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    In this paper, we suggest that affect meets the traditional definition of "cognition" such that the affect-cognition distinction is phenomenological, rather than ontological. We review how the affect-cognition distinction is not respected in the human brain, and discuss the neural mechanisms by which affect influences sensory processing. As a result of this sensory modulation, affect performs several basic "cognitive" functions. Affect appears to be necessary for normal conscious experience, language fluency, and memory. Finally, we suggest that understanding the differences between affect and cognition will require systematic study of how the phenomenological distinction characterising the two comes about, and why such a distinction is functional.
    Affect
    Citations (513)
    Three experiments tested the hypothesis that need for affect and need for cognition influence receptivity to affect- and cognition-based persuasive messages. Experiment 1 found that an affective message elicited more positive attitudes among individuals high in need for affect and low in need for cognition, whereas a cognitive message elicited more positive attitudes among individuals low in need for affect and high in need for cognition. Experiment 2 found that individual differences in need for affect influenced receptivity to an affect-based (but not cognition-based) message, whereas individual differences in need for cognition influenced receptivity to a cognition-based (but not affect-based) message. Experiment 3 found that individual differences in need for affect were associated with increased recognition of information from an affect-based (but not cognition-based) message, whereas individual differences in need for cognition were associated with increased recognition of information from a cognition-based (but not affect-based) message. Overall, the studies point to the importance of individual differences in need for affect and need for cognition in understanding how individuals respond to different types of persuasive messages.
    Affect
    Need for cognition
    Citations (189)
    Human brain
    Superior frontal gyrus
    Brain Function
    Brain mapping
    Middle frontal gyrus
    Inferior frontal gyrus
    Abstract Twin studies suggest that variation in human brain volume is genetically influenced. The genes involved in human brain volume variation are still largely unknown, but several candidate genes have been suggested. An overview of structural Magnetic Resonance (brain) Imaging studies in twins is presented, which focuses on the influence of genetic factors on variation in healthy human brain volume. Twin studies have shown that genetic effects varied regionally within the brain, with high heritabilities of frontal lobe volumes (90–95%), moderate estimates in the hippocampus (40–69%), and environmental factors influencing several medial brain areas. High heritability estimates of brain structures were revealed for regional amounts of gray matter (density) in medial frontal cortex, Heschl's gyrus, and postcentral gyrus. In addition, moderate to high heritabilities for densities of Broca's area, anterior cingulate, hippocampus, amygdala, gray matter of the parahippocampal gyrus, and white matter of the superior occipitofrontal fasciculus were reported. The high heritability for (global) brain volumes, including the intracranium, total brain, cerebral gray, and white matter, seems to be present throughout life. Estimates of genetic and environmental influences on age‐related changes in brain structure in children and adults await further longitudinal twin‐studies. For prefrontal cortex volume, white matter, and hippocampus volumes, a number of candidate genes have been identified, whereas for other brain areas, only a few or even a single candidate gene has been found so far. New techniques such as genome‐wide scans may become helpful in the search for genes that are involved in the regulation of human brain volume throughout life. Hum Brain Mapp, 2007. © 2007 Wiley‐Liss, Inc.
    Human brain
    Parahippocampal gyrus
    Brain morphometry
    Grey matter
    Gyrus
    Citations (425)
    During evolution, the mammalian cerebral cortex has expanded disproportionately to brain volume. As a consequence, most mammals with large brains have profusely convoluted cortices. The human cortex is a good example of this trend, however, given the large variability in human brain size, it is not clear how cortical folding varies from the smallest to the largest brains. We analyzed cortical folding in a large cohort of human subjects exhibiting a 1.7-fold variation in brain volume. We show that the same disproportionate increase of cortical surface relative to brain volume observed across species can be also observed across human brains: the largest brains can have up to 20% more surface than a scaled-up small brain. We introduce next a novel local measure of cortical folding, and we show that the correlation between cortical folding and size varies along a rostro-caudal gradient, being especially significant in the prefrontal cortex. The expansion of the cerebral cortex, and in particular that of its prefrontal region, is a major evolutionary landmark in the emergence of human cognition. Our results suggest that this may be, at least in part, a natural outcome of increasing brain size.
    Human brain
    Folding (DSP implementation)
    Gyrification
    Citations (246)