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Ren Y, Chen P, Li Y, Zhou Z, Dong Y, Li S, Qian R, Yang J, Wu J, Yang W. Perceptual training improves audiovisual integration by enhancing alpha-band oscillations and functional connectivity in older adults. Cereb Cortex 2024; 34:bhae216. [PMID: 39183363 DOI: 10.1093/cercor/bhae216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/27/2024] [Accepted: 04/29/2024] [Indexed: 08/27/2024] Open
Abstract
Numerous studies on perceptual training exist, however, most have focused on the precision of temporal audiovisual perception, while fewer have concentrated on ability promotion for audiovisual integration (AVI). To investigate these issues, continuous 5-day audiovisual perceptual training was applied, during which electroencephalography was performed in response to auditory-only (A), visual-only (V) and audiovisual (AV) stimuli before and after training. The results showed that the perceptual sensitivity was greater for training group than for control group and was greater in the posttest than in the pretest. The response to the AV stimulus was significantly faster in the posttest than in the pretest for the older training group but was significantly greater for A and V stimuli for the younger training group. Electroencephalography analysis found higher P3 AVI amplitudes [AV-(A + V)] in the posttest than in the pretest for training group, which were subsequently reflected by an increased alpha (8-12 Hz) oscillatory response and strengthened global functional connectivity (weighted phase lag index). Furthermore, these facilitations were greater for older training groups than for younger training groups. These results confirm the age-related compensatory mechanism for AVI may be strengthened as audiovisual perceptual training progresses, providing an effective candidate for cognitive intervention in older adults.
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Affiliation(s)
- Yanna Ren
- Department of Psychology, College of Humanities and Management, Guizhou University of Traditional Chinese Medicine, No. 4, Dongqing Road, Huaxi District, Guiyang, 550025, China
| | - Peng Chen
- Department of Psychology, College of Humanities and Management, Guizhou University of Traditional Chinese Medicine, No. 4, Dongqing Road, Huaxi District, Guiyang, 550025, China
| | - Yan Li
- Department of Psychology, College of Humanities and Management, Guizhou University of Traditional Chinese Medicine, No. 4, Dongqing Road, Huaxi District, Guiyang, 550025, China
| | - Zhenhua Zhou
- Department of Psychology, College of Humanities and Management, Guizhou University of Traditional Chinese Medicine, No. 4, Dongqing Road, Huaxi District, Guiyang, 550025, China
| | - Yanping Dong
- Department of Psychology, College of Humanities and Management, Guizhou University of Traditional Chinese Medicine, No. 4, Dongqing Road, Huaxi District, Guiyang, 550025, China
| | - Shujing Li
- Department of Psychology, College of Humanities and Management, Guizhou University of Traditional Chinese Medicine, No. 4, Dongqing Road, Huaxi District, Guiyang, 550025, China
| | - Runqi Qian
- Department of Psychology, College of Humanities and Management, Guizhou University of Traditional Chinese Medicine, No. 4, Dongqing Road, Huaxi District, Guiyang, 550025, China
| | - Jiajia Yang
- Applied Brain Science Lab Interdisciplinary Science and Engineering in Health Systems, Okayama University, 1-1, Tsushimachu 1-chome, Kita-ku, Okayama, 7008530, Japan
| | - Jinglong Wu
- Research Center for Medical Artificial Intelligence, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, No. 1068, Xueyuan Avenue, Shenzhen University Town, Xili, Nanshan District, Shenzhen, 518055, China
| | - Weiping Yang
- Department of Psychology, Faculty of Education, Hubei University, No. 368, Youyi Avenue, Wuchang District, Wuhan, 430062, China
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Smyre SA, Bean NL, Stein BE, Rowland BA. The brain can develop conflicting multisensory principles to guide behavior. Cereb Cortex 2024; 34:bhae247. [PMID: 38879756 PMCID: PMC11179994 DOI: 10.1093/cercor/bhae247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 05/23/2024] [Accepted: 05/30/2024] [Indexed: 06/19/2024] Open
Abstract
Midbrain multisensory neurons undergo a significant postnatal transition in how they process cross-modal (e.g. visual-auditory) signals. In early stages, signals derived from common events are processed competitively; however, at later stages they are processed cooperatively such that their salience is enhanced. This transition reflects adaptation to cross-modal configurations that are consistently experienced and become informative about which correspond to common events. Tested here was the assumption that overt behaviors follow a similar maturation. Cats were reared in omnidirectional sound thereby compromising the experience needed for this developmental process. Animals were then repeatedly exposed to different configurations of visual and auditory stimuli (e.g. spatiotemporally congruent or spatially disparate) that varied on each side of space and their behavior was assessed using a detection/localization task. Animals showed enhanced performance to stimuli consistent with the experience provided: congruent stimuli elicited enhanced behaviors where spatially congruent cross-modal experience was provided, and spatially disparate stimuli elicited enhanced behaviors where spatially disparate cross-modal experience was provided. Cross-modal configurations not consistent with experience did not enhance responses. The presumptive benefit of such flexibility in the multisensory developmental process is to sensitize neural circuits (and the behaviors they control) to the features of the environment in which they will function. These experiments reveal that these processes have a high degree of flexibility, such that two (conflicting) multisensory principles can be implemented by cross-modal experience on opposite sides of space even within the same animal.
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Affiliation(s)
- Scott A Smyre
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Blvd., Winston Salem, NC 27157, United States
| | - Naomi L Bean
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Blvd., Winston Salem, NC 27157, United States
| | - Barry E Stein
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Blvd., Winston Salem, NC 27157, United States
| | - Benjamin A Rowland
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Blvd., Winston Salem, NC 27157, United States
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3
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Wang L, Xin H, Buren Q, Zhang Y, Han Y, Ouyang B, Sun Z, Bao Y, Dong C. Specific rules for time and space of multisensory plasticity in the superior colliculus. Brain Res 2024; 1828:148774. [PMID: 38244758 DOI: 10.1016/j.brainres.2024.148774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 12/28/2023] [Accepted: 01/15/2024] [Indexed: 01/22/2024]
Abstract
Cat superior colliculus (SC) neurons commonly combine information from different senses, which facilitates event detection and localization. Integration in SC multisensory neurons depends on the spatial and temporal relationships between cross-modal cues. Here, we revealed the parallel process of short-term plasticity in the temporal/spatial integration process during adulthood that adapts multisensory integration to reliable changes in environmental conditions. Short-term experience alters the temporal preferences of SC multisensory neurons, and this short-term plasticity in the temporal/spatial integration process is limited to changes in cross-modal timing (a factor commonly induced by events at different distances from the receiver). However, this plasticity was not evident in response to changes in the cross-modal spatial configuration.
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Affiliation(s)
- Linghong Wang
- School of Basic Medicine, Inner Mongolia Medical University, Inner Mongolia, Hohhot 010110, China
| | - Hongmei Xin
- School of Humanities Education, Inner Mongolia Medical University, Inner Mongolia, Hohhot 010110, China
| | - Qiqige Buren
- School of Basic Medicine, Inner Mongolia Medical University, Inner Mongolia, Hohhot 010110, China
| | - Yan Zhang
- School of Basic Medicine, Inner Mongolia Medical University, Inner Mongolia, Hohhot 010110, China
| | - Yaxin Han
- School of Basic Medicine, Inner Mongolia Medical University, Inner Mongolia, Hohhot 010110, China
| | - Biao Ouyang
- School of Basic Medicine, Inner Mongolia Medical University, Inner Mongolia, Hohhot 010110, China
| | - Zhe Sun
- School of Basic Medicine, Inner Mongolia Medical University, Inner Mongolia, Hohhot 010110, China
| | - Yulong Bao
- School of Basic Medicine, Inner Mongolia Medical University, Inner Mongolia, Hohhot 010110, China.
| | - Chao Dong
- School of Basic Medicine, Inner Mongolia Medical University, Inner Mongolia, Hohhot 010110, China.
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Yu L, Xu J. The Development of Multisensory Integration at the Neuronal Level. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1437:153-172. [PMID: 38270859 DOI: 10.1007/978-981-99-7611-9_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
Multisensory integration is a fundamental function of the brain. In the typical adult, multisensory neurons' response to paired multisensory (e.g., audiovisual) cues is significantly more robust than the corresponding best unisensory response in many brain regions. Synthesizing sensory signals from multiple modalities can speed up sensory processing and improve the salience of outside events or objects. Despite its significance, multisensory integration is testified to be not a neonatal feature of the brain. Neurons' ability to effectively combine multisensory information does not occur rapidly but develops gradually during early postnatal life (for cats, 4-12 weeks required). Multisensory experience is critical for this developing process. If animals were restricted from sensing normal visual scenes or sounds (deprived of the relevant multisensory experience), the development of the corresponding integrative ability could be blocked until the appropriate multisensory experience is obtained. This section summarizes the extant literature on the development of multisensory integration (mainly using cat superior colliculus as a model), sensory-deprivation-induced cross-modal plasticity, and how sensory experience (sensory exposure and perceptual learning) leads to the plastic change and modification of neural circuits in cortical and subcortical areas.
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Affiliation(s)
- Liping Yu
- Key Laboratory of Brain Functional Genomics (Ministry of Education and Shanghai), School of Life Sciences, East China Normal University, Shanghai, China.
| | - Jinghong Xu
- Key Laboratory of Brain Functional Genomics (Ministry of Education and Shanghai), School of Life Sciences, East China Normal University, Shanghai, China
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Bean NL, Stein BE, Rowland BA. Cross-modal exposure restores multisensory enhancement after hemianopia. Cereb Cortex 2023; 33:11036-11046. [PMID: 37724427 PMCID: PMC10646694 DOI: 10.1093/cercor/bhad343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/28/2023] [Accepted: 08/30/2023] [Indexed: 09/20/2023] Open
Abstract
Hemianopia is a common consequence of unilateral damage to visual cortex that manifests as a profound blindness in contralesional space. A noninvasive cross-modal (visual-auditory) exposure paradigm has been developed in an animal model to ameliorate this disorder. Repeated stimulation of a visual-auditory stimulus restores overt responses to visual stimuli in the blinded hemifield. It is believed to accomplish this by enhancing the visual sensitivity of circuits remaining after a lesion of visual cortex; in particular, circuits involving the multisensory neurons of the superior colliculus. Neurons in this midbrain structure are known to integrate spatiotemporally congruent visual and auditory signals to amplify their responses, which, in turn, enhances behavioral performance. Here we evaluated the relationship between the rehabilitation of hemianopia and this process of multisensory integration. Induction of hemianopia also eliminated multisensory enhancement in the blinded hemifield. Both vision and multisensory enhancement rapidly recovered with the rehabilitative cross-modal exposures. However, although both reached pre-lesion levels at similar rates, they did so with different spatial patterns. The results suggest that the capability for multisensory integration and enhancement is not a pre-requisite for visual recovery in hemianopia, and that the underlying mechanisms for recovery may be more complex than currently appreciated.
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Affiliation(s)
- Naomi L Bean
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, United States
| | - Barry E Stein
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, United States
| | - Benjamin A Rowland
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, United States
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Murray CA, Shams L. Crossmodal interactions in human learning and memory. Front Hum Neurosci 2023; 17:1181760. [PMID: 37266327 PMCID: PMC10229776 DOI: 10.3389/fnhum.2023.1181760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/02/2023] [Indexed: 06/03/2023] Open
Abstract
Most studies of memory and perceptual learning in humans have employed unisensory settings to simplify the study paradigm. However, in daily life we are often surrounded by complex and cluttered scenes made up of many objects and sources of sensory stimulation. Our experiences are, therefore, highly multisensory both when passively observing the world and when acting and navigating. We argue that human learning and memory systems are evolved to operate under these multisensory and dynamic conditions. The nervous system exploits the rich array of sensory inputs in this process, is sensitive to the relationship between the sensory inputs, and continuously updates sensory representations, and encodes memory traces based on the relationship between the senses. We review some recent findings that demonstrate a range of human learning and memory phenomena in which the interactions between visual and auditory modalities play an important role, and suggest possible neural mechanisms that can underlie some surprising recent findings. We outline open questions as well as directions of future research to unravel human perceptual learning and memory.
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Affiliation(s)
- Carolyn A. Murray
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Ladan Shams
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, United States
- Department of Bioengineering, Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, United States
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7
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Smyre SA, Bean NL, Stein BE, Rowland BA. Predictability alters multisensory responses by modulating unisensory inputs. Front Neurosci 2023; 17:1150168. [PMID: 37065927 PMCID: PMC10090419 DOI: 10.3389/fnins.2023.1150168] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
The multisensory (deep) layers of the superior colliculus (SC) play an important role in detecting, localizing, and guiding orientation responses to salient events in the environment. Essential to this role is the ability of SC neurons to enhance their responses to events detected by more than one sensory modality and to become desensitized (‘attenuated’ or ‘habituated’) or sensitized (‘potentiated’) to events that are predictable via modulatory dynamics. To identify the nature of these modulatory dynamics, we examined how the repetition of different sensory stimuli affected the unisensory and multisensory responses of neurons in the cat SC. Neurons were presented with 2HZ stimulus trains of three identical visual, auditory, or combined visual–auditory stimuli, followed by a fourth stimulus that was either the same or different (‘switch’). Modulatory dynamics proved to be sensory-specific: they did not transfer when the stimulus switched to another modality. However, they did transfer when switching from the visual–auditory stimulus train to either of its modality-specific component stimuli and vice versa. These observations suggest that predictions, in the form of modulatory dynamics induced by stimulus repetition, are independently sourced from and applied to the modality-specific inputs to the multisensory neuron. This falsifies several plausible mechanisms for these modulatory dynamics: they neither produce general changes in the neuron’s transform, nor are they dependent on the neuron’s output.
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Bean NL, Smyre SA, Stein BE, Rowland BA. Noise-rearing precludes the behavioral benefits of multisensory integration. Cereb Cortex 2023; 33:948-958. [PMID: 35332919 PMCID: PMC9930622 DOI: 10.1093/cercor/bhac113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 11/14/2022] Open
Abstract
Concordant visual-auditory stimuli enhance the responses of individual superior colliculus (SC) neurons. This neuronal capacity for "multisensory integration" is not innate: it is acquired only after substantial cross-modal (e.g. auditory-visual) experience. Masking transient auditory cues by raising animals in omnidirectional sound ("noise-rearing") precludes their ability to obtain this experience and the ability of the SC to construct a normal multisensory (auditory-visual) transform. SC responses to combinations of concordant visual-auditory stimuli are depressed, rather than enhanced. The present experiments examined the behavioral consequence of this rearing condition in a simple detection/localization task. In the first experiment, the auditory component of the concordant cross-modal pair was novel, and only the visual stimulus was a target. In the second experiment, both component stimuli were targets. Noise-reared animals failed to show multisensory performance benefits in either experiment. These results reveal a close parallel between behavior and single neuron physiology in the multisensory deficits that are induced when noise disrupts early visual-auditory experience.
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Affiliation(s)
- Naomi L Bean
- Corresponding author: Wake Forest School of Medicine, Medical Center Blvd., Winston Salem, NC 27157, United States.
| | | | - Barry E Stein
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Blvd., Winston Salem, NC 27157, United States
| | - Benjamin A Rowland
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Blvd., Winston Salem, NC 27157, United States
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Idris A, Christensen BA, Walker EM, Maier JX. Multisensory integration of orally-sourced gustatory and olfactory inputs to the posterior piriform cortex in awake rats. J Physiol 2023; 601:151-169. [PMID: 36385245 PMCID: PMC9869978 DOI: 10.1113/jp283873] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 11/09/2022] [Indexed: 11/18/2022] Open
Abstract
Flavour refers to the sensory experience of food, which is a combination of sensory inputs sourced from multiple modalities during consumption, including taste and odour. Previous work has demonstrated that orally-sourced taste and odour cues interact to determine perceptual judgements of flavour stimuli, although the underlying cellular- and circuit-level neural mechanisms remain unknown. We recently identified a region of the piriform olfactory cortex in rats that responds to both taste and odour stimuli. Here, we investigated how converging taste and odour inputs to this area interact to affect single neuron responsiveness ensemble coding of flavour identity. To accomplish this, we recorded spiking activity from ensembles of single neurons in the posterior piriform cortex (pPC) in awake, tasting rats while delivering taste solutions, odour solutions and taste + odour mixtures directly into the oral cavity. Our results show that taste and odour inputs evoke highly selective, temporally-overlapping responses in multisensory pPC neurons. Comparing responses to mixtures and their unisensory components revealed that taste and odour inputs interact in a non-linear manner to produce unique response patterns. Taste input enhances trial-by-trial decoding of odour identity from small ensembles of simultaneously recorded neurons. Together, these results demonstrate that taste and odour inputs to pPC interact in complex, non-linear ways to form amodal flavour representations that enhance identity coding. KEY POINTS: Experience of food involves taste and smell, although how information from these different senses is combined by the brain to create our sense of flavour remains unknown. We recorded from small groups of neurons in the olfactory cortex of awake rats while they consumed taste solutions, odour solutions and taste + odour mixtures. Taste and smell solutions evoke highly selective responses. When presented in a mixture, taste and smell inputs interacted to alter responses, resulting in activation of unique sets of neurons that could not be predicted by the component responses. Synergistic interactions increase discriminability of odour representations. The olfactory cortex uses taste and smell to create new information representing multisensory flavour identity.
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Affiliation(s)
- Ammar Idris
- Department of Neurobiology & AnatomyWake Forest School of MedicineWinston‐SalemNCUSA
| | - Brooke A. Christensen
- Department of Neurobiology & AnatomyWake Forest School of MedicineWinston‐SalemNCUSA
| | - Ellen M. Walker
- Department of Neurobiology & AnatomyWake Forest School of MedicineWinston‐SalemNCUSA
| | - Joost X. Maier
- Department of Neurobiology & AnatomyWake Forest School of MedicineWinston‐SalemNCUSA
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Shaikh D. Learning multisensory cue integration: A computational model of crossmodal synaptic plasticity enables reliability-based cue weighting by capturing stimulus statistics. Front Neural Circuits 2022; 16:921453. [PMID: 36004009 PMCID: PMC9393257 DOI: 10.3389/fncir.2022.921453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 07/15/2022] [Indexed: 11/13/2022] Open
Abstract
The brain forms unified, coherent, and accurate percepts of events occurring in the environment by integrating information from multiple senses through the process of multisensory integration. The neural mechanisms underlying this process, its development and its maturation in a multisensory environment are yet to be properly understood. Numerous psychophysical studies suggest that the multisensory cue integration process follows the principle of Bayesian estimation, where the contributions of individual sensory modalities are proportional to the relative reliabilities of the different sensory stimuli. In this article I hypothesize that experience dependent crossmodal synaptic plasticity may be a plausible mechanism underlying development of multisensory cue integration. I test this hypothesis via a computational model that implements Bayesian multisensory cue integration using reliability-based cue weighting. The model uses crossmodal synaptic plasticity to capture stimulus statistics within synaptic weights that are adapted to reflect the relative reliabilities of the participating stimuli. The model is embodied in a simulated robotic agent that learns to localize an audio-visual target by integrating spatial location cues extracted from of auditory and visual sensory modalities. Results of multiple randomized target localization trials in simulation indicate that the model is able to learn modality-specific synaptic weights proportional to the relative reliabilities of the auditory and visual stimuli. The proposed model with learned synaptic weights is also compared with a maximum-likelihood estimation model for cue integration via regression analysis. Results indicate that the proposed model reflects maximum-likelihood estimation.
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Affiliation(s)
- Danish Shaikh
- SDU Biorobotics, Maersk Mc-Kinney Moller Institute, University of Southern Denmark, Odense, Denmark
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Jure R. The “Primitive Brain Dysfunction” Theory of Autism: The Superior Colliculus Role. Front Integr Neurosci 2022; 16:797391. [PMID: 35712344 PMCID: PMC9194533 DOI: 10.3389/fnint.2022.797391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 04/19/2022] [Indexed: 11/20/2022] Open
Abstract
A better understanding of the pathogenesis of autism will help clarify our conception of the complexity of normal brain development. The crucial deficit may lie in the postnatal changes that vision produces in the brainstem nuclei during early life. The superior colliculus is the primary brainstem visual center. Although difficult to examine in humans with present techniques, it is known to support behaviors essential for every vertebrate to survive, such as the ability to pay attention to relevant stimuli and to produce automatic motor responses based on sensory input. From birth to death, it acts as a brain sentinel that influences basic aspects of our behavior. It is the main brainstem hub that lies between the environment and the rest of the higher neural system, making continuous, implicit decisions about where to direct our attention. The conserved cortex-like organization of the superior colliculus in all vertebrates allows the early appearance of primitive emotionally-related behaviors essential for survival. It contains first-line specialized neurons enabling the detection and tracking of faces and movements from birth. During development, it also sends the appropriate impulses to help shape brain areas necessary for social-communicative abilities. These abilities require the analysis of numerous variables, such as the simultaneous evaluation of incoming information sustained by separate brain networks (visual, auditory and sensory-motor, social, emotional, etc.), and predictive capabilities which compare present events to previous experiences and possible responses. These critical aspects of decision-making allow us to evaluate the impact that our response or behavior may provoke in others. The purpose of this review is to show that several enigmas about the complexity of autism might be explained by disruptions of collicular and brainstem functions. The results of two separate lines of investigation: 1. the cognitive, etiologic, and pathogenic aspects of autism on one hand, and two. the functional anatomy of the colliculus on the other, are considered in order to bridge the gap between basic brain science and clinical studies and to promote future research in this unexplored area.
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Jiang H, Stanford TR, Rowland BA, Stein BE. Association Cortex Is Essential to Reverse Hemianopia by Multisensory Training. Cereb Cortex 2021; 31:5015-5023. [PMID: 34056645 DOI: 10.1093/cercor/bhab138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/19/2021] [Accepted: 04/19/2021] [Indexed: 11/14/2022] Open
Abstract
Hemianopia induced by unilateral visual cortex lesions can be resolved by repeatedly exposing the blinded hemifield to auditory-visual stimuli. This rehabilitative "training" paradigm depends on mechanisms of multisensory plasticity that restore the lost visual responsiveness of multisensory neurons in the ipsilesional superior colliculus (SC) so that they can once again support vision in the blinded hemifield. These changes are thought to operate via the convergent visual and auditory signals relayed to the SC from association cortex (the anterior ectosylvian sulcus [AES], in cat). The present study tested this assumption by cryogenically deactivating ipsilesional AES in hemianopic, anesthetized cats during weekly multisensory training sessions. No signs of visual recovery were evident in this condition, even after providing animals with up to twice the number of training sessions required for effective rehabilitation. Subsequent training under the same conditions, but with AES active, reversed the hemianopia within the normal timeframe. These results indicate that the corticotectal circuit that is normally engaged in SC multisensory plasticity has to be operational for the brain to use visual-auditory experience to resolve hemianopia.
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Affiliation(s)
- Huai Jiang
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | - Terrence R Stanford
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | - Benjamin A Rowland
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | - Barry E Stein
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
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Smyre SA, Wang Z, Stein BE, Rowland BA. Multisensory enhancement of overt behavior requires multisensory experience. Eur J Neurosci 2021; 54:4514-4527. [PMID: 34013578 DOI: 10.1111/ejn.15315] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 05/11/2021] [Accepted: 05/14/2021] [Indexed: 11/27/2022]
Abstract
The superior colliculus (SC) is richly endowed with neurons that integrate cues from different senses to enhance their physiological responses and the overt behaviors they mediate. However, in the absence of experience with cross-modal combinations (e.g., visual-auditory), they fail to develop this characteristic multisensory capability: Their multisensory responses are no greater than their most effective unisensory responses. Presumably, this impairment in neural development would be reflected as corresponding impairments in SC-mediated behavioral capabilities such as detection and localization performance. Here, we tested that assumption directly in cats raised to adulthood in darkness. They, along with a normally reared cohort, were trained to approach brief visual or auditory stimuli. The animals were then tested with these stimuli individually and in combination under ambient light conditions consistent with their rearing conditions and home environment as well as under the opposite lighting condition. As expected, normally reared animals detected and localized the cross-modal combinations significantly better than their individual component stimuli. However, dark-reared animals showed significant defects in multisensory detection and localization performance. The results indicate that a physiological impairment in single multisensory SC neurons is predictive of an impairment in overt multisensory behaviors.
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Affiliation(s)
- Scott A Smyre
- Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA
| | - Zhengyang Wang
- Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA
| | - Barry E Stein
- Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA
| | - Benjamin A Rowland
- Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA
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Isa T, Marquez-Legorreta E, Grillner S, Scott EK. The tectum/superior colliculus as the vertebrate solution for spatial sensory integration and action. Curr Biol 2021; 31:R741-R762. [PMID: 34102128 DOI: 10.1016/j.cub.2021.04.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The superior colliculus, or tectum in the case of non-mammalian vertebrates, is a part of the brain that registers events in the surrounding space, often through vision and hearing, but also through electrosensation, infrared detection, and other sensory modalities in diverse vertebrate lineages. This information is used to form maps of the surrounding space and the positions of different salient stimuli in relation to the individual. The sensory maps are arranged in layers with visual input in the uppermost layer, other senses in deeper positions, and a spatially aligned motor map in the deepest layer. Here, we will review the organization and intrinsic function of the tectum/superior colliculus and the information that is processed within tectal circuits. We will also discuss tectal/superior colliculus outputs that are conveyed directly to downstream motor circuits or via the thalamus to cortical areas to control various aspects of behavior. The tectum/superior colliculus is evolutionarily conserved among all vertebrates, but tailored to the sensory specialties of each lineage, and its roles have shifted with the emergence of the cerebral cortex in mammals. We will illustrate both the conserved and divergent properties of the tectum/superior colliculus through vertebrate evolution by comparing tectal processing in lampreys belonging to the oldest group of extant vertebrates, larval zebrafish, rodents, and other vertebrates including primates.
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Affiliation(s)
- Tadashi Isa
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan; Institute for the Advanced Study of Human Biology, Kyoto University, Kyoto, 606-8501, Japan
| | | | - Sten Grillner
- Department of Neuroscience, Karolinska Institutet, Stockholm SE-17177, Sweden
| | - Ethan K Scott
- The Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia.
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