Cognitive and visual processing skills and their relationship to mutation size in full and premutation female fragile X carriers

Psycho-Cognitive Model of Knowledge Creation Theory

Humans perform activities collaboratively or individually, and these activities, more often than not, involve both physical and mental processes. However, irrespective of whether individual or collective functioning, knowledge creation is a personal experience. Nevertheless, the general tenet of this paper is that knowledge is created in a human’s mind and resides in the head. Hence, it posits that knowledge creation is cognitive (associated with the neurological structures of the brain) and psychological (involving consciousness)—a psycho-cognitive process. This study thus employs a “Cognaction” mechanism that is based on the assumptions captured below. The mechanism premised that the human cognitive chamber consists of 3C modes of comprehension (for interpreting stimuli transmitted to the brain by sensory organs), contextualisation (for mindful connecting of chunks to existing schemas), and conceptualisation (for evaluative reflection in a manner that leads to drawing inference and building themes or new concepts). It demonstrates that as diverse skill sets are applied to a task, they generate varieties of effects and outcomes. The outcomes though are distinctive and at the same time are cospecialised. Thus, the psycho-cognitive perspective demonstrates knowledge creation as a cocreation process and sees knowledge as a mix of cocreated, cognitive structures. In view of these, the study provides the missing explanation on how the knowledge archetypes emerged. And it provides the missing link between the belief that “knowledge is created in the head” and knowledge creation theory.

Altered brain-wide auditory networks in a zebrafish model of fragile X syndrome

BACKGROUND

Loss or disrupted expression of the FMR1 gene causes fragile X syndrome (FXS), the most common monogenetic form of autism in humans. Although disruptions in sensory processing are core traits of FXS and autism, the neural underpinnings of these phenotypes are poorly understood. Using calcium imaging to record from the entire brain at cellular resolution, we investigated neuronal responses to visual and auditory stimuli in larval zebrafish, using fmr1 mutants to model FXS. The purpose of this study was to model the alterations of sensory networks, brain-wide and at cellular resolution, that underlie the sensory aspects of FXS and autism.

RESULTS

Combining functional analyses with the neurons' anatomical positions, we found that fmr1-/- animals have normal responses to visual motion. However, there were several alterations in the auditory processing of fmr1-/- animals. Auditory responses were more plentiful in hindbrain structures and in the thalamus. The thalamus, torus semicircularis, and tegmentum had clusters of neurons that responded more strongly to auditory stimuli in fmr1-/- animals. Functional connectivity networks showed more inter-regional connectivity at lower sound intensities (a - 3 to - 6 dB shift) in fmr1-/- larvae compared to wild type. Finally, the decoding capacities of specific components of the ascending auditory pathway were altered: the octavolateralis nucleus within the hindbrain had significantly stronger decoding of auditory amplitude while the telencephalon had weaker decoding in fmr1-/- mutants.

CONCLUSIONS

We demonstrated that fmr1-/- larvae are hypersensitive to sound, with a 3-6 dB shift in sensitivity, and identified four sub-cortical brain regions with more plentiful responses and/or greater response strengths to auditory stimuli. We also constructed an experimentally supported model of how auditory information may be processed brain-wide in fmr1-/- larvae. Our model suggests that the early ascending auditory pathway transmits more auditory information, with less filtering and modulation, in this model of FXS.

The Reliability of Three Visual Perception Tests Used to Assess Adults

The reliability of three adult visual perceptual tests was investigated. Participants aged 20 years and older ( N = 221; 49 adults with neurological impairment, 172 adults without) completed the Developmental Test of Visual Perception–Adolescent and Adult (DTVP–A), the Motor-Free Visual Perception Test-3 (MVPT-3), and the Test of Visual Perceptual Skills (non-motor) Third Edition (TVPS-3). Participants ( n = 46) without neurological impairment completed these tests twice. Cronbach's alpha for the DTVP–A, MVPT-3, and TVPS-3 total scales were .86, .74, and .80 and test-retest correlations .51, .71, and .72, respectively.

The role of cognition and adaptive behavior in employment of people with mental retardation

Few studies have specifically investigated the cognitive correlates of employment for persons with mental retardation. To evaluate the relationship of cognitive and adaptive functioning to work status, 56 competitively employed and 55 unemployed individuals with mental retardation underwent a comprehensive neuropsychological and adaptive behavioral evaluation. Results of multivariate analysis of covariance (MANCOVA) revealed significant group differences in cognitive and adaptive behavioral domains controlling for gender and severity of mental retardation. Follow-up ANCOVAs showed that the employed group performed significantly better than the unemployed group on measures of attention, memory, verbal comprehension, visual perception, and adaptive behavior. Using discriminant function analysis, 73.2 percent of the employed and 76.4 percent of the unemployed people were predicted correctly. These results suggest that adaptive behavior and specific aspects of cognitive functioning are significant predictors of successful employment for persons with mental retardation.

Neuropsychological predictors of everyday functioning in adults with intellectual disabilities

BACKGROUND

Very little is known about the neuropsychological correlates of adaptive functioning in people with intellectual disabilities (ID). This study examined whether specific cognitive deficits and demographic variables predicted everyday functioning in adults with ID.

METHOD

People with ID (n = 101; ages 19-41 years; mean education = 11 years; 34% women; 54% competitively employed; 41% with mild ID) completed a comprehensive neuropsychological battery grouped into four cognitive domains: processing speed, verbal memory and comprehension, visual perception/constructive function, and executive function. In addition, parents completed an 89-item rating scale developed to assess a wide range of independent living skills.

RESULTS

Confirmatory factor analysis results confirmed a correlated four-factor model of cognitive function and a unidimensional model of everyday functioning. Furthermore, structural equation modelling results supported the predictive relationship of verbal memory/comprehension and employment status (standardized regression coefficients 0.45, 0.22, P < or = 0.01 for each) to measures of everyday functioning. The two variables together explained 35% of the variance in everyday functioning.

CONCLUSIONS

Both general cognitive dysfunction and specific verbal memory and comprehension deficit impair daily functions in people with ID. These findings have implications for predictive models of adaptive functioning, and for cognitive rehabilitation and deficit compensation strategies for this group.

Childhood cognitive ability and age at menopause: evidence from two cohort studies

OBJECTIVE

To investigate whether poorer cognitive ability in childhood is associated with an earlier menopause.

DESIGN

Two cohorts were included: a nationally representative British birth cohort study of 1,350 women born in March 1946 and followed up to age 54 years, and an Aberdeen cohort study of 3,465 women born in Aberdeen from 1950 to 1956 and followed up to age 44 to 50 years. Both cohorts had prospective information on childhood cognitive ability at age 7 or 8 years.

RESULTS

In both cohorts, women with lower cognitive scores in childhood reached menopause earlier than women with higher scores. With follow-up of menopause to 49 years, the hazard ratio (HR) for one standard deviation of the cognitive score was 0.80 (95% CI, 0.72-0.90) in the Aberdeen cohort and 0.84 (95% CI, 0.73-0.97) in the older 1946 birth cohort. The effect was still evident in the 1946 birth cohort with follow-up of menopause to 53 years (HR = 0.87; 95% CI, 0.79-0.95). These ratios were weakly attenuated by adjustment for potential confounding effects of lifetime socioeconomic circumstances, parity, and smoking.

CONCLUSIONS

The association between early cognitive ability and timing of menopause only partially reflects common risk factors, although residual confounding remains a possibility. Alternatively, early environmental or genetic programming may explain this association, perhaps through setting lifelong patterns of hormone release or causing transient hormonal changes at sensitive periods of development. These findings have implications for the interpretation of studies investigating an association between age at menopause and adult cognitive function.