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Dugan C, Zikopoulos B, Yazdanbakhsh A. A neural modeling approach to study mechanisms underlying the heterogeneity of visual spatial frequency sensitivity in schizophrenia. bioRxiv 2023:2023.10.18.563001. [PMID: 37904992 PMCID: PMC10614973 DOI: 10.1101/2023.10.18.563001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Patients with schizophrenia exhibit abnormalities in spatial frequency sensitivity, and it is believed that these abnormalities indicate more widespread dysfunction and dysregulation of bottom-up processing. The early visual system, including the first-order Lateral Geniculate Nucleus of the thalamus (LGN) and the primary visual cortex (V1), are key contributors to spatial frequency sensitivity. Medicated and unmedicated patients with schizophrenia exhibit contrasting changes in spatial frequency sensitivity, thus making it a useful probe for examining potential effects of the disorder and antipsychotic medications in neural processing. We constructed a parameterized, rate-based neural model of on-center/off-surround neurons in the early visual system to investigate the impacts of changes to the excitatory and inhibitory receptive field subfields. By incorporating changes in both the excitatory and inhibitory subfields that are associated with pathophysiological findings in schizophrenia, the model successfully replicated perceptual data from behavioral/functional studies involving medicated and unmedicated patients. Among several plausible mechanisms, our results highlight the dampening of excitation and/or increase in the spread and strength of the inhibitory subfield in medicated patients and the contrasting decreased spread and strength of inhibition in unmedicated patients. Given that the model was successful at replicating results from perceptual data under a variety of conditions, these elements of the receptive field may be useful markers for the imbalances seen in patients with schizophrenia.
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Affiliation(s)
- Caroline Dugan
- Program in Neuroscience, Boston University, Boston, MA, United States
| | - Basilis Zikopoulos
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, Boston, MA, United States
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
| | - Arash Yazdanbakhsh
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
- Computational Neuroscience and Vision Laboratory, Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
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He D, Nguyen DT, Ogmen H, Nishina S, Yazdanbakhsh A. Perception of rigidity in three- and four-dimensional spaces. Front Psychol 2023; 14:1180561. [PMID: 37663341 PMCID: PMC10470465 DOI: 10.3389/fpsyg.2023.1180561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 08/02/2023] [Indexed: 09/05/2023] Open
Abstract
Our brain employs mechanisms to adapt to changing visual conditions. In addition to natural changes in our physiology and those in the environment, our brain is also capable of adapting to "unnatural" changes, such as inverted visual-inputs generated by inverting prisms. In this study, we examined the brain's capability to adapt to hyperspaces. We generated four spatial-dimensional stimuli in virtual reality and tested the ability to distinguish between rigid and non-rigid motion. We found that observers are able to differentiate rigid and non-rigid motion of hypercubes (4D) with a performance comparable to that obtained using cubes (3D). Moreover, observers' performance improved when they were provided with more immersive 3D experience but remained robust against increasing shape variations. At this juncture, we characterize our findings as "3 1/2 D perception" since, while we show the ability to extract and use 4D information, we do not have yet evidence of a complete phenomenal 4D experience.
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Affiliation(s)
- Dongcheng He
- Department of Electrical and Computer Engineering, Laboratory of Perceptual and Cognitive Dynamics, University of Denver, Denver, CO, United States
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, Berkeley, CA, United States
| | - Dat-Thanh Nguyen
- Department of Psychological and Brain Sciences, Computational Neuroscience and Vision Lab, Center for Systems Neuroscience, Graduate Program for Neuroscience, Boston University, Boston, MA, United States
| | - Haluk Ogmen
- Department of Electrical and Computer Engineering, Laboratory of Perceptual and Cognitive Dynamics, University of Denver, Denver, CO, United States
| | | | - Arash Yazdanbakhsh
- Department of Psychological and Brain Sciences, Computational Neuroscience and Vision Lab, Center for Systems Neuroscience, Graduate Program for Neuroscience, Boston University, Boston, MA, United States
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Zhu J, Zikopoulos B, Yazdanbakhsh A. A neural model of modified excitation/inhibition and feedback levels in schizophrenia. Front Psychiatry 2023; 14:1199690. [PMID: 37900297 PMCID: PMC10600455 DOI: 10.3389/fpsyt.2023.1199690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/20/2023] [Indexed: 10/31/2023] Open
Abstract
Introduction The strength of certain visual illusions, including contrast-contrast and apparent motion, is weakened in individuals with schizophrenia. Such phenomena have been interpreted as the impaired integration of inhibitory and excitatory neural responses, and impaired top-down feedback mechanisms. Methods To investigate whether and how these factors influence the perceived contrast-contrast and apparent motion illusions in individuals with schizophrenia, we propose a two-layer network, with top-down feedback from layer 2 to layer 1 that can model visual receptive fields (RFs) and their inhibitory and excitatory subfields. Results Our neural model suggests that illusion perception changes in individuals with schizophrenia can be influenced by altered top-down mechanisms and the organization of the on-center off-surround receptive fields. Alteration of the RF inhibitory surround and/or the excitatory center can replicate the difference of illusion precepts between individuals with schizophrenia within certain clinical states and normal controls. The results show that the simulated top-down feedback modulation enlarges the difference of the model illusion representations, replicating the difference between the two groups. Discussion We propose that the heterogeneity of visual and in general sensory processing in certain clinical states of schizophrenia can be largely explained by the degree of top-down feedback reduction, emphasizing the critical role of top-down feedback in illusion perception, and to a lesser extent on the imbalance of excitation/inhibition. Our neural model provides a mechanistic explanation for the modulated visual percepts of contrast-contrast and apparent motion in schizophrenia with findings that can explain a broad range of visual perceptual observations in previous studies. The two-layer motif of the current model provides a general framework that can be tailored to investigate subcortico-cortical (such as thalamocortical) and cortico-cortical networks, bridging neurobiological changes in schizophrenia and perceptual processing.
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Affiliation(s)
- Jiating Zhu
- Program in Brain, Behavior & Cognition, Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
| | - Basilis Zikopoulos
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, Boston, MA, United States
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
| | - Arash Yazdanbakhsh
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
- Computational Neuroscience and Vision Laboratory, Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
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Yazdanbakhsh A, Barbas H, Zikopoulos B. Sleep spindles in primates: Modeling the effects of distinct laminar thalamocortical connectivity in core, matrix, and reticular thalamic circuits. Netw Neurosci 2023; 7:743-768. [PMID: 37397882 PMCID: PMC10312265 DOI: 10.1162/netn_a_00311] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 03/01/2023] [Indexed: 10/16/2023] Open
Abstract
Sleep spindles are associated with the beginning of deep sleep and memory consolidation and are disrupted in schizophrenia and autism. In primates, distinct core and matrix thalamocortical (TC) circuits regulate sleep spindle activity through communications that are filtered by the inhibitory thalamic reticular nucleus (TRN); however, little is known about typical TC network interactions and the mechanisms that are disrupted in brain disorders. We developed a primate-specific, circuit-based TC computational model with distinct core and matrix loops that can simulate sleep spindles. We implemented novel multilevel cortical and thalamic mixing, and included local thalamic inhibitory interneurons, and direct layer 5 projections of variable density to TRN and thalamus to investigate the functional consequences of different ratios of core and matrix node connectivity contribution to spindle dynamics. Our simulations showed that spindle power in primates can be modulated based on the level of cortical feedback, thalamic inhibition, and engagement of model core versus matrix, with the latter having a greater role in spindle dynamics. The study of the distinct spatial and temporal dynamics of core-, matrix-, and mix-generated sleep spindles establishes a framework to study disruption of TC circuit balance underlying deficits in sleep and attentional gating seen in autism and schizophrenia.
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Affiliation(s)
- Arash Yazdanbakhsh
- Computational Neuroscience and Vision Lab, Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston, MA, USA
| | - Helen Barbas
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston, MA, USA
- Neural Systems Laboratory, Program in Human Physiology, Department of Health Sciences, College of Health and Rehabilitation Sciences (Sargent College), Boston University, Boston, MA, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston University, Boston, MA, USA
| | - Basilis Zikopoulos
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston, MA, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston University, Boston, MA, USA
- Human Systems Neuroscience Laboratory, Program in Human Physiology, Department of Health Sciences, College of Health and Rehabilitation Sciences (Sargent College), Boston University, Boston, MA, USA
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Zhu J, Zikopoulos B, Yazdanbakhsh A. A neural model of modified excitation/inhibition and feedback levels in schizophrenia. bioRxiv 2023:2023.04.24.538166. [PMID: 37162902 PMCID: PMC10168241 DOI: 10.1101/2023.04.24.538166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The strength of certain visual illusions is weakened in individuals with schizophrenia. Such phenomena have been interpreted as the impaired integration of inhibitory and excitatory neural responses, and impaired top-down feedback mechanisms. To investigate whether and how these factors influence the perceived illusions in individuals with schizophrenia, we propose a two-layer network that can model visual receptive fields (RFs), their inhibitory and excitatory subfields, and the top-down feedback. Our neural model suggests that illusion perception changes in individuals with schizophrenia can be influenced by altered top-down mechanisms and the organization of the on-center off-surround receptive fields. Alteration of the RF inhibitory surround and/or the excitatory center can replicate the difference of illusion precepts between individuals with schizophrenia and normal controls. The results show that the simulated top-down feedback modulation enlarges the difference of the model illusion representations, replicating the difference between the two groups. We propose that the heterogeneity of visual and in general sensory processing in schizophrenia can be largely explained by the degree of top-down feedback reduction, emphasizing the critical role of top-down feedback in illusion perception, and to a lesser extent on the imbalance of excitation/inhibition. Our neural model provides a mechanistic explanation for the modulated visual percepts in schizophrenia with findings that can explain a broad range of visual perceptual observations in previous studies. The two-layer motif of the current model provides a general framework that can be tailored to investigate subcortico-cortical (such as thalamocortical) and cortico-cortical networks, bridging neurobiological changes in schizophrenia and perceptual processing.
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Affiliation(s)
- Jiating Zhu
- Program in Brain, Behavior & Cognition, Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
| | - Basilis Zikopoulos
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, Boston, MA, United States
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, MA, United States
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
| | - Arash Yazdanbakhsh
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
- Computational Neuroscience and Vision Laboratory, Department of Psychological and Brain Sciences, Boston University, Boston, MA, United States
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Park S, Zikopoulos B, Yazdanbakhsh A. Visual illusion susceptibility in autism: A neural model. Eur J Neurosci 2022; 56:4246-4265. [PMID: 35701859 PMCID: PMC9541695 DOI: 10.1111/ejn.15739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 04/04/2022] [Accepted: 06/06/2022] [Indexed: 11/26/2022]
Abstract
While atypical sensory perception is reported among individuals with autism spectrum disorder (ASD), the underlying neural mechanisms of autism that give rise to disruptions in sensory perception remain unclear. We developed a neural model with key physiological, functional and neuroanatomical parameters to investigate mechanisms underlying the range of representations of visual illusions related to orientation perception in typically developed subjects compared to individuals with ASD. Our results showed that two theorized autistic traits, excitation/inhibition imbalance and weakening of top‐down modulation, could be potential candidates for reduced susceptibility to some visual illusions. Parametric correlation between cortical suppression, balance of excitation/inhibition, feedback from higher visual areas on one hand and susceptibility to a class of visual illusions related to orientation perception on the other hand provide the opportunity to investigate the contribution and complex interactions of distinct sensory processing mechanisms in ASD. The novel approach used in this study can be used to link behavioural, functional and neuropathological studies; estimate and predict perceptual and cognitive heterogeneity in ASD; and form a basis for the development of novel diagnostics and therapeutics.
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Affiliation(s)
- Sangwook Park
- Computational Neuroscience and Vision Laboratory, Boston University, Boston, Massachusetts, USA
| | - Basilis Zikopoulos
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, Boston, Massachusetts, USA.,Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA.,Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA.,Graduate Program for Neuroscience, Boston University, Boston, Massachusetts, USA
| | - Arash Yazdanbakhsh
- Computational Neuroscience and Vision Laboratory, Boston University, Boston, Massachusetts, USA.,Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA.,Graduate Program for Neuroscience, Boston University, Boston, Massachusetts, USA.,Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA
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Wilmerding LK, Yazdanbakhsh A, Hasselmo ME. Impact of optogenetic pulse design on CA3 learning and replay: A neural model. Cell Rep Methods 2022; 2:100208. [PMID: 35637904 PMCID: PMC9142690 DOI: 10.1016/j.crmeth.2022.100208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 10/22/2021] [Accepted: 04/11/2022] [Indexed: 11/23/2022]
Abstract
Optogenetic manipulation of hippocampal circuitry is an important tool for investigating learning in vivo. Numerous approaches to pulse design have been employed to elicit desirable circuit and behavioral outcomes. Here, we systematically test the outcome of different single-pulse waveforms in a rate-based model of hippocampal memory function at the level of mnemonic replay extension and de novo synaptic weight formation in CA3 and CA1. Lower-power waveforms with long forward or forward and backward ramps yield more natural sequence replay dynamics and induce synaptic plasticity that allows for more natural memory replay timing, in contrast to square or backward ramps. These differences between waveform shape and amplitude are preserved with the addition of noise in membrane potential, light scattering, and protein expression, improving the potential validity of predictions for in vivo work. These results inform future optogenetic experimental design choices in the field of learning and memory.
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Affiliation(s)
- Lucius K. Wilmerding
- Department of Psychological and Brain Sciences, Boston University, Boston, MA 02215, USA
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
| | - Arash Yazdanbakhsh
- Department of Psychological and Brain Sciences, Boston University, Boston, MA 02215, USA
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
| | - Michael E. Hasselmo
- Department of Psychological and Brain Sciences, Boston University, Boston, MA 02215, USA
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
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8
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Vinke LN, Yazdanbakhsh A. Lightness induction enhancements and limitations at low frequency modulations across a variety of stimulus contexts. PeerJ 2020; 8:e8918. [PMID: 32351782 PMCID: PMC7183748 DOI: 10.7717/peerj.8918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 03/16/2020] [Indexed: 11/20/2022] Open
Abstract
Lightness illusions are often studied under static viewing conditions with figures varying in geometric design, containing different types of perceptual grouping and figure-ground cues. A few studies have explored the perception of lightness induction while modulating lightness illusions continuously in time, where changes in perceived lightness are often linked to the temporal modulation frequency, up to around 2–4 Hz. These findings support the concept of a cut-off frequency for lightness induction. However, another critical change (enhancement) in the magnitude of perceived lightness during slower temporal modulation conditions has not been addressed in previous temporal modulation studies. Moreover, it remains unclear whether this critical change applies to a variety of lightness illusion stimuli, and the degree to which different stimulus configurations can demonstrate enhanced lightness induction in low modulation frequencies. Therefore, we measured lightness induction strength by having participants cancel out any perceived modulation in lightness detected over time within a central target region, while the surrounding context, which ultimately drives the lightness illusion, was viewed in a static state or modulated continuously in time over a low frequency range (0.25–2 Hz). In general, lightness induction decreased as temporal modulation frequency was increased, with the strongest perceived lightness induction occurring at lower modulation frequencies for visual illusions with strong grouping and figure-ground cues. When compared to static viewing conditions, we found that slow continuous surround modulation induces a strong and significant increase in perceived lightness for multiple types of lightness induction stimuli. Stimuli with perceptually ambiguous grouping and figure-ground cues showed weaker effects of slow modulation lightness enhancement. Our results demonstrate that, in addition to the existence of a cut-off frequency, an additional critical temporal modulation frequency of lightness induction exists (0.25–0.5 Hz), which instead maximally enhances lightness induction and seems to be contingent upon the prevalence of figure-ground and grouping organization.
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Affiliation(s)
- Louis Nicholas Vinke
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience (CSN), Boston University, Boston, MA, USA
| | - Arash Yazdanbakhsh
- Graduate Program for Neuroscience, Boston University, Boston, MA, USA
- Center for Systems Neuroscience (CSN), Boston University, Boston, MA, USA
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
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Ogmen H, Shibata K, Yazdanbakhsh A. Perception, Cognition, and Action in Hyperspaces: Implications on Brain Plasticity, Learning, and Cognition. Front Psychol 2020; 10:3000. [PMID: 32038384 PMCID: PMC6987450 DOI: 10.3389/fpsyg.2019.03000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/18/2019] [Indexed: 11/30/2022] Open
Abstract
We live in a three-dimensional (3D) spatial world; however, our retinas receive a pair of 2D projections of the 3D environment. By using multiple cues, such as disparity, motion parallax, perspective, our brains can construct 3D representations of the world from the 2D projections on our retinas. These 3D representations underlie our 3D perceptions of the world and are mapped into our motor systems to generate accurate sensorimotor behaviors. Three-dimensional perceptual and sensorimotor capabilities emerge during development: the physiology of the growing baby changes hence necessitating an ongoing re-adaptation of the mapping between 3D sensory representations and the motor coordinates. This adaptation continues in adulthood and is quite general to successfully deal with joint-space changes (longer arms due to growth), skull and eye size changes (and still being able of accurate eye movements), etc. A fundamental question is whether our brains are inherently limited to 3D representations of the environment because we are living in a 3D world, or alternatively, our brains may have the inherent capability and plasticity of representing arbitrary dimensions; however, 3D representations emerge from the fact that our development and learning take place in a 3D world. Here, we review research related to inherent capabilities and limitations of brain plasticity in terms of its spatial representations and discuss whether with appropriate training, humans can build perceptual and sensorimotor representations of spatial 4D environments, and how the presence or lack of ability of a solid and direct 4D representation can reveal underlying neural representations of space.
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Affiliation(s)
- Haluk Ogmen
- Laboratory of Perceptual and Cognitive Dynamics, Electrical & Computer Engineering, Ritchie School of Engineering & Computer Science, University of Denver, Denver, CO, United States
| | - Kazuhisa Shibata
- Laboratory for Human Cognition and Learning, RIKEN Center for Brain Science, Wako, Japan
| | - Arash Yazdanbakhsh
- Department of Psychological and Brain Sciences, Computational Neuroscience and Vision Lab, Center for Systems Neuroscience, Boston University, Boston, MA, United States
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Qaribi M, Yazdanbakhsh A, Ahmadi K, Maghsoudi MR, Farshin V, Ahmadi A, Jokar A. The Effects of Filgrastim on Complications of Patients with Cerebral Hemorrhage Due To Head Trauma. Open Access Maced J Med Sci 2018; 6:2030-2034. [PMID: 30559855 PMCID: PMC6290401 DOI: 10.3889/oamjms.2018.412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/09/2018] [Accepted: 10/10/2018] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Filgrastim, a neopogen brand, is a blood-forming agent and a natural protein in the body that plays a role in stimulating the growth of white blood cells and protecting them against infectious agents. To the best of knowledge, human and animal specimens have shown the effect of Filgrastim on treating brain injuries regarding bone marrow transfusion into the blood, neuroprotection, stimulation of neurons for forming new neural networks and reducing the risk of bacterial infections. AIM This study aimed to investigate the effect of Filgrastim on the prognosis of a cerebral haemorrhage in patients with traumatic brain injury. METHODS This study was conducted as a clinical trial, in which the initial diagnosis of patients with cerebral haemorrhage due to head trauma was performed with a clinical examination and CT scan. After the patient arrives at the emergency room, the patient's initial examination is performed, and blood tests are taken from the patient. Moreover, CBC values (Hb, Platelet, Hematocrit) were checked and recorded in the checklist. The intervention group received 150 mcg/day Filgrastim injected subcutaneously for 4 days. Furthermore, patients in the control group received the same amount of sterile water. At the end of the treatment period, blood tests were performed again in all patients, and their results were then recorded. All data were analysed by SPSS v.21 software package. RESULTS Our findings revealed that the mean volume of bleeding in the intervention group based on CT scan was significantly reduced after four days as compared to the control group. Moreover, the mean score of consciousness and muscular strength of patients in the intervention group was significantly higher than the control group. Also, WBCs in the intervention group exhibited a significant increase after four days of intervention, while platelet and hematocrit levels in the intervention group decreased significantly compared to the control group. CONCLUSION Regarding the results, the therapeutic application of filtration is considered to be effective. Given the lack of serious complications of the proposed dosages, the use of this drug can be suggested.
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Affiliation(s)
- Morteza Qaribi
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Arash Yazdanbakhsh
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Koorosh Ahmadi
- Department of Emergency Medicine, Alborz University of Medical Sciences, Karaj, Iran
| | | | - Vagefe Farshin
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Ali Ahmadi
- Iran University of Medical Sciences, Iran
| | - Abolfazl Jokar
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
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Jamshidi F, Yazdanbakhsh A, Jamalian M, Khademhosseini P, Ahmadi K, Sistani A, Jokar A. Therapeutic Effect of Adding Magnesium Sulfate in Treatment of Organophosphorus Poisoning. Open Access Maced J Med Sci 2018; 6:2051-2056. [PMID: 30559859 PMCID: PMC6290410 DOI: 10.3889/oamjms.2018.350] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 08/28/2018] [Accepted: 09/03/2018] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND: In recent years, the prevalence of poisoning has increased dramatically due to population growth and access to drugs and toxins. Today poisoning is one of the important reasons for visiting hospitals. AIM: The present study aimed to investigate the effect of magnesium sulfate on organophosphorous toxicity. METHODS: Patients who had inclusion criteria in the study were randomly assigned to one of two groups (control group or case group) by an emergency medicine specialist. Patients’ data including age, sex, ECG, vital signs, arterial oxygen saturation were recorded for patients. Patients in the case group (40 subjects) received 2 mg magnesium sulfate 50%, while the control group (40 subjects) received 100 cc normal saline (as placebo) as an intravenous infusion RESULTS: The distribution of gender in the two groups of patients was the same. Also, the mean age, Stature and weight of patients were similar in both groups. In the group receiving magnesium sulfate, diastolic blood pressure was lower when compared with another group, at 0 and 2 hours after intervention. Moreover, the mean of systolic blood pressure in both groups was determined to be the same at all hours. Furthermore, the heart rate in the group receiving sulfate was lower as compared to the control group for 8 hours, 16 and 24 hours after intervention. CONCLUSION: The use of magnesium sulfate in organophosphate poisoning reduces therapeutic costs an average hospital length of stay and mortality compared to those who did not receive magnesium sulfate.
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Affiliation(s)
- Fatemeh Jamshidi
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Arash Yazdanbakhsh
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | | | - Peyman Khademhosseini
- Department of Emergency Medicine, Karaj University of Medical Sciences, Alborz, Iran
| | - Koroosh Ahmadi
- Department of Emergency Medicine, Karaj University of Medical Sciences, Alborz, Iran
| | - Alireza Sistani
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Abolfazl Jokar
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
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Keshtkar M, Nishina S, Yazdanbakhsh A. Eye Movement Correlates of Figure-Ground Segregation and Border-Ownership. J Vis 2018. [DOI: 10.1167/18.10.595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Mohammad Keshtkar
- Program in Neuroscience, Boston UniversityVision Lab, Center for Research in Sensory Communications and Neural Technology (CReSCNT), Boston University, Boston, MA 02215
| | - Shigeaki Nishina
- Honda Research Institute Japan Co., Ltd., address: 8-1 Honcho, Wako-Shi, Saitama 351-0188
| | - Arash Yazdanbakhsh
- Vision Lab, Center for Research in Sensory Communications and Neural Technology (CReSCNT), Boston University, Boston, MA 02215Department of Psychological & Brain Sciences, Boston University
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Shea C, Bullock D, Yazdanbakhsh A. Assessing Strategies for Involuntary Saccadic Control during Pursuit of Transiently Occluded Targets. J Vis 2018. [DOI: 10.1167/18.10.593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Conor Shea
- Program in Neuroscience, Boston UniversityVision Lab, Center for Research in Sensory Communications and Neural Technology (CReSCNT), Boston University, Boston, MA 02215
| | - Daniel Bullock
- Department of Psychological & Brain Sciences, Boston University
| | - Arash Yazdanbakhsh
- Vision Lab, Center for Research in Sensory Communications and Neural Technology (CReSCNT), Boston University, Boston, MA 02215Department of Psychological & Brain Sciences, Boston University
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14
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Yazdanbakhsh A, Vinke L. Brightness Induction Enhancements and Limitations at Low Frequency Modulations Across a Variety of Stimulus Contexts. J Vis 2018. [DOI: 10.1167/18.10.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Arash Yazdanbakhsh
- Psychological & Brain Sciences, Boston University, Boston, MA 02215Graduate Program for Neuroscience, Boston University, Boston, MA 02215
| | - Louis Vinke
- Graduate Program for Neuroscience, Boston University, Boston, MA 02215Center for Systems Neuroscience, Boston University, Boston, MA 02215
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15
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Mikkelsen C, Yazdanbakhsh A. A Frontotemporal Regional Model of Post-Traumatic Stress Disorder. J Vis 2018. [DOI: 10.1167/18.10.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Catherine Mikkelsen
- Graduate Program for Neuroscience, Boston University, Boston, MA 02215Center for Systems Neuroscience, Boston University, Boston, MA 02215
| | - Arash Yazdanbakhsh
- Graduate Program for Neuroscience, Boston University, Boston, MA 02215Center for Systems Neuroscience, Boston University, Boston, MA 02215
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16
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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17
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Jokar A, Babaei M, Pourmatin S, Taheri M, Almasi-Hashiani A, Yazdanbakhsh A. Effects of Intravenous and Inhaled Nebulized Lignocaine on the Hemodynamic Response of Endotracheal Intubation Patients: A Randomized Clinical Trial. Anesth Essays Res 2018; 12:159-164. [PMID: 29628574 PMCID: PMC5872855 DOI: 10.4103/aer.aer_75_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background Endotracheal intubation is one of the most common measures in the Intensive Care Unit (ICU) which plays an important role in airway management of the critically ill patients. Aims The study aimed to evaluate the effects of lignocaine spray on hemodynamic response of endotracheal intubation patients. Settings and Design This study is a randomized clinical trial on a study population comprising patients admitted to the ICU. Subjects and Methods The patients were divided into three groups using a permuted block randomization. In Group 1, inhaled nebulized lignocaine 4% (75.0 mg/kg) was sprayed around the patients' epiglottis and larynx. In Group 2, intravenous (IV) lignocaine 2% (75.0/mg/kg) was injected. No lignocaine was prescribed for or administered to the control group. One and four minutes after intubation, the patients' hemodynamic and vital signs were measured. Statistical Analysis Used Data analysis was run using Stata 13 software through repeated measure ANOVA tests. Results Although the mean arterial blood pressure (MAP) of Group 1 (inhaled nebulized lignocaine) was smaller than that of Group 2 (IV lignocaine), there was no significant difference between the two groups. Both groups' MAPs were significantly different from that of the control group. As for the average number of pulses, a significant difference was observed between the inhaled and IV lignocaine groups; hence, the average number of pulses in Group 1 (inhalation) was lower than that of Group 2 (IV injection). Conclusion As blood pressure is considered to be normal under 140/90 and may not entail any hemodynamic complications, it can be concluded that inhaled nebulized lignocaine can control the hemodynamic changes of intubation more effectively than IV lignocaine.
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Affiliation(s)
- Abolfazl Jokar
- Department of Medical Emergency, Arak University of Medical Sciences, Arak, Iran
| | - Maryam Babaei
- Department of Medical Emergency, Arak University of Medical Sciences, Arak, Iran
| | - Sahar Pourmatin
- Department of Medical Emergency, Arak University of Medical Sciences, Arak, Iran
| | - Majid Taheri
- Medical Ethics and Law Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Almasi-Hashiani
- Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
| | - Arash Yazdanbakhsh
- Department of Medical Emergency, Arak University of Medical Sciences, Arak, Iran
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18
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Jokar A, Cyrus A, Babaei M, Taheri M, Almasi-Hashiani A, Behzadinia E, Yazdanbakhsh A. The Effect of Magnesium Sulfate on Renal Colic Pain Relief; a Randomized Clinical Trial. Emerg (Tehran) 2017; 5:e25. [PMID: 28286832 PMCID: PMC5325894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Renal colic can be managed by preventing the contraction movements of ureter muscles. By reducing acetylcholine in the nerve terminals, magnesium sulfate could be effective in this regard. The aim of this study is to investigate the effect of magnesium sulfate on acute renal colic pain relief. METHOD The present study was a double-blind clinical trial in which the patients suffering from acute renal colic were randomly divided into 2 groups of who either received standard protocol (intravenous infusion of 0.1 mg/Kg morphine sulfate, 30 mg of Ketorolac, and 100 ml normal saline as placebo/15 minutes) or standard protocol plus 15 mg/Kg of intravenous magnesium sulfate 50%/100 ml normal saline/15 minutes. Severity of patients' pain was measured by visual analogue scale (VAS) at baseline, and 30 and 60 minutes after infusion. The collected data were analyzed using STATA statistical software. RESULTS 100 cases were randomly allocated to intervention or control group. The two groups were similar in baseline pain score and demographic characteristics. At 30 and 60 minutes, mean pain score was less in the intervention group compared to the control group. Moreover, the difference between the two groups was statistically significant regarding the additional amount of morphine, suggesting that the intervention group needed less additional morphine than the control group. CONCLUSION The results of this study showed that Magnesium sulfate can be used as an adjunct drug in treatment of patients suffering from renal colic. It not only alleviates the pain in the patients, but also diminishes the need for pain medications.
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Affiliation(s)
- Abolfazl Jokar
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Ali Cyrus
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Maryam Babaei
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Majid Taheri
- Medical Ethics and Law Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Almasi-Hashiani
- Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
| | - Ezatollah Behzadinia
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran.,Corresponding author: Ezatollah Behzadinia; Department of Emergency Medicine, Vali-Asr Hospital, Arak University of Medical Sciences, Arak, Iran. ; Tel: 08632222003
| | - Arash Yazdanbakhsh
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
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19
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Gagliardi C, Yazdanbakhsh A. Investigating human memory of self-position using a virtual 3-dimensional visual environment. J Vis 2016. [DOI: 10.1167/16.12.354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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20
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Yazdanbakhsh A, Wu CC, Cao B, Dali V, Gagliardi C, Pomplun M, Cronin-Golomb A. Involuntary saccades and binocular coordination during visual pursuit in Parkinson's disease. J Vis 2016. [DOI: 10.1167/16.12.1358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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21
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Clayton KK, Swaminathan J, Yazdanbakhsh A, Zuk J, Patel AD, Kidd G. Executive Function, Visual Attention and the Cocktail Party Problem in Musicians and Non-Musicians. PLoS One 2016; 11:e0157638. [PMID: 27384330 PMCID: PMC4934907 DOI: 10.1371/journal.pone.0157638] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 06/02/2016] [Indexed: 11/24/2022] Open
Abstract
The goal of this study was to investigate how cognitive factors influence performance in a multi-talker, “cocktail-party” like environment in musicians and non-musicians. This was achieved by relating performance in a spatial hearing task to cognitive processing abilities assessed using measures of executive function (EF) and visual attention in musicians and non-musicians. For the spatial hearing task, a speech target was presented simultaneously with two intelligible speech maskers that were either colocated with the target (0° azimuth) or were symmetrically separated from the target in azimuth (at ±15°). EF assessment included measures of cognitive flexibility, inhibition control and auditory working memory. Selective attention was assessed in the visual domain using a multiple object tracking task (MOT). For the MOT task, the observers were required to track target dots (n = 1,2,3,4,5) in the presence of interfering distractor dots. Musicians performed significantly better than non-musicians in the spatial hearing task. For the EF measures, musicians showed better performance on measures of auditory working memory compared to non-musicians. Furthermore, across all individuals, a significant correlation was observed between performance on the spatial hearing task and measures of auditory working memory. This result suggests that individual differences in performance in a cocktail party-like environment may depend in part on cognitive factors such as auditory working memory. Performance in the MOT task did not differ between groups. However, across all individuals, a significant correlation was found between performance in the MOT and spatial hearing tasks. A stepwise multiple regression analysis revealed that musicianship and performance on the MOT task significantly predicted performance on the spatial hearing task. Overall, these findings confirm the relationship between musicianship and cognitive factors including domain-general selective attention and working memory in solving the “cocktail party problem”.
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Affiliation(s)
- Kameron K. Clayton
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States of America
| | - Jayaganesh Swaminathan
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States of America
- * E-mail:
| | - Arash Yazdanbakhsh
- Department for Psychological and Brain Sciences, Boston University, Boston, MA, United States of America
- Center for Computational Neuroscience and Neural Technology (CompNet), Boston University, Boston, MA, United States of America
| | - Jennifer Zuk
- Harvard Medical School, Harvard University, Boston, MA, United States of America
| | - Aniruddh D. Patel
- Department of Psychology, Tufts University, Medford, MA, United States of America
| | - Gerald Kidd
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States of America
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22
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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. Neuropsychol Dev Cogn B Aging Neuropsychol Cogn 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] [What about the content of this article? (0)] [Affiliation(s)] [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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23
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Žaric G, Yazdanbakhsh A, Nishina S, De Weerd P, Watanabe T. Perceived temporal asynchrony between sinusoidally modulated luminance and depth. J Vis 2016; 15:13. [PMID: 26605842 DOI: 10.1167/15.15.13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Simultaneously presented visual events lead to temporally asynchronous percepts. This has led some researchers to conclude that the asynchronous experience is a manifestation of differences in neural processing time for different visual attributes. Others, however, have suggested that the asynchronous experience is due to differences in temporal markers for changes of different visual attributes. Here, two sets of bars were presented, one to each eye. Either the bars were moving or their luminance was gradually changing. Bars moved horizontally in counterphase at low frequencies along short trajectories and were presented stereoscopically, such that the horizontal movements were perceived as back-and-forth motion on a sagittal plane, or monocularly to a dominant eye, preserving a perception of the horizontal movements on a frontal plane. In a control condition, bars were stationary and their luminance was modulated. The changes in stimulus speed or luminance occurred sinusoidally. When asked to adjust the phase of one stimulus to the other to achieve synchronous perception, participants showed a constant phase offset at the lowest frequencies used. Given the absence of abrupt transitions and the presence of similar gradual turning points in our stimuli to control for attentional effects, it can be concluded that asynchronous percepts in multimodal stimuli may at least in part be a manifestation of difference in neural processing time of visual attributes rather than solely a difference in the temporal markers (transitions versus turning points).
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Abstract
Spontaneous heterotopic pregnancy is a rare clinical condition in which intrauterine and extrauterine pregnancies occur at the same time. It is rare, estimated to occur in 1 in 30,000 pregnancies. The case was a 38-year-old woman with spontaneously conceived heterotopic pregnancy. She was admitted to our center with hypovolemic shock. Focused assessment sonography for trauma examination in emergency department showed large amount of free fluid in peritoneal cavity. She was managed surgical laparotomy. Considering spontaneous pregnancies, physician should be aware of the possibility of heterotopic pregnancy in all reproductive age women, especially those with history of recent abortion. It can occur without any predisposing risk factors. Patients should be informed about possible side effects of nonprescription medicines, and also the health care centers must be safe peaceful environment for them without severe legal consequences.
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Affiliation(s)
- Abdolghader Pakniyat
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | - Arash Yazdanbakhsh
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
| | | | - Fatimah Talebi
- Department of Emergency Medicine, Arak University of Medical Sciences, Arak, Iran
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25
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Cao B, Mingolla E, Yazdanbakhsh A. Tuning Properties of MT and MSTd and Divisive Interactions for Eye-Movement Compensation. PLoS One 2015; 10:e0142964. [PMID: 26575648 PMCID: PMC4648577 DOI: 10.1371/journal.pone.0142964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Accepted: 10/29/2015] [Indexed: 11/18/2022] Open
Abstract
The primate brain intelligently processes visual information from the world as the eyes move constantly. The brain must take into account visual motion induced by eye movements, so that visual information about the outside world can be recovered. Certain neurons in the dorsal part of monkey medial superior temporal area (MSTd) play an important role in integrating information about eye movements and visual motion. When a monkey tracks a moving target with its eyes, these neurons respond to visual motion as well as to smooth pursuit eye movements. Furthermore, the responses of some MSTd neurons to the motion of objects in the world are very similar during pursuit and during fixation, even though the visual information on the retina is altered by the pursuit eye movement. We call these neurons compensatory pursuit neurons. In this study we develop a computational model of MSTd compensatory pursuit neurons based on physiological data from single unit studies. Our model MSTd neurons can simulate the velocity tuning of monkey MSTd neurons. The model MSTd neurons also show the pursuit compensation property. We find that pursuit compensation can be achieved by divisive interaction between signals coding eye movements and signals coding visual motion. The model generates two implications that can be tested in future experiments: (1) compensatory pursuit neurons in MSTd should have the same direction preference for pursuit and retinal visual motion; (2) there should be non-compensatory pursuit neurons that show opposite preferred directions of pursuit and retinal visual motion.
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Affiliation(s)
- Bo Cao
- Department of Psychiatry and Behavioral Sciences, Medical School, The University of Texas Health Science Center at Houston, Houston, United States of America
| | - Ennio Mingolla
- Department of Communication Sciences and Disorders, Northeastern University, Boston, United States of America
| | - Arash Yazdanbakhsh
- Center for Computational Neuroscience and Neural Technology, Boston University, Boston, United States of America
- Department of Psychological & Brain Sciences, Boston University, Boston, United States of America
- * E-mail:
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26
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Yazdanbakhsh A, Gagliardi C. Human egocentric position estimation. J Vis 2015. [DOI: 10.1167/15.12.955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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27
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Gagliardi C, Yazdanbakhsh A. Eye Gaze Position before, during and after Percept Switching of Bistable Visual Stimului. J Vis 2015. [DOI: 10.1167/15.12.206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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28
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Abstract
Size constancy is one of the well-known visual phenomena that demonstrates perceptual stability to account for the effect of viewing distance on retinal image size. Although theories involving distance scaling to achieve size constancy have flourished based on psychophysical studies, its underlying neural mechanisms remain unknown. Single cell recordings show that distance-dependent size tuned cells are common along the ventral stream, originating from V1, V2, and V4 leading to IT. In addition, recent research employing fMRI demonstrates that an object's perceived size, associated with its perceived egocentric distance, modulates its retinotopic representation in V1. These results suggest that V1 contributes to size constancy, and its activity is possibly regulated by feedback of distance information from other brain areas. Here, we propose a neural model based on these findings. First, we construct an egocentric distance map in LIP by integrating horizontal disparity and vergence through gain-modulated MT neurons. Second, LIP neurons send modulatory feedback of distance information to size tuned cells in V1, resulting in a spread of V1 cortical activity. This process provides V1 with distance-dependent size representations. The model supports that size constancy is preserved by scaling retinal image size to compensate for changes in perceived distance, and suggests a possible neural circuit capable of implementing this process.
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Affiliation(s)
- Jiehui Qian
- Department of Psychology, Sun Yat-Sen University, Guangzhou, China
| | - Arash Yazdanbakhsh
- Department of Psychological & Brain Sciences, Center for Computational Neuroscience and Neural Technology, Boston University, Boston, Massachusetts, United States of America
- * E-mail:
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29
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Díaz-Santos M, Cao B, Mauro SA, Yazdanbakhsh A, Neargarder S, Cronin-Golomb A. Effect of visual cues on the resolution of perceptual ambiguity in Parkinson's disease and normal aging. J Int Neuropsychol Soc 2015; 21:146-55. [PMID: 25765890 PMCID: PMC5433847 DOI: 10.1017/s1355617715000065] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Parkinson's disease (PD) and normal aging have been associated with changes in visual perception, including reliance on external cues to guide behavior. This raises the question of the extent to which these groups use visual cues when disambiguating information. Twenty-seven individuals with PD, 23 normal control adults (NC), and 20 younger adults (YA) were presented a Necker cube in which one face was highlighted by thickening the lines defining the face. The hypothesis was that the visual cues would help PD and NC to exert better control over bistable perception. There were three conditions, including passive viewing and two volitional-control conditions (hold one percept in front; and switch: speed up the alternation between the two). In the Hold condition, the cue was either consistent or inconsistent with task instructions. Mean dominance durations (time spent on each percept) under passive viewing were comparable in PD and NC, and shorter in YA. PD and YA increased dominance durations in the Hold cue-consistent condition relative to NC, meaning that appropriate cues helped PD but not NC hold one perceptual interpretation. By contrast, in the Switch condition, NC and YA decreased dominance durations relative to PD, meaning that the use of cues helped NC but not PD in expediting the switch between percepts. Provision of low-level cues has effects on volitional control in PD that are different from in normal aging, and only under task-specific conditions does the use of such cues facilitate the resolution of perceptual ambiguity.
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Affiliation(s)
- Mirella Díaz-Santos
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts
| | - Bo Cao
- Center for Computational Neuroscience and Neural Technology, Boston University, Boston, Massachusetts
| | - Samantha A. Mauro
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts
| | - Arash Yazdanbakhsh
- Center for Computational Neuroscience and Neural Technology, Boston University, Boston, Massachusetts
| | - Sandy Neargarder
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts
- Department of Psychology, Hart Hall, Bridgewater State University, Bridgewater, Massachusetts
| | - Alice Cronin-Golomb
- Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts
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31
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Grossberg S, Srinivasan K, Yazdanbakhsh A. Binocular fusion and invariant category learning due to predictive remapping during scanning of a depthful scene with eye movements. Front Psychol 2015; 5:1457. [PMID: 25642198 PMCID: PMC4294135 DOI: 10.3389/fpsyg.2014.01457] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 11/28/2014] [Indexed: 12/02/2022] Open
Abstract
How does the brain maintain stable fusion of 3D scenes when the eyes move? Every eye movement causes each retinal position to process a different set of scenic features, and thus the brain needs to binocularly fuse new combinations of features at each position after an eye movement. Despite these breaks in retinotopic fusion due to each movement, previously fused representations of a scene in depth often appear stable. The 3D ARTSCAN neural model proposes how the brain does this by unifying concepts about how multiple cortical areas in the What and Where cortical streams interact to coordinate processes of 3D boundary and surface perception, spatial attention, invariant object category learning, predictive remapping, eye movement control, and learned coordinate transformations. The model explains data from single neuron and psychophysical studies of covert visual attention shifts prior to eye movements. The model further clarifies how perceptual, attentional, and cognitive interactions among multiple brain regions (LGN, V1, V2, V3A, V4, MT, MST, PPC, LIP, ITp, ITa, SC) may accomplish predictive remapping as part of the process whereby view-invariant object categories are learned. These results build upon earlier neural models of 3D vision and figure-ground separation and the learning of invariant object categories as the eyes freely scan a scene. A key process concerns how an object's surface representation generates a form-fitting distribution of spatial attention, or attentional shroud, in parietal cortex that helps maintain the stability of multiple perceptual and cognitive processes. Predictive eye movement signals maintain the stability of the shroud, as well as of binocularly fused perceptual boundaries and surface representations.
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Affiliation(s)
- Stephen Grossberg
- Center for Adaptive Systems, Graduate Program in Cognitive and Neural Systems, Center of Excellence for Learning in Education, Science and Technology, Center for Computational Neuroscience and Neural Technology, and Department of Mathematics Boston University, Boston, MA, USA
| | - Karthik Srinivasan
- Center for Adaptive Systems, Graduate Program in Cognitive and Neural Systems, Center of Excellence for Learning in Education, Science and Technology, Center for Computational Neuroscience and Neural Technology, and Department of Mathematics Boston University, Boston, MA, USA
| | - Arash Yazdanbakhsh
- Center for Adaptive Systems, Graduate Program in Cognitive and Neural Systems, Center of Excellence for Learning in Education, Science and Technology, Center for Computational Neuroscience and Neural Technology, and Department of Mathematics Boston University, Boston, MA, USA
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32
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Abstract
Camouflaged animals that have very similar textures to their surroundings are difficult to detect when stationary. However, when an animal moves, humans readily see a figure at a different depth than the background. How do humans perceive a figure breaking camouflage, even though the texture of the figure and its background may be statistically identical in luminance? We present a model that demonstrates how the primate visual system performs figure-ground segregation in extreme cases of breaking camouflage based on motion alone. Border-ownership signals develop as an emergent property in model V2 units whose receptive fields are nearby kinetically defined borders that separate the figure and background. Model simulations support border-ownership as a general mechanism by which the visual system performs figure-ground segregation, despite whether figure-ground boundaries are defined by luminance or motion contrast. The gradient of motion- and luminance-related border-ownership signals explains the perceived depth ordering of the foreground and background surfaces. Our model predicts that V2 neurons, which are sensitive to kinetic edges, are selective to border-ownership (magnocellular B cells). A distinct population of model V2 neurons is selective to border-ownership in figures defined by luminance contrast (parvocellular B cells). B cells in model V2 receive feedback from neurons in V4 and MT with larger receptive fields to bias border-ownership signals toward the figure. We predict that neurons in V4 and MT sensitive to kinetically defined figures play a crucial role in determining whether the foreground surface accretes, deletes, or produces a shearing motion with respect to the background.
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Affiliation(s)
- Oliver W Layton
- Department of Cognitive Science, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA; 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.
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Sojak V, Koolbergen DR, Bruggemans E, Yazdanbakhsh A, Kooij M, Hazekamp M. 031 * A SINGLE-CENTRE 37-YEAR EXPERIENCE WITH REOPERATION FOR ATRIOVENTRICULAR SEPTAL DEFECT. Interact Cardiovasc Thorac Surg 2014. [DOI: 10.1093/icvts/ivu276.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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34
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Layton OW, Mingolla E, Yazdanbakhsh A. Neural dynamics of feedforward and feedback processing in figure-ground segregation. Front Psychol 2014; 5:972. [PMID: 25346703 PMCID: PMC4193330 DOI: 10.3389/fpsyg.2014.00972] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/15/2014] [Indexed: 11/13/2022] Open
Abstract
Determining whether a region belongs to the interior or exterior of a shape (figure-ground segregation) is a core competency of the primate brain, yet the underlying mechanisms are not well understood. Many models assume that figure-ground segregation occurs by assembling progressively more complex representations through feedforward connections, with feedback playing only a modulatory role. We present a dynamical model of figure-ground segregation in the primate ventral stream wherein feedback plays a crucial role in disambiguating a figure's interior and exterior. We introduce a processing strategy whereby jitter in RF center locations and variation in RF sizes is exploited to enhance and suppress neural activity inside and outside of figures, respectively. Feedforward projections emanate from units that model cells in V4 known to respond to the curvature of boundary contours (curved contour cells), and feedback projections from units predicted to exist in IT that strategically group neurons with different RF sizes and RF center locations (teardrop cells). Neurons (convex cells) that preferentially respond when centered on a figure dynamically balance feedforward (bottom-up) information and feedback from higher visual areas. The activation is enhanced when an interior portion of a figure is in the RF via feedback from units that detect closure in the boundary contours of a figure. Our model produces maximal activity along the medial axis of well-known figures with and without concavities, and inside algorithmically generated shapes. Our results suggest that the dynamic balancing of feedforward signals with the specific feedback mechanisms proposed by the model is crucial for figure-ground segregation.
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Affiliation(s)
- Oliver W Layton
- The Perception and Action Lab, Department of Cognitive Science, Rensselaer Polytechnic Institute Troy, NY, USA ; Vision Lab, Center for Computational Neuroscience and Neural Technology, Boston University Boston, MA, USA
| | - Ennio Mingolla
- Computational Vision Laboratory, Department of Speech-Language Pathology and Audiology, Northeastern University Boston, MA, USA
| | - Arash Yazdanbakhsh
- Vision Lab, Center for Computational Neuroscience and Neural Technology, Boston University Boston, MA, USA
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35
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Qian J, Yazdanbakhsh A. A neural model of distance-dependent percept of object size constancy. J Vis 2014. [DOI: 10.1167/14.10.1187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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36
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Cao B, Yazdanbakhsh A. A novel 3D/dichoptic presentation system compatible with large field eye tracking. J Vis 2014. [DOI: 10.1167/14.10.967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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37
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Abstract
An object-centric reference frame is a spatial representation in which objects or their parts are coded relative to others. The existence of object-centric representations is supported by the phenomenon of induced motion, in which the motion of an inducer frame in a particular direction induces motion in the opposite direction in a target dot. We report on an experiment made with an induced motion display where a degree of slant is imparted to the inducer frame using either perspective or binocular disparity depth cues. Critically, the inducer frame oscillates perpendicularly to the line of sight, rather than moving in depth. Participants matched the perceived induced motion of the target dot in depth using a 3D rotatable rod. Although the frame did not move in depth, we found that subjects perceived the dot as moving in depth, either along the slanted frame or against it, when depth was given by perspective and disparity, respectively. The presence of induced motion is thus not only due to the competition among populations of planar motion filters, but rather incorporates 3D scene constraints. We also discuss this finding in the context of the uncertainty related to various depth cues, and to the locality of representation of reference frames.
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Affiliation(s)
- Jasmin Léveillé
- Center for Computational Neuroscience and Neural Technology, Boston University, Boston, MA, USA
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Koolbergen DR, Manshanden JSJ, Yazdanbakhsh A, Bouma BJ, Blom NA, Mulder BJ, Hazekamp M. 176 * REOPERATION FOR NEO-AORTIC ROOT PATHOLOGY AFTER THE ARTERIAL SWITCH OPERATION. Interact Cardiovasc Thorac Surg 2013. [DOI: 10.1093/icvts/ivt372.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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39
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Yazdanbakhsh A, Rijssen LBV, Koolbergen DR, Konig AM, Hazekamp M. 307 * LONG-TERM FOLLOW-UP OF TRACHEOPLASTY USING AUTOLOGOUS PERICARDIAL PATCH AND STRIPS OF COSTAL CARTILAGE. Interact Cardiovasc Thorac Surg 2013. [DOI: 10.1093/icvts/ivt372.307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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40
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Abstract
Biologically plausible strategies for visual scene integration across spatial and temporal domains continues to be a challenging topic. The fundamental question we address is whether classical problems in motion integration, such as the aperture problem, can be solved in a model that samples the visual scene at multiple spatial and temporal scales in parallel. We hypothesize that fast interareal connections that allow feedback of information between cortical layers are the key processes that disambiguate motion direction. We developed a neural model showing how the aperture problem can be solved using different spatial sampling scales between LGN, V1 layer 4, V1 layer 6, and area MT. Our results suggest that multiscale sampling, rather than feedback explicitly, is the key process that gives rise to end-stopped cells in V1 and enables area MT to solve the aperture problem without the need for calculating intersecting constraints or crafting intricate patterns of spatiotemporal receptive fields. Furthermore, the model explains why end-stopped cells no longer emerge in the absence of V1 layer 6 activity (Bolz & Gilbert, 1986), why V1 layer 4 cells are significantly more end-stopped than V1 layer 6 cells (Pack, Livingstone, Duffy, & Born, 2003), and how it is possible to have a solution to the aperture problem in area MT with no solution in V1 in the presence of driving feedback. In summary, while much research in the field focuses on how a laminar architecture can give rise to complicated spatiotemporal receptive fields to solve problems in the motion domain, we show that one can reframe motion integration as an emergent property of multiscale sampling achieved concurrently within lamina and across multiple visual areas.
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Affiliation(s)
- Lena Sherbakov
- Center for Computational Neuroscience and Neural Technology, Boston University, Boston, MA, USA
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41
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Abstract
Receptive field sizes of neurons in early primate visual areas increase with eccentricity, as does temporal processing speed. The fovea is evidently specialized for slow, fine movements while the periphery is suited for fast, coarse movements. In either the fovea or periphery discrete flashes can produce motion percepts. Grossberg and Rudd (1989) used traveling Gaussian activity profiles to model long-range apparent motion percepts. We propose a neural model constrained by physiological data to explain how signals from retinal ganglion cells to V1 affect the perception of motion as a function of eccentricity. Our model incorporates cortical magnification, receptive field overlap and scatter, and spatial and temporal response characteristics of retinal ganglion cells for cortical processing of motion. Consistent with the finding of Baker and Braddick (1985), in our model the maximum flash distance that is perceived as an apparent motion (Dmax) increases linearly as a function of eccentricity. Baker and Braddick (1985) made qualitative predictions about the functional significance of both stimulus and visual system parameters that constrain motion perception, such as an increase in the range of detectable motions as a function of eccentricity and the likely role of higher visual processes in determining Dmax. We generate corresponding quantitative predictions for those functional dependencies for individual aspects of motion processing. Simulation results indicate that the early visual pathway can explain the qualitative linear increase of Dmax data without reliance on extrastriate areas, but that those higher visual areas may serve as a modulatory influence on the exact Dmax increase.
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Affiliation(s)
- Jeremy Wurbs
- Center for Computational Neuroscience and Neural Technology, Program of Cognitive and Neural Systems, Boston University, Boston, MA, USA.
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42
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Jia N, Yazdanbakhsh A. Perisaccadic predictive remapping: a neural model of thalamo-cortical interactions. J Vis 2013. [DOI: 10.1167/13.9.521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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43
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Yazdanbakhsh A, Layton O. Multi-scale selectivity to figures in primate V4. J Vis 2013. [DOI: 10.1167/13.9.711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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44
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Ruda H, Mingolla E, Grossberg S, Yazdanbakhsh A. Modeling Hyperacuity Data with a Hierarchical Neural Vision Network and Modified Hebbian Learning. J Vis 2013. [DOI: 10.1167/13.9.276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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45
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46
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Yazdanbakhsh A, Layton O, Mingolla E. A neural model of border-ownership and motion in early vision. J Vis 2012. [DOI: 10.1167/12.9.759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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47
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Srinivasan K, Grossberg S, Yazdanbakhsh A. Predictive Remapping of Binocularly Fused Images under Saccadic Eye Movements. J Vis 2012. [DOI: 10.1167/12.9.44] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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48
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Cao B, Mingolla E, Yazdanbakhsh A. The role of feedback and long-range horizontal connections in brightness-related responses in visual cortex: a computational model. J Vis 2012. [DOI: 10.1167/12.9.1220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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49
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Wurbs J, Mingolla E, Yazdanbakhsh A. Modeling a space-variant cortical representation for motion under continuous and phi motion conditions. J Vis 2012. [DOI: 10.1167/12.9.762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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50
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Gori S, Giora E, Yazdanbakhsh A, Mingolla E. The novelty of the "Accordion Grating Illusion". Neural Netw 2012; 39:52. [PMID: 22951095 DOI: 10.1016/j.neunet.2012.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 07/19/2012] [Accepted: 07/20/2012] [Indexed: 11/29/2022]
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