"We are not teaching skills; we are activating neurology." - Daniel Kish
eural Correlates of Natural Human Echolocation in Early and Late Blind Echolocation Experts
PLoS ONE (Public Library of Science) - May, 2011by Thaler L, Arnott SR, Goodale MA
University, Western Ontario
A small percentage of blind people are adept at echolocating silent objects simply by producing mouth clicks and listening to the returning echoes. The neural architecture underlying this type of human echolocation has not previously been investigated. The functional brain activity of Daniel Kish (early blind) and Brian Bushway (late blind) were measured while they listened to their own echolocation sounds. When brain activity were compared for sounds that contained both clicks and the returning echoes vs. brain activity for control sounds that did not contain the echoes, but were otherwise acoustically matched, activity was found in the visual cortex in both individuals. Importantly, for the same comparison, a difference in activity in auditory cortex was not observed. The activity in Daniel's visual cortex was found to be greater for echoes reflected from surfaces located in contralateral space - the side of the visual cortex opposite to the side at which the sound/echo was presented. These findings suggest that processing of click-echoes recruits brain regions typically devoted to vision rather than audition in both early and late blind echolocation experts, and that the patterns of processing echoes closely resemble those of processing visual input. "We thank Daniel Kish and Brian Bushway ... who acted as consultants throughout the experiments, providing invaluable technical and practical advice about echolocation and the nature of the testing materials ..." More articles about this work and related topics can be found on our "Health and Well Being" page.
"It is important to emphasize that the use of echolocation in the blind goes well beyond localizing objects in the environment. The experts we studied were also able to use echolocation to perceive object shape and motion – and even object identity. In addition, they were able to use passive listening with 10-kHz cut-off to do these kinds of tasks – which made it possible for us to probe neural substrates of their abilities. ... our data clearly show that EB and LB use echolocation in a way that seems uncannily similar to vision. In this way, our study shows that echolocation can provide blind people with a high degree of independence and self-reliance in their daily life. This has broad practical implications in that echolocation is a trainable skill that can potentially offer powerful and liberating opportunities for blind and vision-impaired people."
Shape-specific activation of occipital cortex in an early blind echolocation expert
Neuropsychologia - February, 2013Stephen Arnott, Lore Thaler, Jennifer Milne, Daniel Kish, Melvyn Goodale
We have previously reported that an early-blind echolocating individual (EB) showed robust occipital activation when he identified distant, silent objects based on echoes from his tongue clicks (Thaler, Arnott, & Goodale, 2011). In the present study we investigated the extent to which echolocation activation in EB's occipital cortex reflected general echolocation processing per se versus feature-specific processing.
Psychophysics of human echolocation
Adv Exp Med Biol - 2013Sven Schörnich, Ludwig Wallmeier, Nikodemus Gessele, Andreas Nagy, Michael Schranner, Daniel Kish, Lutz Wiegrebe
"The skills of some blind humans orienting in their environment through the auditory analysis of reflections from self-generated sounds, has received only little scientific attention to date. Here we present data from a series of formal psychophysical experiments with sighted subjects trained to evaluate features of a virtual echo-acoustic space, allowing for rigid and fine-grain control of the stimulus parameters. The data show how subjects shape both their vocalisations and auditory analysis of the echoes to serve specific echo-acoustic tasks."
Neural Correlates of Motion Processing through Echolocation, Source Hearing and Vision in Blind Echolocation Experts and Sighted Echolocation Novices
Journal of Neurophysiology - October 16, 2013American Physiological Society
Lore Thaler, Jennifer L Milne, Stephen R Arnott, Daniel Kish, and Melvyn A Goodale
"We have shown in previous research that motion processing through echolocation activates temporal-occipital cortex in blind echolocation experts. Here we investigated how neural substrates of echo-motion are related to neural substrates of auditory source-motion and visual motion. ... Our data suggest a functional segregation of processing of auditory source-motion and echo-motion in human temporal-occipital cortex. Furthermore, the data suggest that the echo-motion response in blind experts may represent a reorganization rather than exaggeration of response observed in sighted novices. There is the possibility that this reorganization [in the blind echolocators] involves the recruitment of 'visual' cortical areas."
The Value of FlashSonar
Insight Magazine, United Kingdom - September, 2008Gordon Dutton, Emeritus Professor of Vision Science, Glasgow
Caledonian University, Consultant Ophthalmologist
Professor Gordon Dutton, highly reputed Neural Pediatric Ophthalmologist gives his perspective on the positive impact of FlashSonar training on blind children.
Echolocation in People: Neural Perspectives
Toward a Science of Consciousness - April, 2012Prof. Lore Thaler
Lore Thaler presents the current brain scan research to indicate the role of the visual cortex and other brain mechanisms in the processing of human FlashSonar.
A Spot Light on FlashSonar and Brain Science
Articles and news pieces on the plasticity of blind brains that learn to see.
Parahippocampal cortex is involved in material processing via echoes in blind echolocation experts
Vision Research - July, 2014,By Jennifer Milne, Stephen Arnott, Daniel Kish, Melvyn Goodale, Lore Thaler Brain and Mind Institute, University of Western Ontario, Canada
"Some blind humans use sound to navigate by emitting mouth-clicks and listening to the echoes that reflect from silent objects and surfaces in their surroundings. These echoes contain information about the size, shape, location, and material properties of objects. Here we present results from an fMRI experiment that investigated the neural activity underlying the processing of materials through echolocation. … a whole brain analysis, in which we isolated the processing of just the reflected echoes, revealed a material-related increase in BOLD activation in a region of left parahippocampal cortex in the echolocating participants, but not in the blind or sighted control participants. Our results, in combination with previous findings about brain areas involved in material processing, are consistent with the idea that material processing by means of echolocation relies on a multi-modal material processing area in parahippocampal cortex."
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Echolocation in the Brain
Toward a Science of Consciousness - April, 2012Lore Thaler Presents