1,720,977 research outputs found
Brain connectivity patterns associated with individual differences in the access to experience-near personal semantics: a resting-state fMRI study
No full textIt has been proposed that a continuum of specificity exists between episodic and semantic autobiographical memory. Personal semantics have been theorized to situate intermediately on this continuum, with more "experience-near" personal semantics (enPS) closer to the episodic end. We used individual differences in behavior as a model to investigate brain networks associated with the access to episodic autobiographical (EAM) and enPS information, assessing the relation between performance in the EAM and enPS conditions of the Autobiographical Fluency Task (AFT) and intrinsic brain connectivity. Results of an intrinsic connectivity contrast analysis showed that the global connectivity of two clusters in the left and right posterior cingulate cortex (PCC) was predicted by performance in the enPS conditions. Moreover, enPS scores predicted the connectivity strength of the right PCC with the bilateral anterior hippocampus (aHC), anterior middle temporal gyrus (aMTG) and medial orbitofrontal cortex, and the left aMTG and PCC. enPS scores also predicted the connectivity strength of the left PCC with the bilateral HC and MTG. The network highlighted involves parts of the core and of the dorsal medial subsystems of the Default Mode Network, in line with the proposal that enPS represents an intermediate entity between episodic and semantic memory
Field dependence–independence differently affects retrospective time estimation and flicker-induced time dilation
No full textField 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
The autobiographical fluency task: Validity and reliability of a tool to assess episodic autobiographical memory and experience-near personal semantics
No full text: The assessment of autobiographical memory is challenging in clinical settings. The Autobiographical Fluency Task (AFT) - that is designed to test both Episodic Autobiographical Memory (EAM) and experience-near Personal Semantics (enPS) - may represent a feasible and rapid method to test access to autobiographical memories. Here we tested the reliability and the construct validity of the AFT. A total number of 51 individuals participated in the present study, with 24 included in Experiment 1 and 27 in Experiment 2. In Experiment 1, participants performed both the AFT and the Survey of Autobiographical Memory (SAM). In Experiment 2, participants completed the AFT and the Autobiographical Interview (AI). The AFT showed a moderate-to-high reliability. Also, EAM and enPS scores significantly correlated with the episodic subscale of the SAM. Results of Experiment 1 were replicated and expanded in Experiment 2. Again, the AFT showed a high reliability. Both EAM and enPS showed a significant correlation with the number of internal details produced during the AI; enPS also correlated with the number of external details. Overall, the present results show that the AFT may be a feasible instrument to assess autobiographical memory, especially for testing episodic autobiographical memory and experience-near personal semantics in clinical settings
Common and specific activations supporting optic flow processing and navigation as revealed by a meta-analysis of neuroimaging studies
No full text: Optic flow provides useful information in service of spatial navigation. However, whether brain networks supporting these two functions overlap is still unclear. Here we used Activation Likelihood Estimation (ALE) to assess the correspondence between brain correlates of optic flow processing and spatial navigation and their specific neural activations. Since computational and connectivity evidence suggests that visual input from optic flow provides information mainly during egocentric navigation, we further tested the correspondence between brain correlates of optic flow processing and that of both egocentric and allocentric navigation. Optic flow processing shared activation with egocentric (but not allocentric) navigation in the anterior precuneus, suggesting its role in providing information about self-motion, as derived from the analysis of optic flow, in service of egocentric navigation. We further documented that optic flow perception and navigation are partially segregated into two functional and anatomical networks, i.e., the dorsal and the ventromedial networks. Present results point to a dynamic interplay between the dorsal and ventral visual pathways aimed at coordinating visually guided navigation in the environment
Commonalities and specificities between environmental navigation and autobiographical memory: A synthesis and a theoretical perspective
No full textIt 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
Temporal features of spatial knowledge: representing order and duration of topographical information
No full textEnvironmental 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
Inter-individual differences in resting-state functional connectivity are linked to interval timing in irregular contexts
No full textBehavioral evidence suggests that different mechanisms mediate duration perception depending on whether regular or irregular cues for time estimation are provided, and that individual differences in interoceptive processing may affect duration perception only in the latter case. However, no study has addressed brain correlates of this proposed distinction. Here participants performed a duration reproduction task in two conditions: with unevenly spaced stimuli during time estimation/reproduction (irregular), with regu- larly spaced stimuli provided during the same task (regular). They also underwent resting- state fMRI to assess regional functional connectivity, in order to link individual differences in behavioral performance to variations in patterns of intrinsic brain oscillations. Resting- state functional connectivity of the right precentral gyrus with the ipsilateral insula and putamen was predicted by duration reproduction performance selectively in the irregular condition. The connectivity of the right posterior insula, within a network modulated by participants’ degree of interoceptive awareness, correlated positively with performance in the irregular condition only. Findings support the distinction between brain networks involved in duration processing with or without regular cues, and the hypothesis that the multimodal integration of interoceptive and exteroceptive cues is specifically involved in the latter
Lifelong impairment in episodic re-experiencing: Neuropsychological and neuroimaging examination of a new case of Severely Deficient Autobiographical Memory
Full text link: 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
Temporal organization of episodic and experience-near semantic autobiographical memories: neural correlates and context-dependent connectivity
Full text linkAutobiographical memory includes a representation of personal life events with a unique spatiotemporal context (episodic autobiographical memory) and factual self-knowledge (personal semantics). Whereas "experience-far" personal semantics have undergone complete abstraction, "experience-near" personal semantics are still linked to a spatiotemporal context. The representation of one's own past involves an autobiographical knowledge base, in the form of a personal timeline, along which autobiographical information is temporally organized into different lifetime periods. Commonalities and differences between brain networks supporting this temporal organization for autobiographical information with different contextual specificity, however, have not been investigated to date. Here, we used task-based fMRI to assess neural substrates of temporal ordering along the personal timeline for real autobiographical episodic and experience-near personal semantic memories. Within a distributed network, the left calcarine cortex was more strongly activated for episodic autobiographical memory than personal semantics, whereas the left ventromedial pFC and right posterior cingulate cortex (PCC), angular gyrus (AG), and anterior middle temporal gyrus (aMTG) showed stronger activation for personal semantics than episodic autobiographical memory. Findings were confirmed by analyses in independently derived ROIs. Generalized psychophysiological interaction analyses between the same regions showed that, during personal semantics compared with episodic autobiographical memory, memory category modulated activity in the left PCC and right PCC, AG, and aMTG. Findings provide insights on how personal events and facts are represented in the timescale of years, suggesting that the temporal organization of autobiographical memory exploits properties of situation models developed within posteromedial, lateral parietal, and medial prefrontal regions
The Verbal Judgement Task: Normative data of verbal abstract reasoning in a sample of 18- to 40-years old
No full textIn 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
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