Human echolocation: Basic mechanisms and neuroplasticity

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The human brain has many amazing perceptual abilities. One of these is the ability to echolocate. To echolocate, an organism makes a sound, and listens to the returning echoes. Echolocation is best known from bats. In people it has received comparably little research attention, even though investigations in the 1940s already established the reality of this skill.Recent studies suggest that echolocation may be related to vision. For example, blind echolocation experts can sense their environment through echolocation in a way that seems uncannily similar to vision, and neuroimaging research has shown that blind echo experts use 'visual' brain areas to process echoes. Interestingly, and relatedly, even though echolocation is mediated through hearing, recent research suggests that there might be different processes involved. Recent echolocation research has also confirmed that young people can learn echolocation. Yet, even though there are increasing numbers of people with age related vision loss for whom echolocation might be useful, it has not been investigated how older people might learn it.Following up on these recent developments, the proposed research will investigate how echolocation is related to vision, and 'regular' spatial hearing, and it will investigate this in young and old people. The overarching goal is to advance our understanding of information processing in the human brain. The research has the potential to improve well-being of people with vision loss.The proposed research will make us of behavioural experiments and brain imaging techniques (magnetic resonance imaging, MRI). We will train blind and sighted, and young and old people to echolocate, and we will measure their echolocation behaviour and their brain activity and structure with MRI. Furthermore, we will measure how echolocation is related to people's 'regular' spatial hearing. We will do this by investigating if echolocation improves people's abilities to localize sound sources, and if people's echolocation accuracy is influenced by their expectations about the echolocation sounds.The impact strategy for the proposed research is based on communicating our scientific results to academics, professionals, and the general public. We propose to do this via presentation at scientific conferences, publication of articles in scientific and professional journals, public lectures, and working with the media to publicize our research, and through the creation of a website showcasing our findings. Furthermore, even though the research is focused on human brain and behaviour, our findings are expected to benefit research in engineering (remote sensing, signal acquisition and processing, development of assistive devices for blind people). In addition, the research is expected to inform echolocation research in non-human animals, and in this way it may lead to reduction of use of animals for research.Within the UK approx. 360,000 people are registered partially sighted / blind, and approx. 300,000 of these are older than 50 years. There is already scientific evidence that echolocation offers functional advantages to blind people, for example to detect and avoid obstacles during walking, or to navigate unfamiliar environments. Yet, within the UK (but also worldwide) echolocation is not endorsed for mobility and orientation training for blind people. The proposed research will advance scientific understanding of echolocation and add to existing scientific evidence demonstrating usefulness of echolocation for blind people. In combination with the proposed impact strategy the proposed research has the potential to increase acceptance of echolocation as part of mobility and orientation training for blind people and in this way to improve well-being of people with visual impairments.