Sensory Substitution: From Sensations to Phenomenology

Author(s):  
Laurent Renier

Sensory substitution refers to the use of one sensory modality (e.g. hearing) to supply environmental information normally gathered by another sense (e.g. vision) while still preserving some of the key functions of the original sense. For example, the use of auditory signals might give information about visual scenes. The development of sensory substitution devices has profoundly changed the classical definition of sensory modalities and contributed to the emergence of a new form of perception. In the last decade, our knowledge about cognitive and brain mechanisms involved in sensory substitution has grown considerably, bringing new insights into human perception. The phenomenological experience of perceiving via a sensory substitution device can now be discussed in the light of current scientific knowledge. Thanks to technological advances and scientific achievements, sensory substitution has become a real alternative for restoring some functions of a defective sensory organ (e.g. sight in the case of blindness or hearing in the case of deafness). This essay addresses some of the major questions raised by sensory substitution, including discussions regarding the nature of perception arising from the use of such devices, demonstrates how the study of sensory substitution enhances our understanding of human perception and brain plasticity and provides a short overview of rehabilitation potentialities.

Author(s):  
Thomas D. Wright ◽  
Jamie Ward

There has been considerable effort devoted towards understanding sensory substitution devices in terms of their relationship to canonical sensory modalities. The approach taken in this essay is rather different, although complementary, in that we seek to define a broad conceptual space of ‘sensory tools’ in which sensory substitution devices can be situated. Such devices range from telescopes, to cochlear implants, to attempts to create a magnetic sense. One feature of these devices is that they operate at the level of ‘raw’ sensory information. As such, systems such as Braille which operate at a symbolic/conceptual level do not count as a sensory tool (or a sensory substitution device) and nor would a device such as CCTV which, although capturing raw sensory information, would not meet a conventional definition of a tool. With this approach, we hope to avoid the circularity inherent in previous attempts at defining sensory substitution and provide a better starting point to explore the effects of sensory tools, more generally, on the functioning of the nervous system.


Life ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 296
Author(s):  
Rodrigo Araneda ◽  
Sandra Silva Moura ◽  
Laurence Dricot ◽  
Anne G. De Volder

Using functional magnetic resonance imaging, here we monitored the brain activity in 12 early blind subjects and 12 blindfolded control subjects, matched for age, gender and musical experience, during a beat detection task. Subjects were required to discriminate regular (“beat”) from irregular (“no beat”) rhythmic sequences composed of sounds or vibrotactile stimulations. In both sensory modalities, the brain activity differences between the two groups involved heteromodal brain regions including parietal and frontal cortical areas and occipital brain areas, that were recruited in the early blind group only. Accordingly, early blindness induced brain plasticity changes in the cerebral pathways involved in rhythm perception, with a participation of the visually deprived occipital brain areas whatever the sensory modality for input. We conclude that the visually deprived cortex switches its input modality from vision to audition and vibrotactile sense to perform this temporal processing task, supporting the concept of a metamodal, multisensory organization of this cortex.


2018 ◽  
Vol 26 (3) ◽  
pp. 111-127 ◽  
Author(s):  
Weronika Kałwak ◽  
Magdalena Reuter ◽  
Marta Łukowska ◽  
Bartosz Majchrowicz ◽  
Michał Wierzchoń

Information that is normally accessed through a sensory modality (substituted modality, e.g., vision) is provided by sensory substitution devices (SSDs) through an alternative modality such as hearing or touch (i.e., substituting modality). SSDs usually support disabled users by replacing sensory inputs that have been lost, but they also offer a unique opportunity to study adaptation and flexibility in human perception. Current debates in sensory substitution (SS) literature focus mostly on its neural correlates and behavioural consequences. In particular, studies have demonstrated the neural plasticity of the visual brain regions that are activated by the substituting modality. Participants also adapt to using the devices for a broad spectrum of cognitive tasks that usually require sight. However, little is known about the SS experience. Also, there is no agreement on how the phenomenology of SS should be studied. Here, we offer guidelines for the methodology of studies investigating behavioural adaptation to SS and the effects of this adaptation on the subjective SS experience. We also discuss factors that may influence the results of SS studies: (1) the type of SSD, (2) the effects of training, (3) the role of sensory deprivation, (4) the role of the experimental environment, (5) the role of the tasks participants follow, and (6) the characteristics of the participants. In addition, we propose combining qualitative and quantitative methods and discuss how this should be achieved when studying the neural, behavioural, and experiential consequences of SS.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adriana M. De Mendoza ◽  
Soňa Michlíková ◽  
Johann Berger ◽  
Jens Karschau ◽  
Leoni A. Kunz-Schughart ◽  
...  

AbstractRadiotherapy can effectively kill malignant cells, but the doses required to cure cancer patients may inflict severe collateral damage to adjacent healthy tissues. Recent technological advances in the clinical application has revitalized hyperthermia treatment (HT) as an option to improve radiotherapy (RT) outcomes. Understanding the synergistic effect of simultaneous thermoradiotherapy via mathematical modelling is essential for treatment planning. We here propose a theoretical model in which the thermal enhancement ratio (TER) relates to the cell fraction being radiosensitised by the infliction of sublethal damage through HT. Further damage finally kills the cell or abrogates its proliferative capacity in a non-reversible process. We suggest the TER to be proportional to the energy invested in the sensitisation, which is modelled as a simple rate process. Assuming protein denaturation as the main driver of HT-induced sublethal damage and considering the temperature dependence of the heat capacity of cellular proteins, the sensitisation rates were found to depend exponentially on temperature; in agreement with previous empirical observations. Our findings point towards an improved definition of thermal dose in concordance with the thermodynamics of protein denaturation. Our predictions well reproduce experimental in vitro and in vivo data, explaining the thermal modulation of cellular radioresponse for simultaneous thermoradiotherapy.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jacques Pesnot Lerousseau ◽  
Gabriel Arnold ◽  
Malika Auvray

AbstractSensory substitution devices aim at restoring visual functions by converting visual information into auditory or tactile stimuli. Although these devices show promise in the range of behavioral abilities they allow, the processes underlying their use remain underspecified. In particular, while an initial debate focused on the visual versus auditory or tactile nature of sensory substitution, since over a decade, the idea that it reflects a mixture of both has emerged. In order to investigate behaviorally the extent to which visual and auditory processes are involved, participants completed a Stroop-like crossmodal interference paradigm before and after being trained with a conversion device which translates visual images into sounds. In addition, participants' auditory abilities and their phenomenologies were measured. Our study revealed that, after training, when asked to identify sounds, processes shared with vision were involved, as participants’ performance in sound identification was influenced by the simultaneously presented visual distractors. In addition, participants’ performance during training and their associated phenomenology depended on their auditory abilities, revealing that processing finds its roots in the input sensory modality. Our results pave the way for improving the design and learning of these devices by taking into account inter-individual differences in auditory and visual perceptual strategies.


2021 ◽  
pp. 214-220
Author(s):  
Wei Lin Toh ◽  
Neil Thomas ◽  
Susan L. Rossell

There has been burgeoning interest in studying hallucinations in psychosis occurring across multiple sensory modalities. The current study aimed to characterize the auditory hallucination and delusion profiles in patients with auditory hallucinations only versus those with multisensory hallucinations. Participants with psychosis were partitioned into groups with voices only (AVH; <i>n</i> = 50) versus voices plus hallucinations in at least one other sensory modality (AVH+; <i>n</i> = 50), based on their responses on the Scale for the Assessment of Positive Symptoms (SAPS). Basic demographic and clinical information was collected, and the Questionnaire for Psychotic Experiences (QPE) was used to assess psychosis phenomenology. Relative to the AVH group, greater compliance to perceived commands, auditory illusions, and sensed presences was significantly elevated in the AVH+ group. The latter group also had greater levels of delusion-related distress and functional impairment and was more likely to endorse delusions of reference and misidentification. This preliminary study uncovered important phenomenological differences in those with multisensory hallucinations. Future hallucination research extending beyond the auditory modality is needed.


2020 ◽  
Vol 32 ◽  
pp. 03054
Author(s):  
Akshata Parab ◽  
Rashmi Nagare ◽  
Omkar Kolambekar ◽  
Parag Patil

Vision is one of the very essential human senses and it plays a major role in human perception about surrounding environment. But for people with visual impairment their definition of vision is different. Visually impaired people are often unaware of dangers in front of them, even in familiar environment. This study proposes a real time guiding system for visually impaired people for solving their navigation problem and to travel without any difficulty. This system will help the visually impaired people by detecting the objects and giving necessary information about that object. This information may include what the object is, its location, its precision, distance from the visually impaired etc. All these information will be conveyed to the person through audio commands so that they can navigate freely anywhere anytime with no or minimal assistance. Object detection is done using You Only Look Once (YOLO) algorithm. As the process of capturing the video/images and sending it to the main module has to be carried at greater speed, Graphics Processing Unit (GPU) is used. This will help in enhancing the overall speed of the system and will help the visually Impaired to get the maximum necessary instructions as quickly as possible. The process starts from capturing the real time video, sending it for analysis and processing and get the calculated results. The results obtained from analysis are conveyed to user by means of hearing aid. As a result by this system the blind or the visually impaired people can visualize the surrounding environment and travel freely from source to destination on their own.


2020 ◽  
Vol 45 (7) ◽  
pp. 523-531
Author(s):  
Sara Touj ◽  
Samie Cloutier ◽  
Amel Jemâa ◽  
Mathieu Piché ◽  
Gilles Bronchti ◽  
...  

Abstract It is well established that early blindness results in enhancement of the remaining nonvisual sensory modalities accompanied by functional and anatomical brain plasticity. While auditory and tactile functions have been largely investigated, the results regarding olfactory functions remained less explored and less consistent. In the present study, we investigated olfactory function in blind mice using 3 tests: the buried food test, the olfactory threshold test, and the olfactory performance test. The results indicated better performance of blind mice in the buried food test and odor performance test while there was no difference in the olfactory threshold test. Using histological measurements, we also investigated if there was anatomical plasticity in the olfactory bulbs (OB), the most salient site for olfactory processing. The results indicated a larger volume of the OB driven by larger glomerular and granular layers in blind mice compared with sighted mice. Structural plasticity in the OB may underlie the enhanced olfactory performance in blind mice.


1996 ◽  
Vol 1 (1) ◽  
pp. 1-2

'Organised sound' - the term coined by Edgard Varèse for a new definition of musical constructivism - denotes for our increasingly technologically dominated culture an urge towards the recognition of the human impulse behind the 'system'. Such is the diversity of activity in today's computer music, we need to maintain a balance between technological advances and musically creative and scholarly endeavour, at all levels of an essentially educative process. The model of 'life-long learning' makes a special kind of sense when we can explore our musical creativity in partnership with the computer, a machine now capable of sophisticated response from a humanly embedded intelligence.


2006 ◽  
Vol 18 (12) ◽  
pp. 2077-2087 ◽  
Author(s):  
Kirsten G. Volz ◽  
D. Yves von Cramon

According to the Oxford English Dictionary, intuition is “the ability to understand or know something immediately, without conscious reasoning.” Most people would agree that intuitive responses appear as ideas or feelings that subsequently guide our thoughts and behaviors. It is proposed that people continuously, without conscious attention, recognize patterns in the stream of sensations that impinge upon them. What exactly is being recognized is not clear yet, but we assume that people detect potential content based on only a few aspects of the input (i.e., the gist). The result is a vague perception of coherence which is not explicitly describable but instead embodied in a “gut feeling” or an initial guess, which subsequently biases thought and inquiry. To approach the nature of intuitive processes, we used functional magnetic resonance imaging when participants were working at a modified version of the Waterloo Gestalt Closure Task. Starting from our conceptualization that intuition involves an informed judgment in the context of discovery, we expected activation within the median orbito-frontal cortex (OFC), as this area receives input from all sensory modalities and has been shown to be crucially involved in emotionally driven decisions. Results from a direct contrast between intuitive and nonintuitive judgments, as well as from a parametric analysis, revealed the median OFC, the lateral portion of the amygdala, anterior insula, and ventral occipito-temporal regions to be activated. Based on these findings, we suggest our definition of intuition to be promising and a good starting point for future research on intuitive processes.


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