1,721,038 research outputs found
Spatial attention and representation of time intervals in childhood
Full text linkSpatial attention and spatial representation of time are strictly linked in the human brain. In young adults, a leftward shift of spatial attention by prismatic adaptation (PA), is associated with an underestimation whereas a rightward shift is associated with an overestimation of time both for visual and auditory stimuli. These results suggest a supra-modal representation of time left-to-right oriented that is modulated by a bilateral attentional shift. However, there is evidence of unilateral, instead of bilateral, effects of PA on time in elderly adults suggesting an influence of age on these effects. Here we studied the effects of spatial attention on time representation focusing on childhood. Fifty-four children aged from 5 to 11 years-old performed a temporal bisection task with visual and auditory stimuli before and after PA inducing a leftward or a rightward attentional shift. Results showed that children underestimated time after a leftward attentional shift either for visual or auditory stimuli, whereas a rightward attentional shift had null effect on time. Our results are discussed as a partial maturation of the link between spatial attention and time representation in childhood, due to immaturity of interhemispheric interactions or of executive functions necessary for the attentional complete influence on time representation
The illusion of having a tall or short body differently modulates interpersonal and peripersonal space
No full textThe brain constructs a functional representation of the space around the body, the so called peripersonal space (PPS), which is a sensorimotor interface used to ensure suitable motor acts. However, this sector of space is also involved in social interactions. Individuals indeed, maintain an interpersonal space (IPS) indicating how close they prefer to stand relative to others. Here, we investigated whether a change in one's own body height representation can differently modulate action and social space. To this aim, we measured IPS and PPS in a similar way through a Reaching-distance and a Comfort-distance task, respectively, before and after participants experienced the illusion of having a tall (Experiment 1), or a short (Experiment 2), body. The illusion of having a tall body significantly reduced the IPS and enlarged PPS. On the other hand, the illusion of having a short body contracted the IPS, leaving the PPS intact. A further experiment (Experiment 3), showed that the illusory ownership for the tall or short body is a necessary condition to update the participants’ height representation. Thus, a change in body height representation was effective to reveal a dissociation in the representation of the space around the body, depending on whether this sector of space is used for programming actions, or for regulating social interactions
The plasticity of the interpersonal space in autism spectrum disorder
Full text linkIn recent years, there has been a dramatic increase in research examining interpersonal space, i.e., the sector of space immediately around the body in which we interact with other people. These studies have consistently revealed impairments of interpersonal space regulation in psychopathological disorders characterized by social disability, such as autism, schizophrenia and social anxiety. The primary goal of this review is to discuss several key points that have emerged in research on interpersonal space regulation in autism spectrum disorders. Particularly, we review recent behavioral evidence revealing that individuals with autism prefer abnormally larger or shorter interpersonal distance than healthy controls, indicating a deficit in regulating the size of interpersonal space (permeability). Then, we focus on how individuals with autism fail to modify their interpersonal space following a brief cooperative interaction with an unfamiliar adult, suggesting a deficit in adapting interpersonal space to the social context (plasticity). Moreover, we discuss evidence indicating that space regulation deficits primarily affect interpersonal (i.e., social), but not peripersonal (i.e., action), space in autism. Finally, we take into consideration the variables influencing interpersonal space plasticity such as person's perspective and severity of social impairment as well as its neural underpinnings. These findings may provide a critical contribution to understanding of the functional mechanisms underlying interpersonal space regulation and its rehabilitation in autism spectrum disorders
Neglect in temporal domain: Amelioration following a prismatic adaptation treatment and implications in everyday life. A single case study
No full textAs in line bisection, in time bisection, neglect patients fail to process the first/left part of time representation (Mental-Time-Line-MTL) resulting in a rightward shift of the interval midpoint. A leftward shift of spatial attention after one session of prismatic-adaptation (PA) reduces this deficit. The impact on daily life of time deficit is little investigated in neglect. Here we study the time deficit and its ecological impact in an outpatient with neglect (LL) and the effects of a PA-treatment (ten sessions) on the deficit and its impact. Before and after PA-treatment, LL completed a: time-bisection-task assessing the MTL in the milliseconds-seconds range; lifespan-task assessing the MTL in the lifespan range; qualitative interview assessing the impact on daily routines. Patient's performance on the tasks was compared with the performance of non-neurological controls. Before PA-treatment, LL showed a rightward shift in the time-bisection-task and a compression of life events distribution in the lifespan-task. The feeling “to be forward in time” emerged in the interview. The PA-treatment reduced the deficits in the tasks and the feeling “to be forward in time” in the interview. PA-treatment is suggested as a powerful instrument for the reduction of time deficit and its ecological impact in neglect patients
An asymmetry in past and future mental time travel following vmPFC damage
Full text linkThe role of ventromedial prefrontal cortex (vmPFC) in mental time travel toward the past and the future is debated. Here, patients with focal lesions to the vmPFC and brain-damaged and healthy controls mentally projected themselves to a past, present or future moment of subjective time (self-projection) and classified a series of events as past or future relative to the adopted temporal self-location (self-reference). We found that vmPFC patients were selectively impaired in projecting themselves to the future and in recognizing relative-future events. These findings indicate that vmPFC damage hinders the mental processing of and movement toward future events, pointing to a prominent, multifaceted role of vmPFC in future-oriented mental time travel
Mental time travel and functional daily life activities in neglect patients: Recovery effects of rehabilitation by prism adaptation.
No full textAbstract
Recent neuropsychological evidence put forward impaired ability in processing particular aspects of time, such as Mental Time Travel (MTT), in brain damaged patients exhibiting a deficit of spatial attention (i.e., neglect) and the possibility to recover this MTT deficit through a manipulation of spatial attention by prism adaptation (PA). The aim of the present study was twofold. First, we explored whether the neglect patients' impairment in MTT is linked with an impairment in functional competences, such as processing temporal duration of everyday activities, motor abilities and independence in daily living. Second, we focused on rehabilitation, investigating the long-term duration of the benefits induced by a PA treatment on both mental time travel and the above-mentioned functional abilities.
To these aims, neglect patients were submitted to a MTT task, as well as to a battery of tests assessing spatial attention, estimation of time duration, motor competence and independence in activities of daily living. All tests were performed before, at the end, and one week after 10 daily sessions of PA treatment inducing a leftward shift of spatial attention.
Results suggest that neglect patients' impairment in MTT ability correlates with spatial attention deficit and with difficulties in producing reasonable temporal estimation of daily life activities. Crucially, the PA treatment induces a long-lasting and stable amelioration of MTT, spatial attention and functional competences
Prismatic Lenses Shift Time Perception.
No full textPrevious studies have demonstrated the involvement of spatial codes in the representation of time and numbers. We took advantage of a well-known spatial modulation (prismatic adaptation) to test the hypothesis that the representation of time is spatially oriented from left to right, with smaller time intervals being represented to the left of larger time intervals. Healthy subjects performed a time-reproduction task and a time-bisection task, before and after leftward and rightward prismatic adaptation. Results showed that prismatic adaptation inducing a rightward orientation of spatial attention produced an overestimation of time intervals, whereas prismatic adaptation inducing a leftward shift of spatial attention produced an underestimation of time intervals. These findings not only confirm that temporal intervals are represented as horizontally arranged in space, but also reveal that spatial modulation of time processing most likely occurs via cuing of spatial attention, and that spatial attention can influence the spatial coding of quantity in different dimensions
Time perception in a neglected space
No full textWe have studied the distortion of perceived time in a patient with left neglect. This patient consistently overestimated the duration of stimuli in the neglected space. Overestimation was observed both with an interval comparison (300/700 ms) and with a time production (1 s) paradigm. We suggest that encoding duration in the hundreds of milliseconds range is a process based on an internal clock mechanism. The functioning of that clock varies as a function of the processing load
Biodegradation of 4-(1-nonyl)phenol by axenic cultures of the yeast Candida aquaetextoris. Identification of microbial breakdown products and proposal of a possible metabolic pathway
No full textCandida aquaetextoris, a yeast recently described for its ability to use 4-(1-nonyl)phenol (pNP) as the sole carbon and energy source
in aerobic conditions, has been studied in order to determine the degradation products deriving from the growth on such a compound which
is of environmental concern because of its proved toxicity to several organisms. Two main metabolites, namely trans-4-hydroxy-cinnamic
acid and 4-hydroxy-acetophenone (4-acetylphenol), have been identi'ed through either TLC and NMR spectrometry analyses of liquid
substrate from cultures of C. aquaetextoris grown on pNP, with 4-acetylphenol that accumulates without any further degradation. These
'ndings suggest that C. aquaetextoris might metabolise pNP via terminal oxidation of the alkyl chain, followed by a beta-oxidation pathway.
On the basis of this evidence, a novel metabolic route for the microbial degradation of 4-(1-nonyl)phenol, at least in certain yeasts, is
proposed
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