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Gallina J, Ronconi L, Marsicano G, Bertini C. Alpha and theta rhythm support perceptual and attentional sampling in vision. Cortex 2024; 177:84-99. [PMID: 38848652 DOI: 10.1016/j.cortex.2024.04.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 04/18/2024] [Accepted: 04/18/2024] [Indexed: 06/09/2024]
Abstract
The visual system operates rhythmically, through timely coordinated perceptual and attentional processes, involving coexisting patterns in the alpha range (7-13 Hz) at ∼10 Hz, and theta (3-6 Hz) range, respectively. Here we aimed to disambiguate whether variations in task requirements, in terms of attentional demand and side of target presentation, might influence the occurrence of either perceptual or attentional components in behavioral visual performance, also uncovering possible differences in the sampling mechanisms of the two cerebral hemispheres. To this aim, visuospatial performance was densely sampled in two versions of a visual detection task where the side of target presentation was fixed (Task 1), with participants monitoring one single hemifield, or randomly varying across trials, with participants monitoring both hemifields simultaneously (Task 2). Performance was analyzed through spectral decomposition, to reveal behavioral oscillatory patterns. For Task 1, when attentional resources where focused on one hemifield only, the results revealed an oscillatory pattern fluctuating at ∼10 Hz and ∼6-9 Hz, for stimuli presented to the left and the right hemifield, respectively, possibly representing a perceptual sampling mechanism with different efficiency within the left and the right hemispheres. For Task 2, when attentional resources were simultaneously deployed to the two hemifields, a ∼5 Hz rhythm emerged both for stimuli presented to the left and the right, reflecting an attentional sampling process, equally supported by the two hemispheres. Overall, the results suggest that distinct perceptual and attentional sampling mechanisms operate at different oscillatory frequencies and their prevalence and hemispheric lateralization depends on task requirements.
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Affiliation(s)
- Jessica Gallina
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, Cesena, Italy; Department of Psychology, University of Bologna, Viale Berti Pichat 5, Bologna, Italy
| | - Luca Ronconi
- School of Psychology, Vita-Salute San Raffaele University, Milan, Italy; Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Gianluca Marsicano
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, Cesena, Italy; Department of Psychology, University of Bologna, Viale Berti Pichat 5, Bologna, Italy
| | - Caterina Bertini
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, Cesena, Italy; Department of Psychology, University of Bologna, Viale Berti Pichat 5, Bologna, Italy.
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2
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Tarasi L, Romei V. Individual Alpha Frequency Contributes to the Precision of Human Visual Processing. J Cogn Neurosci 2024; 36:602-613. [PMID: 37382485 DOI: 10.1162/jocn_a_02026] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Abstract
Brain oscillatory activity within the alpha band has been associated with a wide range of processes encompassing perception, memory, decision-making, and overall cognitive functioning. Individual alpha frequency (IAF) is a specific parameter accounting for the mean velocity of the alpha cycling activity, conventionally ranging between ∼7 and ∼13 Hz. One influential hypothesis has proposed a fundamental role of this cycling activity in the segmentation of sensory input and in the regulation of the speed of sensory processing, with faster alpha oscillations resulting in greater temporal resolution and more refined perceptual experience. However, although several recent theoretical and empirical studies would support this account, contradictory evidence suggests caution and more systematic approaches in the assessment and interpretation of this hypothesis. For example, it remains to be explored to what degree IAF shapes perceptual outcomes. In the present study, we investigated whether inter-individual differences in bias-free visual contrast detection threshold in a large sample of individuals in the general population (n = 122) could be explained by inter-individual differences in alpha pace. Our results show that the contrast needed to correctly identify target stimuli (individual perceptual threshold) is associated with alpha peak frequency (not amplitude). Specifically, individuals who require reduced contrast show higher IAF than individuals requiring higher contrasts. This suggests that inter-individual differences in alpha frequency contribute to performance variability in low-level perceptual tasks, supporting the hypothesis that IAF underlies a fundamental temporal sampling mechanism that shapes visual objective performance, with higher frequencies promoting enhanced sensory evidence per time unit.
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Affiliation(s)
- Luca Tarasi
- Università di Bologna and Centro Studi e Ricerche in Neuroscienze Cognitive, Università di Bologna, Cesena, Italy
| | - Vincenzo Romei
- Università di Bologna and Centro Studi e Ricerche in Neuroscienze Cognitive, Università di Bologna, Cesena, Italy
- Universidad Antonio de Nebrija, Madrid, Spain
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3
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Trajkovic J, Di Gregorio F, Thut G, Romei V. Transcranial magnetic stimulation effects support an oscillatory model of ERP genesis. Curr Biol 2024; 34:1048-1058.e4. [PMID: 38377998 DOI: 10.1016/j.cub.2024.01.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 10/06/2023] [Accepted: 01/26/2024] [Indexed: 02/22/2024]
Abstract
Whether prestimulus oscillatory brain activity contributes to the generation of post-stimulus-evoked neural responses has long been debated, but findings remain inconclusive. We first investigated the hypothesized relationship via EEG recordings during a perceptual task with this correlational evidence causally probed subsequently by means of online rhythmic transcranial magnetic stimulation. Both approaches revealed a close link between prestimulus individual alpha frequency (IAF) and P1 latency, with faster IAF being related to shorter latencies, best explained via phase-reset mechanisms. Moreover, prestimulus alpha amplitude predicted P3 size, best explained via additive (correlational and causal evidence) and baseline shift mechanisms (correlational evidence), each with distinct prestimulus alpha contributors. Finally, in terms of performance, faster prestimulus IAF and shorter P1 latencies were both associated with higher task accuracy, while lower prestimulus alpha amplitudes and higher P3 amplitudes were associated with higher confidence ratings. Our results are in favor of the oscillatory model of ERP genesis and modulation, shedding new light on the mechanistic relationship between prestimulus oscillations and functionally relevant evoked components.
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Affiliation(s)
- Jelena Trajkovic
- Centro studi e ricerche in Neuroscienze Cognitive, Dipartimento di Psicologia, Alma Mater Studiorum - Università di Bologna, Campus di Cesena, Cesena 47521, Italy; Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - Francesco Di Gregorio
- Centro studi e ricerche in Neuroscienze Cognitive, Dipartimento di Psicologia, Alma Mater Studiorum - Università di Bologna, Campus di Cesena, Cesena 47521, Italy
| | - Gregor Thut
- Centre for Cognitive Neuroimaging, School of Psychology and Neuroscience, MVLS, University of Glasgow, Glasgow G128QB, UK
| | - Vincenzo Romei
- Centro studi e ricerche in Neuroscienze Cognitive, Dipartimento di Psicologia, Alma Mater Studiorum - Università di Bologna, Campus di Cesena, Cesena 47521, Italy; Facultad de Lenguas y Educación, Universidad Antonio de Nebrija, Madrid 28015, Spain.
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4
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Diana L, Casati C, Melzi L, Bianchi Marzoli S, Bolognini N. The effects of occipital and parietal tDCS on chronic visual field defects after brain injury. Front Neurol 2024; 15:1340365. [PMID: 38419713 PMCID: PMC10899507 DOI: 10.3389/fneur.2024.1340365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/24/2024] [Indexed: 03/02/2024] Open
Abstract
Introduction Homonymous visual field defects (HVFDs) following acquired brain lesions affect independent living by hampering several activities of everyday life. Available treatments are intensive and week- or month-long. Transcranial Direct current stimulation (tDCS), a plasticity-modulating non-invasive brain stimulation technique, could be combined with behavioral trainings to boost their efficacy or reduce treatment duration. Some promising attempts have been made pairing occipital tDCS with visual restitution training, however less is knows about which area/network should be best stimulated in association with compensatory approaches, aimed at improving exploratory abilities, such as multisensory trainings. Methods In a proof-of-principle, sham-controlled, single-blind study, 15 participants with chronic HVFDs underwent four one-shot sessions of active or sham anodal tDCS applied over the ipsilesional occipital cortex, the ipsilesional or contralesional posterior parietal cortex. tDCS was delivered during a compensatory multisensory (audiovisual) training. Before and immediately after each tDCS session, participants carried out a visual detection task, and two visual search tasks (EF and Triangles search tests). Accuracy (ACC) and response times (RTs) were analyzed with generalized mixed models. We investigated differences in baseline performance, clinical-demographic and lesion factors between tDCS responders and non-responders, based on post-tDCS behavioral improvements. Lastly, we conducted exploratory analyses to compare left and right brain-damaged participants. Results RTs improved after active ipsilesional occipital and parietal tDCS in the visual search tasks, while no changes in ACC were detected. Responders to ipsilesional occipital tDCS (Triangle task) had shorter disease duration and smaller lesions of the parietal cortex and the superior longitudinal fasciculus. On the other end, on the EF test, those participants with larger damage of the temporo-parietal cortex or the fronto-occipital white matter tracts showed a larger benefit from contralesional parietal tDCS. Overall, the visual search RTs improvements were larger in participants with right-sided hemispheric lesions. Conclusion The present result shows the facilitatory effects of occipital and parietal tDCS combined with compensatory multisensory training on visual field exploration in HVFDs, suggesting a potential for the development of new neuromodulation treatments to improve visual scanning behavior in brain-injured patients.
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Affiliation(s)
- Lorenzo Diana
- Laboratory of Neuropsychology, Department of Neurorehabilitation Sciences, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Carlotta Casati
- Laboratory of Neuropsychology, Department of Neurorehabilitation Sciences, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Lisa Melzi
- Neuro-Ophthalmology Center and Ocular Electrophysiology Laboratory, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Stefania Bianchi Marzoli
- Neuro-Ophthalmology Center and Ocular Electrophysiology Laboratory, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Nadia Bolognini
- Laboratory of Neuropsychology, Department of Neurorehabilitation Sciences, IRCCS Istituto Auxologico Italiano, Milan, Italy
- Department of Psychology, University of Milano-Bicocca and NeuroMI, Milan, Italy
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Raposo I, Szczepanski SM, Haaland K, Endestad T, Solbakk AK, Knight RT, Helfrich RF. Periodic attention deficits after frontoparietal lesions provide causal evidence for rhythmic attentional sampling. Curr Biol 2023; 33:4893-4904.e3. [PMID: 37852264 PMCID: PMC10842514 DOI: 10.1016/j.cub.2023.09.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/08/2023] [Accepted: 09/26/2023] [Indexed: 10/20/2023]
Abstract
Contemporary models conceptualize spatial attention as a blinking spotlight that sequentially samples visual space. Hence, behavior fluctuates over time, even in states of presumed "sustained" attention. Recent evidence has suggested that rhythmic neural activity in the frontoparietal network constitutes the functional basis of rhythmic attentional sampling. However, causal evidence to support this notion remains absent. Using a lateralized spatial attention task, we addressed this issue in patients with focal lesions in the frontoparietal attention network. Our results revealed that frontoparietal lesions introduce periodic attention deficits, i.e., temporally specific behavioral deficits that are aligned with the underlying neural oscillations. Attention-guided perceptual sensitivity was on par with that of healthy controls during optimal phases but was attenuated during the less excitable sub-cycles. Theta-dependent sampling (3-8 Hz) was causally dependent on the prefrontal cortex, while high-alpha/low-beta sampling (8-14 Hz) emerged from parietal areas. Collectively, our findings reveal that lesion-induced high-amplitude, low-frequency brain activity is not epiphenomenal but has immediate behavioral consequences. More generally, these results provide causal evidence for the hypothesis that the functional architecture of attention is inherently rhythmic.
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Affiliation(s)
- Isabel Raposo
- Hertie Institute for Clinical Brain Research, University Medical Center Tübingen, 72076 Tübingen, Germany; International Max Planck Research School for the Mechanisms of Mental Function and Dysfunction, University of Tübingen, Tübingen, Germany
| | - Sara M Szczepanski
- Department of Psychology and the Helen Wills Neuroscience Institute, UC Berkeley, Berkeley, CA 94720, USA
| | - Kathleen Haaland
- Department of Psychiatry and Behavioral Sciences, University of New Mexico Health Sciences, Albuquerque, NM 87102, USA
| | - Tor Endestad
- Department of Psychology, University of Oslo, 0373 Oslo, Norway; RITMO Centre for Interdisciplinary Studies in Rhythm, Time, and Motion, University of Oslo, 0371 Oslo, Norway
| | - Anne-Kristin Solbakk
- Department of Psychology, University of Oslo, 0373 Oslo, Norway; RITMO Centre for Interdisciplinary Studies in Rhythm, Time, and Motion, University of Oslo, 0371 Oslo, Norway; Department of Neurosurgery, Oslo University Hospital, 0372 Oslo, Norway; Department of Neuropsychology, Helgeland Hospital, 8656 Mosjøen, Norway
| | - Robert T Knight
- Department of Psychology and the Helen Wills Neuroscience Institute, UC Berkeley, Berkeley, CA 94720, USA
| | - Randolph F Helfrich
- Hertie Institute for Clinical Brain Research, University Medical Center Tübingen, 72076 Tübingen, Germany.
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6
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Gallina J, Marsicano G, Romei V, Bertini C. Electrophysiological and Behavioral Effects of Alpha-Band Sensory Entrainment: Neural Mechanisms and Clinical Applications. Biomedicines 2023; 11:biomedicines11051399. [PMID: 37239069 DOI: 10.3390/biomedicines11051399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/28/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
Alpha-band (7-13 Hz) activity has been linked to visuo-attentional performance in healthy participants and to impaired functionality of the visual system in a variety of clinical populations including patients with acquired posterior brain lesion and neurodevelopmental and psychiatric disorders. Crucially, several studies suggested that short uni- and multi-sensory rhythmic stimulation (i.e., visual, auditory and audio-visual) administered in the alpha-band effectively induces transient changes in alpha oscillatory activity and improvements in visuo-attentional performance by synchronizing the intrinsic brain oscillations to the external stimulation (neural entrainment). The present review aims to address the current state of the art on the alpha-band sensory entrainment, outlining its potential functional effects and current limitations. Indeed, the results of the alpha-band entrainment studies are currently mixed, possibly due to the different stimulation modalities, task features and behavioral and physiological measures employed in the various paradigms. Furthermore, it is still unknown whether prolonged alpha-band sensory entrainment might lead to long-lasting effects at a neural and behavioral level. Overall, despite the limitations emerging from the current literature, alpha-band sensory entrainment may represent a promising and valuable tool, inducing functionally relevant changes in oscillatory activity, with potential rehabilitative applications in individuals characterized by impaired alpha activity.
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Affiliation(s)
- Jessica Gallina
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, 47521 Cesena, Italy
- Department of Psychology, University of Bologna, Viale Berti Pichat 5, 40121 Bologna, Italy
| | - Gianluca Marsicano
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, 47521 Cesena, Italy
- Department of Psychology, University of Bologna, Viale Berti Pichat 5, 40121 Bologna, Italy
| | - Vincenzo Romei
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, 47521 Cesena, Italy
- Department of Psychology, University of Bologna, Viale Berti Pichat 5, 40121 Bologna, Italy
| | - Caterina Bertini
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, 47521 Cesena, Italy
- Department of Psychology, University of Bologna, Viale Berti Pichat 5, 40121 Bologna, Italy
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7
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Di Gregorio F, Petrone V, Casanova E, Lullini G, Romei V, Piperno R, La Porta F. Hierarchical psychophysiological pathways subtend perceptual asymmetries in Neglect. Neuroimage 2023; 270:119942. [PMID: 36796529 DOI: 10.1016/j.neuroimage.2023.119942] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/25/2023] [Accepted: 02/13/2023] [Indexed: 02/16/2023] Open
Abstract
Stroke patients with left Hemispatial Neglect (LHN) show deficits in perceiving left contralesional stimuli with biased visuospatial perception towards the right hemifield. However, very little is known about the functional organization of the visuospatial perceptual neural network and how this can account for the profound reorganization of space representation in LHN. In the present work, we aimed at (1) identifying EEG measures that discriminate LHN patients against controls and (2) devise a causative neurophysiological model between the discriminative EEG measures. To these aims, EEG was recorded during exposure to lateralized visual stimuli which allowed for pre-and post-stimulus activity investigation across three groups: LHN patients, lesioned controls, and healthy individuals. Moreover, all participants performed a standard behavioral test assessing the perceptual asymmetry index in detecting lateralized stimuli. The between-groups discriminative EEG patterns were entered into a Structural Equation Model for the identification of causative hierarchical associations (i.e., pathways) between EEG measures and the perceptual asymmetry index. The model identified two pathways. A first pathway showed that the combined contribution of pre-stimulus frontoparietal connectivity and individual-alpha-frequency predicts post-stimulus processing, as measured by visual-evoked N100, which, in turn, predicts the perceptual asymmetry index. A second pathway directly links the inter-hemispheric distribution of alpha-amplitude with the perceptual asymmetry index. The two pathways can collectively explain 83.1% of the variance in the perceptual asymmetry index. Using causative modeling, the present study identified how psychophysiological correlates of visuospatial perception are organized and predict the degree of behavioral asymmetry in LHN patients and controls.
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Affiliation(s)
- Francesco Di Gregorio
- UOC Medicina Riabilitativa e Neuroriabilitazione, Azienda Unità Sanitaria Locale, Bologna 40133, Italy
| | - Valeria Petrone
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Emanuela Casanova
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Giada Lullini
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Vincenzo Romei
- Dipartimento di Psicologia, Centro Studi E Ricerche in Neuroscienze Cognitive, Alma Mater Studiorum - Università di Bologna, Campus di Cesena, Cesena 47521, Italy
| | - Roberto Piperno
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Fabio La Porta
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy.
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8
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Di Gregorio F, La Porta F, Petrone V, Battaglia S, Orlandi S, Ippolito G, Romei V, Piperno R, Lullini G. Accuracy of EEG Biomarkers in the Detection of Clinical Outcome in Disorders of Consciousness after Severe Acquired Brain Injury: Preliminary Results of a Pilot Study Using a Machine Learning Approach. Biomedicines 2022; 10:biomedicines10081897. [PMID: 36009445 PMCID: PMC9405912 DOI: 10.3390/biomedicines10081897] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/04/2022] [Accepted: 07/29/2022] [Indexed: 11/18/2022] Open
Abstract
Accurate outcome detection in neuro-rehabilitative settings is crucial for appropriate long-term rehabilitative decisions in patients with disorders of consciousness (DoC). EEG measures derived from high-density EEG can provide helpful information regarding diagnosis and recovery in DoC patients. However, the accuracy rate of EEG biomarkers to predict the clinical outcome in DoC patients is largely unknown. This study investigated the accuracy of psychophysiological biomarkers based on clinical EEG in predicting clinical outcomes in DoC patients. To this aim, we extracted a set of EEG biomarkers in 33 DoC patients with traumatic and nontraumatic etiologies and estimated their accuracy to discriminate patients’ etiologies and predict clinical outcomes 6 months after the injury. Machine learning reached an accuracy of 83.3% (sensitivity = 92.3%, specificity = 60%) with EEG-based functional connectivity predicting clinical outcome in nontraumatic patients. Furthermore, the combination of functional connectivity and dominant frequency in EEG activity best predicted clinical outcomes in traumatic patients with an accuracy of 80% (sensitivity = 85.7%, specificity = 71.4%). These results highlight the importance of functional connectivity in predicting recovery in DoC patients. Moreover, this study shows the high translational value of EEG biomarkers both in terms of feasibility and accuracy for the assessment of DoC.
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Affiliation(s)
- Francesco Di Gregorio
- UO Medicina Riabilitativa e Neuroriabilitazione, Azienda Unità Sanitaria Locale, 40133 Bologna, Italy
| | - Fabio La Porta
- IRCCS Istituto delle Scienze Neurologiche di Bologna
- Correspondence:
| | | | - Simone Battaglia
- Centro Studi e Ricerche in Neuroscienze Cognitive, Dipartimento di Psicologia, Alma Mater Studiorum—Università di Bologna, Campus di Cesena, 47521 Cesena, Italy
- Dipartimento di Psicologia, Università di Torino, 10124 Torino, Italy
| | - Silvia Orlandi
- Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Viale Risorgimento, 2, 40136 Bologna, Italy
| | - Giuseppe Ippolito
- Centro Studi e Ricerche in Neuroscienze Cognitive, Dipartimento di Psicologia, Alma Mater Studiorum—Università di Bologna, Campus di Cesena, 47521 Cesena, Italy
| | - Vincenzo Romei
- Centro Studi e Ricerche in Neuroscienze Cognitive, Dipartimento di Psicologia, Alma Mater Studiorum—Università di Bologna, Campus di Cesena, 47521 Cesena, Italy
| | | | - Giada Lullini
- IRCCS Istituto delle Scienze Neurologiche di Bologna
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Gallina J, Zanon M, Mikulan E, Pietrelli M, Gambino S, Ibáñez A, Bertini C. Alterations in resting-state functional connectivity after brain posterior lesions reflect the functionality of the visual system in hemianopic patients. Brain Struct Funct 2022; 227:2939-2956. [PMID: 35585290 DOI: 10.1007/s00429-022-02502-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 04/21/2022] [Indexed: 12/13/2022]
Abstract
Emerging evidence suggests a role of the posterior cortices in regulating alpha oscillatory activity and organizing low-level processing in non-alpha frequency bands. Therefore, posterior brain lesions, which damage the neural circuits of the visual system, might affect functional connectivity patterns of brain rhythms. To test this hypothesis, eyes-closed resting state EEG signal was acquired from patients with hemianopia with left and right posterior lesions, patients without hemianopia with more anterior lesions and healthy controls. Left-lesioned hemianopics showed reduced intrahemispheric connectivity in the range of upper alpha only in the lesioned hemisphere, whereas right-lesioned hemianopics exhibited reduced intrahemispheric alpha connectivity in both hemispheres. In terms of network topology, these impairments were characterized by reduced local functional segregation, with no associated change in global functional integration. This suggests a crucial role of posterior cortices in promoting functional connectivity in the range of alpha. Right-lesioned hemianopics revealed also additional impairments in the theta range, with increased connectivity in this frequency band, characterized by both increased local segregated activity and decreased global integration. This indicates that lesions to right posterior cortices lead to stronger impairments in alpha connectivity and induce additional alterations in local and global low-level processing, suggesting a specialization of the right hemisphere in generating alpha oscillations and in coordinating complex interplays with lower frequency bands. Importantly, hemianopic patient's visual performance in the blind field was linked to alpha functional connectivity, corroborating the notion that alpha oscillatory patterns represent a biomarker of the integrity and the functioning of the underlying visual system.
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Affiliation(s)
- Jessica Gallina
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, Italy.,Department of Psychology, University of Bologna, Bologna, Italy
| | - Marco Zanon
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, Italy.,Department of Psychology, University of Bologna, Bologna, Italy.,Neuroscience Area, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Ezequiel Mikulan
- Department of Biomedical and Clinical Sciences "L. Sacco", University of Milan, Milan, Italy
| | - Mattia Pietrelli
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, Italy.,Department of Psychology, University of Bologna, Bologna, Italy.,Department of Psychiatry, University of WI-Madison, Wisconsin, USA
| | - Silvia Gambino
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, Italy.,Department of Psychology, University of Bologna, Bologna, Italy
| | - Agustín Ibáñez
- Latin American Brain Health (BrainLat), Universidad Adolfo Ibáñez, Santiago, Chile.,Cognitive Neuroscience Center (CNC), Universidad de San Andrés, Buenos Aires, Argentina.,National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina.,Global Brain Health Institute, University of California-San Francisco, San Francisco, CA, USA.,Trinity College Dublin, Dublin, Ireland
| | - Caterina Bertini
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, Italy. .,Department of Psychology, University of Bologna, Bologna, Italy.
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10
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Räty S, Ruuth R, Silvennoinen K, Sabel BA, Tatlisumak T, Vanni S. Resting-state Functional Connectivity After Occipital Stroke. Neurorehabil Neural Repair 2021; 36:151-163. [PMID: 34949135 DOI: 10.1177/15459683211062897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Resting-state functional magnetic resonance imaging (rsfMRI) reflects spontaneous activation of cortical networks. After stroke, these networks reorganize, both due to structural lesion and reorganization of functional connectivity (FC). OBJECTIVE We studied FC in chronic phase occipital stroke patients with homonymous visual field defects before and after repetitive transorbital alternating current stimulation (rtACS). METHODS This spin-off study, embedded in the randomized, sham-controlled REVIS trial, comprised 16 chronic occipital stroke patients with visual field defect and 12 healthy control subjects. The patients underwent rsfMRI at baseline, after two weeks of rtACS or sham treatment, and after two months of treatment-free follow-up, whereas the control subjects were measured once. We used a multivariate regression connectivity model to determine mutual prediction accuracy between 74 cortical regions of interest. Additionally, the model parameters were included into a graph to analyze average path length, centrality eigenvector, centrality degree, and clustering of the network. The patients and controls at baseline and the two treatment groups were compared with multilevel modeling. RESULTS Before treatment, the patients and controls had similar whole-network prediction accuracy and network parameters, whereas centrality eigenvector differed in perilesional regions, indicating local modification in connectivity. In line with behavioral results, neither prediction accuracy nor any network parameter changed systematically as a result of rtACS rehabilitation compared to sham. CONCLUSIONS Whole-network FC showed no difference between occipital stroke patients and healthy population, congruent with the peripheral location of the visual network in relation to the high-density cortical core. rtACS treatment in the given setting did not affect FC.
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Affiliation(s)
- Silja Räty
- Department of Neurology, 3836Helsinki University Hospital and University of Helsinki, Helsinki, Finland.,Advanced Magnetic Imaging Centre, 174277Aalto University, Espoo, Finland
| | - Riikka Ruuth
- HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Katri Silvennoinen
- Department of Neurology, 3836Helsinki University Hospital and University of Helsinki, Helsinki, Finland.,Department of Clinical and Experimental Epilepsy, 61554UCL Queen Square Institute of Neurology, London, UK
| | - Bernhard A Sabel
- Institute of Medical Psychology, Medical Faculty, Otto-v, -Guericke University of Magdeburg, Magdeburg, Germany
| | - Turgut Tatlisumak
- Department of Clinical Neurosciences/Neurology, 70712Institute of Neurosciences and Physiology, Sahlgrenska Academy at University of Gothenburg and Department of Neurology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Simo Vanni
- Department of Neurology, 3836Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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Bennett CR, Bauer CM, Bex PJ, Bottari D, Merabet LB. Visual search performance in cerebral visual impairment is associated with altered alpha band oscillations. Neuropsychologia 2021; 161:108011. [PMID: 34474066 PMCID: PMC8488018 DOI: 10.1016/j.neuropsychologia.2021.108011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/30/2021] [Accepted: 08/26/2021] [Indexed: 11/15/2022]
Abstract
Individuals with cerebral visual impairment (CVI) often present with deficits related to visuospatial processing. However, the neurophysiological basis underlying these higher order perceptual dysfunctions have not been clearly identified. We assessed visual search performance using a novel virtual reality based task paired with eye tracking to simulate the exploration of a naturalistic scene (a virtual toy box). This was combined with electroencephalography (EEG) recordings and an analysis pipeline focusing on time frequency decomposition of alpha oscillatory activity. We found that individuals with CVI showed an overall impairment in visual search performance (as indexed by decreased success rate, as well as increased reaction time, visual search area, and gaze error) compared to controls with neurotypical development. Analysis of captured EEG activity following stimulus onset revealed that in the CVI group, there was a distinct lack of strong and well defined posterior alpha desynchronization; an important signal involved in the coordination of neural activity related to visual processing. Finally, an exploratory analysis revealed that in CVI, the magnitude of alpha desynchronization was associated with impaired visual search performance as well as decreased volume of specific thalamic nuclei implicated in visual processing. These results suggest that impairments in visuospatial processing related to visual search in CVI are associated with alterations in alpha band oscillations as well as early neurological injury at the level of visual thalamic nuclei.
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Affiliation(s)
- Christopher R Bennett
- The Laboratory for Visual Neuroplasticity, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Corinna M Bauer
- The Laboratory for Visual Neuroplasticity, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Peter J Bex
- Translational Vision Lab, Department of Psychology, Northeastern University, Boston, MA, USA
| | | | - Lotfi B Merabet
- The Laboratory for Visual Neuroplasticity, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA.
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12
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Allaman L, Mottaz A, Guggisberg AG. Disrupted resting-state EEG alpha-band interactions as a novel marker for the severity of visual field deficits after brain lesion. Clin Neurophysiol 2021; 132:2101-2109. [PMID: 34284245 DOI: 10.1016/j.clinph.2021.05.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 05/10/2021] [Accepted: 05/25/2021] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Homonymous visual field deficits (HFVDs) are frequent following brain lesions. Current restoration treatments aim at activating areas of residual vision through numerous stimuli, but show limited effect. Recent findings suggest that spontaneous neural α-band coupling is more efficient for enabling visual perception in healthy humans than task-induced activations. Here, we evaluated whether it is also associated with the severity of HFVD. METHODS Ten patients with HFVDs after brain damage in the subacute to chronic stage and ten matched healthy controls underwent visual stimulation with alternating checkerboards and electroencephalography recordings of stimulation-induced power changes and of spontaneous neural interactions during rest. RESULTS Visual areas of the affected hemisphere showed reduced event-related power decrease in α and β frequency bands, but also reduced spontaneous α-band interactions during rest, as compared to contralesional areas and healthy controls. A multivariate stepwise regression retained the degree of disruption of spontaneous interactions, but not the reduced task-induced power changes as predictor for the severity of the visual deficit. CONCLUSIONS Spontaneous α-band interactions of visual areas appear as a better marker for the severity of HFVDs than task-induced activations. SIGNIFICANCE Treatment attempts of HFVDs should try to enhance spontaneous α-band coupling of structurally intact ipsilesional areas.
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Affiliation(s)
- Leslie Allaman
- Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital of Geneva, Av. de Beau-Séjour 26, 1211 Genève 14, Switzerland
| | - Anaïs Mottaz
- Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital of Geneva, Av. de Beau-Séjour 26, 1211 Genève 14, Switzerland
| | - Adrian G Guggisberg
- Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital of Geneva, Av. de Beau-Séjour 26, 1211 Genève 14, Switzerland.
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13
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Right Hemisphere Dominance for Unconscious Emotionally Salient Stimuli. Brain Sci 2021; 11:brainsci11070823. [PMID: 34206214 PMCID: PMC8301990 DOI: 10.3390/brainsci11070823] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/13/2021] [Accepted: 06/18/2021] [Indexed: 12/30/2022] Open
Abstract
The present review will focus on evidence demonstrating the prioritization in visual processing of fear-related signals in the absence of awareness. Evidence in hemianopic patients without any form of blindsight or affective blindsight in classical terms will be presented, demonstrating that fearful faces, via a subcortical colliculo-pulvinar-amygdala pathway, have a privileged unconscious visual processing and facilitate responses towards visual stimuli in the intact visual field. Interestingly, this fear-specific implicit visual processing in hemianopics has only been observed after lesions to the visual cortices in the left hemisphere, while no effect was found in patients with damage to the right hemisphere. This suggests that the subcortical route for emotional processing in the right hemisphere might provide a pivotal contribution to the implicit processing of fear, in line with evidence showing enhanced right amygdala activity and increased connectivity in the right colliculo-pulvinar-amygdala pathway for unconscious fear-conditioned stimuli and subliminal fearful faces. These findings will be discussed within a theoretical framework that considers the amygdala as an integral component of a constant and continuous vigilance system, which is preferentially invoked with stimuli signaling ambiguous environmental situations of biological relevance, such as fearful faces.
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14
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Gallina J, Pietrelli M, Zanon M, Bertini C. Hemispheric differences in altered reactivity of brain oscillations at rest after posterior lesions. Brain Struct Funct 2021; 227:709-723. [PMID: 33895865 PMCID: PMC8844183 DOI: 10.1007/s00429-021-02279-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/10/2021] [Indexed: 01/11/2023]
Abstract
A variety of evidence supports the dominance of the right hemisphere in perceptual and visuo-spatial processing. Although growing evidence shows a strong link between alpha oscillations and the functionality of the visual system, asymmetries in alpha oscillatory patterns still need to be investigated. Converging findings indicate that the typical alpha desynchronization occurring in the transition from the eyes-closed to the eyes-open resting state might represent an index of reactivity of the visual system. Thus, investigating hemispheric asymmetries in EEG reactivity at the opening of the eyes in brain-lesioned patients may shed light on the contribution of specific cortical sites and each hemisphere in regulating the oscillatory patterns reflecting the functionality of the visual system. To this aim, EEG signal was recorded during eyes-closed and eyes-open resting state in hemianopic patients with posterior left or right lesions, patients without hemianopia with anterior lesions and healthy controls. Hemianopics with both left and right posterior lesions showed a reduced alpha reactivity at the opening of the eyes, suggesting that posterior cortices have a pivotal role in the functionality of alpha oscillations. However, right-lesioned hemianopics showed a greater dysfunction, demonstrated by a reactivity reduction more distributed over the scalp, compared to left-lesioned hemianopics. Moreover, they also revealed impaired reactivity in the theta range. This favors the hypothesis of a specialized role of the right hemisphere in orchestrating oscillatory patterns, both coordinating widespread alpha oscillatory activity and organizing focal processing in the theta range, to support visual processing at the opening of the eyes.
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Affiliation(s)
- Jessica Gallina
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, 47521, Cesena, Italy.,Department of Psychology, University of Bologna, Viale Berti Pichat 5, 40121, Bologna, Italy
| | - Mattia Pietrelli
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, 47521, Cesena, Italy.,Department of Psychology, University of Bologna, Viale Berti Pichat 5, 40121, Bologna, Italy.,Department of Psychiatry, University of Wisconsin-Madison, 6001 Research Park Blvd, Madison, WI, 53719, USA
| | - Marco Zanon
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, 47521, Cesena, Italy.,Department of Psychology, University of Bologna, Viale Berti Pichat 5, 40121, Bologna, Italy.,Neuroscience Area, International School for Advanced Studies (SISSA), Via Bonomea, 265, 34136, Trieste, Italy
| | - Caterina Bertini
- Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Via Rasi e Spinelli 176, 47521, Cesena, Italy. .,Department of Psychology, University of Bologna, Viale Berti Pichat 5, 40121, Bologna, Italy.
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15
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Makin ADJ, Tyson-Carr J, Rampone G, Morris A, Bertamini M. Right lateralized alpha desynchronization increases with the proportion of symmetry in the stimulus. Eur J Neurosci 2021; 53:3175-3184. [PMID: 33675549 DOI: 10.1111/ejn.15176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 02/28/2021] [Accepted: 02/28/2021] [Indexed: 11/27/2022]
Abstract
Research into the neural basis of symmetry perception has intensified in the last two decades; however, the functional role of neural oscillations remains unclear. In previous work Makin et al. (2014, Journal of Vision, 14, 1-12) and Wright et al. (2015, Psychophysiology, 52, 638-647) examined occipital alpha event-related desynchronization (alpha ERD). It was concluded that alpha ERD is right lateralized during active regularity discrimination but not during a secondary task. Furthermore, alpha ERD was unaffected by stimulus properties, such as the type of regularity. These conclusions are refuted by new time-frequency analysis on an electroencephalography (EEG) data set first introduced by Makin et al. (2020, Journal of Cognitive Neuroscience, 32, 353-366). We compared alpha ERD across five tasks. First, we found that right lateralization of alpha ERD was evident in all tasks, not just active regularity discrimination. This was caused by hemispheric differences in alpha power during prestimulus baseline (left < right), which equalized after stimulus onset (left = right). Second, we found that Alpha ERD increased with the proportion of symmetric elements in the image (PSYMM). Sensitivity to PSYMM was stronger on the right. These findings suggest that known extrastriate symmetry activations are accompanied by reduced alpha power.
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Affiliation(s)
- Alexis D J Makin
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK
| | - John Tyson-Carr
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK
| | - Giulia Rampone
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK
| | - Amie Morris
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK
| | - Marco Bertamini
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK.,Department of General Psychology, University of Padova, Padova, Italy
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16
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Grasso PA, Gallina J, Bertini C. Shaping the visual system: cortical and subcortical plasticity in the intact and the lesioned brain. Neuropsychologia 2020; 142:107464. [PMID: 32289349 DOI: 10.1016/j.neuropsychologia.2020.107464] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/08/2020] [Indexed: 02/06/2023]
Abstract
Visual system is endowed with an incredibly complex organization composed of multiple visual pathway affording both hierarchical and parallel processing. Even if most of the visual information is conveyed by the retina to the lateral geniculate nucleus of the thalamus and then to primary visual cortex, a wealth of alternative subcortical pathways is present. This complex organization is experience dependent and retains plastic properties throughout the lifespan enabling the system with a continuous update of its functions in response to variable external needs. Changes can be induced by several factors including learning and experience but can also be promoted by the use non-invasive brain stimulation techniques. Furthermore, besides the astonishing ability of our visual system to spontaneously reorganize after injuries, we now know that the exposure to specific rehabilitative training can produce not only important functional modifications but also long-lasting changes within cortical and subcortical structures. The present review aims to update and address the current state of the art on these topics gathering studies that reported relevant modifications of visual functioning together with plastic changes within cortical and subcortical structures both in the healthy and in the lesioned visual system.
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Affiliation(s)
- Paolo A Grasso
- Department of Neuroscience, Psychology, Pharmacology and Child Health, University of Florence, Florence, 50135, Italy.
| | - Jessica Gallina
- Department of Psychology, University of Bologna, Bologna, 40127, Italy; CsrNC, Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, 47521, Italy
| | - Caterina Bertini
- Department of Psychology, University of Bologna, Bologna, 40127, Italy; CsrNC, Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Cesena, 47521, Italy
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