Calcarine Sulcus

Functional data: GRE-EPI sequence, 20 slices lay perpendicular to the calcarine sulcus, TR: 2 s, TE: 40 ms, FA: 90 degrees, Phase: 128, FOV: 19 cm, matrix: 64x64, slice: 3 mm, gap: 0, resolution: 2.9 mmx2.9 mmx3.0 mm.  

The relative length of calcarine sulcus lineally increased between EDs 90 and 130, and the gyri in the "occipital region" generated in a dorso-ventral manner: the gyrus convolutions occurred first in the "phylogenetically older" striate and dorsal extrastriate cortices, and then in the "phylogenetically newer" ventral extrastriate cortex.  

Occipital spikes were classified into two subgroups, located at the calcarine sulcus and parieto-occipital sulcus.  

Furthermore, the amplitude of the BOLD response in the anterior calcarine sulcus of early blind subjects correlated with their discrimination performance on the auditory backward masking task.  

The distributed MRI-constrained MEG source estimates demonstrated decreased alpha (10 Hz) activity in and around the parieto-occipital sulcus and in the calcarine sulcus of the occipital lobe, following from increased GABA(A)-inhibition by lorazepam.  

When auditory and tactile stimuli were presented simultaneously with subjects alternating attention between sensory streams, only the calcarine sulcus continued to respond to stimuli in both modalities.  

In the medial occipital region, the calcarine sulcus was the longest and most constant sulcus.  

The average distance from the tip of the anterior Meyer loop to the calcarine sulcus was 105 mm (range 95-114 mm).  

The dipole moments around the calcarine sulcus (CaS) and posterior fusiform gyrus (pFuG) increased at latencies around 70-350 ms.  

randomised presentations revealed significant increases in the fMRI signal in the bilateral lingual and fusiform gyri as well as in the right calcarine sulcus, in conjunction with a larger amplitude of the posterior P1 component of ERPs, but no modulation of the amplitude of the N1 component.  

Instead, a reverse effect of area was found in a region of the calcarine sulcus.  

The sources of gamma-band activity were in the calcarine sulcus in all subjects.  

The estimated location of the equivalent-current dipole for response at 100-ms latency was in the calcarine sulcus and that of the dipole for the response at 150 ms was in the collateral sulcus in the ventro-occipital area. The average of lags between MEG responses from the calcarine sulcus and ventro-occipital area was 43 ms, which suggests sequential processing of color information across the visual cortices..  

RESULTS: Eleven (84.6%) patients showed clustered ECDs in the areas alongside the parietooccipital sulcus (eight of 13; 61.5%) and/or the calcarine sulcus (four of 13; 30.8%).  

P100m sources around the calcarine sulcus did not vary with check size or ISI.  

When the high-resolution MRI brain images were analyzed quantitatively with optimized voxel-based morphometry, results indicated that adults and children with amblyopia have decreased gray matter volume in visual cortical regions, including the calcarine sulcus, known to contain primary visual cortex.  

Wiener filter-MEG imaging with upper and lower quadrant field stimulation demonstrated V1 responses differentially distributed respectively in the lower and upper banks of the calcarine sulcus.  

Activation was found in regions corresponding to the retinotopic visual areas of sighted humans, including the calcarine sulcus (V1).  

METHODS: We studied 50 normal fetuses for visibility of cerebral sulci, especially sulci which appear early in anatomical studies, namely the parieto-occipital fissure, calcarine sulcus, cingulate sulcus, convexity sulci and insula/Sylvian fissure. The earliest gestational ages at which specific sulci could be seen in any fetus were as follows: parieto-occipital fissure 18.5 weeks, calcarine sulcus 18.5 weeks, cingulate sulcus 23.2 weeks and convexity sulci 23.2 weeks. In the present series, the gestational ages at which these sulci were always visible were as follows: parieto-occipital fissure >20.5 weeks, calcarine sulcus >21.9 weeks, cingulate sulcus >24.3 weeks and convexity sulci >27.9 weeks.  

To address the extent to which the visual foveal representation is split, we examined a 29-year-old patient with a lower right quadrantanopia following surgical removal of the left occipital cortex above the calcarine sulcus and compared her performance with subjects receiving transcranial magnetic stimulation (TMS) over the occipital lobes.  

In addition, both limb movements and saccades to a detected stimulus produced stronger signals than stimulus detection without motor movements ('covert detection') in the calcarine sulcus and lingual gyrus.  

Activations in the polar visual cortex around the calcarine sulcus (BA 17, BA 18) were larger and more significant during linearvection.  

The major peak of each function occurred at about 120 ms latency and was well modeled by a current dipole near the calcarine sulcus.  

VN has a lower right quadranopia following surgical removal of the left occipital cortex above the calcarine sulcus, therefore, there are no remaining islands of intact visual cortex within this area.  

Circular checkerboard pattern stimuli with radii from 1.8 to 5.2 degrees were presented at eccentricity of 8 degrees and angular position of 45 degrees in the lower quadrant of the visual field to excite the dorsal part of V1 which is distant from the V1/V2 border and from the fundus of the calcarine sulcus.  

Neural sources were localized in the calcarine sulcus (M1) and the posterior fusiform gyrus (M2) of the hemisphere contralateral to the stimuli, the intraparietal sulcus and the posterior superior temporal sulcus (M3) in either of the hemispheres, and the calcarine sulcus (M4) of the same hemisphere in which the early processing (M1 and M2) occurred.  

The HRSN processing significantly reduced the individual anatomical variability: GM mismatch was reduced by a factor of two and the mean calcarine sulcus overlap frequency was improved from 37 to 68%. This is believed to be the variability of individual areas within the calcarine sulcus, and cannot be resolved by sulcal match.  

This includes striate cortex (V1), i.e., banks of calcarine sulcus, and several higher visual areas in lingual, fusiform, cuneus, lateral occipital, inferior temporal, and middle temporal gyri.  

This decrease was more rostro-dorsal compared to the relative rCBF increase along the calcarine sulcus found during visual stimulation in the awake state.  

Also, anatomical details of structures such as the calcarine sulcus and preoccipital notch were evaluated.  

SPM99-processed results showed for both sessions activation in the calcarine sulcus and local activation foci, mainly in the occipito-parietal region. Other studies involving figurative mental imagery using verbal cues, have shown activation in the occipito-temporal area, but none in the calcarine sulcus or in the dorsal route.  

In a young man with bilateral parieto-occipital microgyria extending into the calcarine sulcus, visual stimuli increased ICoh as in normal individuals, but the response was weaker.  

In neocortex, 5-HT(2C) mRNA was detected in layer V of all cortical regions examined except in the calcarine sulcus, which was devoid of signal.  

We used event-related functional magnetic resonance imaging (ER-fMRI) to detect and characterize the activity in the calcarine sulcus (which contains the primary visual cortex) during single instances of mental imagery.  

Statistical parametric mapping (SPM) revealed a decreased occipital FDG uptake in the patient, particularly at the posterior bank of the parieto-occipital sulcus (putative visual area PO/V6), in the region ventrally bordering V5, and anterolaterally in the calcarine sulcus.  

Activated voxels, identified by correlation with an empirically derived reference waveform, were found for both groups in cortex along the calcarine sulcus and in the fusiform gyrus, with the mean HDR latency in calcarine cortex peaking approximately 300 ms earlier than the HDR evoked in the fusiform gyrus.  

Three pairs of homologous areas in each hemisphere were selected for further analysis: posterior calcarine sulcus (PCS), fusiform gyrus (FM), and the amygdaloid complex (AM).  

On the dorsal bank of the calcarine sulcus, we also defined a transitional zone, area 30v, located between the retrosplenial cortex and the prestriate visual cortex..  

Area prostriata is a poorly understood cortical area located in the anterior portion of the calcarine sulcus.  

The orientation-specific changes, on the other hand, were restricted to the striate and extrastriate visual cortex, more precisely the right calcarine sulcus, the left lingual gyrus, the left middle occipital, and the right inferior occipital gyrus.  

In the older children and the adults, it encompassed the whole length of the calcarine sulcus, whereas it was restricted to the anterior and medial part of the calcarine sulcus in the younger infants.  

MR imaging examinations of the brain 100 consecutive patients, ages ranging from 1 year to 66 years, were evaluated in order to investigate the frequency of a deep calcarine sulcus and prominent calcar avis. Twenty-four cases (24%) were found with a deep calcarine sulcus and prominent calcar avis. A deep calcarine sulcus and prominent calcar avis should be distinguished from disorders of neuronal migration and organization such as schizencephaly and heterotopia. Also, based on our findings in this study, we speculate that it is the deep calcarine sulcus and prominent calcar avis which creates the appearance of the so-called accessory occipital ventricle..  

Significant correlations were found among the spatial extents for the posterior floor of the right temporal horn of the lateral ventricle (r = -0.89, p < 0.001 for vertical extent) and right anterior calcarine sulcus (r = -0.75, p < 0.01 for anterior-posterior extent) with copying ability of the Rey-Osterrieth Complex Figure; the right anterior calcarine also had a significant relationship (r = -0.72, p = 0.02 for anterior-posterior extent) with performance on the Block Design subtest from the Wechsler Adult Intelligence Scale-Revised.  

The pre/parasubiculum contributed with area 29 m to the lateral bank of the calcarine sulcus as far as the most caudal extent of the hippocampal formation.  

In comparison with both position and brightness discrimination tasks, the color discrimination task activated the posterior inferior temporal cortex and a ventromedial occipital region, which is located along the anterior one-third of the calcarine sulcus.  

3) Although most of the cortex surrounding V1 corresponds to V2, one-quarter of the perimeter of V1 is formed by agranular cortex within the rostral calcarine sulcus, including area prostriata. V2 forms a second-order representation of the visual field, with the area centralis being represented laterally and the visual field periphery medially, near the calcarine sulcus.  

The ventral portion of the calcarine sulcus was significantly dilated on MR images in all patients.  

The results show that the medial extrastriate region above the calcarine sulcus projects mainly to the lateral pulvinar (PL), medial pulvinar (PM), and lateral posterior (LP) nuclei.  

The parieto-occipital sulcus, the anterior and posterior rami of the calcarine sulcus, the cingulate and marginal sulci, and the supracallosal sulcus were delineated manually on sagittally resampled sections.  

Connected systems of parametric meshes were used to model the internal course of the following structures in both hemispheres: the parieto-occipital sulcus, the anterior and posterior rami of the calcarine sulcus, the cingulate and marginal sulci, and the supracallosal sulcus.  

With the increase of size (FO-length) and weight of the brain, these sulci became longer, but there were no significant differences in the ratio of the calcarine sulcus to the FO-length among these four species.  

The human primary visual cortex consists of a region buried in the calcarine sulcus and a region outside this sulcus on the free surface of the occipital lobe. Since the depth of the calcarine sulcus can be easily estimated in magnetic resonance images of the living human brain, in vivo morphometry of the human primary visual cortex would be feasible for studying development, intersubject variability and interhemispheric asymmetry if the sulcal depth or a correlated measure such as the intracalcarine surface area would be a precise and reliable estimate of the total volume of the human primary visual cortex. The intracalcarine surface area or the depth of the calcarine sulcus are thus useful parameters for in vivo estimates of the total size of the striate cortex..  

The distribution of accumulated inorganic mercury deposits in the cortex of the calcarine sulcus of adult female Macaca fascicularis following long-term subclinical exposure to methyl-mercury (MeHg) and mercuric chloride (inorganic mercury-IHg) has been determined by autometallography. It is concluded that the astrocytes, and possibly microglia, are the primary location of the demethylation of MeHg into IHg within the cortex of the calcarine sulcus..  

PURPOSE: To determine whether the length and depth of the calcarine sulcus are associated and can be used for estimating the size of the primary visual area (area 17) and other regions in MR images of the human occipital lobe. METHODS: The length and depth of the calcarine sulcus and the projection areas of the mesial surface of the occipital lobe and of the total hemisphere were measured in MR images of 23 healthy subjects. The projection area of the mesial cortical surface of the occipital lobe is correlated with the length of the calcarine sulcus, but both parameters are not correlated with the depth of the calcarine sulcus and, therefore, also not with the size of the part of area 17 buried in the sulcus. CONCLUSION: The size of area 17 cannot be estimated by the length of the calcarine sulcus in MR images. Depth and length of the calcarine sulcus grow independently in the human brain.  

The number of neurons, astrocytes, reactive glia, oligodendrocytes, endothelia, and pericytes in the cortex of the calcarine sulcus of adult female Macaca fascicularis following long-term subclinical exposure to methyl mercury (MeHg) and mercuric chloride (inorganic mercury; IHg) has been estimated by use of the optical volume fractionator stereology technique.  

This investigation describes the variability in location of functionally important persylvian landmarks and of the calcarine sulcus within the Talairach stereotaxic grid, a system frequently used for cortical localization in functional images. Outlines of the following structures were directly identified on sagittal 5-mm MR sections and marked on individual proportional grid overlays: inferior central sulcus, inferior precentral sulcus, inferior postcentral sulcus, anterior ascending ramus and posterior rami of the sylvian fissure, superior temporal sulcus, and calcarine sulcus.  

Using magnetic resonance imaging in 16 healthy volunteers, the location and variability were studied for the superior central sulcus, the sylvian fissure, the calcarine sulcus and the anterobasal temporal lobe.  

The middle third of the rostrocaudal area 17 above the left calcarine sulcus was selected for observation.  

V2 forms a continuous belt of variable width around striate cortex (V1) except at the most anterior portion of the calcarine sulcus.  

In the first type (42.9%), the terminal division was located either in the calcarine sulcus or in the quadrigeminal cistern.  

The retrosplenial region (areas 30 and 29), including its caudal extension along the rostral calcarine sulcus and its ventral extension into the temporal lobe, contained numerous labeled cells.  

Correlation of magnetic resonance (MR) images with cryomicrotome sections and formalin-fixed sections of human brain documents that spin-echo MR imaging with short repetition time/short echo time pulse sequences can display the surface gyri of the inferomedial temporal lobe, including the temporal pole, the parahippocampal gyrus, the isthmus of the cingulate gyrus, the lateral and medial occipitotemporal gyri, and the inferior temporal gyrus; the associated sulci including the rhinal and collateral sulci, the occipitotemporal sulcus, and the anterior calcarine sulcus; the components and fiber tracts of the hippocampal formation including the pes hippocampi, the hippocampus, the subiculum, the dentate gyrus, the subsplenial gyri, the alveus, the fimbria, and the fornix; the fissures and sulci associated with the hippocampal formation, including the hippocampal fissure, dentatofimbrial fissure, and the choroidal fissure; the continuity between the cingulate gyrus and the parahippocampal gyrus through the isthmus of the cingulate gyrus; and the continuity between the callosal sulcus and the hippocampal fissure..  

The equivalent of the calcarine sulcus of man, is the caudal part of the intralimbic sulcus, the axial sulcus of the striate area.  

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