A natural history of the human mind: tracing evolutionary changes in brain and cognition

Sherwood, Chet C.; Subiaul, Francys; Zawidzki, Tadeusz Wiesław

doi:10.1111/j.1469-7580.2008.00868.x

Cited by 303 publications

(159 citation statements)

References 324 publications

(512 reference statements)

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“…3B and Table S7), less than half the heritability for brain size. The temporal and inferior parietal regions, the variation of which is associated with the lowest heritability values, are involved in cognitive functions in humans that include language, attention, and memory (29). Our findings highlight the importance of cortical plasticity as a foundation for the emergence of high-order cognitive functions (29) because environmental influence on areas dedicated to these functions is substantially greater in humans than in chimpanzees.…”

Section: Resultsmentioning

confidence: 74%

Relaxed genetic control of cortical organization in human brains compared with chimpanzees

Gómez‐Robles

Hopkins

Schapiro

et al. 2015

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

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164

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The study of hominin brain evolution has focused largely on the neocortical expansion and reorganization undergone by humans as inferred from the endocranial fossil record. Comparisons of modern human brains with those of chimpanzees provide an additional line of evidence to define key neural traits that have emerged in human evolution and that underlie our unique behavioral specializations. In an attempt to identify fundamental developmental differences, we have estimated the genetic bases of brain size and cortical organization in chimpanzees and humans by studying phenotypic similarities between individuals with known kinship relationships. We show that, although heritability for brain size and cortical organization is high in chimpanzees, cerebral cortical anatomy is substantially less genetically heritable than brain size in humans, indicating greater plasticity and increased environmental influence on neurodevelopment in our species. This relaxed genetic control on cortical organization is especially marked in association areas and likely is related to underlying microstructural changes in neural circuitry. A major result of increased plasticity is that the development of neural circuits that underlie behavior is shaped by the environmental, social, and cultural context more intensively in humans than in other primate species, thus providing an anatomical basis for behavioral and cognitive evolution. brain evolution | plasticity | hominins | neocortex | altriciality C ompared with nonhuman primates, human brains are significantly enlarged, reorganized, and have a disproportionately expanded neocortex (1-3). The fossil evidence demonstrates that these changes occurred in the hominin lineage over the last ∼6-8 My (4-9) in parallel with modifications to neurodevelopmental rates (10-13). Although some of these changes have been linked to certain genetic variants in the human lineage [either shared with other late hominin species or exclusive to modern humans (14, 15)], exploring brain evolution in hominins is challenging because of the limitations of the endocranial fossil record (4, 5). Comparisons of chimpanzee and human brains therefore are essential to reveal the neural traits that differ between the two species, that underlie their behavioral specializations, and that must have evolved after they split from their last common ancestor.Human behavioral and cognitive development is highly dependent on cultural influences and social learning (16,17). Notably, modern human behavioral adaptations for living in diverse habitats depend on skills and information learned from others (18). Similarly, it has been demonstrated that enculturated great apes perform better in different tasks related to physical and, especially, social cognition (19), underscoring the importance of environmental influences in shaping behavior. These observations are congruent with experimental studies in mouse models showing that variation in sensory experience early in postnatal life causes reorganization of neural circuits that underlie...

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Section: Resultsmentioning

confidence: 74%

Relaxed genetic control of cortical organization in human brains compared with chimpanzees

Gómez‐Robles

Hopkins

Schapiro

et al. 2015

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

Self Cite

164

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“…Directly studying cortical expansion in human evolution would entail comparisons to evolutionary ancestors using the limited information in the fossil record. Important inferences can nonetheless be made through comparative studies with extant nonhuman primates (13,21). Human and macaque cortex differ ≈10-fold in total surface area.…”

Section: Resultsmentioning

confidence: 99%

“…The preset result suggests that many cortical regions that expanded rapidly in evolution were also under evolutionary pressure to remain structurally immature during gestation. In particular, the lateral temporal, parietal, and frontal regions associated with high expansion in human postnatal development and in evolution are generally implicated in higher cognitive functions that distinguish humans from nonhuman primates (21). These regions may have been under pressure to remain immature to do the following: (i) to facilitate the contributions of postnatal experience to the development of selected regions; (ii) to minimize the use of prenatal resources for development of cortical regions less crucial for early survival; or (iii) to limit overall brain size at birth by focusing development/ expansion primarily on those areas needed for immediate postnatal survival, thereby minimizing head size as a mechanical obstacle to emergence from the uterus (54).…”

Section: High-expanding Regions Have Greater Cellular Complexity In Amentioning

confidence: 99%

Similar patterns of cortical expansion during human development and evolution

Hill¹,

Inder²,

Neil³

et al. 2010

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

686

589

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The cerebral cortex of the human infant at term is complexly folded in a similar fashion to adult cortex but has only one third the total surface area. By comparing 12 healthy infants born at term with 12 healthy young adults, we demonstrate that postnatal cortical expansion is strikingly nonuniform: regions of lateral temporal, parietal, and frontal cortex expand nearly twice as much as other regions in the insular and medial occipital cortex. This differential postnatal expansion may reflect regional differences in the maturity of dendritic and synaptic architecture at birth and/or in the complexity of dendritic and synaptic architecture in adults. This expression may also be associated with differential sensitivity of cortical circuits to childhood experience and insults. By comparing human and macaque monkey cerebral cortex, we infer that the pattern of human evolutionary expansion is remarkably similar to the pattern of human postnatal expansion. To account for this correspondence, we hypothesize that it is beneficial for regions of recent evolutionary expansion to remain less mature at birth, perhaps to increase the influence of postnatal experience on the development of these regions or to focus prenatal resources on regions most important for early survival.T he human cerebral cortex is characterized by regional nonuniformities in cellular structure that change with age. Near term, there are regional variations in synaptic density (1, 2), dendritic length, and dendritic spine density (3). Postnatally, synaptic density increases dramatically, reaches a peak density in early childhood, and then undergoes synaptic pruning with a 2-fold or greater reduction (4). The time course of these synaptic changes differs across regions, with primary sensory areas attaining peak density and adult levels earlier than higher order "association" areas (2, 5). In adults, there are large regional nonuniformities in neuronal density (6), dendritic size, branching complexity, and spine density (7).This evidence for cellular nonuniformities provides grounds for anticipating regional differences in macroscopic aspects of postnatal cortical maturation. Indeed, studies of gray matter volume and overall brain growth provide evidence for complex regional patterns of morphological change during childhood and adolescence (8, 9). We recently used a surface-based approach to compare cortical structure in human term infants to adults. That analysis suggested that although many adult cortical shape characteristics are well established at birth, there may be regional differences in the maturity of cortical folding in term infants compared with adults (10).Comparisons with nonhuman primates, especially the intensively studied macaque monkey, provide another basis for evaluating regional differences in cortical maturation. Since the evolutionary divergence between humans and macaques ∼25 million years ago (11), cortical expansion has been far greater in human lineage than in the macaque lineage. Compared with the macaque cortex, the human c...

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“…However, such 'von Economo cells' have recently been found in some cetaceans and in elephants as well, but not consistently in all largebrained mammals [44,51]. Whether this mosaic existence of 'von Economo cells' is owing to independent evolution or, when absent, to secondary loss, is unclear, as is their specific significance for cognition [52]. Furthermore, it is unlikely that superior mental abilities are based on the presence of a single type of neurons.…”

Section: Specialties Of the Cytoarchitecture Of The Mammalian Cortexmentioning

confidence: 99%

Neuronal factors determining high intelligence

Dicke¹,

Roth²

2016

Phil. Trans. R. Soc. B

146

107

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One contribution of 16 to a discussion meeting issue 'Homology and convergence in nervous system evolution'. Many attempts have been made to correlate degrees of both animal and human intelligence with brain properties. With respect to mammals, a much-discussed trait concerns absolute and relative brain size, either uncorrected or corrected for body size. However, the correlation of both with degrees of intelligence yields large inconsistencies, because although they are regarded as the most intelligent mammals, monkeys and apes, including humans, have neither the absolutely nor the relatively largest brains. The best fit between brain traits and degrees of intelligence among mammals is reached by a combination of the number of cortical neurons, neuron packing density, interneuronal distance and axonal conduction velocity-factors that determine general information processing capacity (IPC), as reflected by general intelligence. The highest IPC is found in humans, followed by the great apes, Old World and New World monkeys. The IPC of cetaceans and elephants is much lower because of a thin cortex, low neuron packing density and low axonal conduction velocity. By contrast, corvid and psittacid birds have very small and densely packed pallial neurons and relatively many neurons, which, despite very small brain volumes, might explain their high intelligence. The evolution of a syntactical and grammatical language in humans most probably has served as an additional intelligence amplifier, which may have happened in songbirds and psittacids in a convergent manner.

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A natural history of the human mind: tracing evolutionary changes in brain and cognition

Cited by 303 publications

References 324 publications

Relaxed genetic control of cortical organization in human brains compared with chimpanzees

Relaxed genetic control of cortical organization in human brains compared with chimpanzees

Similar patterns of cortical expansion during human development and evolution

Neuronal factors determining high intelligence

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