scholarly journals Expansion of cortical layers 2 and 3 in human left temporal cortex associates with verbal intelligence

2021 ◽  
Author(s):  
DB Heyer ◽  
R Wilbers ◽  
AA Galakhova ◽  
E Hartsema ◽  
S Braak ◽  
...  

AbstractThe expansion of supragranular cortical layers is thought to have enabled evolutionary development of human cognition and language. However, whether increased volume of supragranular cortical layers can actually support greater cognitive and language abilities in humans has not been demonstrated. Here, we find that subjects with higher general and verbal intelligence test (VIQ) scores have selectively expanded layers 2 and 3 only in the left temporal cortex, an area associated with language and IQ-test performance. This expansion is accompanied by lower neuron densities and larger cell-body size. Furthermore, individuals with higher VIQ scores had neurons with larger dendritic trees in left temporal cortex, potentially impacting their function. Indeed, neurons of subjects with higher VIQ scores had faster action potential upstroke kinetics, which improves information processing. These data show that expansion of supragranular layer volume, cortical and cellular micro-architecture and function are associated with improved verbal mental ability in human subjects.

2016 ◽  
Vol 219 (2) ◽  
pp. 478-485 ◽  
Author(s):  
N. C. Netzer ◽  
K. P. Strohl ◽  
J. Högel ◽  
H. Gatterer ◽  
R. Schilz

1985 ◽  
Vol 58 (2) ◽  
pp. 409-415 ◽  
Author(s):  
L. A. Wolfe ◽  
R. P. Martin ◽  
D. D. Watson ◽  
R. D. Lasley ◽  
D. E. Bruns

Twelve healthy well-trained participants in a supervised exercise program (mean age, 41.3 yr) were compared with 12 sedentary control subjects (mean age, 38.9 yr) with physical characteristics similar to the exercised group (EG) before training. Resting echocardiograms revealed significantly lower heart rates (HR) in the EG compared with control group (CG) but no evidence for cardiac structural differences between groups. Radionuclide angiograms performed at rest and during two levels of supine cycling (HR targets: 120 and 140 beats X min-1) resulted in increases in background-corrected end-diastolic counts [EDC(bc)] and confirmed use of the Frank-Starling mechanism in the majority of subjects. Mean values (+/- SD) for ejection fraction (EF) and normalized peak systolic ejection rate (PSER) (P greater than 0.05 between groups) were the following. (Formula: see text) The results suggested that fitness training does not induce significant cardiac enlargement as apparent from measurements at rest or important changes in contractile state during exercise. Increases in exercise stroke volume with such training may be the result of an increased end-diastolic volume.


2020 ◽  
Vol 10 (6) ◽  
pp. 367
Author(s):  
Sarah M. Keesom ◽  
Laura M. Hurley

For social animals that communicate acoustically, hearing loss and social isolation are factors that independently influence social behavior. In human subjects, hearing loss may also contribute to objective and subjective measures of social isolation. Although the behavioral relationship between hearing loss and social isolation is evident, there is little understanding of their interdependence at the level of neural systems. Separate lines of research have shown that social isolation and hearing loss independently target the serotonergic system in the rodent brain. These two factors affect both presynaptic and postsynaptic measures of serotonergic anatomy and function, highlighting the sensitivity of serotonergic pathways to both types of insult. The effects of deficits in both acoustic and social inputs are seen not only within the auditory system, but also in other brain regions, suggesting relatively extensive effects of these deficits on serotonergic regulatory systems. Serotonin plays a much-studied role in depression and anxiety, and may also influence several aspects of auditory cognition, including auditory attention and understanding speech in challenging listening conditions. These commonalities suggest that serotonergic pathways are worthy of further exploration as potential intervening mechanisms between the related conditions of hearing loss and social isolation, and the affective and cognitive dysfunctions that follow.


Anthropology ◽  
2020 ◽  
Author(s):  
Frederick L. Coolidge ◽  
Thomas Wynn

Cognitive archaeology may be divided into two branches. Evolutionary cognitive archaeology (ECA) is the discipline of prehistoric archaeology that studies the evolution of human cognition. Practitioners are united by a methodological commitment to the idea that archaeological traces of past activity provide access to the minds of the agents responsible. The second branch, ideational cognitive archaeology, encompasses archaeologists who strive to discover the meaning of symbolic system, primarily through the analysis of iconography. This approach differs from ECA in its epistemology, historical roots, and citation universes, and focuses on comparatively recent time periods (after 10,000 years ago). Evolutionary cognitive archaeologists are concerned with the nature of cognition itself, and its evolutionary development from the time of the last common ancestor with chimpanzees to the final ascendancy of modern humans at the end of the Pleistocene. Although ECA methods are primarily archaeological, its theoretical grounding is in the cognitive sciences, including cognitive psychology, neuropsychology, and cognitive neuroscience. It is by its nature interdisciplinary. ECA differs from the allied discipline of evolutionary psychology in several important respects. Methodologically, ECA is a macroevolutionary science that studies physical evidence of past human cognition, including archaeological and fossil remains. Evolutionary psychology relies heavily on reverse engineering from controlled experiments on living humans. Theoretically, ECA is more eclectic, drawing on a variety of cognitive and evolutionary models; evolutionary psychology is committed to a neo-Darwinian, selectionist understanding of evolutionary change. The two approaches tend to study different components of human mental life, but are not inherently contradictory. ECA practitioners reconstruct prehistoric activities using well-established archaeological methods and techniques, including morphological analysis of artifacts to identify action sequences and decision patterns, functional analyses (e.g., microwear) to identify use patterns, and spatial patterns within sites to recognize activity loci (e.g., hearths). An increasingly important method is the actualistic recreation of prehistoric technologies to identify features not preserved in the archaeological remains. Neuroarchaeologists enhance such actualistic research by imaging the brains of the participants (most typically using fMRI), an approach that also contributes directly to cognitive science’s understanding of the neural basis of technical cognition. ECA practitioners take two non-mutually exclusive approaches to documenting human cognitive evolution. The first approach enriches the understanding of specific hominin taxa (i.e., Homo sapiens and their direct ancestors since 6 million years ago) by providing accounts of their cognitive life worlds, or by contrasting two taxa with one another. This approach is famously exemplified by attempts to contrast the abilities of Neandertals with those of modern humans. The second approach traces the evolution of specific cognitive abilities from the first appearance of stone tools 3.3 million years ago to the emergence of city-states 5,000 years ago. The range of accessible cognitive abilities is limited by the nature of archaeological remains, but evolutionary cognitive archaeologists have been able to trace developments in spatial cognition, memory, cognitive control, technical expertise, theory of mind, aesthetic cognition, symbolism, language, and numeracy.


1998 ◽  
Vol 80 (5) ◽  
pp. 2790-2796 ◽  
Author(s):  
A. R. McIntosh ◽  
R. E. Cabeza ◽  
N. J. Lobaugh

McIntosh, A. R., R. E. Cabeza, and N. J. Lobaugh. Analysis of neural interactions explains the activation of occipital cortex by an auditory stimulus . J. Neurophysiol. 80: 2790–2796, 1998. Large-scale neural interactions were characterized in human subjects as they learned that an auditory stimulus signaled a visual event. Once learned, activation of left dorsal occipital cortex (increased regional cerebral blood flow) was observed when the auditory stimulus was presented alone. Partial least-squares analysis of the interregional correlations (functional connectivity) between the occipital area and the rest of the brain identified a pattern of covariation with four dominant brain areas that could have mediated this activation: prefrontal cortex (near Brodmann area 10, A10), premotor cortex (A6), superior temporal cortex (A41/42), and contralateral occipital cortex (A18). Interactions among these regions and the occipital area were quantified with structural equation modeling to identify the strongest sources of the effect on left occipital activity (effective connectivity). Learning-related changes in feedback effects from A10 and A41/42 appeared to account for this change in occipital activity. Influences from these areas on the occipital area were initially suppressive, or negative, becoming facilitory, or positive, as the association between the auditory and visual stimuli was acquired. Evaluating the total effects within the functional models showed positive influences throughout the network, suggesting enhanced interactions may have primed the system for the now-expected visual discrimination. By characterizing both changes in activity and the interactions underlying sensory associative learning, we demonstrated how parts of the nervous system operate as a cohesive network in learning about and responding to the environment.


2014 ◽  
Vol 37 (6) ◽  
pp. 563-564 ◽  
Author(s):  
Tobias A. Mattei

AbstractIn self-adapting dynamical systems, a significant improvement in the signaling flow among agents constitutes one of the most powerful triggering events for the emergence of new complex behaviors. Ackermann and colleagues' comprehensive phylogenetic analysis of the brain structures involved in acoustic communication provides further evidence of the essential role which speech, as a breakthrough signaling resource, has played in the evolutionary development of human cognition viewed from the standpoint of complex adaptive system analysis.


2013 ◽  
Vol 16 (7) ◽  
pp. 1577-1586 ◽  
Author(s):  
Magdalena Nord ◽  
Sjoerd J. Finnema ◽  
Christer Halldin ◽  
Lars Farde

AbstractSelective serotonin reuptake inhibitors (SSRIs) are widely prescribed for treatment of psychiatric disorders. The exact mechanism underlying the clinical effects of SSRIs remains unclear, although increased synaptic serotonin concentrations have been hypothesized to be an initial step. [11C]AZ10419369 is a novel 5-HT1B receptor selective radioligand, which is sensitive to changes in endogenous serotonin concentrations. To assess whether a single dose of the SSRI escitalopram affects endogenous serotonin concentrations in serotonergic projection areas and in the raphe nuclei (RN), three cynomolgus monkeys and nine human subjects underwent PET examinations with [11C]AZ10419369 at baseline conditions and after escitalopram administration. In monkeys, the binding potential (BPND) was significantly lower post dose compared to baseline in dorsolateral prefrontal cortex, occipital cortex, thalamus, midbrain and RN (p < 0.05). In humans, the BPND tended to decrease in RN post dose (p = 0.08). In all serotonergic projection areas, the BPND was conversely higher post dose compared to baseline. The increase was significant in a combined region of all projection areas (p = 0.01) and in occipital and temporal cortex (p < 0.05). SSRIs are generally assumed to elevate endogenous serotonin concentrations in projection areas, evoking the antidepressant effect. In the present study, a single, clinically relevant, dose of escitalopram was found to decrease serotonin concentrations in serotonergic projection areas in humans. Hypothetically, desensitization of inhibitory serotonergic autoreceptors will cause the serotonin concentration in projection areas to increase over time with chronic administration. Thus, the findings in the present study might aid in understanding the mechanism of SSRIs' delayed onset of clinical effect.


1995 ◽  
Vol 2 (1) ◽  
pp. 25-31 ◽  
Author(s):  
David V Bates

Part 1 of this review is concerned with theoretical issues of ozone dosimetry, animal and cellular studies that illustrate the mechanism of action of ozone on living tissues, and with clinical studies. Animal studies have indicated that there are long term effects from low level long term ozone exposure. Clinical studies involve controlled ozone exposures on human subjects, both normals and asthmatics. Exercise concomitant with the ozone exposure increases the effect of the gas. It is concluded that the induction of an inflammatory response in the airway, both in the nose and in the lung, is the striking and earliest feature of ozone exposure. Current unexplained observations include: the dissociation between the inflammatory and function test response; the mechanisms of ‘adaptation’ and of airway hyperresponsiveness; and the phenomena that underlie the effect of ozone on maximal athletic performance.


2019 ◽  
Author(s):  
Antonio Benítez-Burraco ◽  
Evgeny Chekalin ◽  
Sergey Bruskin ◽  
Irina Morozova

AbstractHuman evolution resulted from changes in our biology, behavior, and culture. One source of these changes has been hypothesized to be our self-domestication (that is, the development in humans of features commonly found in domesticated strains of mammals, seemingly as a result of selection for reduced aggression). Signals of domestication, notably brain size reduction, have increased in recent times. In this paper we compare whole-genome data between Late Neolithic/Bronze Age individuals and modern Europeans and show that genes associated with mammal domestication and with neural crest development and function are significantly differently enriched in nonsynonymous single nucleotide polymorphisms between these two groups. We hypothesize how these changes might account for the increased features of self-domestication in modern humans and ultimately, for subtle recent changes in human cognition and behavior, including language.


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