Tosoni A.,University of Chieti Pescara |
Tosoni A.,Institute for Advanced Biomedical Technologies |
Corbetta M.,University of Washington |
Calluso C.,University of Chieti Pescara |
And 8 more authors.
European Journal of Neuroscience | Year: 2014
During simple perceptual decisions, sensorimotor neurons in monkey fronto-parietal cortex represent a decision variable that guides the transformation of sensory evidence into a motor response, supporting the view that mechanisms for decision-making are closely embedded within sensorimotor structures. Within these structures, however, decision signals can be dissociated from motor signals, thus indicating that sensorimotor neurons can play multiple and independent roles in decision-making and action selection/planning. Here we used functional magnetic resonance imaging to examine whether response-selective human brain areas encode signals for decision-making or action planning during a task requiring an arbitrary association between face pictures (male vs. female) and specific actions (saccadic eye vs. hand pointing movements). The stimuli were gradually unmasked to stretch the time necessary for decision, thus maximising the temporal separation between decision and action planning. Decision-related signals were measured in parietal and motor/premotor regions showing a preference for the planning/execution of saccadic or pointing movements. In a parietal reach region, decision-related signals were specific for the stimulus category associated with its preferred pointing response. By contrast, a saccade-selective posterior intraparietal sulcus region carried decision-related signals even when the task required a pointing response. Consistent signals were observed in the motor/premotor cortex. Whole-brain analyses indicated that, in our task, the most reliable decision signals were found in the same neural regions involved in response selection. However, decision- and action-related signals within these regions can be dissociated. Differences between the parietal reach region and posterior intraparietal sulcus plausibly depend on their functional specificity rather than on the task structure. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.
Tosoni A.,University of Chieti Pescara |
Tosoni A.,Institute for Advanced Biomedical Technologies ITAB |
Pitzalis S.,Foro Italico University of Rome |
Pitzalis S.,Laboratory of Neuropsychology |
And 6 more authors.
Brain Structure and Function | Year: 2015
According to recent models of visuo-spatial processing, the medial parieto-occipital cortex is a crucial node of the dorsal visual stream. Evidence from neurophysiological studies in monkeys has indicated that the parieto-occipital sulcus (POS) contains three functionally and cytoarchitectonically distinct areas: the visual area V6 in the fundus of the POS, and the visuo-motor areas V6Av and V6Ad in a progressively dorsal and anterior location with respect to V6. Besides different topographical organization, cytoarchitectonics, and functional properties, these three monkey areas can also be distinguished based on their patterns of cortico-cortical connections. Thanks to wide-field retinotopic mapping, areas V6 and V6Av have been also mapped in the human brain. Here, using a combined approach of resting-state functional connectivity and task-evoked activity by fMRI, we identified a new region in the anterior POS showing a pattern of functional properties and cortical connections that suggests a homology with the monkey area V6Ad. In addition, we observed distinct patterns of cortical connections associated with the human V6 and V6Av which are remarkably consistent with those showed by the anatomical tracing studies in the corresponding monkey areas. Consistent with recent models on visuo-spatial processing, our findings demonstrate a gradient of functional specialization and cortical connections within the human POS, with more posterior regions primarily dedicated to the analysis of visual attributes useful for spatial navigation and more anterior regions primarily dedicated to analyses of spatial information relevant for goal-directed action. © 2014, Springer-Verlag Berlin Heidelberg.
Bonato M.,University of Padua |
Priftis K.,University of Padua |
Priftis K.,Laboratory of Neuropsychology |
Umilta C.,University of Padua |
Zorzi M.,University of Padua
Behavioural Neurology | Year: 2013
We tested a group of ten post-acute right-hemisphere damaged patients. Patients had no neglect according to paper-and-pencil cancellation tasks. They were administered computer-based single- and dual-tasks, requiring to orally name the position of appearance (e.g. left vs. right) of briefly-presented lateralized targets. Patients omitted a consistent number of contralesional targets (≈ 40%) under the single-task condition. When required to perform a concurrent task which recruited additional attentional resources (dual-tasks), patients' awareness for contralesional hemispace was severely affected, with less than one third of contralesional targets detected (≈ 70% of omissions). In contrast, performance for ipsilesional (right-sided) targets was close to ceiling, showing that the deficit unveiled by computer-based testing selectively affected the contralesional hemispace. We conclude that computer-based, attention-demanding tasks are strikingly more sensitive than cancellation tasks in detecting neglect, because they are relatively immune to compensatory strategies that are often deployed by post-acute patients. © 2013 - IOS Press and the authors. All rights reserved.
Di Russo F.,Foro Italico University of Rome |
Di Russo F.,Laboratory of Neuropsychology |
Bultrini A.,Foro Italico University of Rome |
Brunelli S.,Santa Lucia Foundation IRCCS |
And 6 more authors.
Journal of Neurotrauma | Year: 2010
We investigated the effect of sports activity on physically-disabled individuals using behavioral and electrophysiological techniques. Visual go/no-go discriminative and simple response tasks were used. Participants included 17 disabled athletes, 9 from open-skill (wheelchair basketball) and eight from closed-skill (swimming) sports, and 18 healthy non-athletes. Reaction times of the disabled athletes were slower than those of healthy non-athletes on both tasks (7% and 13% difference, respectively). Intra-individual variations in reaction times, switch cost, and number of false alarms, were higher in the swimmers, but comparable to healthy non-athletes, in the basketball group. Event-related potentials (ERPs) early components P1, N1, and P2 had longer latencies in the disabled athletes. The late P3 component had longer latency and smaller amplitude in the disabled athletes only in the discriminative response task. The N2 component, which reflected inhibition/execution processing in the discriminative response task, was delayed and reduced in the swimmer group, but was comparable to healthy subjects in the basketball group. Our results show that (1) the ERP components related to perceptual processing, and late components related to executive processing, were impaired in disabled subjects; and (2) open-skill sports such as basketball may partially compensate for executive control impairment by fostering the stability of motor responses and favoring response flexibility. © Copyright 2010, Mary Ann Liebert, Inc.
Bartolo M.,Neurorehabilitation Service Majorana |
Bartolo M.,Neurological Institute NEUROMED |
De Luca D.,Neurorehabilitation Service Majorana |
Serrao M.,Neurological Institute NEUROMED |
And 4 more authors.
Journal of Rehabilitation Medicine | Year: 2010
Objective: The aim of this study was to analyse the burden on caregivers of chronic neurological patients taking part in community neurorehabilitation programmes, and to describe caregivers' socio-demographic features and needs. Subjects: A total of 118 pairs of chronic neurological patients and their caregivers. Methods: Caregivers completed the Caregiver Burden Inventory, the Beck Depression Inventory, and an ad hoc socio-demographic questionnaire. The EuroQol-5D was used to measure patients' quality of life. Patients' cognitive status and functional independence status were assessed using the Mini-Mental State Examination and Barthel Index, respectively. Results: Data from 105 patient-caregiver pairs were analysed. The majority of caregivers (mean age 63.01 years (standard deviation 12.3)) were women (58%); 72% were spouses/partners. The burden of care was distributed across the 5 domains of the Caregiver Burden Inventory as follows: objective burden (34%), developmental burden (25%), physical burden (22%), social burden (10%), emotional burden (9%). Care burden correlated negatively with patient's functional independence (p = 0.008) and quality of life (p = 0.000) and positively with caregiver depression (p = 0.000). Of the caregivers, 65.7% requested interventions aimed at reducing their burden. Conclusion: There is a need to defne structured interventions for assessing, preventing or managing problems related to stressful caregiving situations across the care continuum. © 2010 The Authors.
Liu N.,Laboratory of Brain and Cognition |
Hadj-Bouziane F.,Laboratory of Brain and Cognition |
Hadj-Bouziane F.,French Institute of Health and Medical Research |
Jones K.B.,Laboratory of Brain and Cognition |
And 4 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015
Increasing evidence has shown that oxytocin (OT), a mammalian hormone, modifies the way social stimuli are perceived and the way they affect behavior. Thus, OT may serve as a treatment for psychiatric disorders, many of which are characterized by dysfunctional social behavior. To explore the neural mechanisms mediating the effects of OT in macaque monkeys, we investigated whether OT would modulate functional magnetic resonance imaging (fMRI) responses in face-responsive regions (faces vs. blank screen) evoked by the perception of various facial expressions (neutral, fearful, aggressive, and appeasing). In the placebo condition, we found significantly increased activation for emotional (mainly fearful and appeasing) faces compared with neutral faces across the face-responsive regions. OT selectively, and differentially, altered fMRI responses to emotional expressions, significantly reducing responses to both fearful and aggressive faces in face-responsive regions while leaving responses to appeasing as well as neutral faces unchanged. We also found that OT administration selectively reduced functional coupling between the amygdala and areas in the occipital and inferior temporal cortex during the viewing of fearful and aggressive faces, but not during the viewing of neutral or appeasing faces. Taken together, our results indicate homologies between monkeys and humans in the neural circuits mediating the effects of OT. Thus, the monkey may be an ideal animal model to explore the development of OT-based pharmacological strategies for treating patients with dysfunctional social behavior. © 2015, National Academy of Sciences. All rights reserved.
Sulpizio V.,Laboratory of Neuropsychology |
Committeri G.,Advanced Imaging Technologies |
Galati G.,Laboratory of Neuropsychology |
Galati G.,University of Rome La Sapienza
Frontiers in Human Neuroscience | Year: 2014
Keeping oriented in the environment is a multifaceted ability that requires knowledge of at least three pieces of information: one’s own location (“place”) and orientation (“heading”) within the environment, and which location in the environment one is looking at (“view”). We used functional magnetic resonance imaging (fMRI) in humans to examine the neural signatures of these information. Participants were scanned while viewing snapshots which varied for place, view and heading within a virtual room. We observed adaptation effects, proportional to the physical distances between consecutive places and views, in scene-responsive (retrosplenial complex and parahippocampal gyrus), fronto-parietal and lateral occipital regions. Multivoxel pattern classification of signals in scene-responsive regions and in the hippocampus allowed supra-chance decoding of place, view and heading, and revealed the existence of map-like representations, where places and views closer in physical space entailed activity patterns more similar in neural representational space. The pattern of hippocampal activity reflected both view- and place-based distances, the pattern of parahippocampal activity preferentially discriminated between views, and the pattern of retrosplenial activity combined place and view information, while the fronto-parietal cortex only showed transient effects of changes in place, view, and heading. Our findings provide evidence for the presence of map-like spatial representations which reflect metric distances in terms of both one’s own and landmark locations. © 2014 Sulpizio, Committeri and Galati.
Di Russo F.,Foro Italico University of Rome |
Spinelli D.,Laboratory of Neuropsychology
Psychophysiology | Year: 2010
We measured ERPs of professional boxers in a Go/No-Go task, comparing them to fencers and non-athletes. Results showed that fencing improved attention and motor response control, but boxing did not. More strikingly, in boxers, as in brain trauma patients, the P3 component was delayed and reduced. The P3 delay of boxers was correlated with the amount of performed sport exercise. Furthermore, in terms of behavior, boxers showed increased intra-individual variability and switch cost. Results were consistent with the hypothesis of specific impairment at the level of response inhibition processing. We suggest that this impairment is derived from the cumulative effect of blows to the head. The changes found in boxers suggest that ERPs and reaction times may be a tool for early detection of specific brain dysfunction. © 2009 Society for Psychophysiological Research.
PubMed | Laboratory of Neuropsychology, U.S. National Institutes of Health and Laboratory of Neuropsychology and
Type: | Journal: Cerebral cortex (New York, N.Y. : 1991) | Year: 2016
We have an incomplete picture of how the brain links object representations to reward value, and how this information is stored and later retrieved. The orbitofrontal cortex (OFC), medial frontal cortex (MFC), and ventrolateral prefrontal cortex (VLPFC), together with the amygdala, are thought to play key roles in these processes. There is an apparent discrepancy, however, regarding frontal areas thought to encode value in macaque monkeys versus humans. To address this issue, we used fMRI in macaque monkeys to localize brain areas encoding recently learned image values. Each week, monkeys learned to associate images of novel objects with a high or low probability of water reward. Areas responding to the value of recently learned reward-predictive images included MFC area 10 m/32, VLPFC area 12, and inferior temporal visual cortex (IT). The amygdala and OFC, each thought to be involved in value encoding, showed little such effect. Instead, these 2 areas primarily responded to visual stimulation and reward receipt, respectively. Strong image value encoding in monkey MFC compared with OFC is surprising, but agrees with results from human imaging studies. Our findings demonstrate the importance of VLPFC, MFC, and IT in representing the values of recently learned visual images.
PubMed | Laboratory of Neuropsychology
Type: Journal Article | Journal: Behavioral neuroscience | Year: 2016
Dopamine and serotonin have opponent interactions on aspects of impulsivity. Therefore we wanted to test the hypothesis that dopamine and serotonin would have opposing effects on speed-accuracy trade offs in a perceptual decision making task. Unlike other behavioral measures of impulsivity, perceptual decision making allows us to determine whether decreasing premature responses, often interpreted as decreased impulsivity, corresponds to increased behavioral performance. We administered GBR-12909 (a dopamine transporter blocker), escitalopram (a serotonin transporter blocker), or saline in separate sessions to 3 rhesus macaques. We found that animals had slower reaction times (RTs) on escitalopram than on GBR-12909 or saline. However, they were also least accurate on escitalopram. Animals were faster, although nonsignificantly, on GBR than saline and had equivalent accuracy. Administration of GBR-12909 did cause animals to be faster in error trials than correct trials. Therefore, from the point of view of RTs the animals were less impulsive on escitalopram. However, the decreased accuracy of the monkeys shows that they were not able to make use of their slower response times to make more accurate decisions. Therefore, impulsivity was reduced on escitalopram, but at the expense of a slower information-processing rate in the perceptual inference task. (PsycINFO Database Record