The Fine-Scale Functional Correlation of Striate Cortex in Sighted and Blind People

Butt, Omar H.; Benson, Noah C.; Datta, Ritobrato; Aguirre, Geoffrey K.

doi:10.1523/jneurosci.0363-13.2013

Cited by 74 publications

(105 citation statements)

References 62 publications

(5 reference statements)

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“…The cortical visual system extends far beyond this point, and blindness has been found to alter both the properties of these higher visual areas and the connections of visual cortex to other brain regions [25, 77, 78]. We regard the relationship between the anatomical variation we have measured and the properties of higher visual areas and their connections as a promising area for future study.…”

Section: Discussionmentioning

confidence: 95%

Patterns of Individual Variation in Visual Pathway Structure and Function in the Sighted and Blind

et al. 2016

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Many structural and functional brain alterations accompany blindness, with substantial individual variation in these effects. In normally sighted people, there is correlated individual variation in some visual pathway structures. Here we examined if the changes in brain anatomy produced by blindness alter the patterns of anatomical variation found in the sighted. We derived eight measures of central visual pathway anatomy from a structural image of the brain from 59 sighted and 53 blind people. These measures showed highly significant differences in mean size between the sighted and blind cohorts. When we examined the measurements across individuals within each group we found three clusters of correlated variation, with V1 surface area and pericalcarine volume linked, and independent of the thickness of V1 cortex. These two clusters were in turn relatively independent of the volumes of the optic chiasm and lateral geniculate nucleus. This same pattern of variation in visual pathway anatomy was found in the sighted and the blind. Anatomical changes within these clusters were graded by the timing of onset of blindness, with those subjects with a post-natal onset of blindness having alterations in brain anatomy that were intermediate to those seen in the sighted and congenitally blind. Many of the blind and sighted subjects also contributed functional MRI measures of cross-modal responses within visual cortex, and a diffusion tensor imaging measure of fractional anisotropy within the optic radiations and the splenium of the corpus callosum. We again found group differences between the blind and sighted in these measures. The previously identified clusters of anatomical variation were also found to be differentially related to these additional measures: across subjects, V1 cortical thickness was related to cross-modal activation, and the volume of the optic chiasm and lateral geniculate was related to fractional anisotropy in the visual pathway. Our findings show that several of the structural and functional effects of blindness may be reduced to a smaller set of dimensions. It also seems that the changes in the brain that accompany blindness are on a continuum with normal variation found in the sighted.

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Section: Discussionmentioning

confidence: 95%

Patterns of Individual Variation in Visual Pathway Structure and Function in the Sighted and Blind

et al. 2016

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“…This observation is consistent with a study of resting state fMRI that reported decreased functional connectivity between the two occipital cortices in congenitally blind subjects (Liu et al, 2007). Butt et al (2013) found an alteration of the pattern of between-hemispheric striate correlation, but age of blindness onset had no impact on this parameter.…”

Section: Callosal Plasticity: How Visual Input Impacts On Interhemispmentioning

confidence: 97%

Reorganization of Visual Callosal Connections Following Alterations of Retinal Input and Brain Damage

Restani

Caleo

2016

Front. Syst. Neurosci.

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Vision is a very important sensory modality in humans. Visual disorders are numerous and arising from diverse and complex causes. Deficits in visual function are highly disabling from a social point of view and in addition cause a considerable economic burden. For all these reasons there is an intense effort by the scientific community to gather knowledge on visual deficit mechanisms and to find possible new strategies for recovery and treatment. In this review, we focus on an important and sometimes neglected player of the visual function, the corpus callosum (CC). The CC is the major white matter structure in the brain and is involved in information processing between the two hemispheres. In particular, visual callosal connections interconnect homologous areas of visual cortices, binding together the two halves of the visual field. This interhemispheric communication plays a significant role in visual cortical output. Here, we will first review the essential literature on the physiology of the callosal connections in normal vision. The available data support the view that the callosum contributes to both excitation and inhibition to the target hemisphere, with a dynamic adaptation to the strength of the incoming visual input. Next, we will focus on data showing how callosal connections may sense visual alterations and respond to the classical paradigm for the study of visual plasticity, i.e., monocular deprivation (MD). This is a prototypical example of a model for the study of callosal plasticity in pathological conditions (e.g., strabismus and amblyopia) characterized by unbalanced input from the two eyes. We will also discuss the findings of callosal alterations in blind subjects. Noteworthy, we will discuss data showing that inter-hemispheric transfer mediates recovery of visual responsiveness following cortical damage. Finally, we will provide an overview of how callosal projections dysfunction could contribute to pathologies such as neglect and occipital epilepsy. A particular focus will be on reviewing noninvasive brain stimulation techniques and optogenetic approaches that allow to selectively manipulate callosal function and to probe its involvement in cortical processing and plasticity. Overall, the data indicate that experience can potently impact on transcallosal connectivity, and that the callosum itself is crucial for plasticity and recovery in various disorders of the visual pathway.

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“…In visual cortex, regions selective for either foveal or peripheral stimuli, show correlated blood-oxygen level-dependent (BOLD) activity in anesthetized (7) and resting (8) monkeys. In human subjects, BOLD activity in visual areas is organized into highly specific maps (9-11), the organization of which reflect anatomy (12) and the specificity of which is affected by blindness (13). The finding of robust intrinsic networks using fMRI led to a large number of studies (14), which have recently demonstrated the functional importance of intrinsic networks.…”

mentioning

confidence: 99%

Stimulus-induced visual cortical networks are recapitulated by spontaneous local and interareal synchronization

Lewis

Bosman

Womelsdorf

2016

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

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Intrinsic covariation of brain activity has been studied across many levels of brain organization. Between visual areas, neuronal activity covaries primarily among portions with similar retinotopic selectivity. We hypothesized that spontaneous interareal coactivation is subserved by neuronal synchronization. We performed simultaneous high-density electrocorticographic recordings across the dorsal aspect of several visual areas in one hemisphere in each of two awake monkeys to investigate spatial patterns of local and interareal synchronization. We show that stimulation-induced patterns of interareal coactivation were reactivated in the absence of stimulation for the visual quadrant covered. Reactivation occurred through both interareal cofluctuation of local activity and interareal phase synchronization. Furthermore, the trial-by-trial covariance of the induced responses recapitulated the pattern of interareal coupling observed during stimulation, i.e., the signal correlation. Reactivation-related synchronization showed distinct peaks in the theta, alpha, and gamma frequency bands. During passive states, this rhythmic reactivation was augmented by specific patterns of arrhythmic correspondence. These results suggest that networks of intrinsic covariation observed at multiple levels and with several recording techniques are related to synchronization and that behavioral state may affect the structure of intrinsic dynamics.vision | intrinsic activity | oscillations | connectivity | networks A classical approach to perceptual neuroscience suggests that the brain should respond identically to repetitions of identical stimuli. In this framework, endogenously driven variance in the brain's response to repeated stimuli is considered noise (1). However, this so-called noise has been found to be highly structured and influenced by behavioral context (2). In fact, such variation is a flavor of the ongoing, spontaneous activity of the brain. Both the variation in the brain's response to identical stimuli and its spontaneous activity in the absence of stimulation are endogenously generated and structured in spatially specific intrinsic networks. Highly specific intrinsic networks have been described at essentially all spatial scales: from two individual neurons up to the whole brain. Membrane potentials of nearby neurons show a high degree of spontaneous correlation (3). Neuronal spike rates cofluctuate across physically identical trials, and this socalled noise correlation between neurons is related to the similarity in their stimulus selectivity (4). Correspondingly, when entire maps of population activity are investigated, patterns of activation induced by stimuli are found to reoccur spontaneously (5). The same holds across neighboring maps in auditory cortex, where population activity spontaneously reproduces the tonotopic organization (6). Such coactivations can also be observed with functional MRI (fMRI). In visual cortex, regions selective for either foveal or peripheral stimuli, show correlated blood-oxygen level-d...

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The Fine-Scale Functional Correlation of Striate Cortex in Sighted and Blind People

Cited by 74 publications

References 62 publications

Patterns of Individual Variation in Visual Pathway Structure and Function in the Sighted and Blind

Patterns of Individual Variation in Visual Pathway Structure and Function in the Sighted and Blind

Reorganization of Visual Callosal Connections Following Alterations of Retinal Input and Brain Damage

Stimulus-induced visual cortical networks are recapitulated by spontaneous local and interareal synchronization

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