Spacing of cytochrome oxidase blobs in visual cortex of normal and strabismic monkeys

Murphy, Kathryn; Jones, David; Fenstemaker, Suzanne; Pegado, Victor; Kiorpes, Lynne; Movshon, J. Anthony

doi:10.1093/cercor/8.3.237

Cited by 36 publications

(36 citation statements)

References 62 publications

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“…To calculate an average distance between iso-orientation columns, activation foci were determined, and then the average distance of neighboring foci was determined by the nearest-neighbor spatial analysis technique (Murphy et al, 1998) within the range of interpeak distances between 313 m and 2 mm. The CNR of the orientation-selective signal was calculated by dividing the signal magnitude at 0.0125 Hz in the active ROI by that in the noise ROI.…”

Section: Methodsmentioning

confidence: 99%

Neural Interpretation of Blood Oxygenation Level-Dependent fMRI Maps at Submillimeter Columnar Resolution

Moon

Fukuda²,

Park³

et al. 2007

Journal of Neuroscience

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Whether conventional gradient-echo (GE) blood oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is able to map submillimeter-scale functional columns remains debatable mainly because of the spatially nonspecific large vessel contribution, poor sensitivity and reproducibility, and lack of independent evaluation. Furthermore, if the results from optical imaging of intrinsic signals are directly applicable, regions with the highest BOLD signals may indicate neurally inactive domains rather than active columns when multiple columns are activated. To examine these issues, we performed BOLD fMRI at a magnetic field of 9.4 tesla to map orientation-selective columns of isoflurane-anesthetized cats. We could not convincingly map orientation columns using conventional block-design stimulation and differential analysis method because of large fluctuations of signals. However, we successfully obtained GE BOLD iso-orientation maps with high reproducibility (r ϭ 0.74) using temporally encoded continuous cyclic orientation stimulation with Fourier data analysis, which reduces orientation-nonselective signals such as draining artifacts and is less sensitive to signal fluctuations. We further reduced large vessel contribution using the improved spin-echo (SE) BOLD method but with overall decreased sensitivity. Both GE and SE BOLD iso-orientation maps excluding large pial vascular regions were significantly correlated to maps with a known neural interpretation, which were obtained in contrast agent-aided cerebral blood volume fMRI and total hemoglobin-based optical imaging of intrinsic signals at a hemoglobin iso-sbestic point (570 nm). These results suggest that, unlike the expectation from deoxyhemoglobin-based optical imaging studies, the highest BOLD signals are localized to the sites of increased neural activity when column-nonselective signals are suppressed.

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Section: Methodsmentioning

confidence: 99%

Neural Interpretation of Blood Oxygenation Level-Dependent fMRI Maps at Submillimeter Columnar Resolution

Moon

Fukuda²,

Park³

et al. 2007

Journal of Neuroscience

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“…For example, the effect of monocular or binocular deprivation during cortical maturation can be so severe that it leads to blindness (Kalloniatis & Harwerth, 1993). Monocular deprivation results in dramatic loss of influence of the deprived eye on cells in V1 both anatomically and physiologically (Murphy et al 1998;Kiorpes, 2006). The main physiological result is the loss of cortical binocularity, whereas anatomically the normal-eye input invades the region of deprived-eye input.…”

Section: Perturbations Of Normal Maturationmentioning

confidence: 99%

Unravelling the development of the visual cortex: implications for plasticity and repair

Bourne

2010

Journal of Anatomy

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The visual cortex comprises over 50 areas in the human, each with a specified role and distinct physiology, connectivity and cellular morphology. How these individual areas emerge during development still remains something of a mystery and, although much attention has been paid to the initial stages of the development of the visual cortex, especially its lamination, very little is known about the mechanisms responsible for the arealization and functional organization of this region of the brain. In recent years we have started to discover that it is the interplay of intrinsic (molecular) and extrinsic (afferent connections) cues that are responsible for the maturation of individual areas, and that there is a spatiotemporal sequence in the maturation of the primary visual cortex (striate cortex, V1) and the multiple extrastriate ⁄ association areas. Studies in both humans and non-human primates have started to highlight the specific neural underpinnings responsible for the maturation of the visual cortex, and how experience-dependent plasticity and perturbations to the visual system can impact upon its normal development. Furthermore, damage to specific nuclei of the visual cortex, such as the primary visual cortex (V1), is a common occurrence as a result of a stroke, neurotrauma, disease or hypoxia in both neonates and adults alike. However, the consequences of a focal injury differ between the immature and adult brain, with the immature brain demonstrating a higher level of functional resilience. With better techniques for examining specific molecular and connectional changes, we are now starting to uncover the mechanisms responsible for the increased neural plasticity that leads to significant recovery following injury during this early phase of life. Further advances in our understanding of postnatal development ⁄ maturation and plasticity observed during early life could offer new strategies to improve outcomes by recapitulating aspects of the developmental program in the adult brain.

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“…Such specific patterning is not as surprising as it may seem, however, because the primate visual cortex is developmentally distinct. Specialization of magnocellular and parvocellular subsystems is apparent early and is independent of patterned activity (Kuljis and Rakic, 1990;Dehay et al, 1991;Rakic, 1991;Rakic et al, 1991;Rakic and Lidow, 1995;Bourgeois and Rakic, 1996;Meissirel et al, 1997;Snider et al, 1999), and other aspects of the visual cortex's functional organization are also established early and not modifiable by experience (Dehay and Kennedy, 1988;Kennedy and Dehay, 1993;Rakic and Lidow, 1995;Bourgeois and Rakic, 1996;Godecke and Bonhoeffer, 1996;Horton and Hocking, 1996;Murphy et al, 1998). Moreover, the superior colliculus, the midbrain visual center, develops normally in the absence of mature patterns of visual activity: receptive field properties develop properly in newborn monkeys (Wallace et al, 1997) and corticocollicular projections are normal in anophthalmic mice (Khachab and Bruce, 1999).…”

Section: Areal Distributionmentioning

confidence: 99%

Molecular Evidence for the Early Specification of Presumptive Functional Domains in the Embryonic Primate Cerebral Cortex

1999

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To identify molecules that may play a role in the initiation of cerebral cortical area formation, we examined the expression of the Eph receptors and their ligands, the ephrins, during primate corticogenesis. We selected the macaque monkey neocortex because of its clear areal subdivisions, large surface area, protracted development (gestation ϭ 165 d), and similarity to the human brain. In situ hybridizations, performed at early [embryonic day 65 (E65)], middle (E80), and late (E95) stages of cortical development, revealed that EphA system family members are expressed in distinct gradients and laminar and areal domains in the embryonic neocortex. Indeed, several regionally restricted molecular patterns are already apparent within the cortical plate at E65, before the formation of thalamocortical connections, suggesting that the initial expression of some EphA system members is regulated by programs intrinsic to cortical cells. For example, EphA3, EphA6, and EphA7 are all selectively expressed within the presumptive visual cortex. However, although EphA6 and EphA7 are present throughout this region, EphA3 is only expressed in the prospective extrastriate cortex, suggesting that cortical cells harbor functional biases that may influence the formation of appropriate synaptic connections. Although several patterns of early gene expression are stable (e.g., EphA3, EphA4, and EphA6), others change as development proceeds (e.g., EphA5, EphA7, ephrin-A2, ephrin-A3, and ephrin-A5), perhaps responding to extrinsic cues. Thus, at E95, after connections between the cortical plate and thalamus have formed, receptor subtypes EphA3, EphA5, EphA6, and EphA7 and the ligand ephrin-A5 are expressed in posterior regions, whereas EphA4 and ephrin-A2 and ephrin-A3 are either uniformly distributed or anteriorly biased. Taken together, our results demonstrate molecular distinctions among cells of the embryonic primate neocortex, revealing hitherto unrecognized compartmentalization early in corticogenesis.

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Spacing of cytochrome oxidase blobs in visual cortex of normal and strabismic monkeys

Cited by 36 publications

References 62 publications

Neural Interpretation of Blood Oxygenation Level-Dependent fMRI Maps at Submillimeter Columnar Resolution

Neural Interpretation of Blood Oxygenation Level-Dependent fMRI Maps at Submillimeter Columnar Resolution

Unravelling the development of the visual cortex: implications for plasticity and repair

Molecular Evidence for the Early Specification of Presumptive Functional Domains in the Embryonic Primate Cerebral Cortex

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