1,721,065 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
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
Segregation of Neural Circuits Involved in Social Gaze and Non-Social Arrow Cues: Evidence from an Activation Likelihood Estimation Meta-Analysis
No full text: Orienting attention by social gaze cues shares some characteristics with orienting attention by non-social arrow cues, but it is unclear whether they rely on similar neural mechanisms. The present ALE-meta-analysis assessed the pattern of brain activation reported in 40 single experiments (18 with arrows, 22 with gaze), with a total number of 806 participants. Our findings show that the network for orienting attention by social gaze and by non-social arrow cues is in part functionally segregated. Orienting by both types of cues relies on the activity of brain regions involved in endogenous attention (the superior frontal gyrus). Importantly, only orienting by gaze cues was also associated with the activity of brain regions involved in exogenous attention (medial frontal gyrus), processing gaze, and mental state attribution (superior temporal sulcus, temporoparietal junction)
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
How treatment affects the brain: metaanalysis evidence of neural substrates underpinning drug therapy and psychotherapy in major depression
No full textThe idea that modifications of affect, behavior and
cognition produced by psychotherapy are mediated by biological
underpinnings predates the advent of the modern neurosciences.
Recently, several studies demonstrated that psychotherapy
outcomes are linked to modifications in specific brain
regions. This opened the debate over the similarities and dissimilarities
between psychotherapy and pharmacotherapy. In
this study, we used activation likelihood estimation metaanalysis
to investigate the effects of psychotherapy (PsyTh)
and pharmacotherapy (DrugTh) on brain functioning in Major
Depression (MD). Our results demonstrate that the two therapies
modify different neural circuits. Specifically, PsyTh induces
selective modifications in the left inferior and superior
frontal gyri, middle temporal gyrus, lingual gyrus and
middle cingulate cortex, as well as in the right middle
frontal gyrus and precentral gyrus. Otherwise, DrugTh selectively
affected brain activation in the right insula in MD patients.
These results are in line with previous evidence of the
synergy between psychotherapy and pharmacotherapy but
they also demonstrate that the two therapies have different
neural underpinnings
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
Restructuring the navigational field: individual predisposition towards field independence predicts preferred navigational strategy
No full textTo successfully navigate within an environment, individuals have to organize the spatial information in terms of salient landmarks, paths and general layout of the navigational environment. They may differ in the strategy they adopt to orientate themselves, with some individuals preferring to use salient landmarks (landmark spatial style, L-SS), others preferring to plan routes or paths
through an egocentric strategy in which landmarks are connected with each other (route spatial style, R-SS) and others
still create a global map-like configuration of the environment regardless of their own position in the environment
(survey spatial style, S-SS). Here, we assessed whether Field independence (FI), that is the extent to which the individual perceives part of a field as discrete from the surrounding field rather than embedded in the field, predicted the individual’s spatial style. We assessed the individual’s spatial style using the spatial cognitive style test (SCST)
and measured FI using the group embedded figure test (GEFT). We found that FI predicted general spatial ability,
with a higher level of FI being associated with better performances on the SCST. Also, Field-independent individuals
showed a marked preference for an S-SS. These results suggest that a higher level of FI is associated with better performance on higher level spatial tasks (i.e. R-SS and S-SS) that is tasks requiring individuals to restructure the “navigational field” according to the navigational goal. The results also suggest that a higher level of FI makes individuals more prone to use a global and complex map-like representation of 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
The meditative mind: a comprehensive meta-analysis of MRI studies
Full text linkOver the past decade mind and body practices, such as yoga and meditation, have raised interest in different scientific fields; in particular, the physiological mechanisms underlying the beneficial effects observed in meditators have been investigated. Neuroimaging studies have studied the effects of meditation on brain structure and function and findings have helped clarify the biological underpinnings of the positive effects of meditation practice and the possible integration of this technique in standard therapy. The large amount of data collected thus far allows drawing some conclusions about the neural effects of meditation practice. In the present study we used activation likelihood estimation (ALE) analysis to make a coordinate-based meta-analysis of neuroimaging data on the effects of meditation on brain structure and function. Results indicate that meditation leads to activation in brain areas involved in processing self-relevant information, self-regulation, focused problem-solving, adaptive behavior, and interoception. Results also show that meditation practice induces functional and structural brain modifications in expert meditators, especially in areas involved in self-referential processes such as self-awareness and self-regulation. These results demonstrate that a biological substrate underlies the positive pervasive effect of meditation practice and suggest that meditation techniques could be adopted in clinical populations and to prevent disease
Topological map of the body in post-stroke patients: lesional and hodological aspects
Full text linkObjective: It has been repeatedly hypothesized that at least 3 distinct types of body representations do exist: body schema, a representation derived from multiple sensory and motor inputs; topological map of the body, a structural description of spatial relations among the body parts; and body semantics, a lexical-semantic representation. Although several studies have assessed neural correlates of the topological map of the body in healthy participants, a systematic investigation of neural underpinnings of the topological map of the body in brain-damaged patients is still lacking. Method: Here we investigated the neural substrates of topological map of the body in 23 brain-damaged patients, both from a topological and an hodological perspectives, using Voxel Lesion Symptom Mapping and atlas-based track-wise statistical analysis. Besides neuroimaging investigation, consisting of T1-weighted and FLAIR sequences, patients underwent the frontal body-evocation subtest (FBE) to assess the topological map of the body. Results: The present results reveal a large-scale brain network involved in the topological map of the body assessed with FBE, encompassing both regions of primary elaboration and multisensory associative areas, in the temporal, parietal, frontal, and insular cortices. Hodological analysis revealed significant association between processing of the body topological map and the disconnection of the frontomarginal tract. Conclusions: These findings suggest that the topological map of the body is built up basing on both external and internal information that comes from the body and are constantly updated and integrated. The theoretical and clinical relevance of these results is discussed
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