3,610 research outputs found
Glucose modulates event-related potential components of recollection and familiarity in healthy adolescents.
No full textIntroduction Behavioural evidence supports the notion that oral glucose ingestion enhances recognition memory judgements based on recollection, but not familiarity. The present study sought to clarify and extend upon these behavioural findings by investigating the influence of glucose administration on event-related potential (ERP) components that are thought to be differentially mediated by recollection and familiarity processes in healthy adolescents. Methods In a within-subjects design, participants performed a recognition memory task, during which time electroencephalogram (EEG) was recorded, subsequent to ingestion of either (a) glucose or (b) placebo in a counterbalanced order. Results Response times during the recognition memory task were observed to be faster for the glucose condition, relative to a placebo control. Further, glucose ingestion was associated with an enhanced left parietal old/new ERP effect (a marker of recollection) and an enhanced mid-frontal old/new ERP effect (known to be mediated by familiarity). Discussion These findings (a) support the results of previous research that the ‘glucose memory facilitation effect’ can be extended to healthy adolescents, but (b) suggest that glucose enhances both the recollection and familiarity components of recognition memory. The observed ERP profile has important implications for the proposal that glucose specifically targets the hippocampus in modulating cognitive performance
Spontaneous and cued gaze-following in autism and Williams syndrome
No full textBackground: From a young age the typical development of social functioning relies upon the allocation of attention to socially relevant information, which in turn allows experience at processing such information and thus enhances social cognition. As such, research has attempted to identify the developmental processes that are derailed in some neuro-developmental disorders that impact upon social functioning. Williams syndrome (WS) and Autism are disorders of development that are characterized by atypical yet divergent social phenotypes and atypicalities of attention to people. Methods: We used eye tracking to explore how individuals with WS and Autism attended to, and subsequently interpreted, an actor’s eye gaze cue within a social scene. Images were presented for three seconds, initially with an instruction simply to look at the picture. The images were then shown again, with the participant asked to identify the object being looked at. Allocation of eye-gaze in each condition was analyzed by ANOVA and accuracy of identification was compared with t-tests. Results: Participants with WS allocated more gaze time to face and eyes than their matched controls both with and without being asked to identify the item being looked at; while participants with Autism spent less time on face and eyes in both conditions. When cued to follow gaze, participants with WS increased gaze to the correct targets, while those with Autism looked more at the face and eyes but did not increase gaze to the correct targets, while continuing to look much more than their controls at implausible targets. Both groups identified fewer objects than their controls. Conclusions: The atypicalities found are likely to be entwined with the deficits shown in interpreting social cognitive cues from the images. WS and Autism are characterised by atypicalities of social attention that impact upon socio-cognitive expertise but importantly the type of atypicality is syndrome-specific
Lifestyle, glucose regulation and the cognitive effects of glucose load in middle-aged adults
No full textInterventions aimed at improving glucose regulatory mechanisms have been suggested as a possible source of cognitive enhancement in the elderly. In particular, previous research has identified episodic memory as a target for facilitation after either moderate increases in glycaemia (after a glucose drink) or after improvements in glucose regulation. The present study aimed to extend this research by examining the joint effects of glucose ingestion and glucose regulation on cognition. In addition, risk factors associated with the development of poor glucose regulation in middle-aged adults were considered. In a repeated measures design, thirty-three middle-aged adults (aged 35–55 years) performed a battery of memory and non-memory tasks after either 25 g or 50 g glucose or a sweetness matched placebo drink. To assess the impact of individual differences in glucose regulation, blood glucose measurements were taken on four occasions during testing. A lifestyle and diet questionnaire was also administered. Consistent with previous research, episodic memory ability benefited from glucose ingestion when task demands were high. Blood glucose concentration was also found to predict performance across a number of cognitive domains. Interestingly, the risk factors associated with poor glucose regulation were linked to dietary impacts traditionally associated with poor health, e.g. the consumption of high-sugar sweets and drinks. The research replicates earlier work suggesting that task demands are critical to the glucose facilitation effect. Importantly, the data demonstrate clear associations between elevated glycaemia and relatively poor cognitive performance, which may be partly due to the effect of dietary and lifestyle factors
Exploring the forgetting mechanisms in working memory: Evidence from a reasoning span test
No full textThis is an electronic version of an article published in [Saito, S., C. Jarrold, and D. M. Riby. 2009. Exploring the forgetting mechanisms in working memory: Evidence from a reasoning span test. Quarterly Journal of Experimental Psychology 62, (7): 1401-1419.]. This Article is available online at: http://www.informaworld.com/smpp/content~db=all?content=10.1080/17470210802426924In working memory (WM) span tests participants have to maintain to-be-remembered information while processing other, potentially distracting, information. Previous studies have shown that WM span scores are greater when span lists start with a long processing task and end with a short processing task than when these processing tasks are presented in the reverse order (e.g., Towse, Hitch, Hutton, 2000). In Experiment 1, we obtained a similar stimulus order effect in a reasoning span test, using reasoning sentences that were equated for length in terms of the number of constituent words, but which differed in processing complexity; span scores were greater when lists began with a complex sentence and ended with a simple sentence than when this stimulus order was reversed. In Experiment 2, the stimulus order effect was not found when processing duration was held constant while sentence complexity was varied using a computer-paced moving window presentation paradigm. These results suggest that duration-based constraints can affect degree of forgetting independently of the load generated during processing phases in WM span performance and therefore imply that time-related forgetting can occur in WM span tests, particularly when the difficulty of the processing component blocks active maintenance of to-be-remembered material
Viewing it differently: social scene perception in Williams syndrome and Autism
No full textThe genetic disorder Williams syndrome (WS) is associated with a propulsion towards social stimuli and interactions with people. In contrast, the neuro-developmental disorder autism is characterised by social withdrawal and lack of interest in socially relevant information. Using eye-tracking techniques we investigate how individuals with these two neuro-developmental disorders associated with distinct social characteristics view scenes containing people. The way individuals with these disorders view social stimuli may impact upon successful social interactions and communication. Whilst individuals with autism spend less time than is typical viewing people and faces in static pictures of social interactions, the opposite is apparent for those with WS whereby exaggerated fixations are prevalent towards the eyes. The results suggest more attention should be drawn towards understanding the implications of atypical social preferences in WS, in the same way that attention has been drawn to the social deficits associated with autism
Gaze aversion as a cognitive load management strategy in autism spectrum disorder and Williams syndrome
No full textDuring face-to-face questioning typically developing children and adults use gaze aversion (GA), away from their questioner, when thinking. GA increases with question difficulty and improves the accuracy of responses. This is the first study to investigate whether individuals with autism spectrum disorder (ASD; associated with reduced sociability and atypical face gaze) and Williams syndrome (WS; associated with hypersociability and atypical face gaze) use GA to manage cognitive load during face-to-face interactions
Neurodevelopmental Disorders: Research Challenges and Solutions
No full textInterest in the field of neurodevelopmental disorders has grown exponentially in recent years across a range of disciplines, including psychology, psychiatry, education and neuroscience. The research itself has become more sophisticated, using multidisciplinary methods to probe interdisciplinary questions. Neurodevelopmental Disorders: Research Challenges and Solutions provides a thorough overview of the key issues involved in researching neurodevelopmental disorders. The volume includes 14 chapters, arranged over three sections. Chapters in the first section address general research challenges for the study of neurodevelopmental disorders. The second section draws upon specific disorders (such as Williams syndrome, Autism Spectrum Disorders, Down Syndrome, Fragile X Syndrome, ADHD, and Language Disorders) to consider the syndrome-specific issues or challenges that may be crucial to advancing our understanding of aspects of cognition and behavior associated with them. The final section considers how research evidence may be translated into practice to begin making an impact upon the lives of individuals who have neurodevelopmental disorders and their families. Each chapter in the book also includes ‘practical tips’ for either conducting research with individuals who have neurodevelopmental disorders or considering wider practical issues. The book will be indispensable reading for advanced students, researchers, and practitioners in the fields of developmental psychology, developmental psychopathology, special needs education, neuropsychology, and neurodevelopmental disorders
Looking at Movies and Cartoons: Eye-tracking evidence from Williams syndrome and Autism
No full textBackground: Autism and Williams syndrome (WS) are neuro-developmental disorders associated with distinct social phenotypes. Whilst individuals with autism show a lack of interest in socially important cues, individuals with WS often show increased interest in socially relevant information. Methods: The current eye-tracking study explores how individuals with WS and autism preferentially attend to social scenes and movie extracts containing human actors and cartoon characters. The proportion of gaze time spent fixating on faces, bodies and the scene background was investigated. Results: Whilst individuals with autism preferentially attended to characters’ faces for less time than was typical, individuals with WS attended to the same regions for longer than typical. For individuals with autism atypical gaze behaviours extended across human actor and cartoon images or movies but for WS atypicalities were restricted to human actors. Conclusions: The reported gaze behaviours provide experimental evidence of the divergent social interests associated with autism and WS
Hippocampal involvement in glucose facilitation of recognition memory: Event-related potential components in a dual-task paradigm
No full textBackground - Glucose administration may facilitate hippocampus-mediated recognition memory (‘remember’ rather than familiarity ‘know’ responses).
Objective - This study aimed to investigate the electrophysiological correlates of this phenomenon in a cohort of older individuals.
Methods - In this double-blind placebo-controlled cross-over study, 12 older participants (mean age = 69.33 ± 1.69 years) completed the remember-know paradigm both with and without a concurrent tracking task while recording event-related potentials (ERPs).
Results - Counter to predictions, glucose reduced overall accuracy. No treatment effects were found for proportion of Remember, Know and Guess responses, although there was a trend towards greater accuracy for ‘Remember’ responses following glucose. There was weak evidence for dissociation of drink effects on tracking with glucose being associated with preferential allocation of resources to ‘Remember’ over ‘Know’ responses. At P3 and F3 electrode sites, a significantly greater left parietal (LP) recollection effect and greater FN400 effect respectively were found for glucose.
Conclusions - These findings do not support task effort modulation of the memory-enhancing effects of glucose. There was evidence of a greater glucose facilitatory effect for hippocampus-mediated LP recollection
Tracking eye movements proves informative for the study of gaze direction detection in autism
No full textConsiderable research effort has been dedicated to exploring how well children with autistic spectrum disorders infer eye gaze direction from the face of an actor. Here we combine task performance (accuracy to correctly label a target item) and eye movement information (‘where’ the participant fixates when completing the task) to understand more about the components involved in completing eye direction detection tasks. Fifteen participants with autism were significantly less accurate at interpreting eye direction and detecting a target item (array sizes 4 and 6 items) than typically developing participants of comparable nonverbal ability. Eye movement data revealed subtly different fixation patterns for participants with and without autism that might contribute to differences in overall task performance. Although the amount of time spent fixating on the target item did not differ across groups, participants with autism took significantly longer to complete several components of the task and fixate upon the regions of the picture required for task completion (e.g. face or target). The data have implications for the design of tasks for individuals with autism and provide insights into the usefulness of including measures of visual attention in understanding task performance
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