Laura M. Pidgeon

Age-related increases in false recognition: the role of perceptual and conceptual similarity

Older adults (OAs) are more likely to falsely recognize novel events than young adults, and recent behavioral and neuroimaging evidence points to a reduced ability to distinguish overlapping information due to decline in hippocampal pattern separation. However, other data suggest a critical role for semantic similarity. Koutstaal et al. [(2003) false recognition of abstract vs. common objects in older and younger adults: testing the semantic categorization account, J. Exp. Psychol. Learn. 29, 499–510] reported that OAs were only vulnerable to false recognition of items with pre-existing semantic representations. We replicated Koutstaal et al.’s (2003) second experiment and examined the influence of independently rated perceptual and conceptual similarity between stimuli and lures. At study, young and OAs judged the pleasantness of pictures of abstract (unfamiliar) and concrete (familiar) items, followed by a surprise recognition test including studied items, similar lures, and novel unrelated items. Experiment 1 used dichotomous “old/new” responses at test, while in Experiment 2 participants were also asked to judge lures as “similar,” to increase explicit demands on pattern separation. In both experiments, OAs showed a greater increase in false recognition for concrete than abstract items relative to the young, replicating Koutstaal et al.’s (2003) findings. However, unlike in the earlier study, there was also an age-related increase in false recognition of abstract lures when multiple similar images had been studied. In line with pattern separation accounts of false recognition, OAs were more likely to misclassify concrete lures with high and moderate, but not low degrees of rated similarity to studied items. Results are consistent with the view that OAs are particularly susceptible to semantic interference in recognition memory, and with the possibility that this reflects age-related decline in pattern separation.

Safe and efficient in vitro and in vivo gene delivery: tripodal cationic lipids with programmed biodegradability

The therapeutic use of nucleic acids has long been heralded as a panacea of medicinal opportunity, a vision enhanced by the introduction of RNA interference technology. The Achilles heel of such an approach is the in vivo delivery of the desired nucleic acid into cells, a practice that lacks selectivity, safety and/or efficiency. Herein we report the safe and efficacious in vitro and in vivo delivery of nucleic acids using tripodal biodegradable cationic lipids. Toxicity reduction and transfection potency of these novel amphiphiles were addressed by designing the compounds to undergo complete intracellular degradation thereby enhancing cargo release while minimising toxicity and potential tissue accumulation. Compounds demonstrated high-efficiency in transfecting DNA into cells both in vitro and in vivo with no signs of toxicity, thus potentially offering a safer alternative to viral transfection for gene therapy application.

Genome-wide analysis of self-reported risk-taking behaviour and cross-disorder genetic correlations in the UK Biobank cohort

Risk-taking behaviour is a key component of several psychiatric disorders and could influence lifestyle choices such as smoking, alcohol use, and diet. As a phenotype, risk-taking behaviour therefore fits within a Research Domain Criteria (RDoC) approach, whereby identifying genetic determinants of this trait has the potential to improve our understanding across different psychiatric disorders. Here we report a genome-wide association study in 116,255 UK Biobank participants who responded yes/no to the question “Would you consider yourself a risk taker?” Risk takers (compared with controls) were more likely to be men, smokers, and have a history of psychiatric disorder. Genetic loci associated with risk-taking behaviour were identified on chromosomes 3 (rs13084531) and 6 (rs9379971). The effects of both lead SNPs were comparable between men and women. The chromosome 3 locus highlights CADM2, previously implicated in cognitive and executive functions, but the chromosome 6 locus is challenging to interpret due to the complexity of the HLA region. Risk-taking behaviour shared significant genetic risk with schizophrenia, bipolar disorder, attention-deficit hyperactivity disorder, and post-traumatic stress disorder, as well as with smoking and total obesity. Despite being based on only a single question, this study furthers our understanding of the biology of risk-taking behaviour, a trait that has a major impact on a range of common physical and mental health disorders.

Functional neuroimaging of visual creativity: a systematic review and meta-analysis

The generation of creative visual imagery contributes to technological and scientific innovation and production of visual art. The underlying cognitive and neural processes are, however, poorly understood.

A systematic review of protocol studies on conceptual design cognition

This paper reports the first systematic review and synthesis of protocol studies on conceptual design cognition. 47 studies from the domains of architectural design, engineering design, and product design engineering were reviewed towards answering the following question: What is our current understanding of the cognitive processes involved in conceptual design tasks carried out by individual designers? Studies were found to reflect three viewpoints on the cognitive nature of designing: design as search; design as exploration; and design activities. Synthesising the findings of individual studies revealed ten categories of executive and non-executive function studied across the viewpoints: visual perception; mental imagery; semantic association; long term memory; working memory; selective attention; creative thinking; evaluation and decision making; externalisation; and reasoning and problem solving. The review highlights several avenues for future research, centering on the need for general formalisms, more objective methods to supplement protocol analysis, and a shared ontology of cognitive processes.

Genome-wide analysis of risk-taking behaviour and cross-disorder genetic correlations in 116,255 individuals from the UK Biobank cohort

Risk-taking behaviour is a key component of several psychiatric disorders and could influence lifestyle choices such as smoking, alcohol use and diet. As a phenotype, risk-taking behaviour therefore fits within a Research Domain Criteria (RDoC) approach, whereby identifying genetic determinants of this trait has the potential to improve our understanding across different psychiatric disorders. Here we report a genome wide association study in 116 255 UK Biobank participants who responded yes/no to the question “Would you consider yourself a risk-taker?” Risk-takers (compared to controls) were more likely to be men, smokers and have a history of psychiatric disorder. Genetic loci associated with risk-taking behaviour were identified on chromosomes 3 (rs13084531) and 6 (rs9379971). The effects of both lead SNPs were comparable between men and women. The chromosome 3 locus highlights CADM2, previously implicated in cognitive and executive functions, but the chromosome 6 locus is challenging to interpret due to the complexity of the HLA region. Risk-taking behaviour shared significant genetic risk with schizophrenia, bipolar disorder, attention deficit hyperactivity disorder and post-traumatic stress disorder, as well as with smoking and total obesity. Despite being based on only a single question, this study furthers our understanding of the biology of risk-taking behaviour, a trait which has a major impact on a range of common physical and mental health disorders.

The challenges in computer supported conceptual engineering design

Computer Aided Engineering Design (CAED) supports the engineering design process during the detail design, but it is not commonly used in the conceptual design stage. This article explores through literature why this is and how the engineering design research community is responding through the development of new conceptual CAED systems and HCI (Human Computer Interface) prototypes. First the requirements and challenges for future conceptual CAED and HCI solutions to better support conceptual design are explored and categorised. Then the prototypes developed in both areas, since 2000, are discussed. Characteristics already considered and those required for future development of CAED systems and HCIs are proposed and discussed, one of the key ones being experience. The prototypes reviewed offer innovative solutions, but only address selected requirements of conceptual design, and are thus unlikely to not provide a solution which would fit the wider needs of the engineering design industry. More importantly, while the majority of prototypes show promising results they are of low maturity and require further development.

Genome-wide analysis in UK Biobank identifies four loci associated with mood instability and genetic correlation with MDD, anxiety disorder and schizophrenia

Mood instability is a core clinical feature of affective and psychotic disorders. In keeping with the Research Domain Criteria (RDoC) approach, it may be a useful construct for identifying biology that cuts across psychiatric categories. We aimed to investigate the biological validity of a simple measure of mood instability and evaluate its genetic relationship with major depressive disorder (MDD), bipolar disorder (BD), schizophrenia and attention deficit hyperactivity disorder (ADHD). We conducted a genome-wide association study (GWAS) of mood instability in 53,525 cases and 60,443 controls from UK Biobank, identifying four independently-associated loci (on chromosomes eight, nine, 14 and 18), and a common single nucleotide polymorphism (SNP)-based heritability estimate of approximately 8%. We found a strong genetic correlation between mood instability and MDD (rg=0.60, SE=0.07, p=8.95x10−17) and a small but significant genetic correlation with schizophrenia (rg=0.11, SE=0.04, p=0.01), but no genetic correlation with BD or ADHD. Several genes at the associated loci may have a role in mood instability, including the deleted in colorectal cancer (DCC) gene, eukaryotic initiation factor 2B (eIF2B2), placental growth factor (PGF), and protein tyrosine phosphatase, receptor type D (PTPRD). Strengths of this study include the very large sample size but our measure of mood instability may be limited by the use of a single question. Overall, this work suggests a polygenic basis for mood instability. This simple measure can be obtained in very large samples; our findings suggest that doing so may offer the opportunity to illuminate the fundamental biology of mood regulation.Mood instability is a core clinical feature of affective disorders, particularly major depressive disorder (MDD) and bipolar disorder (BD). It may be a useful construct in line with the Research Domain Criteria (RDoC) approach, which proposes studying dimensional psychopathological traits that cut across diagnostic categories as a more effective strategy for identifying the underlying biology of psychiatric disorders. Here we report a genome-wide association study (GWAS) of mood instability in a very large study of 53,525 cases and 60,443 controls from the UK Biobank cohort, the only such GWAS reported to date. We identified four independent loci (on chromosomes eight, nine, 14 and 18) significantly associated with mood instability, with a common SNP-based heritability estimate for mood instability of approximately 8%. We also found a strong genetic correlation between mood instability and MDD (0.60, SE=0.07, p=8.95x10-17), a small but statistically significant genetic correlation with schizophrenia (0.11, SE=0.04, p=0.01), but no genetic correlation with BD. Several candidate genes harbouring variants in linkage disequilibrium with the associated loci may have a role in the pathophysiology of mood disorders, including the DCC netrin 1 receptor (DCC), eukaryotic initiation factor 2B (EIF2B2), placental growth factor (PGF) and protein tyrosine phosphatase, receptor type D (PTPRD) genes. Strengths of this study include the large sample size; however, our measure of mood instability may be limited by the use of a single self-reported question. Overall, this work suggests a polygenic basis for mood instability and opens up the field for the further biological investigation of this important cross-diagnostic psychopathological trait.