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Abstract
When facing ambiguous images, the brain switches between mutually exclusive interpretations, a phenomenon known as bistable perception. Despite years of research, a consensus on whether bistability is driven primarily by bottom-up or top-down mechanisms has not been achieved. Here, we adopted a Bayesian approach to reconcile these two theories. Fifty-five healthy participants were exposed to an adaptation of the Necker cube paradigm, in which we manipulated sensory evidence and prior knowledge. Manipulations of both sensory evidence and priors significantly affected the way participants perceived the Necker cube. However, we observed an interaction between the effect of the cue and the effect of the instructions, a finding that is incompatible with Bayes-optimal integration. In contrast, the data were well predicted by a circular inference model. In this model, ambiguous sensory evidence is systematically biased in the direction of current expectations, ultimately resulting in a bistable percept.
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Wu CC, Cao B, Dali V, Gagliardi C, Barthelemy OJ, Salazar RD, Pomplun M, Cronin-Golomb A, Yazdanbakhsh A. Eye movement control during visual pursuit in Parkinson's disease. PeerJ 2018; 6:e5442. [PMID: 30155357 PMCID: PMC6109371 DOI: 10.7717/peerj.5442] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 07/24/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Prior studies of oculomotor function in Parkinson's disease (PD) have either focused on saccades without considering smooth pursuit, or tested smooth pursuit while excluding saccades. The present study investigated the control of saccadic eye movements during pursuit tasksand assessed the quality of binocular coordinationas potential sensitive markers of PD. METHODS Observers fixated on a central cross while a target moved toward it. Once the target reached the fixation cross, observers began to pursue the moving target. To further investigate binocular coordination, the moving target was presented on both eyes (binocular condition), or on one eye only (dichoptic condition). RESULTS The PD group made more saccades than age-matched normal control adults (NC) both during fixation and pursuit. The difference between left and right gaze positions increased over time during the pursuit period for PD but not for NC. The findings were not related to age, as NC and young-adult control group (YC) performed similarly on most of the eye movement measures, and were not correlated with classical measures of PD severity (e.g., Unified Parkinson's Disease Rating Scale (UPDRS) score). DISCUSSION Our results suggest that PD may be associated with impairment not only in saccade inhibition, but also in binocular coordination during pursuit, and these aspects of dysfunction may be useful in PD diagnosis or tracking of disease course.
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Affiliation(s)
- Chia-Chien Wu
- Center for Computational Neuroscience and Neural Technology, Boston University, Boston, MA, USA
| | - Bo Cao
- Department of Psychiatry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Veena Dali
- Center for Computational Neuroscience and Neural Technology, Boston University, Boston, MA, USA
| | - Celia Gagliardi
- Center for Computational Neuroscience and Neural Technology, Boston University, Boston, MA, USA
| | | | - Robert D. Salazar
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
| | - Marc Pomplun
- Department of Computer Science, University of Massachusetts at Boston, Boston, MA, USA
| | - Alice Cronin-Golomb
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
| | - Arash Yazdanbakhsh
- Center for Computational Neuroscience and Neural Technology, Boston University, Boston, MA, USA
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
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Díaz-Santos M, Mauro S, Cao B, Yazdanbakhsh A, Neargarder S, Cronin-Golomb A. Bistable perception in normal aging: perceptual reversibility and its relation to cognition. AGING NEUROPSYCHOLOGY AND COGNITION 2016; 24:115-134. [PMID: 27116194 DOI: 10.1080/13825585.2016.1173646] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The effects of age on the ability to resolve perceptual ambiguity are unknown, though it depends on frontoparietal attentional networks known to change with age. We presented the bistable Necker cube to 24 middle-aged and OAs (older adults; 56-78 years) and 20 YAs (younger adults; 18-24 years) under passive-viewing and volitional control conditions: Hold one cube percept and Switch between cube percepts. During passive viewing, OAs had longer dominance durations (time spent on each percept) than YAs. In the Hold condition, OAs were less able than YAs to increase dominance durations. In the Switch condition, OAs and YAs did not differ in performance. Dominance durations in either condition correlated with performance on tests of executive function mediated by the frontal lobes. Eye movements (fixation deviations) did not differ between groups. These results suggest that OAs' reduced ability to hold a percept may arise from reduced selective attention. The lack of correlation of performance between Hold and executive-function measures suggests at least a partial segregation of underlying mechanisms.
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Affiliation(s)
- Mirella Díaz-Santos
- a Department of Psychological and Brain Sciences , Boston University , Boston , MA , USA
| | - Samantha Mauro
- a Department of Psychological and Brain Sciences , Boston University , Boston , MA , USA
| | - Bo Cao
- b Center for Computational Neuroscience and Neural Technology , Boston University , Boston , MA , USA
| | - Arash Yazdanbakhsh
- b Center for Computational Neuroscience and Neural Technology , Boston University , Boston , MA , USA
| | - Sandy Neargarder
- a Department of Psychological and Brain Sciences , Boston University , Boston , MA , USA.,c Department of Psychology , Hart Hall, Bridgewater State University , Bridgewater , MA , USA
| | - Alice Cronin-Golomb
- a Department of Psychological and Brain Sciences , Boston University , Boston , MA , USA
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Multistable Perception in Older Adults: Constructing a Whole from Fragments. Brain Sci 2016; 6:brainsci6010010. [PMID: 27011204 PMCID: PMC4810180 DOI: 10.3390/brainsci6010010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/07/2016] [Accepted: 03/15/2016] [Indexed: 11/23/2022] Open
Abstract
Visual perception is constructive in nature; that is, a coherent whole is generated from ambiguous fragments that are encountered in dynamic visual scenes. Creating this coherent whole from fragmented sensory inputs requires one to detect, identify, distinguish and organize sensory input. The organization of fragments into a coherent whole is facilitated by the continuous interactions between lower level sensory inputs and higher order processes. However, age-related declines are found in both neural structures and cognitive processes (e.g., attention and inhibition). The impact of these declines on the constructive nature of visual processing was the focus of this study. Here we asked younger adults, young-old (65–79 years), and old-old adults (80+ years) to view a multistable figure (i.e., Necker cube) under four conditions (free, priming, volition, and adaptation) and report, via a button press, when percepts spontaneously changed. The oldest-olds, unlike young-olds and younger adults, were influenced by priming, had less visual stability during volition and showed less ability to adapt to multistable stimuli. These results suggest that the ability to construct a coherent whole from fragments declines with age. More specifically, vision is constructed differently in the old-olds, which might influence environmental interpretations and navigational abilities in this age group.
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Díaz-Santos M, Cao B, Yazdanbakhsh A, Norton DJ, Neargarder S, Cronin-Golomb A. Perceptual, cognitive, and personality rigidity in Parkinson's disease. Neuropsychologia 2015; 69:183-93. [PMID: 25640973 PMCID: PMC4344854 DOI: 10.1016/j.neuropsychologia.2015.01.044] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Revised: 01/27/2015] [Accepted: 01/29/2015] [Indexed: 12/18/2022]
Abstract
Parkinson's disease (PD) is associated with motor and non-motor rigidity symptoms (e.g., cognitive and personality). The question is raised as to whether rigidity in PD also extends to perception, and if so, whether perceptual, cognitive, and personality rigidities are correlated. Bistable stimuli were presented to 28 non-demented individuals with PD and 26 normal control adults (NC). Necker cube perception and binocular rivalry were examined during passive viewing, and the Necker cube was additionally used for two volitional-control conditions: Hold one percept in front, and Switch between the two percepts. Relative to passive viewing, PD were significantly less able than NC to reduce dominance durations in the Switch condition, indicating perceptual rigidity. Tests of cognitive flexibility and a personality questionnaire were administered to explore the association with perceptual rigidity. Cognitive flexibility was not correlated with perceptual rigidity for either group. Personality (novelty seeking) correlated with dominance durations on Necker passive viewing for PD but not NC. The results indicate the presence in mild-moderate PD of perceptual rigidity and suggest shared neural substrates with novelty seeking, but functional divergence from those supporting cognitive flexibility. The possibility is raised that perceptual rigidity may be a harbinger of cognitive inflexibility later in the disease course.
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Affiliation(s)
- Mirella Díaz-Santos
- Department of Psychological and Brain Sciences, Boston University, 648 Beacon Street, 2nd floor, Boston, MA 02215, USA.
| | - Bo Cao
- Center for Computational Neuroscience and Neural Technology, Boston University, 677 Beacon Street, Boston, MA 02215, USA.
| | - Arash Yazdanbakhsh
- Center for Computational Neuroscience and Neural Technology, Boston University, 677 Beacon Street, Boston, MA 02215, USA.
| | - Daniel J Norton
- Department of Psychological and Brain Sciences, Boston University, 648 Beacon Street, 2nd floor, Boston, MA 02215, USA.
| | - Sandy Neargarder
- Department of Psychological and Brain Sciences, Boston University, 648 Beacon Street, 2nd floor, Boston, MA 02215, USA; Department of Psychology, Hart Hall, Bridgewater State University, Bridgewater, MA 02325, USA.
| | - Alice Cronin-Golomb
- Department of Psychological and Brain Sciences, Boston University, 648 Beacon Street, 2nd floor, Boston, MA 02215, USA.
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