In cognitive network neuroscience, the connectivity and community structure of the brain network is related to cognition. Much of this research has focused on two measures of connectivity - ...modularity and flexibility - which frequently have been examined in isolation. By using resting state fMRI data from 52 young adults, we investigate the relationship between modularity, flexibility and performance on cognitive tasks. We show that flexibility and modularity are highly negatively correlated. However, we also demonstrate that flexibility and modularity make unique contributions to explain task performance, with modularity predicting performance for simple tasks and flexibility predicting performance on complex tasks that require cognitive control and executive functioning. The theory and results presented here allow for stronger links between measures of brain network connectivity and cognitive processes.
Recent work in cognitive neuroscience has focused on analyzing the brain as a network, rather than as a collection of independent regions. Prior studies taking this approach have found that ...individual differences in the degree of modularity of the brain network relate to performance on cognitive tasks. However, inconsistent results concerning the direction of this relationship have been obtained, with some tasks showing better performance as modularity increases and other tasks showing worse performance. A recent theoretical model (Chen & Deem, 2015) suggests that these inconsistencies may be explained on the grounds that high-modularity networks favor performance on simple tasks whereas low-modularity networks favor performance on more complex tasks. The current study tests these predictions by relating modularity from resting-state fMRI to performance on a set of simple and complex behavioral tasks. Complex and simple tasks were defined on the basis of whether they did or did not draw on executive attention. Consistent with predictions, we found a negative correlation between individuals' modularity and their performance on a composite measure combining scores from the complex tasks but a positive correlation with performance on a composite measure combining scores from the simple tasks. These results and theory presented here provide a framework for linking measures of whole brain organization from network neuroscience to cognitive processing.
Cyclin/cyclin‐dependent kinase (CDK) heterodimers have multiple phosphorylation targets and may alter the activity of these targets. Proteins from different metabolic processes are among the ...phosphorylation targets, that is, enzymes of central carbon metabolism. This work explores the interaction of Cyc/CDK complex members with the glycolytic enzymes hexokinase 7 (HXK7) and glyceraldehyde‐3‐phosphate dehydrogenase (GAP). Both enzymes interacted steadily with CycD2;2, CycB2;1 and CDKA;1 but not with CDKB1;1. However, Cyc/CDKB1;1 complexes phosphorylated both enzymes, decreasing their activities. Treatment with a CDK‐specific inhibitor (RO‐3306) or with lambda phosphatase after kinase assay restored total HXK7 activity, but not GAP activity. In enzymatic assays, increasing concentrations of CDKB1;1, but not of CycD2;2, CycB2;1 or CycD2;2/CDKB1;1 complex, decreased GAP activity. Cell cycle regulators may modulate carbon channeling in glycolysis by two different mechanisms: Cyc/CDK‐mediated phosphorylation of targets (e.g., HXK7; canonical mechanism) or by direct and transient interaction of the metabolic enzyme (e.g., GAP) with CDKB1;1 without a Cyc partner (alternative mechanism).
Cell cycle regulators from maize may alter the pace of carbon channeling in glycolysis by two different mechanisms: (a) Cyclin/cyclin‐dependent kinase (CDK) complexes interact with and phosphorylate hexokinase 7; (b) the presence of CDKB, without a cyclin partner, alters the activity of glyceraldehyde‐3‐phosphate dehydrogenase. In both cases, the cell cycle regulators exert an inhibitory effect on the glycolytic enzymes.
Smartphones took the world by storm in the 2000s. Over the years, smartphones have become vital in everyday life. Each generation responds to technology differently. The younger generation is much ...more involved with smartphones as well as technology as a whole. Thus, spending too much time on a smartphone could be related to individual’s well-being. The purpose of the present study is to measure Emotional Intelligence (EI), mindfulness, and social competence among different age cohorts and see if there are differences in phone use. Our hypothesis is that participants who score higher on EI, Social Skills, and Mindfulness will score lower on the Problematic Phone Usage Scale. Younger adults will score lower on EI, Social Skills, and Mindfulness and higher on Problematic Phone Usage than middle aged and older adults. We ran correlational analyses among, mindfulness, social competence, and problematic phone usage and an ex-post facto comparison between the four cohorts with ages ranging 18-30 (n=105), 31-40 years old (n= 30), 41-50 (n= 30), and 51 and older (n= 21). Survey questions included the Trait Emotional Intelligence Questionnaire- Short Form (TEIQ-SF), Kentucky Inventory of Mindfulness Skills, Social Competence, and Problematic Phone Usage Scale. Data showed that as age increased phone use decreased. EI, mindfulness, and social competence scores for younger adults were much lower than for middle aged and older adults while younger adults had a significantly larger problematic phone use than middle aged.
Maize CycD3;1 associates to CDKA or CDKB1;1 proteins during germination and the complexes formed develop kinase activity. These complexes appear to vary in size as germination proceeds, suggesting ...association to different sets of proteins. CycD3;1 and associated CDK proteins respond to phytohormones and sucrose. Results revealed a reduction in the CycD3;1 protein amount along germination in the presence of indoleacetic acid (IAA) or abscisic acid (ABA), although in the latter protein levels recover at the end of germination. While the levels of CDKA increase with IAA, they decrease with ABA. Both phytohormones, IAA and ABA, increase levels of CDKB1;1 only during the early germination times. CycD3;1 associated kinase activity is only reduced by both phytohormones towards the end of the germination period. On the other hand, lack of sucrose in the imbibition medium strongly reduces CycD3;1 protein levels without affecting the levels of neither CDKA nor CDKB1;1. The corresponding CycD3;1 associated kinase activity is also severely decreased. The presence of sucrose in the medium appears to stabilize the CycD3;1 protein levels.
Written language is a human invention that our brains did not evolve for. Yet, most research has focused on finding a single theory of reading, identifying the common set of cognitive and neural ...processes shared across individuals, neglecting individual differences. In contrast, we investigated variation in single word reading. Using a novel statistical method for analyzing heterogeneity in multi-subject task-based functional magnetic resonance imaging (fMRI), we clustered readers based on their brain's response to written stimuli. Separate behavioral testing and neuroimaging analysis shows that these clusters differed in the role of the sublexical pathway in processing written language, but not in reading skill. Taken together, these results suggest that individuals vary in the cognitive and neural mechanisms involved in word reading. In general, neurocognitive theories need to account not only for what tends to be true of the population, but also the types of variation that exist, even within a neurotypical population.
Previous studies have found neural similarities between verbal and nonverbal processes. Given these findings, performance in one task may predict neural mechanisms in the other task. The current ...study investigated how performance in a nonverbal executive control task predicts brain activity in a verbal task using a regression analysis method. Spanish-English adult bilinguals (n=46) performed verbal language switching and nonverbal rule-changing tasks while inside the fMRI scanner. Participants overtly named objects in three conditions: Spanish only, English only and mixed (alternating between Spanish and English) in a picture-naming task. The nonverbal task was a rule-switching paradigm in which participants responded using a button box to color or shape, with the dimension of interest changing after a small number of trials, as indicated by a cue. We performed a regression analysis using the behavioral error rates from the nonverbal task as regressors to predict neural activity in the single language and mixed conditions of the verbal task. Our results show that participants with higher error rates in the nonverbal task showed increased activity in frontoparietal, cingulate, and caudate regions associated with cognitive control processes. Participants with lower error rates presented with increased activity in sensorimotor areas such as precentral and postcentral cortices, rolandic operculum, and occipital cortex in the verbal task. Our results suggest a direct connection between nonverbal control and verbal task performance. These findings are consistent with models suggesting a link between cognitive control and language processing in bilinguals.
Previous research found that bilinguals outperform monolinguals on cognitive control tasks, but few studies have examined differences within the bilingual population. This study aims at comparing ...cognitive control performance in groups of bilinguals divided along their proficiencies in two languages. Spanish-English adult bilinguals (n=47) performed a nonverbal rule-switching task while inside the fMRI scanner. Participants were required to respond as quickly as they could using a button box to either the color or shape of stimuli, with the dimension of interest changing (switch trials) or staying the same (non-switch trials), indicated by a cue. Proficiency was measured using the vocabulary and sentence comprehension portions of the Woodcock Language Proficiency Battery-Revised in English and Spanish. Balanced bilinguals were defined as those individuals who have similar scores on both the English and Spanish tests. Unbalanced bilinguals are those with large differences between their English and Spanish proficiencies. Our results indicate that proficiency balance has significant effects on neural activation while bilinguals engage in a nonverbal rule-switching task. Specifically, unbalanced bilinguals present with large activation patterns in brain areas related to executive function in the rule-switch condition. In contrast, there are little to no activations in the unbalanced group in the non-switch condition, and under both conditions in the balanced group. From these results we can conclude that nonverbal task-switching is more effortful for the unbalanced group than the balanced group. These results are consistent with the view that the bilingual advantage most likely emerges from the consistent use of two languages.
•E2F transcription factors family in maize consists of 12 genes.•E2F and DP complexes act as activators or putative repressors of transcription.•E2F binding to cell cycle gene promoters change ...dynamically during germination.•RBR1 associates to promoters with E2F responsive elements.
For seed germination, it is necessary to restart the cell cycle, a process regulated at multiple levels including transcriptional control, that is executed by the E2F family of transcription factors. We identified 12 genes of the E2F family in maize that are expressed differentially during the first 28 h post imbibition (HAI). E2Fa/b1;1 and E2Fc proteins were characterized as an activator and a putative repressor respectively, both forming heterodimers with DPb2 that bind differentially to consensus E2F response elements in promoters of E2F target genes. Transcripts of target genes for these transcription factors accumulate during germination; in dry seeds E2Fc protein is enriched in the target promoters and is replaced by E2Fa/b1;1 as germination advances. RBR1 is found in the same promoters in non-imbibed and 28 HAI seeds, when DNA replication has concluded, and transcription of the E2F targets should stop. During germination promoters of these target genes seem to be decorated with histone marks related to relaxed chromatin structure. Therefore, E2Fs appear to occupy their target genes in a context of open chromatin, with RBR1 fine tuning the progression between the phases.
Cell proliferation during seed germination is determinant for an appropriate seedling establishment. The present work aimed to evaluate the participation of two maize B-type Cyclins during ...germination and under the stimulus of two simple sugars: sucrose and glucose. We found out that the corresponding genes, ZmCycB1;2 and ZmCycB2;1, increased their expression at 24 h of germination, but only ZmCycB1;2 responded negatively to sugar type at the highest sugar concentration tested (120 mM). Also, CycB1;2 showed differential protein levels along germination in response to sugar, or its absence. Both CycBs interacted with CDKA;1 and CDKB1;1 by pull down assays. By an immunoprecipitation approach, it was found that each CycB associated with two CDKB isoforms (34 and 36 kDa). A higher proportion of CycB1;2-CDKB-36kDa was coincident to an increased kinase activity in the presence of sugar and particularly in glucose treatment at 36 h of imbibition. CycB1;2-CDKB activity increased in parallel to germination advance and this was dependent on sugar: glucose > sucrose > No sugar treatment. At RAM, CycB1;2 was more abundant in nuclei on Glucose at late germination; DNA-CycB1;2 colocalization was parallel to CycB1;2 inside the nucleus. Overall, results point out CycB1;2 as a player on promoting proliferation during germination by binding a specific CDKB isoform partner and changing its cellular localization to nuclei, co-localizing with DNA, being glucose a triggering signal.
•CycBs protein patterns are differentially modified by sugars along germination.•CycB1; 2 and 2;1 form active complexes with CDKB1;1 during maize germination.•Glucose promoted CycB1;2 localization in the nucleus at late germination in RAM.
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