Sensory Input–Based Adaptation and Brain Architecture

Ptito, Maurice; Desgent, Sébastien

doi:10.1017/cbo9780511499722.007

Cited by 12 publications

(10 citation statements)

References 45 publications

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“…Following enucleation, the density of PV-Ir neurons is now greater in layer IV than the controls. This contrasts with the lower density of PV-Ir neurons in layer V. The resulting pattern of laminar distribution of PV-Ir cells in the primary visual cortex resembles that of the primary auditory cortex (adapted from Ptito et al, 2001a ; Ptito and Desgent, 2006 ; Desgent et al, 2010 ).…”

Section: Animal Studiesmentioning

confidence: 96%

“…Indeed, several regimens of visual deprivation such as dark-rearing, enucleation, or eye-lid suturing lead to alterations of the visual system. Conversely, environmental enrichment also produces regional changes in brain anatomy such as increased dendritic space for synapses, increased cortical thickness, and elevated gene expression (Ptito and Desgent, 2006 ).…”

Section: Animal Studiesmentioning

confidence: 99%

“…The loss of a particular sense leads to the invasion of the deprived cortical area by inputs originating from other modalities, illustrating the remarkable capacity of the cerebral cortex for plasticity and reorganization (Ptito and Desgent, 2006 ; Pietrini et al, 2009 ; Merabet and Pascual-Leone, 2010 ). These inter-modal connections result from a phenomenon called cross-modal plasticity.…”

Section: Animal Studiesmentioning

confidence: 99%

“…In the case of early brain damage, however, abnormal neuronal connectivity patterns can be produced and an alternative approach to study cross-modal plasticity resides in the tampering with “blue prints” during prenatal development. Relevant to this approach are the numerous studies on “rewiring” in hamsters (Ptito and Desgent, 2006 ) and in ferrets (reviewed in Lyckman and Sur, 2002 ).…”

Section: Animal Studiesmentioning

confidence: 99%

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The Nature of Consciousness in the Visually Deprived Brain

Kupers¹,

Pietrini²,

Ricciardi³

et al. 2011

Front. Psychology

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Vision plays a central role in how we represent and interact with the world around us. The primacy of vision is structurally imbedded in cortical organization as about one-third of the cortical surface in primates is involved in visual processes. Consequently, the loss of vision, either at birth or later in life, affects brain organization and the way the world is perceived and acted upon. In this paper, we address a number of issues on the nature of consciousness in people deprived of vision. Do brains from sighted and blind individuals differ, and how? How does the brain of someone who has never had any visual perception form an image of the external world? What is the subjective correlate of activity in the visual cortex of a subject who has never seen in life? More in general, what can we learn about the functional development of the human brain in physiological conditions by studying blindness? We discuss findings from animal research as well from recent psychophysical and functional brain imaging studies in sighted and blind individuals that shed some new light on the answers to these questions.

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Section: Animal Studiesmentioning

confidence: 96%

Section: Animal Studiesmentioning

confidence: 99%

Section: Animal Studiesmentioning

confidence: 99%

Section: Animal Studiesmentioning

confidence: 99%

See 2 more Smart Citations

The Nature of Consciousness in the Visually Deprived Brain

Kupers¹,

Pietrini²,

Ricciardi³

et al. 2011

Front. Psychology

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“…Abnormal environmental inputs, during the critical period of development either through sensory deprivation (e.g., eyelid suturing, dark rearing, and enucleation) or cortical injuries lead to dramatic changes at the cellular level and in brain circuitry (reviewed in [16, 17]). The mechanisms underlying visual recovery from large cortical lesions associated with brain plasticity are still unclear and remains an upmost challenge in understanding human patients with lesions restricted to the primary visual cortex (area V1) and those with massive lesions that include all of the visual cortical areas of one cerebral hemisphere (as in hemispherectomy).…”

Section: Sensory and Motor Assessmentmentioning

confidence: 99%

Adaptive Neuroplastic Responses in Early and Late Hemispherectomized Monkeys

2012

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Behavioural recovery in children who undergo medically required hemispherectomy showcase the remarkable ability of the cerebral cortex to adapt and reorganize following insult early in life. Case study data suggest that lesions sustained early in childhood lead to better recovery compared to those that occur later in life. In these children, it is possible that neural reorganization had begun prior to surgery but was masked by the dysfunctional hemisphere. The degree of neural reorganization has been difficult to study systematically in human infants. Here we present a 20-year culmination of data on our nonhuman primate model (Chlorocebus sabeus) of early-life hemispherectomy in which behavioral recovery is interpreted in light of plastic processes that lead to the anatomical reorganization of the early-damaged brain. The model presented here suggests that significant functional recovery occurs after the removal of one hemisphere in monkeys with no preexisting neurological dysfunctions. Human and primate studies suggest a critical role for subcortical and brainstem structures as well as corticospinal tracts in the neuroanatomical reorganization which result in the remarkable behavioral recovery following hemispherectomy. The non-human primate model presented here offers a unique opportunity for studying the behavioral and functional neuroanatomical reorganization that underlies developmental plasticity.

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TMS of the occipital cortex induces tactile sensations in the fingers of blind Braille readers

et al. 2007

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Various non-visual inputs produce cross-modal responses in the visual cortex of early blind subjects. In order to determine the qualitative experience associated with these occipital activations, we systematically stimulated the entire occipital cortex using single pulse transcranial magnetic stimulation (TMS) in early blind subjects and in blindfolded seeing controls. Whereas blindfolded seeing controls reported only phosphenes following occipital cortex stimulation, some of the blind subjects reported tactile sensations in the fingers that were somatotopically organized onto the visual cortex. The number of cortical sites inducing tactile sensations appeared to be related to the number of hours of Braille reading per day, Braille reading speed and dexterity. These data, taken in conjunction with previous anatomical, behavioural and functional imaging results, suggest the presence of a polysynaptic cortical pathway between the somatosensory cortex and the visual cortex in early blind subjects. These results also add new evidence that the activity of the occipital lobe in the blind takes its qualitative expression from the character of its new input source, therefore supporting the cortical deference hypothesis.

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Sensory Input–Based Adaptation and Brain Architecture

Cited by 12 publications

References 45 publications

The Nature of Consciousness in the Visually Deprived Brain

The Nature of Consciousness in the Visually Deprived Brain

Adaptive Neuroplastic Responses in Early and Late Hemispherectomized Monkeys

TMS of the occipital cortex induces tactile sensations in the fingers of blind Braille readers

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