Cerebral blood flow predicts multiple demand network activity and fluid intelligence across the lifespan

The preservation of cognitive function into old age is a public health priority. Cerebral hypoperfusion is a hallmark of dementia but its impact on maintaining cognitive ability across the lifespan is less clear. We investigated the relationship between baseline cerebral blood flow (CBF) and blood oxygenation level-dependent (BOLD) response during a fluid reasoning task in a population-based adult lifespan cohort (N=227, age 18-88 years). As age differences in baseline CBF could lead to non-neuronal contributions to the BOLD signal, we introduced commonality analysis to neuroimaging, in order to dissociate performance-related CBF effects from the physiological confounding effects of CBF on the BOLD response. Accounting for CBF, we confirmed that performance- and age-related differences in BOLD responses in the multiple-demand network (MDN) implicated in fluid reasoning. Differences in baseline CBF across the lifespan explained not only performance-related BOLD responses, but also performance-independent BOLD responses. Our results suggest that baseline CBF is important for maintaining cognitive function, while its non-neuronal contributions to BOLD signals reflect an age-related confound. Maintaining perfusion into old age may serve to support brain function with behavioural advantage, regulating brain health.

Cognitive Development by Zone of Proximal Development (ZPD)

Aim/Thesis: The aim of this research is to promote the use of the three concepts-- the Zone of Proximal Development (ZPD), the Gettier Problem, and Corpus Linguistics (Contextual Learning)--to increase the academic performance of early undergraduate engineering students. Concept/Methods: 30 Engineering students completed one untimed Mensa IQ Test of 10 questions and one Simon-Binet IQ Test of 50 random IQ questions with a 12 minute time limit. These 30 students were chosen from two different college sections: 15 students from each section. Before the second Simon-Binet Test, one group, G(a), was given ZPD scaffolding in three major topics — Working Memory, Fluid Reasoning and Spatial Reasoning —as they had answered questions based on these concepts incorrectly in their first Mensa IQ test. The second group, G(b), was not given the ZPD scaffolding. A statistical t-test that was later performed indicated that G(a), with scaffolding, outperformed G(b), without the scaffolding, in the second IQ test. Results and conclusion: Using the t-test, it is seen that the hypothesis of this research that ZPD, Gettier Problem and Corpus Linguistics can enhance the performance of the students in a short time period is correct. After the first Mensa IQ test, the level of both the groups G(a) and G(b) of engineering students was almost the same, indicated by a very similar mean results. However, after supporting G(a) utilizing ZPD, Gettier Problem and Corpus Linguistics for their three problem areas - Working Memory, Fluid Reasoning and Spatial Reasoning - identified after their first IQ test where the students needed scaffolding, the performance of this group improved more in comparison to G(b), as indicated by the results of the second online Simon-Binet Test. Research restrictions: It was not possible to provide all the random questions of the online Simon-Binet test given to all 30 students because the total number of questions would be 30*50=1500. Only the first ten questions of the Mensa IQ test are included in this research paper. Further, the third and fourth year engineering students are not included in this research as it is assumed that they have had already developed expertise and the effect of the investigated tools would not be clearly visible. Practical application: ZPD scaffolding was applied to the students when the students’ major problem areas were identified as requiring contextual learning and support. The Gettier Problem-- an epistemological concept-- was also used to keep their mind open at all the times during the learning process and Linguistics Corpus gave the contextual support as ZPD proposes the social-contextual mode of learning. Originality/Cognitive value: The paper presents empirical research on engineering students demonstrating the practical utility of ZPD, Gettier Problem and Corpus Linguistics in the process of learning, potentially irrespective of any discipline.

Revisiting the Factor Structure of the German WISC-V for Clinical Interpretability: An Exploratory and Confirmatory Approach on the 10 Primary Subtests

With the exception of a recently published study and the analyses provided in the test manual, structural validity is mostly uninvestigated for the German version of the Wechsler Intelligence Scale for Children - Fifth Edition (WISC-V). Therefore, the main aim of the present study was to examine the latent structure of the 10 WISC-V primary subtests on a bifurcated extended population-representative German standardization sample (N=1,646) by conducting both exploratory (EFA; n=823) and confirmatory (CFA; n=823) factor analyses on the original data. Since no more than one salient subtest loading could be found on the Fluid Reasoning (FR) factor in EFA, results indicated a four-factor rather than a five-factor model solution when the extraction of more than two suggested factors was forced. Likewise, a bifactor model with four group factors was found to be slightly superior in CFA. Variance estimation from both EFA and CFA revealed that the general factor dominantly accounted for most of the subtest variance and construct reliability estimates further supported interpretability of the Full Scale Intelligence Quotient (FSIQ). In both EFA and CFA, most group factors explained rather small proportions of common subtest variance and produced low construct replicability estimates, suggesting that the WISC-V primary indexes were of lower interpretive value and should be evaluated with caution. Clinical interpretation should thus be primarily based on the FSIQ and include a comprehensive analysis of the cognitive profile derived from the WISC-V primary indexes rather than analyses of each single primary index.

A-5 Brain-Derived Neurotrophic Factor Val66Met and Neuropsychological Functioning Following Early Childhood Traumatic Brain Injury

Objective The present study examined the differential effect of the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism on neuropsychological functioning in children with traumatic brain injury (TBI) relative to children with orthopedic injury (OI). Method Participants were drawn from a prospective, longitudinal study of children who sustained a TBI (n = 69) or OI (n = 72) between 3 and 7 years of age. Children completed a battery of neuropsychological measures targeting attention, memory, and executive functions at four time points spanning the immediate post-acute period to 18 months post-injury. Children also completed a comparable age-appropriate battery of measures approximately 7 years post-injury. Parents rated children’s executive functioning at all time points. Results Longitudinal mixed models revealed a significant allele status x injury group interaction for verbal fluency (p = 0.007) and a non-significant trend for parent-rated dysexecutive behaviors (p = 0.069), and cross-sectional models at 7 years post-injury revealed a non-significant trend for the allele status x injury group interaction for fluid reasoning skills (p = 0.074). Post hoc analyses suggested a consistent pattern of poorer neuropsychological functioning in Met carriers relative to Val/Val homozygotes in the TBI group; in contrast, the opposite trend was observed in the OI group. Conclusions The results suggest a differential effect of the BDNF Val66Met polymorphism on verbal fluency, dysexecutive behaviors, and fluid reasoning skills in children with early TBI relative to OI, and that the Met allele—associated with reduced activity-dependent secretion of BDNF—confers risk for poorer neuropsychological functioning in children with TBI.

Predictors of training efficacy during n-back training

Numerous studies have investigated the efficacy of various cognitive trainings, with working memory being the most often trained cognitive aspect. In this regard, executive aspects of working memory have received the most attention, with updating training being vastly explored. In this study, we aimed to examine the differential contribution of some individual characteristics to the efficacy of updating training using a well-established n-back training paradigm. More specifically, we examined the contribution of fluid reasoning (gf), and personality (neuroticism, conscientiousness) to training efficacy. Participants (N = 47) took part in a 15-session, dual n-back training, spread over 4 weeks. They were pretested for fluid reasoning (CFT-3), personality (IPIP-100), and performed the initial testing on the OSPAN task. OSPAN was measured in three additional measurement points (after 5th, 10th, 15th session). The data was analyzed within the multilevel modeling approach. Initial hypotheses were partly confirmed, in that: 1) training was efficient in terms of OSPAN score, which grew linearly over time and the trajectory was similar between participants, 2) although the growth was similar for all participants, differences were found in intercepts, and 3) these differences could be partly explained by differences in fluid reasoning, but not with personality traits of conscientiousness and neuroticism.