Influence of aging on the neural correlates of autobiographical, episodic, and semantic memory retrieval

We used fMRI to assess the neural correlates of autobiographical, semantic, and episodic memory retrieval in healthy young and older adults. Participants were tested with an eventrelated paradigm in which retrieval demand was the only factor varying between trials. A spatio-temporal partial least square analysis was conducted to identify the main patterns of activity characterizing the groups across conditions. We identified brain regions activated by all three memory conditions relative to a control condition. This pattern was expressed equally in both age groups and replicated previous findings obtained in a separate group of younger adults. We also identified regions whose activity differentiated among the different memory conditions. These patterns of differentiation were expressed less strongly in the older adults than in the young adults, a finding that was further confirmed by a barycentric discriminant analysis. This analysis showed an age-related dedifferentiation in autobiographical and episodic memory tasks but not in the semantic memory task or the control condition. These findings suggest that the activation of a common memory retrieval network is maintained with age, whereas the specific aspects of brain activity that differ with memory content are more vulnerable and less selectively engaged in older adults. Our results provide a potential neural mechanism for the well-known age differences in episodic/autobiographical memory, and preserved semantic memory, observed when older adults are compared with younger adults

Adaptive Motor Imagery: A Multimodal Study of Immobilization-Induced Brain Plasticity.

The consequences of losing the ability to move a limb are traumatic. One approach that examines the impact of pathological limb nonuse on the brain involves temporary immobilization of a healthy limb. Here, we investigated immobilization-induced plasticity in the motor imagery (MI) circuitry during hand immobilization. We assessed these changes with a multimodal paradigm, using functional magnetic resonance imaging (fMRI) to measure neural activation, magnetoencephalography (MEG) to track neuronal oscillatory dynamics, and transcranial magnetic stimulation (TMS) to assess corticospinal excitability. fMRI results show a significant decrease in neural activation for MI of the constrained hand, localized to sensorimotor areas contralateral to the immobilized hand. MEG results show a significant decrease in beta desynchronization and faster resynchronization in sensorimotor areas contralateral to the immobilized hand. TMS results show a significant increase in resting motor threshold in motor cortex contralateral to the constrained hand, suggesting a decrease in corticospinal excitability in the projections to the constrained hand. These results demonstrate a direct and rapid effect of immobilization on MI processes of the constrained hand, suggesting that limb nonuse may not only affect motor execution, as evidenced by previous studies, but also MI. These findings have important implications for the effectiveness of therapeutic approaches that use MI as a rehabilitation tool to ameliorate the negative effects of limb nonuse

Autobiographical memories in Older adults

Objetivo: Os autores pretendem rever os principais aspetos no estudo das memórias autobiográficas em adultos idosos. Método: Neste trabalho foi efetuada, através da PsycINFO, uma pesquisa da literatura publicada de 1 de Janeiro de 2000 a 30 de Abril de 2013, utilizando como palavras-chave: "autobiographical memory", "aging" e "older adults". Um total de 59 artigos foram revistos, dos quais 18 foram incluídos na seleção final. Resultados: A revisão dos diferentes estudos permitiu observar que existe um declínio da memória episódica. Este efeito não se observou em relação à memória semântica. Os adultos idosos quando comparados com adultos mais jovens, evocam um maior número de memórias de valência positiva. Conclusão: A qualidade de vida do adulto idoso tem sido objeto de interesse por parte da sociedade atual. Neste sentido, o estudo das funções cognitivas em geral e da memória em particular pode dar um contributo importante, tendo em vista uma melhor compreensão do adulto idoso e dos processos mnésicos a si inerentes, nomeadamente na preservação da memória semântica.ABSTRACT: Aim: The authors intend to review the main aspects in the study of autobiographical memories in older adults. Method: In this work a research of the literature published from 1st of January 2000 to 30th of April 2013, was performed through PsycINFO, using as keywords: "autobiographical memory", "aging" and "older adults." A total of 59 articles were reviewed, which 18 were included in the final selection. Results: A review of different studies allowed checking that there is a decline in episodic memory, whereas the same is not true in relation to semantic memory. Oder adults when compared with younger adults recall a greater number of memories with positive valence. Conclusion: The quality of life of the older adult has been focus of interest from the society. In this sense, psychology can give an important contribution towards a better understanding of the older adult and mnesic processes inherent to itself, namely the preservation of semantic memory

The Revelation Effect in Autobiographical Memory

The revelation effect is a memory illusion in recognition memory where items are more likely to be considered old if they are immediately preceded by a cognitive task (for a review, see Abfalg, Bernstein, & Hockley, 2017). Recent research has shown that the revelation effect appears in past and future episodic judgments so long as the tasks are autobiographical in nature (Westerman, Miller, & Lloyd, 2017). Aging is a factor that has not yet been studied in the revelation effect literature in terms of autobiographical memory. It has implications because of aging’s significant impact on mental time travel. During this experiment, young adults and older adults rated life events based on if those events had occurred in their childhoods or would occur within the next ten years. Half of the life events were preceded by a revelation task (an anagram). Object and spatial imagery skills were measured at the end of each session. Revelation effects did not differ with age. Object and spatial imagery were correlated, consistent with past findings, and object imagery predicted the revelation effect in an age-dependent manner: as object imagery increased, the revelation effect decreased in older adults but increased in young adults. Young adults also gave greater ratings overall while older adults were more conservative. These ratings may reflect both object imagery abilities as well as age-related cognitive decline. Overall, the results support the ones by Thapar & Sniezek (2008) in that they challenge both the original claim that older adults are not susceptible to the revelation effect (Prull et al., 1998), as well as the consensus that aging is associated with higher vulnerability across memory illusions. The findings also highlight the importance of exploring object imagery’s role in aging and autobiographical tasks. Keywords: the revelation effect, illusions, aging, false memory, visual imagery, memor

The Revelation Effect in Autobiographical Memory

The revelation effect is a memory illusion in recognition memory where items are more likely to be considered old if they are immediately preceded by a cognitive task (for a review, see Abfalg, Bernstein, & Hockley, 2017). Recent research has shown that the revelation effect appears in past and future episodic judgments so long as the tasks are autobiographical in nature (Westerman, Miller, & Lloyd, 2017). Aging is a factor that has not yet been studied in the revelation effect literature in terms of autobiographical memory. It has implications because of aging’s significant impact on mental time travel. During this experiment, young adults and older adults rated life events based on if those events had occurred in their childhoods or would occur within the next ten years. Half of the life events were preceded by a revelation task (an anagram). Object and spatial imagery skills were measured at the end of each session. Revelation effects did not differ with age. Object and spatial imagery were correlated, consistent with past findings, and object imagery predicted the revelation effect in an age-dependent manner: as object imagery increased, the revelation effect decreased in older adults but increased in young adults. Young adults also gave greater ratings overall while older adults were more conservative. These ratings may reflect both object imagery abilities as well as age-related cognitive decline. Overall, the results support the ones by Thapar & Sniezek (2008) in that they challenge both the original claim that older adults are not susceptible to the revelation effect (Prull et al., 1998), as well as the consensus that aging is associated with higher vulnerability across memory illusions. The findings also highlight the importance of exploring object imagery’s role in aging and autobiographical tasks. Keywords: the revelation effect, illusions, aging, false memory, visual imagery, memor

Relationship between the functional competence of episodic memory and the factors associated with functional independence of healthy elderly

Objective: This study aimed to describe the relationship between the functional competence of episodic memory and its associations with functional independence of healthy elderly in the city of Juiz de Fora, Minas Gerais state, Brazil. Methods: It is a cross-sectional, descriptive and exploratory research in which 60 healthy elderly comprised the final sample. To evaluate the functional capacity, the Index of Independence of Daily Living and the Lawton Instrumental Activities of Daily Living Scale were used. The episodic memory was assessed by a test of West & Thorn, adapted and validated for the Brazilian population by Yassuda, Lasca e Neri in 2005. Statistical analysis were performed using the 5.0 version of the statistical software Sphinx Léxica and Eureka. Results: Statistically significant association between education level and performance in episodic memory task was found, as well as between the latter and three items of assessment scale of instrumental activities of daily living, although inconclusive. Conclusions: It is believed that these results are due to the fact that there are so many differences between researches with respect to methodology and the choice of instruments that evaluates both episodic memory and the erderly’s functional capacity. Furthermore, the hypothesis that in healthy aging there is a capacity to face gradual losses in episodic memory and compensate them using other strategies and resources, should receive attention in further research.Objetivo: O objetivo deste estudo foi descrever a relação entre competência funcional da memória episódica e fatores associados à independência de idosos saudáveis do município de Juiz de Fora, Minas Gerais, Brasil. Métodos: Trata-se de estudo transversal, descritivo e exploratório em que 60 idosos saudáveis compuseram a amostra final. Para avaliar a capacidade funcional, foram utilizadas as escalas de Katz e de Lawton & Brody. A memória episódica foi avaliada utilizando-se teste de West & Thorn, validado e adaptado para a população brasileira por Yassuda, Lasca e Neri em 2005. A análise estatística foi realizada por meio do software estatístico Sphinx Léxica e Eureka, versão 5.0. Resultados: Foi encontrada associação estatisticamente significante entre escolaridade e desempenho em tarefa de memória episódica e entre esta e três itens da escala de avaliação das atividades instrumentais de vida diária, embora inconclusiva. Conclusões: Acredita-se que esses resultados se devam ao fato de existir muitas diferenças entre os estudos com relação à metodologia empregada e a escolha dos instrumentos que avaliam tanto a memória episódica, quanto a capacidade funcional de idosos. Além disso, a hipótese de que no envelhecimento saudável existe uma capacidade de, frente às perdas graduais na memória episódica, compensá-las utilizando outras estratégias e recursos, deve receber atenção de futuras pesquisas

Motor neuroplasticity: A MEG-fMRI study of motor imagery and execution in healthy ageing

Age-related decline in motor function is associated with over-activation of the sensorimotor circuitry. Using a multimodal MEG-fMRI paradigm, we investigated whether this neural over-recruitment in old age would be related to changes in movement-related beta desynchronization (MRBD), a correlate of the inhibitory neurotransmitter γ-aminobutyric acid (GABA), and whether it would characterize compensatory recruitment or a reduction in neural specialization (dedifferentiation). We used MEG to assess age-related changes in beta band oscillations in primary motor cortices, fMRI to localize age-related changes in brain activity, and the Finger Configuration Task to measure task performance during overt and covert motor processing: motor execution (ME) and motor imagery (MI). The results are threefold: first, showing age-related neuroplasticity during ME of older adults, compared to young adults, as evidenced by increased MRBD in motor cortices and over-recruitment of sensorimotor areas; second, showing similar age-related neuroplastic changes during MI; and finally, showing signs of dedifferentiation during ME in older adults whose performance negatively correlated with connectivity to bilateral primary motor cortex. Together, these findings demonstrate that elevated MRBD levels, reflecting greater GABAergic inhibitory activity, and over-activation of the sensorimotor network during ME may not be compensatory, but rather might reflect an age-related decline of the quality of the underlying neural signal

The relation of structural integrity and task-related functional connectivity in the aging brain.

The relations among structural integrity, functional connectivity (FC), and cognitive performance in the aging brain are still understudied. Here, we used multimodal and multivariate approaches to specifically examine age-related changes in task-related FC, gray-matter volumetrics, white-matter integrity, and performance. Our results are two-fold, showing (i) age-related differences in FC of the working memory network and (ii) age-related recruitment of a compensatory network associated with better accuracy on the task. Increased connectivity in the compensatory network correlates positively with preserved white-matter integrity in bilateral frontoparietal tracks and with larger gray-matter volume of right inferior parietal lobule. These findings demonstrate the importance of structural integrity and FC in working memory performance associated with healthy aging

The impact of aging on the neural networks involved in gaze and emotional processing.

Normal adult aging is associated with difficulties in processing social cues to emotions such as anger and also altered motivation to focus more on positive than negative information. Gaze direction is an important modifier of the social signals conveyed by an emotion, for example, an angry face looking directly at you is considerably more threatening than an angry face looking away. In the present study we tested the hypothesis that older adults would show less neural differentiation to angry faces with direct and avert gaze compared to younger people, with the opposite prediction for happy faces. Healthy older (65-75 years; mean = 69.75) and younger (17-27 years; mean = 20.65) adults completed a functional magnetic resonance imaging experiment in which they were asked to identify happy and angry expressions displayed either with direct or averted gaze. While younger adults showed neural sensitivity to eye-gaze direction during recognition of angry expressions, older adults showed no effect of eye-gaze direction on neural response. In contrast, older adults showed sensitivity to eye-gaze direction during recognition of happy expressions but younger adults did not. Additionally, brain-behavior correlations were conducted to investigate the relationships between emotion recognition and mentalizing brain network in both age groups. Younger (but not older) adults' social cognitive performance was differentially correlated with activation in 2 brain networks when looking at angry faces with direct compared to averted gaze. These novel findings provide evidence for age-related differences in the neural substrates underlying the capacity to integrate facial affect and eye-gaze cues. The results of this study suggest that age-related differences in integrating facial cues may be related to engagement of the mentalizing network, with potentially important implications for social cognitive functioning in late adulthood