A social neuroscience perspective on adolescent risk-taking

This article proposes a framework for theory and research on risk-taking that is informed by developmental neuroscience. Two fundamental questions motivate this review. First, why does risk-taking increase between childhood and adolescence? Second, why does risk-taking decline between adolescence and adulthood? Risk-taking increases between childhood and adolescence as a result of changes around the time of puberty in the brain’s socio-emotional system leading to increased reward-seeking, especially in the presence of peers, fueled mainly by a dramatic remodeling of the brain’s dopaminergic system. Risk-taking declines between adolescence and adulthood because of changes in the brain’s cognitive control system—changes which improve individuals’ capacity for self-regulation. These changes occur across adolescence and young adulthood and are seen in structural and functional changes within the prefrontal cortex and its connections to other brain regions. The differing timetables of these changes make mid-adolescence a time of heightened vulnerability to risky and reckless behavior.     

Air pollution, cognitive deficits and brain abnormalities: a pilot study with children and dogs

Exposure to air pollution is associated with neuroinflammation in healthy children and dogs in Mexico City. Comparative studies were carried out in healthy children and young dogs similarly exposed to ambient pollution in Mexico City. Children from Mexico City (n: 55) and a low polluted city (n:18) underwent psychometric testing and brain magnetic resonance imaging MRI. Seven healthy young dogs with similar exposure to Mexico City air pollution had brain MRI, measurement of mRNA abundance of two inflammatory genes cyclooxygenase-2, and interleukin 1 beta in target brain areas, and histopathological evaluation of brain tissue. Children with no known risk factors for neurological or cognitive disorders residing in a polluted urban environment exhibited significant deficits in a combination of fluid and crystallized cognition tasks. Fifty-six percent of Mexico City children tested showed prefrontal white matter hyperintense lesions and similar lesions were observed in dogs (57%). Exposed dogs had frontal lesions with vascular subcortical pathology associated with neuroinflammation, enlarged Virchow-Robin spaces, gliosis, and ultrafine particulate matter deposition. Based on the MRI findings, the prefrontal cortex was a target anatomical region in Mexico City children and its damage could have contributed to their cognitive dysfunction. The present work presents a groundbreaking, interdisciplinary methodology for addressing relationships between environmental pollution, structural brain alterations by MRI, and cognitive deficits/delays in healthy children.     

How brain arousal systems determine different temperament types and the major dimensions of personality

Theory and research is described which led to the hypothesis that the choleric (E+N+) and melancholic (E−N+) temperaments are determined by differences in thalamocortical inhibition of brain-stem processes. An opportunity to test this hypothesis was provided by the recent discovery of 4, 7, and 10 Hz response waves confounded in EEG averaged evoked potentials [Robinson, D. L. (1999b). The technical, neurological, and psychological significance of ‘alpha’ ‘theta’ and ‘delta’ waves confounded in EEG evoked potentials: 1. A study of peak latencies. Electroencephalography and Clinical Neurophysiology, 110, 1427–1434; (2000). The technical neurological, and psychological significance of ‘alpha’, ‘delta’, and ‘theta’ waves confounded in EEG evoked potentials: A study of peak amplitudes. Personality and Individual Differences, 28, 673–693]. These responses are attributed to the brain-stem, limbic, and thalamocortical arousal systems, respectively, and in the cited reports principal components analysis of data obtained from 93 participants confirmed the existence of predicted excitatory and inhibitory relationships. ANOVA was used in the present study to test the further prediction that there should be strong inhibition of the 4 Hz system by the 10 Hz system in melancholics (E−N+) and weak inhibition of the 4 Hz system in cholerics (E+N+), with median inhibition predicted for the other temperament types. There was a large and statistically significant difference between the mean scores on the PCA inhibition factor obtained for the temperament groups, with temperament defined in terms of high and low EPQ extraversion (E) and neuroticism (N) scores. The significance of these results is discussed with reference to fundamental questions raised by Pavlov's pioneering research but left unanswered for the best part of a century. Implications for the future conduct of personality research are also considered.     

Brain activation on pre-reading tasks reveals at-risk status for dyslexia in 6-year-old children

In this fMRI-study, 6-year-old children considered at risk for dyslexia were compared with an age-/gender-matched control group for differences in brain activation when presented with visual stimuli differing in demands for literacy processing. Stimuli were nameable pictures, brand logos familiar to children, and written words - these were either regularly spelled using early-acquired rules ("alphabetic") or more complex ("orthographic"). Brain responses distinguished between the presentation conditions, as a function of group, within many cortical areas. Activation in the alphabetic and orthographic conditions in the left angular gyrus correlated with individual at-risk index scores, and activation in inferior occipito-temporal regions further indicated differential activation for the two groups related to orthographic processing, especially. Since similar patterns are reported in adult dyslexics when processing written words, it appears that sensitivity to the cortical differentiation of reading networks is established prior to formal literacy training.     

Putative sex differences in verbal abilities and language cortex: a critical review

This review brings together evidence from a diverse field of methods for investigating sex differences in language processing. Differences are found in certain language-related deficits, such as stuttering, dyslexia, autism and schizophrenia. Common to these is that language problems may follow from, rather than cause the deficit. Large studies have been conducted on sex differences in verbal abilities within the normal population, and a careful reading of the results suggests that differences in language proficiency do not exist. Early differences in language acquisition show a slight advantage for girls, but this gradually disappears. A difference in language lateralization of brain structure and function in adults has also been suggested, perhaps following size differences in the corpus callosum. Neither of these claims is substantiated by evidence. In addition, overall results from studies on regional grey matter distribution using voxel-based morphometry, indicate no consistent differences between males and females in language-related cortical regions. Language function in Wada tests, aphasia, and in normal ageing also fails to show sex differentiation.     

Hemispheric connectivity and the visual–spatial divergent-thinking component of creativity

Background/hypothesis

Divergent thinking is an important measurable component of creativity. This study tested the postulate that divergent thinking depends on large distributed inter- and intra-hemispheric networks. Although preliminary evidence supports increased brain connectivity during divergent thinking, the neural correlates of this characteristic have not been entirely specified. It was predicted that visuospatial divergent thinking would correlate with right hemisphere white matter volume (WMV) and with the size of the corpus callosum (CC).

Methods

Volumetric magnetic resonance imaging (MRI) analyses and the Torrance Tests of Creative Thinking (TTCT) were completed among 21 normal right-handed adult males.

Results

TTCT scores correlated negatively with the size of the CC and were not correlated with right or, incidentally, left WMV.

Conclusions

Although these results were not predicted, perhaps, as suggested by Bogen and Bogen (1988), decreased callosal connectivity enhances hemispheric specialization, which benefits the incubation of ideas that are critical for the divergent-thinking component of creativity, and it is the momentary inhibition of this hemispheric independence that accounts for the illumination that is part of the innovative stage of creativity. Alternatively, decreased CC size may reflect more selective developmental pruning, thereby facilitating efficient functional connectivity.     

Massive redeployment,exaptation, and the functional integration of cognitive operations

The massive redeployment hypothesis (MRH) is a theory about the functional topography of the human brain, offering a middle course between strict localization on the one hand, and holism on the other. Central to MRH is the claim that cognitive evolution proceeded in a way analogous to component reuse in software engineering, whereby existing components—originally developed to serve some specific purpose—were used for new purposes and combined to support new capacities, without disrupting their participation in existing programs. If the evolution of cognition was indeed driven by such exaptation, then we should be able to make some specific empirical predictions regarding the resulting functional topography of the brain. This essay discusses three such predictions, and some of the evidence supporting them. Then, using this account as a background, the essay considers the implications of these findings for an account of the functional integration of cognitive operations. For instance, MRH suggests that in order to determine the functional role of a given brain area it is necessary to consider its participation across multiple task categories, and not just focus on one, as has been the typical practice in cognitive neuroscience. This change of methodology will motivate (even perhaps necessitate) the development of a new, domain-neutral vocabulary for characterizing the contribution of individual brain areas to larger functional complexes, and direct particular attention to the question of how these various area roles are integrated and coordinated to result in the observed cognitive effect. Finally, the details of the mix of cognitive functions a given area supports should tell us something interesting not just about the likely computational role of that area, but about the nature of and relations between the cognitive functions themselves. For instance, growing evidence of the role of “motor” areas like M1, SMA and PMC in language processing, and of “language” areas like Broca’s area in motor control, offers the possibility for significantly reconceptualizing the nature both of language and of motor control.     

Differences in numeric,verbal, and spatial reasoning between engineering and literature students through a neurocognitive lens

This study used electroencephalography to investigate the brain activations of college students of various disciplines when they responded to questions in numeric, verbal, and spatial reasoning tasks. In total, 15 engineering students and 15 literature students were recruited in this experiment and were asked to respond to 12 intelligence test questions. The results were as follows: (i) the participants’ brain activations increased in the frontoparietal network during the numeric reasoning task, and the spectral power in the right anterior temporal cortex was generally higher in the literature students than in the engineering students. (ii) Activations of the language network were observed during the verbal reasoning task, and the spectral power in the right-biased posterior frontal cortex was generally higher in the literature students than in the engineering students; by contrast, the spectral power in the left lateral frontal cortex was generally higher in the engineering students than in the literature students. (iii) The participants’ brain activations increased in the spatial processing network during the spatial reasoning task, and the spectral power in the right posterior temporal cortex was generally higher in the literature students than in the engineering students.