Lifelong impairment in episodic re-experiencing: Neuropsychological and neuroimaging examination of a new case of Severely Deficient Autobiographical Memory

: Autobiographical memory (AM) represents a complex and multimodal cognitive function, that allows an individual to collect and retrieve personal events and facts, enabling to develop and maintain the continuity of the self over time. Here we describe the case of DR (acronym of the fictional name Doriana Rossi), a 53-year-old woman, who complains of a specific and lifelong deficit in recalling autobiographical episodes. Along with an extensive neuropsychological assessment, DR underwent a structural and functional MRI examination to further define this impairment. The neuropsychological assessment revealed a deficit in episodic re-experiencing of her own personal life events. DR showed reduced cortical thickness in the Retrosplenial Complex in the left hemisphere, and in the Lateral Occipital Cortex, in the Prostriate Cortex and the Angular Gyrus in the right hemisphere. An altered pattern of activity in the calcarine cortex was detected during ordering of autobiographical events according to her own personal timeline. The present study provides further evidence about the existence of a severely deficient autobiographical memory condition in neurologically healthy people, with otherwise preserved cognitive functioning. Furthermore, the present data provide new important insights into neurocognitive mechanisms underpinning such a developmental condition

AFT data

Data from Study 1 and

Field dependence–independence differently affects retrospective time estimation and flicker-induced time dilation

Field dependence–independence (FDI) is a stable dimension of individual functioning, transversal to different cognitive domains. While the role of some individual variables in time perception has received considerable attention, it is not clear whether and how FDI influences timing abilities. In this study, we tested the hypothesis that FDI differently affects timing performance depending on whether the task requires cognitive restructuring. Participants were assessed for FDI using the embedded figures test (EFT). They performed a prospective timing task, reproducing the duration of a flickering stimulus, and a retrospective timing task, estimating the duration of the task. We expected performance of field-dependent (FD) and field-independent (FI) individuals not to differ in the prospective task, since restructuring of task material is not needed to reproduce the stimulus duration. Conversely, we predicted that FI individuals should be more accurate than FD ones in the retrospective condition, involving restructuring skills. Results show that while both FD and FI individuals under-reproduced the stimulus duration in the prospective task, only FD participants significantly underestimated the duration of the timing task in the retrospective condition. These results suggest that differences across FD and FI individuals are apparent in timing only when the task requires high-level cognitive processing; conversely, these differences do not affect basic sensory processing

Associative Agreement as a Predictor of Naming Ability in Alzheimer's Disease: A Case for the Semantic Nature of Associative Links

We aimed to address the long-standing issue of the nature of the relationships that link a cue word to words associated with it. In keeping with a recently proposed neuropsychological model of semantic memory (Zannino et al., 2015), we provide support for the hypothesis that associative links are semantic in nature and not lexical. In support of this hypothesis, we demonstrate a relationship in healthy subjects between the probability of producing word X in response to cue word Y in a free association task and the probability of using word X to describe the meaning of word Y. Furthermore, we provide evidence that associative measures are altered in people suffering from Alzheimer's disease (AD) and predict their level of performance in a picture-naming task. We provide a parsimonious account of the experimental data gathered form these different sources of evidence according to the hypothesis that the links between a cue word and its associates can be viewed as binding a concept (the cue) to pieces of information regarding its meaning (the associates)

Temporal features of spatial knowledge: representing order and duration of topographical information

Environmental navigation entails the constant integration of information across space and time; however, the relation between spatial and temporal features involved in wayfinding has not been fully established yet. Here we investigated how two key spatio-temporal aspects of navigation – namely the processing of information concerning the order of landmarks along a route, and the duration of tracts connecting the same landmarks – relate to different types of navigational learning. Participants encoded a path in a real city in both a route and a survey format, and the acquisition of landmark, route and survey knowledge was tested. Participants’ knowledge of landmarks order, and their perception of tracts duration were also assessed. Performance in the survey task, but not in the landmark and route tasks, significantly predicted accuracy in landmark ordering. The influence of tract length on retrospectively estimated tracts duration was also found to be significantly predicted only by accuracy in the survey learning task. These results support recent models of spatial navigation, invoking the dynamic interaction between different representation formats. Furthermore, they are consistent with theoretical views of an integrated account of the role of the hippocampus in navigation and memory

On the road of memory: investigating the relationship between memory, spatial navigation, and Déjà-vu

Objectives: This work has dual objectives, namely investigating the relation between memory and spatial navigation and that between memory and Dèjà-vu. Materials: The experimental protocol included: spatial navigation tasks assessing route (RK), landmark (LK), survey (SK) knowledge and landmark ordering (LO), Survey of Autobiographical Memory (SAM), Prospective and Retrospective Memory Questionnaire (PMRQ), I-DEA questionnaire for assessing Dèjà-vu. Participants and methods: 44 healthy participants took part in this study. Accuracy and a response time index were computed for each spatial navigation task. Four memory dimensions were extracted from SAM: episodic (SAM-E), semantic (SAM-SE), spatial (SAM-SP), and future (SAM-F). Eight factors were extracted from PMRQ, namely Prospective short-term self-cued (PSTSC), Prospective short-term environmentally-cued (PSTEC), Prospective long-term self-cued (PLTSC), Prospective long-term environmentally-cued (PLTEC), Retrospective short-term self-cued (RSTSC), Retrospective short-term environmentally-cued (RSTEC), Retrospective long-term self-cued (RLTSC), Retrospective long-term environmentally-cued (RLTEC). Results: Two-tail Spearman correlations were performed between the abovementioned variables. Results showed a negative correlation between RL and RSTSC; a positive correlation between the response times of RL and SAM-F; a negative correlation between response times on LK and PLTEC; a negative correlation between accuracy on SK and RSTEC and a positive correlation between accuracy on SK and SAM-SP; a negative correlation between accuracy on LO and RSTEC and a positive correlation between response times on LO and SAM-F. Also, results show a positive correlation between I-DEA and SAM-E as well as SAM-F. Discussion: Memory and planning processes have been hypothesized to have evolved from mechanisms developed to support spatial navigation. Our results show that environmental cues, that elicit retrospective short-term memory, can serve as environmental beacons; instead, self-cued retrospective short-memory can play a role when we have to constantly update our location. Both these mechanisms can support path integration and spatial update processes. Dèjà-vu may be associated with different neural responses in several brain regions involved in memory and emotional processes, including the hippocampus. Conclusions: Our results show a connection between Dèjà-vu and the self-perceived abilities to relive past events or imagine future ones. This is consistent with the role of the hippocampus in facilitating the construction of timeless scenes that allow recovering details linked to episodic memories and to imagine future scenes. However, our study is exploratory and further investigations are needed

Commonalities and specificities between environmental navigation and autobiographical memory: A synthesis and a theoretical perspective

It has been proposed that declarative memory evolved from spatial navigation, with episodic memory having its roots in mechanisms of egocentric navigation and semantic memory in those of allocentric navigation; however, whether these brain networks actually overlap is still unclear. Using Activation Likelihood Estimation, we assessed the correspondence between brain correlates of spatial navigation (SN) and autobiographical memory (AM), further testing whether neural substrates of episodic memory (EAM) and egocentric navigation, and those of semantic memory (SAM) and map-like navigation, coincide. SN and AM commonly activated the parahippocampal gyrus and middle hippocampus, posterior cingulate cortex and right angular gyrus, but also involved distinct brain regions. Similarly, EAM and egocentric navigation, besides sharing a network involving the right angular gyrus, bilateral posterior cingulate and parahippocampal gyrus, activated distinct brain regions; no region was commonly activated by SAM and allocentric navigation. We discuss findings in the light of theories on the relation between navigation and memory, and propose a new theoretical perspective, which takes into account the dynamic nature of navigational processes

The Verbal Judgement Task: Normative data of verbal abstract reasoning in a sample of 18- to 40-years old

In this study, normative data for the age-range 18–40 years have been provided for the Verbal Judgment Test (VJT), which underpins abstract reasoning on the basis of four subtests: “Differences”, “Proverbs”, “Absurdities” and “Classifications”. 554 participants (280 males and 274 females) were recruited and the following data were provided: means and standard deviations divided by gender, educational level (8, 13 and 18 years) and age group (18–20 years, 21–25 years, 26–30 years, 31–35 years and 36–40 years) for each subtest and the total score; percentiles for each subtest, divided by age group, and, when appropriate, educational level and/or gender; Rho correlations between age group, gender, educational level, intelligence and VJT scores. Age-, education- and gender differences were also assessed carrying out non parametric tests. Results showed that age and education positively affected performance in the subtests of Differences, Proverbs and Classifications, which are mostly based on previous knowledge, experience, and crystallized intelligence, but did not affect performance in the Absurdities subtest, which encompasses to some extent fluid intelligence. In addition, males showed higher scores than females in the subtests of Differences and Proverbs and in the total VJT, probably reflecting higher knowledge acquisition. Implications for future research are briefly discussed