Time–Frequency Cross Mutual Information Analysis of the Brain Functional Networks Underlying Multiclass Motor Imagery

To study the physiologic mechanism of the brain during different motor imagery (MI) tasks, the authors employed a method of brain-network modeling based on time–frequency cross mutual information obtained from 4-class (left hand, right hand, feet, and tongue) MI tasks recorded as brain–computer interface (BCI) electroencephalography data. The authors explored the brain network revealed by these MI tasks using statistical analysis and the analysis of topologic characteristics, and observed significant differences in the reaction level, reaction time, and activated target during 4-class MI tasks. There was a great difference in the reaction level between the execution and resting states during different tasks: the reaction level of the left-hand MI task was the greatest, followed by that of the right-hand, feet, and tongue MI tasks. The reaction time required to perform the tasks also differed: during the left-hand and right-hand MI tasks, the brain networks of subjects reacted promptly and strongly, but there was a delay during the feet and tongue MI task. Statistical analysis and the analysis of network topology revealed the target regions of the brain network during different MI processes. In conclusion, our findings suggest a new way to explain the neural mechanism behind MI.     

Training to use voice onset time as a cue to talker identification induces a left-ear/right-hemisphere processing advantage

We examined the effect of perceptual training on a well-established hemispheric asymmetry in speech processing. Eighteen listeners were trained to use a within-category difference in voice onset time (VOT) to cue talker identity. Successful learners (n=8) showed faster response times for stimuli presented only to the left ear than for those presented only to the right. The development of a left-ear/right-hemisphere advantage for processing a prototypically phonetic cue supports a model of speech perception in which lateralization is driven by functional demands (talker identification vs. phonetic categorization) rather than by acoustic stimulus properties alone.     

Sit-to-stand movement in children: A longitudinal study based on kinematics data

Although the ability to stand from a seated posture is relevant for clinical practice, there are few studies investigating the process of acquisition and refinement of the motor components involved in sit-to-stand movement (STS) in children. Therefore, this longitudinal study aims to describe kinematic characteristics of the STS movement in children from 12 to 18 months, and also to investigate the relationship between changes in STS movement and childrens’ daily-life mobility. Ten healthy children were evaluated at 12,13,14,15 and 18 months of age. A motion analysis system was used to measure total duration of STS movement and angular movements of each joint, and frequencies of successful and unsupported STS were obtained. The Pediatric Evaluation of Disability Inventory was used to assess childrens’ daily-life mobility. Results showed that children tend to increase the frequency of successful trials over the months by reducing the total duration and decreasing peak ankle dorsiflexion and trunk flexion during STS. Children also started to stand up from chair with decreased trunk flexion angle among ages. At the end of the STS, we observed decreases in trunk flexion and knee flexion over age. Furthermore, kinematic characteristics that reflect improvements in STS movement are related to better performance of functional skills and decreased level of assistance provided by the caregiver in daily-life mobility of younger children. However, the strength of these associations decreases from 14 months of age onwards.     

Task-load manipulation in the Symbol Digit Modalities Test: An alternative measure of information processing speed

ObjectiveTo evaluate the utility of an oral fMRI-adapted version of the Symbol Digit Modalities Test (SDMT) to assess information processing speed (IPS) using three different interstimulus intervals (ISI).MethodsNineteen right-handed healthy controls performed the adapted version of the SDMT, consisting of a block design that had a total of 6 control/activation block pairs with 3 different ISIs (1.5, 2 and 2.5 s) presented in two different runs: in ascending and descending orders. The brain activation patterns during different ISIs were assessed by effective functional connectivity analysis based on independent component analysis.ResultsAs expected, all conditions yielded activations in the fronto-parietal networks (FPNs) related to attention processes. Shorter ISIs (1.5 and 2 s) not only yielded greater patterns of connectivity within fronto-parietal and occipital regions such as the FPN and fronto-occipital network (FON), but also recruited more functional networks overall. Task performance at the shortest ISI was negatively correlated with connectivity at the FPN and activity of the pre-supplementary motor area extending to the cingulate gyrus.ConclusionIncreasing IPS demands due to shorter ISIs resulted in an increased level and number of functional networks required, increased connectivity within the FPN and FON, and enhancement of the prefrontal cortex. IPS does not arise from activity of a single b area but from affective information transfer among distant cortical regions of the frontal and parietal cortices. This adapted version of the SDMT may be useful for studying alterations of IPS in clinical and nonclinical populations.     

Ventral encoding of functional affordances: A neural pathway for identifying errors in action

Functional tool usage is a critical aspect of our daily lives. Not only must we know which tools to use for a specific action goal, we must also know how to manipulate those tools in meaningful way to achieve the goal of the action. The purpose of this study was to identify the regions of the brain critical to supporting the process of understanding errors in tool manipulation. Using fMRI, neural activations were recorded while subjects were presented with images demonstrating typical action scenes (screwdriver used on a screw), but with the tool being manipulated either correctly (screwdriver held by handle) or incorrectly (screwdriver held by bit rather than handle). Activations in fMRI for identifying correct over incorrect tool manipulation were seen along the canonical parietofrontal action network, while activations for identifying incorrect over correct tool manipulation were primarily seen at superior temporal areas and insula. We expand our hypotheses about ventral brain networks identifying contextual error to further suggest mechanisms for understanding functional tool actions, which collectively we regard as functional affordances. This proposes a fundamental role for ventral brain areas in functional action understanding.     

The amygdalostriatal and corticostriatal effective connectivity in anticipation and evaluation of facial attractiveness

Decision-making consists of several stages of information processing, including an anticipation stage and an outcome evaluation stage. Previous studies showed that the ventral striatum (VS) is pivotal to both stages, bridging motivation and action, and it works in concert with the ventral medial prefrontal cortex (vmPFC) and the amygdala. However, evidence concerning how the VS works together with the vmPFC and the amygdala came mainly from neuropathology and animal studies; little is known about the dynamics of this network in the functioning human brain. Here we used fMRI combined with dynamic causal modeling (DCM) to investigate the information flow along amygdalostriatal and corticostriatal pathways in a facial attractiveness guessing task. Specifically, we asked participants to guess whether a blurred photo of female face was attractive and to wait for a few seconds (“anticipation stage”) until an unblurred photo of feedback face, which was either attractive or unattractive, was presented (“outcome evaluation stage”). At the anticipation stage, the bilateral amygdala and VS showed higher activation for the “attractive” than for the “unattractive” guess. At the outcome evaluation stage, the vmPFC and the bilateral VS were more activated by feedback faces whose attractiveness was congruent with the initial guess than by incongruent faces; however, this effect was only significant for attractive faces, not for unattractive ones. DCM showed that at the anticipation stage, the choice-related information entered the amygdalostriatal pathway through the amygdala and was projected to the VS. At the evaluation stage, the outcome-related information entered the corticostriatal pathway through the vmPFC. Bidirectional connectivities existed between the vmPFC and VS, with the VS-to-vmPFC connectivity weakened by unattractive faces. These findings advanced our understanding of the reward circuitry by demonstrating the pattern of information flow along the amygdalostriatal and corticostriatal pathways at different stages of decision-making.     

Divine Action,Resurrection, and the Transformation of the Universe

Abstract

The article examines the notion of self-organization and explores the reality of biological processes from an epistemological point of view. First, I briefly analyze what is currently regarded as one of the most important discoveries not only in physics, but also in biology—namely, complex systems and deterministic chaos; secondly, I offer some reflections on the new frontiers of contemporary biology— namely, functional genomics and systems biology. The central part of the article focuses on the epistemological transition from genetic determinism to the new conception of “meaning” as emergence.     

Fostering innovation in functionally diverse teams: The two faces of transformational leadership

Empirical research on the effects of functional diversity on team innovation has yielded largely inconsistent results, showing positive, negative, as well as nonsignificant effects. For capitalizing on the positive potential inherent in functionally diverse teams, opening the black box between cross-functionality and team innovation by analysing mediating and moderating processes thus seems to be highly relevant. In this article, task and relationship conflicts are introduced as mediators of functional diversity and team innovation. Within this framework, transformational leadership is discussed as a moderator. It will become apparent that the role of transformational leadership in fostering the innovativeness of cross-functional teams is rather ambiguous. The discussed mediators and the moderator transformational leadership are integrated into a comprehensive framework and propositions for future research are derived.     

Extraversion modulates functional connectivity hubs of resting‐state brain networks

Personality dimension extraversion describes individual differences in social behaviour and socio‐emotional functioning. The intrinsic functional connectivity patterns of the brain are reportedly associated with extraversion. However, whether or not extraversion is associated with functional hubs warrants clarification. Functional hubs are involved in the rapid integration of neural processing, and their dysfunction contributes to the development of neuropsychiatric disorders. In this study, we employed the functional connectivity density (FCD) method for the first time to distinguish the energy‐efficient hubs associated with extraversion. The resting‐state functional magnetic resonance imaging data of 71 healthy subjects were used in the analysis. Short‐range FCD was positively correlated with extraversion in the left cuneus, revealing a link between the local functional activity of this region and extraversion in risk‐taking. Long‐range FCD was negatively correlated with extraversion in the right superior frontal gyrus and the inferior frontal gyrus. Seed‐based resting‐state functional connectivity (RSFC) analyses revealed that a decreased long‐range FCD in individuals with high extraversion scores showed a low long‐range functional connectivity pattern between the medial and dorsolateral prefrontal cortex, middle temporal gyrus, and anterior cingulate cortex. This result suggests that decreased RSFC patterns are responsible for self‐esteem, self‐evaluation, and inhibitory behaviour system that account for the modulation and shaping of extraversion. Overall, our results emphasize specific brain hubs, and reveal long‐range functional connections in relation to extraversion, thereby providing a neurobiological basis of extraversion.