84 research outputs found
Awareness is in the eye of the observer: Preserved third-person awareness of deficit in anosognosia for hemiplegia
Get PDFIn recent decades, the research traditions of (first-person) embodied cognition and of (third-person) social cognition have approached the study of self-awareness with relative independence. However, neurological disorders of self-awareness offer a unifying perspective to empirically investigate the contribution of embodiment and social cognition to self-awareness. This study focused on a neuropsychological disorder of bodily self-awareness following right-hemisphere damage, namely anosognosia for hemiplegia (AHP). A previous neuropsychological study has shown AHP patients, relative to neurological controls, to have a specific deficit in third-person perspective taking and allocentric stance (the other unrelated to the self) in higher order mentalizing tasks. However, no study has tested if verbal awareness of motor deficits is influenced by perspective-taking and centrism and identified the related anatomical correlates. Accordingly, two novel experiments were conducted with right-hemisphere stroke patients with (n = 17) and without AHP (n = 17) that targeted either their own (egocentric, experiment 1) or another stooge patients (allocentric, experiment 2) motor abilities from a first-or-third person perspective. In both experiments, neurological controls showed no significant difference in perspective-taking, suggesting that social cognition is not a necessary consequence of right-hemisphere damage. More specifically, experiment 1 found AHP patients more aware of their own motor paralysis (egocentric stance) when asked from a third compared to a first-person perspective, using both group level and individual level analysis. In experiment 2, AHP patients were less accurate than controls in making allocentric judgements about the stooge patient, but with only a trend towards significance and with no difference between perspectives. As predicted, deficits in egocentric and allocentric third-person perspective taking were associated with lesions in the middle frontal gyrus, superior temporal and supramarginal gyri, and white matter disconnections were more prominent with deficits in allocentricity. Behavioural and neuroimaging results demonstrate the intersecting relationship between bodily self-awareness and self-and-other-directed metacognition or mentalisation
Symbolic and non-symbolic numerical representations in old and young subjects: an exploratory EEG study
No full textNumeracy has significant implications throughout the life course. Its agei nduced
decline represents a vulnerability factor in elderly populations when it comes to solving everyday tasks. However, the reasons behind age-induced decline in numeracy are still unclear. In this study, we used a parity judgment task to study variations in number cognition between old and young participants. Since numeracy is associated with both symbolic and nonsymbolic representations, three numerical formats were used: arabic digits (N), finger representations (F), and dots (D). Fifty-three healthy subjects joined the study: 31 young (24.1±4.73 y.o.) and 22 old (68.8±4.38 y.o.). EEG (64 channels) was recorded during the task. Mixed Effects Models analysis showed that performance accuracy for D was significantly lower than for N and F (p = .02).
There were significant main effects for reaction time for Group (old, young), Condition (N, F, D) and Gender. Notably, old adults responded slower than
young adults (p < .001) and both groups performed significantly faster in the
task for N compared to F and D (p < .001). Significant interaction effects showed that performance between males and females were comparable for arabic digits (p = .14), with females showing significantly slower response for non-symbolic stimuli than males (F, p = 0.04; D, p = .007). In sensor space, multivariate pattern analysis shows that the neural correlates supporting the different number representations can be classified as categorically separate, with an early dissociation (~200 ms) between N, F, and D stimuli when compared to each other. This provides provisional evidence that symbolic and non-symbolic representations recruit functionally distinct neuronal processes.
Subjects in the old group showed a slight reduction in decoding and an
increase in its latency. Numerical cognition involves a highly-integrated
network, with a key role of the intraparietal sulcus and fusiform gyrus. In
source space, we found reduced activation levels and increased latency of
response in the primary cortical areas involved in numerical cognition in the
old group. In the same group, all stimuli also induced a wider cortical response
with respect to young subjects. We hypothesize that the reduced activity of the
main cortical areas may contribute to the age-induced decay in numeracy and
that the recruitment of other cortical areas may serve as a compensatory
mechanism. The results of this exploratory study provide further evidence for
the multifaceted processes involved in numerical reasoning and its age-related
decline, with a potentially distinct neural network for symbolic and nonsymbolic
numerical representations
Symbolic and non-symbolic numerical representations in old and young subjects. An exploratory EEG study
No full textNumeracy has significant implications throughout the lifecourse. Its age-induced
decline represents a vulnerability factor in elderly populations when it comes to solving everyday
tasks. However, the reasons behind age-induced decline in numeracy are still unclear. In this
study, we used a parity judgment task to study variations in number cognition between old and
young participants. Since numeracy is associated with both symbolic and non-symbolic
representations, three numerical formats were used: arabic digits (N), finger representations (F),
and dots (D). Fifty-three healthy subjects joined the study: 31 young (24.1±4.73 y.o.) and 22 old
(68.8±4.38 y.o.). EEG (64 channels) was recorded during the task. Mixed Effects Models
analysis showed that performance accuracy for D was significantly lower than for N and F (p =
.02). There were significant main effects for reaction time for Group (old, young), Condition (N,
F, D) and Gender. Notably, old adults responded slower than young adults (p < .001) and both
groups performed significantly faster in the task for N compared to F and D (p < .001).
Significant interaction effects showed that performance between males and females were
comparable for arabic digits (p = .14), with females showing significantly slower response for
non-symbolic stimuli than males (F, p = 0.04; D, p = .007). In sensor space, multivariate pattern
analysis shows that the neural correlates supporting the different number representations can be
classified as categorically separate, with an early dissociation (~200 ms) between N, F, and D
stimuli when compared to each other. This provides provisional evidence that symbolic and non-
symbolic representations recruit functionally distinct neuronal processes. Subjects in the old
group showed a slight reduction in decoding and an increase in its latency. Numerical cognition
involves a highly-integrated network, with a key role of the intraparietal sulcus and fusiform
gyrus. In source space, we found reduced activation levels and increased latency of response in
the primary cortical areas involved in numerical cognition in the old group. In the same group,
all stimuli also induced a wider cortical response with respect to young subjects. We hypothesize
that the reduced activity of the main cortical areas may contribute to the age-induced decay in
numeracy and that the recruitment of other cortical areas may serve as a compensatory
mechanism. The results of this exploratory study provide further evidence for the multifaceted
processes involved in numerical reasoning and its age-related decline, with a potentially distinct
neural network for symbolic and non-symbolic numerical representations
A fronto-insular-parietal network for the sense of body ownership
Get PDF: Neuropsychological disturbances in the sense of limb ownership provide unique opportunities to study the neurocognitive basis of body ownership. Previous small sample studies that showed discrete cortical lesions cannot explain why multisensory, affective, and cognitive manipulations alter disownership symptoms. We tested the novel hypothesis that disturbances in the sense of limb ownership would be associated not only with discrete cortical lesions but also with disconnections of white-matter tracts supporting specific functional networks. We drew on an advanced lesion-analysis and Bayesian statistics approach in 49 right-hemisphere patients (23 with and 26 without limb disownership). Our results reveal that disturbances in the sense of ownership are associated with lesions in the supramarginal gyrus and disconnections of a fronto-insular-parietal network, involving the frontal-insular and frontal inferior longitudinal tracts, confirming previous disconnection hypotheses. Together with previous behavioral and neuroanatomical results, these findings lead us to propose that the sense of body ownership involves the convergence of bottom-up, multisensory integration, and top-down monitoring of sensory salience based on contextual demands
Another perspective on anosognosia: Self-observation in video replay improves motor awareness
Get PDFAnosognosia for hemiplegia (AHP), or unawareness of motor deficits contralateral to a brain lesion, has lasting negative implications for the management and rehabilitation of patients. A recent, bedside psychophysical intervention, namely self-observation by video replay, lead to a lasting remission of severe AHP in an acute stroke patient (Fotopoulou, A., Rudd, A., Holmes, P., & Kopelman, M. (2009). Self-observation reinstates motor awareness in anosognosia for hemiplegia. Neuropsychologia, 47, 1256-1260). This procedure has been adjusted and applied here, as the basis of two intervention protocols administered independently to two patients with severe AHP. The first study used multiple, successive sessions of video-based self-observation in an acute patient, targeting first the awareness of upper limb and subsequently lower limb paralysis. The second study used a single session of video-based, self- and other-observation in a patient at the chronic stage following onset. Both protocols also involved elements of rapport building and emotional support. The results revealed that video-based self-observation had dramatic, immediate effects on awareness in both acute and chronic stages and it seemed to act as an initial trigger for eventual symptom remission. Nevertheless, these effects did not automatically generalise to all functional domains. This study provides provisional support that video-based self-observation may be included in wider rehabilitation programmes for the management and restoration of anosognosia
The Long-Term Health and Human Capital Consequences of Adverse Childhood Experiences in the Birth to Thirty Cohort: Single, Cumulative, and Clustered Adversity
No full textHuman capital—that is the cumulative abilities, education, social skills, and mental and physical health one possesses—is increasingly recognized as key to the reduction of inequality in societies. Adverse childhood experiences have been linked to a range of human capital indicators, with the majority of research in high-income, western settings. This study aims to examine the link between adverse childhood experiences and adult human capital in a South African birth cohort and to test whether associations differ by measurement of adversity. Secondary analysis of data from the Birth to Thirty study was undertaken. Exposure data on adversity was collected prospectively throughout childhood and retrospectively at age 22. Human capital outcomes were collected at age 28. Adversity was measured as single adverse experiences, cumulative adversity, and clustered adversity. All three measurements of adversity were linked to poor human capital outcomes, with risk for poor human capital increasing with the accumulation of adversity. Adversity was clustered by quantity (low versus high) and type (household dysfunction versus abuse). Adversity in childhood was linked to a broad range of negative outcomes in young adulthood regardless of how it was measured. Nevertheless, issues of measurement are important to understand the risk mechanisms that underlie the association between adversity and poor human capital
Breaking the Chains of Intergenerational Childhood Poverty: A Narrative Retrospective Study of Resilience
No full textA research report submitted in partial fulfillment of the requirements for the degree of f Master of Arts in Community-Based Counseling Psychology to the Faculty of Humanities, University of the Witwatersrand, Johannesburg, 2024The experience of poverty is well-documented, however, there is a notable gap in the existing research concerning the unique narratives of university students who have undergone experiences of poverty during childhood. These students have been successful in gaining admission into university despite facing major financial hardships stemming from their experiences of intergenerational childhood poverty. These university students identified with having experiences of childhood poverty as well as resilience, thus becoming an important and under-researched sample. This qualitative study aims to explore these students’ narratives of childhood impoverishment, with an emphasis on the identification and understanding of resilience within these experiences. This topic was investigated through the utilisation of the resilience theoretical framework. The study employed a Narrative Analysis (NA) to assess the experiential and retrospective narrative accounts of emerging adults within the university student demographic using semi-structured interviews. Three overarching themes were identified: (1) narratives within the living environment; (2) the nexus of poverty, education, and opportunity; and (3) participants’ constructions of resilience. The results illustrated that the narrative experience of childhood poverty contained great levels of experienced difficulties within the home and schooling environment, and with emotional implications of poverty resulting in difficulties with coping and social exclusion. However among this plethora of hardship, participants constructions of resilience related to motivation, strength, acceptance, adaptation, and rewriting the narrative towards positive meaning-making. Therefore this study provided further subjective insight into the topic of poverty and resilience by way of presenting the data as experienced by the research participants, as well as having made recommendations for future research.GM202
The role of executive function and socioeconomic status on risk-taking behaviours in the low-to-middle income context of South Africa
No full textA research report Submitted in fulfillment of the requirements for a Degree of Master of Arts by Coursework and Research Report (Psychology) in the Department of Psychology, In the Faculty of Humanities , School of Human and Community Development, University of the Witwatersrand, Johannesburg, 2024Risk taking is a multifaceted construct that can shape our daily decision-making processes. Higher order cognitive processes, specifically executive functioning, underscore risk-taking behaviours, while wider socio-demographic factors, such as socio-economic status, can be related to both executive function and risk-taking. However, the relationship and interplay between these factors is unclear. Accordingly, the primary aim of the study was to investigate how socio-economic status (SES) is associated with executive function (EF), specifically inhibitory control and working memory (WM), and how this association may influence risk- taking behaviour. A non-experimental and cross-sectional study was conducted using a sample of 96 participants, recruited from Johannesburg, Limpopo, and KwaZulu Natal provinces in South Africa. A comprehensive measure of SES was used, drawing on both objective and subjective ratings. Working memory was assessed by the Wechsler Digit Span test and inhibitory control using the Stroop Colour and Word Test. Lastly, a digital task - the Iowa Gambling Task (IGT) - was used to assess risk-taking behaviours. Overall, participants presented with good WM abilities but low inhibition. The IGT showed that participants were more inclined to risk-taking behaviours, however they showed a positive shift in decision making throughout the task, with no association found between EF and risk-taking behaviours. Furthermore, SES was not a predictor of EF abilities or risk-taking behaviours within the current sample. Furthermore, EF did not predict risk-taking behaviours. The results of this study are multifaceted and suggest that these constructs are multidimensional in nature and measuring them are associated with methodological challenges. Nevertheless, there is some preliminary evidence to suggest that these constructs play an interrelated role.MM202
What I think she thinks about my paralysed body: Social inferences about disability-related content in anosognosia for hemiplegia
Get PDFThe neuropsychological disorder of anosognosia for hemiplegia (AHP) can offer unique insights into the neurocognitive processes of body consciousness and representation. Previous studies have found associations between selective social cognition deficits and anosognosia. In this study, we examined how such social cognition deficits may directly interact with representations of one's body as disabled in AHP. We used a modified set of previously validated Theory of Mind (ToM) stories to create disability-related content that was related to post-stroke paralysis and to investigate differences between right hemisphere damage patients with (n = 19) and without (n = 19) AHP. We expected AHP patients to perform worse than controls when trying to infer paralysis-related mental states in the paralysis-related ToM stories and explored whether such differences depended on the inference patients were asked to perform (e.g. self or other referent perspective-taking). Using an advanced structural neuroimaging technique, we expected selective social cognitive deficits to be associated with posterior parietal cortex lesions and deficits in self-referent perspective-taking in paralysis-related mentalising to be associated with frontoparietal disconnections. Group- and individual-level results revealed that AHP patients performed worse than HP controls when trying to infer paralysis-related mental states. Exploratory lesion analysis results revealed some of the hypothesised lesions, but also unexpected white matter disconnections in the posterior body and splenium of the corpus collosum associated with a self-referent perspective-taking in paralysis-related ToM stories. The study has implications for the multi-layered nature of body awareness, including abstract, social perspectives and beliefs about the body
The exploration of self-perception in the educational attainment of high achieving students from a low socioeconomic background in South African
No full textA Research Report Submitted in partial fulfilment of the requirements for the Degree of Master of Arts in Psychology by Coursework and Research Report in the Department of Psychology, School of Human and Community Development, Faculty of Humanities at the University of the Witwatersrand, Johannesburg, 2023.Background: The achievement gap between students’ from lower-and-higher socioeconomic backgrounds is a global challenge that continues to widen. Education inequalities persist more widely with students from low socioeconomic backgrounds who are more likely to drop out of compulsory high school. However, individual characteristic such as resilience, growth-mind and positive self-concept – though largely studied using survey based methods - have been found to lessen the achievement gap. Yet, the influence of such psychological factors, specifically, self-perception as an overarching concept, is poorly understood, especially in low-to-middle income contexts like South Africa.
Aim: This study aimed to understand the lived experiences and processes involved in self-perception of high-achieving first year university students from a low-socio-economic background in the low-to-middle income context of South Africa.
Methods: An ecological systems theory and phenomenological approach guided this study. Semi-structured interviews, incorporating retrospective (high school) and current (university) questions, were conducted with 12 first-year university students.
Findings: The research demonstrated that the lived experiences of self-perception in high achieving students’ that come from a low SES background are both individualised and similar. The findings revealed that validation which was distributed between internal (self-belief) and external (affirmations from external sources) played a significant role in the students’ academic success. Furthermore, the data also demonstrated that the perception of intelligence is largely influenced by what the students’ observe from their different environments. Conclusion: This study adds to our understanding of the role of self-perception in educational inequality which can be used in future school-based, family and wider policy interventions. It further demonstrates the need to understand these complex relationships by drawing on lived experience of students using qualitative approaches.MM202
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