Shape-specific activation of occipital cortex in an early blind echolocation expert

Abstract

. (2013) 'Shape-specic activation of occipital cortex in an early blind echolocation expert.', Neuropsychologia., 51 (5). pp. 938-949. Further information on publisher's website:https://doi.org/10.1016/j.neuropsychologia.2013.01.024Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in Neuropsychologia. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reected in this document. Changes may have been made to this work since it was submitted for publication. A denitive version was subsequently published in Neuropsychologia, 51, 5, April 201351, 5, April , 10.101651, 5, April /j.neuropsychologia.2013.01.024. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractWe 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. In the first experiment, echolocation audio sessions were captured with in-ear microphones in an anechoic chamber or hallway alcove as EB produced tongue clicks in front of a concave or flat object covered in aluminum foil or a cotton towel. All eight echolocation sessions (2 shapes x 2 surface materials x 2 environments) were then randomly presented to him during a sparse-temporal scanning fMRI session. et al., 2011). Specifically, when lying in a magnetic resonance imaging (MRI) machine and listening to binaural in-ear audio recordings of their pre-recorded echolocation mouth clicks sessions that included echo information, both participants were not only able to identify the silent objects present in the recordings, but their corresponding blood oxygen-level dependent (BOLD) activity was found to increase in auditory and occipital cortices. Most impressively, when this brain activity was contrasted with that related to listening to the same sounds but with the very faint echoes removed, activity in occipital but not auditory cortex remained. The results indicated that the processing of the echo information was being carried out in occipital cortex.In the present study we wished to further explore EB's echo-related brain activity Huttenlocher & de Courten...

Neural correlates of motion processing through echolocation, source hearing, and vision in blind echolocation experts and sighted echolocation novices

“…Furthermore, contralateral preference is considered a typical processing characteristic of visual-motion area MTϩ (e.g., Huk et al 2002), and we found evidence for contralateral preference in temporal-occipital echo-motion ROIs in the blind experts. In combination with previous findings (Arnott et al 2013;Thaler et al 2011), the data suggest the involvement of visual cortical areas, and more specifically area MTϩ, in the processing of echo-motion in blind echolocation experts.…”

“…We have found in previous research that blind echolocation experts have a relative increase in BOLD signal in occipital cortex (including calcarine cortex) during the presentation of echolocation sounds compared with echo-less control sounds (Thaler et al 2011). We have also shown that there may be a topographic representation of object shape in the calcarine cortex of an early blind echolocator (Arnott et al 2013;Thaler et al 2011). These data suggest that visual cortical areas are recruited for echolocation in blind experts.…”

Neural Correlates of Human Echolocation of Path Direction During Walking

“…For example, echolocation 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 5 of moving surfaces leads to an increase in activation in temporaloccipital brain areas, potentially encroaching on visual motion area MT+ (Thaler et al, 2011(Thaler et al, , 2014. Furthermore, shape processing through echolocation is associated with activation in LOC (Arnott et al, 2013), and processing of surface materials is associated with an increase in activity in parahippocampal cortex (Milne et al, 2014a). It has also been shown that echolocation of surfaces positioned at one side can lead to a relative increase in brain activity in contralateral calcarine cortex (Thaler et al, 2011), or (for moving surfaces) in contralateral temporal-occipital brain areas (Thaler et al, 2014).…”

“…Skilled echolocators can reliably determine the distance and direction to objects Rosenblum et al, 2000;Schoernich et al, 2013), as well as their azimuth (Thaler et al, 2011;Wallmeier et al, 2013). They can also use echolocation to determine the shape of sound reflecting surfaces in 3D (Arnott et al, 2013;Thaler et al, 2011) and 2D (Milne et al, 2014a), as well as what materials a sound reflecting surface is made of (Arnott et al, 2013;Hausfeld et al, 1982;Milne et al, 2014b).…”

“…primary visual cortex) in skilled blind echolocators (Thaler et al, 2011). Following up on this initial finding, subsequent studies investigated the neural representation of specific echolocation features, such as movement (Thaler et al, 2011(Thaler et al, , 2014, shape (Arnott et al, 2013), or surface material (Milne et al, 2014b). From research to date it appears that there may be a feature specific organization.…”