Wayfinding in the blind: larger hippocampal volume and supranormal spatial navigation

Fortin, M.; Voss, Patrice; Lord, Catherine; Lassonde, Maryse; Pruessner, Jens C.; Saint-Amour, Dave; Rainville, Constant; Leporé, Franco

doi:10.1093/brain/awn250

Cited by 139 publications

(151 citation statements)

References 38 publications

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“…This is consistent with the hypothesis that this region stores spatial representations of the environment and enlarges as more information is stored. Interestingly, in a recent study of hippocampal volume and navigational skills in individuals with blindness, the subjects also had enlarged hippocampi and superior ability to learn new routes, and to perform pointing tasks in a maze and a spatial layout task [Fortin et al, 2008]. Additional studies have shown that limb amputation is associated with decreased gray matter in the thalamus while mathematicians have been reported to have increased gray matter in the parietal cortex [Draganski et al, 2006b;Aydin et al, 2007].…”

Section: Structural Changes In the Brain Associated With Neural Plastmentioning

confidence: 99%

Plasticity in the developing brain: Implications for rehabilitation

Johnston

2009

Dev Disabil Res Revs

442

273

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Neuronal plasticity allows the central nervous system to learn skills and remember information, to reorganize neuronal networks in response to environmental stimulation, and to recover from brain and spinal cord injuries. Neuronal plasticity is enhanced in the developing brain and it is usually adaptive and beneficial but can also be maladaptive and responsible for neurological disorders in some situations. Basic mechanisms that are involved in plasticity include neurogenesis, programmed cell death, and activity-dependent synaptic plasticity. Repetitive stimulation of synapses can cause long-term potentiation or long-term depression of neurotransmission. These changes are associated with physical changes in dendritic spines and neuronal circuits. Overproduction of synapses during postnatal development in children contributes to enhanced plasticity by providing an excess of synapses that are pruned during early adolescence. Clinical examples of adaptive neuronal plasticity include reorganization of cortical maps of the fingers in response to practice playing a stringed instrument and constraint-induced movement therapy to improve hemiparesis caused by stroke or cerebral palsy. These forms of plasticity are associated with structural and functional changes in the brain that can be detected with magnetic resonance imaging, positron emission tomography, or transcranial magnetic stimulation (TMS). TMS and other forms of brain stimulation are also being used experimentally to enhance brain plasticity and recovery of function. Plasticity is also influenced by genetic factors such as mutations in brain-derived neuronal growth factor. Understanding brain plasticity provides a basis for developing better therapies to improve outcome from acquired brain injuries. ' 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 200915:94-101.

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Section: Structural Changes In the Brain Associated With Neural Plastmentioning

confidence: 99%

Plasticity in the developing brain: Implications for rehabilitation

Johnston

2009

Dev Disabil Res Revs

442

273

View full text Add to dashboard Cite

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“…At the same time, hippocampal functionality has additional facets of potential relevance to PTSD. These include spatial/contextual processing (Bilkey, 2007 ;Fortin …”

Section: Introductionmentioning

confidence: 99%

Hippocampal volume and declarative memory function in combat-related PTSD

Woodward

Kaloupek

Grande

et al. 2009

J Int Neuropsychol Soc

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The proposition that declarative memory defi cits are systematically related to smaller hippocampal volume was tested in a relatively large sample ( n = 95) of U.S. military veterans with and without combat-related posttraumatic stress disorder. This correlative analysis was extended by including multiple measures of verbal and visual declarative memory and multiple memory-relevant regional brain volumes that had been shown to exhibit main effects of PTSD in prior work. Small-to-moderate effects were observed on verbal declarative memory in line with a recent meta-analysis; nevertheless, little or no evidence of systematic linear covariation between memory measures and brain volumes was observed. ( JINS , 2009, 15, 830-839. )

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“…Visual cues signaling the location of landmarks play a key role in facilitating the formation of spatial cognitive maps used for path finding in a visual setting (1,2). Despite the importance of vision in spatial cognition, the abilities to recognize a traveled route and to represent spatial information are maintained in blind individuals (3)(4)(5), probably through tactile, auditory, and olfactory cues, as well as motion-related cues arising from the vestibular and proprioceptive systems.…”

mentioning

confidence: 99%

Neural correlates of virtual route recognition in congenital blindness

Kupers

Chebat

Madsen

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

133

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Despite the importance of vision for spatial navigation, blind subjects retain the ability to represent spatial information and to move independently in space to localize and reach targets. However, the neural correlates of navigation in subjects lacking vision remain elusive. We therefore used functional MRI (fMRI) to explore the cortical network underlying successful navigation in blind subjects. We first trained congenitally blind and blindfolded sighted control subjects to perform a virtual navigation task with the tongue display unit (TDU), a tactile-to-vision sensory substitution device that translates a visual image into electrotactile stimulation applied to the tongue. After training, participants repeated the navigation task during fMRI. Although both groups successfully learned to use the TDU in the virtual navigation task, the brain activation patterns showed substantial differences. Blind but not blindfolded sighted control subjects activated the parahippocampus and visual cortex during navigation, areas that are recruited during topographical learning and spatial representation in sighted subjects. When the navigation task was performed under full vision in a second group of sighted participants, the activation pattern strongly resembled the one obtained in the blind when using the TDU. This suggests that in the absence of vision, cross-modal plasticity permits the recruitment of the same cortical network used for spatial navigation tasks in sighted subjects.cross-modal plasticity | parahippocampus | sensory substitution | spatial navigation | visual cortex T he ability to navigate efficiently in large-scale environments was always a predicate for human survival, now applied to the particular challenges of living in a modern, urban society. Visual cues signaling the location of landmarks play a key role in facilitating the formation of spatial cognitive maps used for path finding in a visual setting (1, 2). Despite the importance of vision in spatial cognition, the abilities to recognize a traveled route and to represent spatial information are maintained in blind individuals (3-5), probably through tactile, auditory, and olfactory cues, as well as motion-related cues arising from the vestibular and proprioceptive systems.During successful navigation, spatial information needs to be encoded and retrieved. The role of the hippocampus for navigation in large-scale environments has been amply demonstrated in both animal (6-8) and human studies (9-11). Besides the hippocampus, several other areas in the posterior mesial lobe and posterior parietal, occipital, and infero-temporal cortices also play an important role in navigation (9,(12)(13)(14)(15)(16)(17).The neural correlates of navigation in congenital blindness remain elusive, in part owing to the difficulty in testing navigational skills of blind subjects within the setting of a functional brain imaging study. To circumvent this difficulty, we trained blind and sighted subjects in a spatial navigation task using the tongue display unit (TDU), a vis...

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Wayfinding in the blind: larger hippocampal volume and supranormal spatial navigation

Cited by 139 publications

References 38 publications

Plasticity in the developing brain: Implications for rehabilitation

Plasticity in the developing brain: Implications for rehabilitation

Hippocampal volume and declarative memory function in combat-related PTSD

Neural correlates of virtual route recognition in congenital blindness

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