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Current Biology : CB Jan 2023Color-biased regions have been found between face- and place-selective areas in the ventral visual pathway. To investigate the function of the color-biased regions in a...
Color-biased regions have been found between face- and place-selective areas in the ventral visual pathway. To investigate the function of the color-biased regions in a pathway responsible for object recognition, we analyzed the natural scenes dataset (NSD), a large 7T fMRI dataset from 8 participants who each viewed up to 30,000 trials of images of colored natural scenes over more than 30 scanning sessions. In a whole-brain analysis, we correlated the average color saturation of the images with voxel responses, revealing color-biased regions that diverge into two streams, beginning in V4 and extending medially and laterally relative to the fusiform face area in both hemispheres. We drew regions of interest (ROIs) for the two streams and found that the images for each ROI that evoked the largest responses had certain characteristics: they contained food, circular objects, warmer hues, and had higher color saturation. Further analyses showed that food images were the strongest predictor of activity in these regions, implying the existence of medial and lateral ventral food streams (VFSs). We found that color also contributed independently to voxel responses, suggesting that the medial and lateral VFSs use both color and form to represent food. Our findings illustrate how high-resolution datasets such as the NSD can be used to disentangle the multifaceted contributions of many visual features to the neural representations of natural scenes.
Topics: Humans; Visual Pathways; Visual Perception; Brain; Brain Mapping; Magnetic Resonance Imaging; Pattern Recognition, Visual; Photic Stimulation
PubMed: 36574774
DOI: 10.1016/j.cub.2022.11.063 -
Current Eye Research Jul 2018To determine the relationships between visual function and ganglion cell and inner plexiform layer thickness and neuropsychological measures in multiple sclerosis (MS).
PURPOSE
To determine the relationships between visual function and ganglion cell and inner plexiform layer thickness and neuropsychological measures in multiple sclerosis (MS).
METHODS
Ninety-five relapsing-remitting MS (RRMS) and 36 progressive MS patients underwent 100%-contrast visual acuity (VA), 2.5%- and 1.25%-contrast letter acuity (LA) testing, Cirrus-HD-optical coherence tomography, and neuropsychological assessments. Mixed-effects regression models were used to assess relationships.
RESULTS
Across the cohort, 1.25%-contrast LA was associated with Symbol Digit Modalities Test (SDMT; β = 2.17, p = 0.005) and Brief Visuospatial Memory Test-Revised (BVMT-R) total recall (TR) and delayed recall (DR) scores (β = 0.31, p < 0.001; β = 0.15, p = 0.039, respectively). 2.5%-contrast LA was associated with BVMT-R TR scores (β = 0.27, p = 0.006). In the RRMS cohort, 1.25%-contrast LA was generally more significantly associated with cognitive measures: SDMT (β = 2.97, p = 0.001) and BVMT-R TR (β = 0.32, p < 0.001) and DR (β = 0.22, p = 0.012).
CONCLUSION
This study suggests that visual pathway measures, particularly visual function measures, reflect aspects of cognitive function in MS, further supporting their roles as complementary outcomes in MS neuroprotection trials.
Topics: Adult; Cognition; Disease Progression; Female; Humans; Male; Middle Aged; Multiple Sclerosis; Retina; Tomography, Optical Coherence; Visual Acuity; Visual Pathways
PubMed: 29634379
DOI: 10.1080/02713683.2018.1459730 -
Human Brain Mapping Feb 2019Albinism refers to a group of genetic abnormalities in melanogenesis that are associated neuronal misrouting through the optic chiasm. We perform quantitative assessment...
Albinism refers to a group of genetic abnormalities in melanogenesis that are associated neuronal misrouting through the optic chiasm. We perform quantitative assessment of visual pathway structure and function in 23 persons with albinism (PWA) and 20 matched controls using optical coherence tomography (OCT), volumetric magnetic resonance imaging (MRI), diffusion tensor imaging and visual evoked potentials (VEP). PWA had a higher streamline decussation index (percentage of total tractography streamlines decussating at the chiasm) compared with controls (Z = -2.24, p = .025), and streamline decussation index correlated weakly with inter-hemispheric asymmetry measured using VEP (r = .484, p = .042). For PWA, a significant correlation was found between foveal development index and total number of streamlines (r = .662, p < .001). Significant positive correlations were found between peri-papillary retinal nerve fibre layer thickness and optic nerve (r = .642, p < .001) and tract (r = .663, p < .001) width. Occipital pole cortical thickness was 6.88% higher (Z = -4.10, p < .001) in PWA and was related to anterior visual pathway structures including foveal retinal pigment epithelium complex thickness (r = -.579, p = .005), optic disc (r = .478, p = .021) and rim areas (r = .597, p = .003). We were unable to demonstrate a significant relationship between OCT-derived foveal or optic nerve measures and MRI-derived chiasm size or streamline decussation index. Our novel tractographic demonstration of altered chiasmatic decussation in PWA corresponds to VEP measured cortical asymmetry and is consistent with chiasmatic misrouting in albinism. We also demonstrate a significant relationship between retinal pigment epithelium and visual cortex thickness indicating that retinal pigmentation defects in albinism lead to downstream structural reorganisation of the visual cortex.
Topics: Adult; Albinism; Diffusion Tensor Imaging; Evoked Potentials, Visual; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Retina; Tomography, Optical Coherence; Visual Cortex; Visual Pathways
PubMed: 30511784
DOI: 10.1002/hbm.24411 -
Journal of Alzheimer's Disease : JAD 2015Visual deficits are commonly seen in patients with Alzheimer's disease (AD), but postmortem histology has not found substantial damage in visual cortex regions, leading...
Visual deficits are commonly seen in patients with Alzheimer's disease (AD), but postmortem histology has not found substantial damage in visual cortex regions, leading to the hypothesis that the visual pathway, from eye to the brain, may be damaged in AD. Diffusion tensor imaging (DTI) has been used to characterize white matter abnormalities. However, there is a lack of data examining the optic nerves and tracts in patients with AD. In this study, we used DTI to analyze the visual pathway in healthy controls, patients with mild cognitive impairment (MCI) and AD using scans provided by the Alzheimer's Disease Neuroimaging Initiative (ADNI). We found significant increases in the total diffusivity and radial diffusivity and reductions in fractional anisotropy in optic nerves among AD patients. Similar but less extensive changes in these metrics were seen in MCI patients as compared to controls. The differences in DTI metrics between groups mirrored changes in the splenium of the corpus callosum, which has commonly been shown to exhibit white matter damage during AD and MCI. Our findings indicate that white matter damage extends to the visual system, and may help explain the visual deficits experienced by AD patients.
Topics: Aged; Alzheimer Disease; Cognitive Dysfunction; Corpus Callosum; Diffusion Tensor Imaging; Female; Humans; Image Processing, Computer-Assisted; Male; Optic Nerve; Retina; Statistics, Nonparametric; Visual Pathways
PubMed: 25537012
DOI: 10.3233/JAD-141239 -
The Journal of Comparative Neurology May 2021The mammalian visual system is composed of circuitry connecting sensory input from the retina to the processing core of the visual cortex. The two main retinorecipient...
The mammalian visual system is composed of circuitry connecting sensory input from the retina to the processing core of the visual cortex. The two main retinorecipient brain targets, the superior colliculus (SC) and dorsal lateral geniculate nucleus (dLGN), bridge retinal input and visual output. The primary cilium is a conserved organelle increasingly viewed as a critical sensor for the regulation of developmental and homeostatic pathways in most mammalian cell types. Moreover, cilia have been described as crucial for neurogenesis, neuronal maturation, and survival in the cortex and retina. However, cilia in the visual relay center remain to be fully described. In this study, we characterized the ciliation profile of the SC and dLGN and found that the overall number of ciliated cells declined during development. Interestingly, shorter ciliated cells in both regions were identified as neurons, whose numbers remained stable over time, suggesting that cilia retention is a critical feature for optimal neuronal function in SC and dLGN. Our study suggests that primary cilia are important for neuronal maturation and function in cells of the SC and dLGN.
Topics: Animals; Cilia; Geniculate Bodies; Macaca mulatta; Mice; Mice, Inbred C57BL; Microscopy, Confocal; Neurogenesis; Neurons; Superior Colliculi; Visual Pathways
PubMed: 32939774
DOI: 10.1002/cne.25029 -
Scientific Reports Feb 2020Optic Pathway Glioma (OPG) is a relatively common brain tumour in childhood; however, there is scarce understanding of neuropsychological sequelae in these survivors. In...
Optic Pathway Glioma (OPG) is a relatively common brain tumour in childhood; however, there is scarce understanding of neuropsychological sequelae in these survivors. In this study, 12 children with diagnosis of OPG before 6 years of age received a comprehensive standardised assessment of visual perception, general intelligence and academic achievement, using adjustments to visual materials of the tests, to examine the extent of concurrent impairment in these functional domains. Information about vision, clinical and socio-demographic factors were extracted from medical records to assess the associations of neuropsychological outcomes with clinical and socio-demographic factors. Children with OPG exhibited high within-patient variability and moderate group-level impairment compared to test norms. Visual perception was the most impaired domain, while scholastic progression was age-appropriate overall. For cognition, core verbal and visuo-spatial reasoning skills were intact, whereas deficits were found in working memory and processing speed. Visual function was associated with tasks that rely on visual input. Children with OPG are at moderate risk of neuropsychological impairment, especially for visual perception and cognitive proficiency. Future research should elucidate further the relative contribution of vision loss and neurofibromatosis type 1 co-diagnosis within a large sample.
Topics: Adolescent; Child; Cognition; Female; Glioma; Humans; Male; Neuropsychological Tests; Treatment Outcome; Visual Acuity; Visual Pathways
PubMed: 32094393
DOI: 10.1038/s41598-020-59896-2 -
Journal of Visualized Experiments : JoVE Aug 2014DTI is a technique that identifies white matter tracts (WMT) non-invasively in healthy and non-healthy patients using diffusion measurements. Similar to visual pathways...
DTI is a technique that identifies white matter tracts (WMT) non-invasively in healthy and non-healthy patients using diffusion measurements. Similar to visual pathways (VP), WMT are not visible with classical MRI or intra-operatively with microscope. DIT will help neurosurgeons to prevent destruction of the VP while removing lesions adjacent to this WMT. We have performed DTI on fifty patients before and after surgery between March 2012 to January 2014. To navigate we used a 3DT1-weighted sequence. Additionally, we performed a T2-weighted and DTI-sequences. The parameters used were, FOV: 200 x 200 mm, slice thickness: 2 mm, and acquisition matrix: 96 x 96 yielding nearly isotropic voxels of 2 x 2 x 2 mm. Axial MRI was carried out using a 32 gradient direction and one b0-image. We used Echo-Planar-Imaging (EPI) and ASSET parallel imaging with an acceleration factor of 2 and b-value of 800 s/mm². The scanning time was less than 9 min. The DTI-data obtained were processed using a FDA approved surgical navigation system program which uses a straightforward fiber-tracking approach known as fiber assignment by continuous tracking (FACT). This is based on the propagation of lines between regions of interest (ROI) which is defined by a physician. A maximum angle of 50, FA start value of 0.10 and ADC stop value of 0.20 mm²/s were the parameters used for tractography. There are some limitations to this technique. The limited acquisition time frame enforces trade-offs in the image quality. Another important point not to be neglected is the brain shift during surgery. As for the latter intra-operative MRI might be helpful. Furthermore the risk of false positive or false negative tracts needs to be taken into account which might compromise the final results.
Topics: Brain Neoplasms; Diffusion Tensor Imaging; Glioblastoma; Humans; Neoplasm Recurrence, Local; Neurosurgical Procedures; Software; Visual Pathways; White Matter
PubMed: 25226557
DOI: 10.3791/51946 -
ELife Apr 2020Much of the early visual system is devoted to sifting the visual scene for the few bits of behaviorally relevant information. In the visual cortex of mammals, a...
Much of the early visual system is devoted to sifting the visual scene for the few bits of behaviorally relevant information. In the visual cortex of mammals, a hierarchical system of brain areas leads eventually to the selective encoding of important features, like faces and objects. Here, we report that a similar process occurs in the other major visual pathway, the superior colliculus. We investigate the visual response properties of collicular neurons in the awake mouse with large-scale electrophysiology. Compared to the superficial collicular layers, neuronal responses in the deeper layers become more selective for behaviorally relevant stimuli; more invariant to location of stimuli in the visual field; and more suppressed by repeated occurrence of a stimulus in the same location. The memory of familiar stimuli persists in complete absence of the visual cortex. Models of these neural computations lead to specific predictions for neural circuitry in the superior colliculus.
Topics: Algorithms; Animals; Behavior, Animal; Memory; Mice; Mice, Inbred C57BL; Models, Neurological; Neurons; Superior Colliculi; Visual Pathways; Visual Perception
PubMed: 32286224
DOI: 10.7554/eLife.50678 -
Developmental Medicine and Child... Jan 2007This study investigated the effect of very preterm birth (gestation < or =30wks) and very low birth weight (< or =1500g) on the development of magnocellular and...
This study investigated the effect of very preterm birth (gestation < or =30wks) and very low birth weight (< or =1500g) on the development of magnocellular and parvocellular visual processing streams. Participants were preterm infants (n=55: 31 females, 24 males) born between 24 and 30 weeks'gestation (mean 27.4wks [SD 1.3]), weighing between 720 and 1470g (mean 1015g [SD 215]) and term infants (n=52: 27 females, 25 males) born between 38 and 42 weeks'gestation (mean 39.4wks [SD 0.9]), weighing between 2670 and 4405g (mean 3549g [SD 440]). Visual-evoked potentials to phase-reversing sine-wave gratings, varying in spatial frequency and contrast, were used to elicit magnocellular and parvocellular specific responses. Previous studies found that the N1 component reflects the parvocellular response, while P1 reflects the magnocellular response in adults and infants. Findings from the current study indicate significantly lower P1 amplitudes in preterm compared with term infants under most conditions. No difference was found for the amplitude of the N1 waveform. Results indicate that, for the age-range tested, preterm birth has little effect on the development of parvocellular function, while it appears to disrupt the development of magnocelluar function.
Topics: Contrast Sensitivity; Developmental Disabilities; Evoked Potentials, Visual; Female; Humans; Infant, Newborn; Infant, Premature; Infant, Very Low Birth Weight; Male; Visual Pathways
PubMed: 17209973
DOI: 10.1017/s0012162207000084.x -
Cerebral Cortex (New York, N.Y. : 1991) Jun 2023Considerable research has been devoted to understanding the fundamental organizing principles of the ventral visual pathway. A recent study revealed a series of 3-4...
Considerable research has been devoted to understanding the fundamental organizing principles of the ventral visual pathway. A recent study revealed a series of 3-4 topographical maps arranged along the macaque inferotemporal (IT) cortex. The maps articulated a two-dimensional space based on the spikiness and animacy of visual objects, with "inanimate-spiky" and "inanimate-stubby" regions of the maps constituting two previously unidentified cortical networks. The goal of our study was to determine whether a similar functional organization might exist in human IT. To address this question, we presented the same object stimuli and images from "classic" object categories (bodies, faces, houses) to humans while recording fMRI activity at 7 Tesla. Contrasts designed to reveal the spikiness-animacy object space evoked extensive significant activation across human IT. However, unlike the macaque, we did not observe a clear sequence of complete maps, and selectivity for the spikiness-animacy space was deeply and mutually entangled with category-selectivity. Instead, we observed multiple new stimulus preferences in category-selective regions, including functional sub-structure related to object spikiness in scene-selective cortex. Taken together, these findings highlight spikiness as a promising organizing principle of human IT and provide new insights into the role of category-selective regions in visual object processing.
Topics: Animals; Humans; Pattern Recognition, Visual; Brain Mapping; Visual Cortex; Visual Perception; Magnetic Resonance Imaging; Visual Pathways; Macaca; Photic Stimulation
PubMed: 36958809
DOI: 10.1093/cercor/bhad108