Review Article | Published:

Neural reorganization following sensory loss: the opportunity of change

Nature Reviews Neuroscience volume 11, pages 4452 (2010) | Download Citation

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Abstract

There is growing evidence that sensory deprivation is associated with crossmodal neuroplastic changes in the brain. After visual or auditory deprivation, brain areas that are normally associated with the lost sense are recruited by spared sensory modalities. These changes underlie adaptive and compensatory behaviours in blind and deaf individuals. Although there are differences between these populations owing to the nature of the deprived sensory modality, there seem to be common principles regarding how the brain copes with sensory loss and the factors that influence neuroplastic changes. Here, we discuss crossmodal neuroplasticity with regards to behavioural adaptation after sensory deprivation and highlight the possibility of maladaptive consequences within the context of rehabilitation.

Key points

  • Sensory deprivation is associated with striking crossmodal neuroplastic changes in the brain.

  • Following sensory deprivation (for example, blindness or deafness), there is functional recruitment of brain areas that are normally associated with the processing of the lost sense by those sensory modalities that are spared.

  • These changes seem to underlie adaptive and compensatory behaviours in both blind and deaf individuals.

  • In the case of blindness, occipital cortical areas are recruited to process non-visual forms of sensory information such as touch, hearing and verbal memory.

  • In the case of deafness, auditory and language-related areas are recruited to process tactile as well as linguistic and non-linguistic visual information.

  • Experiments in animal models have helped to uncover potential mechanisms underlying these neuroplastic changes, such as the existence of direct cortico-cortical connections between relevant sensory processing areas.

  • Not all neuroplastic changes are beneficial. There is the possibility of maladaptive consequences, particularly in the context of rehabilitation and the restoration of lost sensory function.

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Acknowledgements

L.B.M. is supported by a K 23 EY016131 award from the National Eye Institute.

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  1. Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, KS-158 Boston, Massachusetts 02215, USA.

    • Lotfi B. Merabet
    •  & Alvaro Pascual-Leone

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Correspondence to Lotfi B. Merabet.

Glossary

Cooperative advantage

With regards to multisensory integration, refers to the interaction of sensory information from the different sensory modalities that can lead to an enhanced perceptual experience.

Neuroplastic changes

The ability of the nervous system to change its functional and structural organization in response to development, experience, the environment, damage or insult.

N1 potential

A large negative-direction evoked potential (measured by electroencephalography) detected over the fronto-central region of the scalp and peaking between 80 and 120 ms after the onset of a stimulus (typically auditory). This potential has been found to be sensitive to features of sounds associated with speech.

Sensory substitution device

(SSD). A device that transforms the characteristics of one sensory modality (for example, vision) into stimuli that can be perceived by another sensory modality (for example, touch or hearing). This strategy is often used in assistive technology to access sensory information normally perceived by an impaired sensory modality by using the remaining intact senses.

Alexia

A neurological disorder characterized by the loss of the ability to read. Alexia typically occurs following damage to specific language-relevant areas of the brain (particularly within the left hemisphere) as well as the occipital and parietal lobes.

Aphasia

A neurological disorder characterized by impaired expression and understanding of language, as well as reading and writing. It is usually the result of damage to areas of the brain involved with language processing.

Usher syndrome

A relatively rare genetic disorder with clinical subtypes characterizing the degree of severity and a leading cause of combined deafness and blindness. Hearing loss is associated with a defective inner ear whereas the visual loss is associated with degeneration of retinal cell function.

Top-down

Pertaining to information processing strategies, a top-down approach describes the flow of sensory information from higher-order cortical areas to lower-order processing levels. This is opposite to 'bottom-up' processing, in which information being processed from lower-order regions flows to higher-order areas of sensory cortex.

Cochlear implant

A surgically implanted electronic device that provides the sense of sound in individuals with profound hearing loss. The device works by electrically stimulating nerve fibres of the cochlea to transmit sensory information provided by external components including a microphone and speech processor.

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