Cytoarchitectonic mapping of the human dorsal extrastriate cortex

The dorsal visual stream consists of several functionally specialized areas, but most of their cytoarchitectonic correlates have not yet been identified in the human brain. The cortex adjacent to Brodmann area 18/V2 was therefore analyzed in serial sections of ten human post-mortem brains using morphometrical and multivariate statistical analyses for the definition of areal borders. Two previously unknown cytoarchitectonic areas (hOc3d, hOc4d) were detected. They occupy the medial and, to a smaller extent, lateral surface of the occipital lobe. The larger area, hOc3d, is located dorso-lateral to area V2 in the region of superior and transverse occipital, as well as parieto-occipital sulci. Area hOc4d was identified rostral to hOc3d; it differed from the latter by larger pyramidal cells in lower layer III, thinner layers V and VI, and a sharp cortex-white-matter borderline. The delineated areas were superimposed in the anatomical MNI space, and probabilistic maps were calculated. They show a relatively high intersubject variability in volume and position. Based on their location and neighborhood relationship, areas hOc3d and hOc4d are putative anatomical substrates of functionally defined areas V3d and V3a, a hypothesis that can now be tested by comparing probabilistic cytoarchitectonic maps and activation studies of the living human brain

Comparison of functional and cytoarchitectonic maps of human visual areas V1, V2, V3d, V3v, and V4(v)

Cytoarchitectonic maps of human striate and extrastriate visual cortex based upon post-mortem brains can be correlated with functionally defined cortical areas using, for example, fMRI. We here assess the correspondence of anatomical maps of the visual cortex with functionally defined in vivo visual areas using retinotopic mapping. To this end, anatomical maximum probability maps (aMPM) derived from individual cytoarchitectonic maps of striate and extrastriate visual areas were compared with functional localisers for the early visual areas. Using fMRI, we delineated dorsal and ventral human retinotopic areas V1, V2, and V3, as well as a quarter-field visual field representation lateral to V3v, V4(v), in 24 healthy subjects. Based on these individual definitions, a functional maximum probability map (fMPM) was then computed in analogy to the aMPM. Functional and anatomical MPMs were highly correlated at group level: 78.5% of activated voxels in the fMPM were correctly assigned by the aMPM. The group aMPM was less effective in predicting functional retinotopic areas in the individual brain due to the large inter-individual variability in the location and extent of visual areas (mean overlap 32-69%). We conclude that cytoarchitectonic maps of striate and extrastriate visual areas may provide a valuable method for assigning functional group activations and thus add valuable a priori knowledge to the analysis of functional imaging data of the visual cortex

Ventral visual cortex in humans: cytoarchitectonic mapping of two extrastriate areas

The extrastriate visual cortex forms a complex system enabling the analysis of visually presented objects. To gain deeper insight into the anatomical basis of this system, we cytoarchitectonically mapped the ventral occipital cortex lateral to BA 18/V2 in 10 human postmortem brains. The anatomical characterization of this part of the ventral stream was performed by examination of cell-body-stained histological sections using quantitative cytoarchitectonic analysis. First, the gray level index (GLI) was measured in the ventral occipital lobe. Cytoarchitectonic borders, i.e., significant changes in the cortical lamination pattern, were then identified using an observer-independent algorithm based on multivariate analysis of GLI profiles. Two distinct cytoarchitectonic areas (hOC3v, hOC4v) were characterized in the ventral extrastriate cortex lateral to BA 18/V2. Area hOC3v was found in the collateral sulcus. hOC4v was located in this sulcus and also covered the fusiform gyrus in more occipital sections. Topographically, these areas thus seem to represent the anatomical substrates of functionally defined areas, VP/V3v and V4/V4v. Following histological analysis, the delineated cytoarchitectonic areas were transferred to 3D reconstructions of the respective postmortem brains, which in turn were spatially normalized to the Montreal Neurological Institute reference space. A probabilistic map was generated for each area which describes how many brains had a representation of this area in a particular voxel. These maps can now be used to identify the anatomical correlates of functional activations observed in neuroimaging experiments to enable a more informed investigation into the many open questions regarding the organization of the human visual cortex

Probabilistic cytoarchitectonic map of Area hOc4lp (LOC) (v3.4)

This dataset contains the distinct architectonic Area hOc4lp (LOC) in the individual, single subject template of the MNI Colin 27 as well as the MNI ICBM 152 2009c nonlinear asymmetric reference space. As part of the Julich-Brain cytoarchitectonic atlas, the area was identified using cytoarchitectonic analysis on cell-body-stained histological sections of 10 human postmortem brains obtained from the body donor program of the University of Düsseldorf. The results of the cytoarchitectonic analysis were then mapped to both reference spaces, where each voxel was assigned the probability to belong to Area hOc4lp (LOC). The probability map of Area hOc4lp (LOC) is provided in the NifTi format for each brain reference space and hemisphere. The Julich-Brain atlas relies on a modular, flexible and adaptive framework containing workflows to create the probabilistic brain maps for these structures. Note that methodological improvements and integration of new brain structures may lead to small deviations in earlier released datasets. Other available data versions of Area hOc4lp (LOC): Malikovic et al. (2018) [Data set, v3.2] [DOI: 10.25493/W4H2-WTM](https://doi.org/10.25493%2FW4H2-WTM) The most probable delineation of Area hOc4lp (LOC) derived from the calculation of a maximum probability map of all currently released Julich-Brain brain structures can be found here: Amunts et al. (2019) [Data set, v1.13] [DOI: 10.25493/Q3ZS-NV6](https://doi.org/10.25493%2FQ3ZS-NV6) Amunts et al. (2019) [Data set, v1.18] [DOI: 10.25493/8EGG-ZAR](https://doi.org/10.25493%2F8EGG-ZAR) Amunts et al. (2020) [Data set, v2.2] [DOI: 10.25493/TAKY-64D](https://doi.org/10.25493%2FTAKY-64D

Micropulse Transscleral Cyclophotocoagulation in Patients with Glaucoma: 1- and 2-year Treatment Outcomes

Précis: Micropulse trans-scleral cyclophotocoagulation (TSCPC) is an effective and safe IOP-lowering treatment for patients with primary or secondary glaucoma. Purpose: To investigate the 1-year and 2-year effect on intraocular pressure (IOP) and safety profile of micropulse TSCPC in patients with glaucoma. Methods: Patients with glaucoma underwent a standardized micropulse TSCPC (MicroPulse P3 probe, Iridex cyclo G6 laser system, Mountain View, CA) at the University Eye Clinic Maastricht from November 2016 to May 2018. Patients with at least 12 months of follow-up were included. Results: A total of 141 eyes of 136 patients were included. The mean age was 67.2±14.5 years, and 56.6% of patients were male individuals. The glaucoma subtypes treated were primary glaucoma (n=99) and secondary glaucoma (n=42). Prior glaucoma surgery was performed in 59 of 141 eyes (41.8%). The mean preoperative IOP was 23.5±9.4 mm Hg. The mean postoperative IOP dropped to 16.8±8.4, 17.0±7.8, and 16.8±9.2 mm Hg, after 12, 18, and 24 months, respectively. The mean number of IOP-lowering medications used preoperatively was 3.3±1.4. The mean number of medications used at 12, 18, and 24 months was respectively 2.6±1.5, 2.5±1.4, and 2.2±1.5. Postoperative complications included cystic macular edema (n=2), hypotony maculopathy (n=1), fibrinous/uveitic reaction (n=1), and rejection of corneal graft (n=1), all reversible after treatment. One patient developed persisting hypotony in the late postoperative period. Conclusions: Micropulse TSCPC is a safe and effective treatment for lowering both IOP and the number of IOP-lowering medications. Micropulse TSCPC can also be considered as a good alternative treatment option for patients after failed incisional glaucoma surgery or patients who are at high risk for incisional surgery