Using structural and functional brain imaging to uncover how the brain adapts to blindness

Abstract

Advances in neuroimaging technology have been instrumental in uncovering the dramatic neurological changes that result from blindness, as well as revealing the inner workings of the human brain. Specifically, modern imaging techniques enable us to examine how the brain adapts and “re-wires” itself as a result of changes in behavior, the environment, injury, or disease; a process referred to as neuroplasticity. Following an overview of commonly employed neuroimaging techniques, we discuss structural and functional neuroplastic brain changes associated with profound visual deprivation. In particular, we highlight how associated structural changes often occur within areas that process intact senses (such as hearing, touch, and smell) while functional changes tend to implicate areas of the brain normally ascribed to the processing of visual information. Evidence will primarily focus on profound blindness due to ocular cause, but related work in cerebral/cortical visual impairment (CVI) will also be discussed. The potential importance of these findings within the context of education and rehabilitation is proposed.

Massive cortical reorganization in sighted Braille readers

“…Cortical reorganization that crosses the sensory boundaries is prominent in blind and deaf humans ( Hirsch et al, 2015 ; Pavani and Roder, 2012 ; Sadato et al, 2002 ) and in congenitally deaf cats ( Lomber et al, 2011 ). In the latter, the deprived auditory areas play a vital role in the deaf cats’ superior visual perception.…”

“…At the systems level, experience-driven plasticity is thought to operate within the limits of sensory divisions, where the visual cortex processes visual stimuli and responds to visual training, the tactile cortex processes tactile stimuli and responds to tactile training, and so on. A departure from this rule is usually reported only during large-scale reorganization induced by sensory loss or injury ( Hirsch et al, 2015 ; Lomber et al, 2011 ; Merabet and Pascual-Leone, 2010 ; Pavani and Roder, 2012 ). The ventral visual cortex, in particular, is activated in blind subjects who read Braille ( Büchel et al, 1998 ; Reich et al, 2011 ; Sadato et al, 2002 , 1996 ) and lesions of this area impair Braille reading ( Hamilton et al, 2000 ).…”

Low Vision and Plasticity: Implications for Rehabilitation

“…In this review, we discuss plasticity and its implications for rehabilitation in low vision. For reviews of neuroplasticity in profound blindness, see Merabet & Pascual-Leone (2010) and Hirsch et al (2015).…”

Neuroimaging insights into the link between depression and Insomnia: A systematic review

“…MRI is a non-invasive imaging method with high spatial resolution without using ionizing radiation (Hirsch, 2015). The brain's tissues can be visualized based on high-quality threedimensional MRI images (Bunge and Kahn, 2009).…”

“…The brain's tissues can be visualized based on high-quality threedimensional MRI images (Bunge and Kahn, 2009). In particular, sMRI is well suited technique to visualize and analyze the anatomical properties and abnormalities in the brain (Hirsch, 2015).…”