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Otsuka S, Gao H, Hiraoka K. Contribution of external reference frame to tactile localization. Exp Brain Res 2024; 242:1957-1970. [PMID: 38918211 DOI: 10.1007/s00221-024-06877-w] [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: 03/07/2024] [Accepted: 06/18/2024] [Indexed: 06/27/2024]
Abstract
The purpose of the present study was to elucidate whether an external reference frame contributes to tactile localization in blindfolded healthy humans. In a session, the right forearm was passively moved until the elbow finally reached to the target angle, and participants reached the left index finger to the right middle fingertip. The locus of the right middle fingertip indicated by the participants deviated in the direction of the elbow extension when vibration was provided to the biceps brachii muscle during the passive movement. This finding indicates that proprioception contributes to the identification of the spatial coordinate of the specific body part in an external reference frame. In another session, the tactile stimulus was provided to the dorsal of the right hand during the passive movement, and the participants reached the left index finger to the spatial locus at which the tactile stimulus was provided. Vibration to the biceps brachii muscle did not change the perceived locus of the tactile stimulus indicated by the left index finger. This finding indicates that an external reference frame does not contribute to tactile localization during the passive movement. Humans may estimate the spatial coordinate of the tactile stimulus based on the time between the movement onset and the time at which the tactile stimulus is provided.
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Affiliation(s)
- Shunsuke Otsuka
- College of Health and Human Sciences, Osaka Prefecture University, Habikino city, Japan
| | - Han Gao
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, Habikino city, Japan
| | - Koichi Hiraoka
- Department of Rehabilitation Science, School of Medicine, Osaka Metropolitan University, Habikino city, Japan.
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Czarnecka M, Rączy K, Szewczyk J, Paplińska M, Jednoróg K, Marchewka A, Hesselmann G, Knops A, Szwed M. Overlapping but separate number representations in the intraparietal sulcus – probing format- and modality-independence in sighted Braille readers. Cortex 2023; 162:65-80. [PMID: 37003099 DOI: 10.1016/j.cortex.2023.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/20/2022] [Accepted: 01/22/2023] [Indexed: 03/06/2023]
Abstract
The Triple-Code Model stipulates that numerical information from different formats and modalities converges on a common magnitude representation in the Intraparietal Sulcus (IPS). To what extent the representations of all numerosity forms overlap remains unsolved. It has been postulated that the representation of symbolic numerosities (for example, Arabic digits) is sparser and grounded in an existing representation that codes for non-symbolic numerosity information (i.e., sets of objects). Other theories argue that numerical symbols represent a separate number category that emerges only during education. Here, we tested a unique group of sighted tactile Braille readers with numerosities 2, 4, 6 and 8 in three number notations: Arabic digits, sets of dots, tactile Braille numbers. Using univariate methods, we showed a consistent overlap in activations evoked by these three number notations. This result shows that all three used notations are represented in the IPS, which may suggest at least a partial overlap between the representations of the three notations used in this experiment. Using MVPA, we found that only non-automatized number information (Braille and sets of dots) allowed successful number classification. However, the numerosity of one notation could not be predicted above chance from the brain activation patterns evoked by another notation (no cross-classification). These results show that the IPS may host independent number codes in overlapping cortical circuits. In addition, they suggest that the level of training in encoding a given type of number information is an important factor that determines the amount of exploitable information and needs to be controlled for in order to identify the neural code underlying numerical information per se.
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Maimon A, Wald IY, Ben Oz M, Codron S, Netzer O, Heimler B, Amedi A. The Topo-Speech sensory substitution system as a method of conveying spatial information to the blind and vision impaired. Front Hum Neurosci 2023; 16:1058093. [PMID: 36776219 PMCID: PMC9909096 DOI: 10.3389/fnhum.2022.1058093] [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: 09/30/2022] [Accepted: 12/13/2022] [Indexed: 01/27/2023] Open
Abstract
Humans, like most animals, integrate sensory input in the brain from different sensory modalities. Yet humans are distinct in their ability to grasp symbolic input, which is interpreted into a cognitive mental representation of the world. This representation merges with external sensory input, providing modality integration of a different sort. This study evaluates the Topo-Speech algorithm in the blind and visually impaired. The system provides spatial information about the external world by applying sensory substitution alongside symbolic representations in a manner that corresponds with the unique way our brains acquire and process information. This is done by conveying spatial information, customarily acquired through vision, through the auditory channel, in a combination of sensory (auditory) features and symbolic language (named/spoken) features. The Topo-Speech sweeps the visual scene or image and represents objects' identity by employing naming in a spoken word and simultaneously conveying the objects' location by mapping the x-axis of the visual scene or image to the time it is announced and the y-axis by mapping the location to the pitch of the voice. This proof of concept study primarily explores the practical applicability of this approach in 22 visually impaired and blind individuals. The findings showed that individuals from both populations could effectively interpret and use the algorithm after a single training session. The blind showed an accuracy of 74.45%, while the visually impaired had an average accuracy of 72.74%. These results are comparable to those of the sighted, as shown in previous research, with all participants above chance level. As such, we demonstrate practically how aspects of spatial information can be transmitted through non-visual channels. To complement the findings, we weigh in on debates concerning models of spatial knowledge (the persistent, cumulative, or convergent models) and the capacity for spatial representation in the blind. We suggest the present study's findings support the convergence model and the scenario that posits the blind are capable of some aspects of spatial representation as depicted by the algorithm comparable to those of the sighted. Finally, we present possible future developments, implementations, and use cases for the system as an aid for the blind and visually impaired.
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Affiliation(s)
- Amber Maimon
- Baruch Ivcher School of Psychology, The Baruch Ivcher Institute for Brain, Cognition, and Technology, Reichman University, Herzliya, Israel,The Ruth and Meir Rosenthal Brain Imaging Center, Reichman University, Herzliya, Israel,*Correspondence: Amber Maimon,
| | - Iddo Yehoshua Wald
- Baruch Ivcher School of Psychology, The Baruch Ivcher Institute for Brain, Cognition, and Technology, Reichman University, Herzliya, Israel,The Ruth and Meir Rosenthal Brain Imaging Center, Reichman University, Herzliya, Israel
| | - Meshi Ben Oz
- Baruch Ivcher School of Psychology, The Baruch Ivcher Institute for Brain, Cognition, and Technology, Reichman University, Herzliya, Israel,The Ruth and Meir Rosenthal Brain Imaging Center, Reichman University, Herzliya, Israel
| | - Sophie Codron
- Baruch Ivcher School of Psychology, The Baruch Ivcher Institute for Brain, Cognition, and Technology, Reichman University, Herzliya, Israel,The Ruth and Meir Rosenthal Brain Imaging Center, Reichman University, Herzliya, Israel
| | - Ophir Netzer
- Gonda Brain Research Center, Bar Ilan University, Ramat Gan, Israel
| | - Benedetta Heimler
- Center of Advanced Technologies in Rehabilitation (CATR), Sheba Medical Center, Ramat Gan, Israel
| | - Amir Amedi
- Baruch Ivcher School of Psychology, The Baruch Ivcher Institute for Brain, Cognition, and Technology, Reichman University, Herzliya, Israel,The Ruth and Meir Rosenthal Brain Imaging Center, Reichman University, Herzliya, Israel
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Altered time-varying local spontaneous brain activity pattern in patients with high myopia: a dynamic amplitude of low-frequency fluctuations study. Neuroradiology 2023; 65:157-166. [PMID: 35953566 DOI: 10.1007/s00234-022-03033-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 07/29/2022] [Indexed: 01/10/2023]
Abstract
PURPOSE To investigate the abnormal time-varying local spontaneous brain activity in patients with high myopia (HM) on the basis of the dynamic amplitude of low-frequency fluctuations (dALFF) approach. METHODS Age and gender matching were performed based on resting-state functional magnetic resonance imaging data from 86 HM patients and 87 healthy controls (HCs). Local spontaneous brain activities were evaluated using the time-varying dALFF method. Support vector machine combined with the radial basis function kernel was used for pattern classification analysis. RESULTS Inter-group comparison between HCs and HM patients has demonstrated that dALFF variability in the left inferior frontal gyrus (orbital part), left lingual gyrus, right anterior cingulate and paracingulate gyri, and right calcarine fissure and surrounding cortex was decreased in HM patients, while increased in the left thalamus, left paracentral lobule, and left inferior parietal (except supramarginal and angular gyri). Pattern classification between HM patients and HCs displayed a classification accuracy of 85.5%. CONCLUSION In this study, the findings mentioned above have suggested the association between local brain activities of HM patients and abnormal variability in brain regions performing visual sensorimotor and attentional control functions. Several useful information has been provided to elucidate the mechanism-related alterations of the myopic nervous system. In addition, the significant role of abnormal dALFF variability has been highlighted to achieve an in-depth comprehension of the pathological alterations and neuroimaging mechanisms in the field of HM.
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