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Abstract

Understanding how humans differ from other animals, as well as how we are like them, requires comparative investigations. For the purpose of documenting the distinctive features of humans, the most informative research involves comparing humans to our closest relatives–the chimpanzees and other great apes. Psychology and anthropology have maintained a tradition of empirical comparative research on human specializations of cognition. The neurosciences, by contrast, have been dominated by the model-animal research paradigm, which presupposes the commonality of "basic" features of brain organization across species and discourages serious treatment of species differences. As a result, the neurosciences have made little progress in understanding human brain specializations. Recent developments in neuroimaging, genomics, and other non-invasive techniques make it possible to directly compare humans and nonhuman species at levels of organization that were previously inaccessible, offering the hope of gaining a better understanding of the species-specific features of the human brain. This hope will be dashed, however, if chimpanzees and other great ape species become unavailable for even non-invasive research.

Diminished perisomatic GABAergic terminals on cortical neurons adjacent to amyloid plaques

“…However, the data obtained in animal models should be treated with caution when trying to extrapolate to the human brain, particularly if we consider that human cortical circuits show remarkable differences when compared to those of mice (Glezer et al, 1993; Hof et al, 2000b; DeFelipe, 2002; Preuss, 2006; DeFelipe et al, 2007). Furthermore, neurofibrillar tangles do not develop in the mouse model of AD used but rather, only deposits of Aβ are evident.…”

Thirst and Drinking Paradigms: Evolution from Single Factor Effects to Brainwide Dynamic Networks

“…However, the exact location, size, structure and connectivity of the ACC in nonhuman primates is not agreed upon by neurophysiologists, and it is not always obvious which areas of the rodent frontal cortex should be considered as equivalent to the human ACC [144]. Similar questions also arise in neuroscience fields other than thirst, where some researchers emphasize mouse-human anatomical and physiological similarities (e.g., Parkinson's disease [173]; the neuroprotective benefits of exercise to counteract effects of aging [174]), some investigators acknowledge obvious mouse-human differences (e.g., size and complexity of the cerebral and cerebellar cortex, hemispheric dominance, hemispheric specialization [145,170,175], whereas others describe both similarities and differences in mouse and human brains (e.g., neural network organization in Alzheimer disease pathways [176]). Thus, after more than 125 years of experimental neuroscience, mouse and rat experiments may or may not have strong generalizability to humans, especially considering the fact that the mammalian cerebral cortex has proven to be far more variable across species than was believed two or three decades ago [175].…”

Is it possible to overcome issues of external validity in preclinical animal research? Why most animal models are bound to fail

“…Nevertheless there is a strong assumption among the biomedical community that gene functions and developmental systems are conserved between animals and humans [ 49 ]. Moreover, there appears to be little interest within the biomedical community in verifying this assumption, or in the evidence emerging from evolutionary developmental biology indicating that gene functions and gene networks diverge through evolution [ 50 ]. Commentators have observed that the animal model paradigm tends to discourage any critical appraisal of species differences, encouraging instead a view that animal based findings are generally applicable to humans [ 50 , 51 ] and emphasising the commonalities rather than the differences [ 21 ].…”

“…Moreover, there appears to be little interest within the biomedical community in verifying this assumption, or in the evidence emerging from evolutionary developmental biology indicating that gene functions and gene networks diverge through evolution [ 50 ]. Commentators have observed that the animal model paradigm tends to discourage any critical appraisal of species differences, encouraging instead a view that animal based findings are generally applicable to humans [ 50 , 51 ] and emphasising the commonalities rather than the differences [ 21 ]. Preuss [ 50 ] suggests that if species differences are acknowledged they tend to be ‘soft-peddled’ or treated as ‘noise’, again noting that researchers focus on ‘commonalities’ and ‘basic uniformity’ instead.…”

“…Commentators have observed that the animal model paradigm tends to discourage any critical appraisal of species differences, encouraging instead a view that animal based findings are generally applicable to humans [ 50 , 51 ] and emphasising the commonalities rather than the differences [ 21 ]. Preuss [ 50 ] suggests that if species differences are acknowledged they tend to be ‘soft-peddled’ or treated as ‘noise’, again noting that researchers focus on ‘commonalities’ and ‘basic uniformity’ instead. But as Perlman [ 36 ] notes, biology is characterized by diversity as well as unity; evolution is ‘descent with modification’ [ 52 ].…”