecifics in humans appear to be analogous to other mammalian pheromone systems. Whichever chemical compounds serve a pheromonal function in humans, another unknown is the receptor. Although the VNO has been implicated in the reception of pheromones in many vertebrates, it is not the only pathway through which such information has access to the central nervous system; there is ample evidence to support the view that the olfactory epithelium can respond to pheromones. Furthermore, if a chemical activates receptors within the VNO, this does not necessarily mean that the compound is a pheromone. An important caveat for humans is that critical components typically found within the functioning VNO of other, nonprimate, mammals are lacking, suggesting that the human VNO does not function in the way that has been described for other mammals. In a broader perspective, pheromones can be classified as primers, signalers, modulators, and releasers. There is good evidence to support the presence of the former three in humans. Examples include affects on the menstrual cycle (primer effects); olfactory recognition of newborn by its mother (signaler); individuals may exude different odors based on mood (suggestive of modulator effects). However, there is no good evidence for releaser effects in adult humans. It is emphasized that no bioassay‐guided study has led to the isolation of true human pheromones, a step that will elucidate specific functions to human chemical signals. © 2004 Wiley‐Liss, Inc.
Convergence of sensory systems in the orbitofrontal cortex in primates and brain design for emotion
Authors: Rolls Edmund T. 
Published: October 2004

AbstractIn primates, stimuli to sensory systems influence motivational and emotional behavior via neural relays to the orbitofrontal cortex. This article reviews studies on the effects of stimuli from multiple sensory modalities on the brain of humans and some other higher primates. The primate orbitofrontal cortex contains the secondary taste cortex, in which the reward value of taste is represented. It also contains the secondary and tertiary olfactory cortical areas, in which information about the identity and also about the reward value of odors is represented. A somatosensory input is revealed by neurons that respond to the viscosity of food in the mouth, to the texture (mouth feel) of fat in the mouth, and to the temperature of liquids placed into the mouth. The orbitofrontal cortex also receives information about the sight of objects from the temporal lobe cortical visual areas. Information about each of these modalities is represented separately by different neurons, but in addition, other neurons show convergence between different types of sensory input. This convergence occurs by associative learning between the visual or olfactory input and the taste. In that emotions can be defined as states elicited by reinforcers, the neurons that respond to primary reinforcers (such as taste and touch), as well as learn associations to visual and olfactory stimuli that become secondary reinforcers, provide a basis for understanding the functions of the orbitofrontal cortex in emotion. In complementary neuroimaging studies in humans, it is being found that areas of the orbitofrontal cortex are activated by pleasant touch, by painful touch, by taste, by smell, and by more abstract reinforcers such as winning or losing money. Damage to the orbitofrontal cortex in humans can impair the learning and reversal of stimulus‐reinforcement associations and thus the correction of behavioral responses when these are no longer appropriate because previous reinforcement contingencies change. It is striking that humans and other catarrhines, being visual specialists like other anthropoids, interface the visual system to other sensory systems (e.g., taste and smell) in the orbitofrontal cortex. © 2004 Wiley‐Liss, Inc.