Pathological changes in the primary visual cortex (Area V1) in Creutzfeldt-Jakob syndrome

About 10% of patients with Creutzfeldt-Jakob syndrome (disease) (CJD) exhibit visual symptoms at presentation and approximately 50% during the course of the disease. The objectives of the present study were to determine, in two subtypes of CJD, viz., sporadic CJD (sCJD) and variant CJD (vCJD), the degree of pathological change in the primary visual cortex (area V1) and the extent to which pathology in V1 may influence visual function. The vacuolation (‘spongiform change’), surviving neurons, glial cell nuclei, and deposits of prion protein (PrP) were quantified in V1 obtained post-mortem in nine cases of sCJD and eleven cases of vCJD. In sCJD, the vacuoles and PrP deposits were regularly distributed along the cortex parallel to the pia mater in clusters with a mean dimension from 450 to 1000 µm. Across the cortex, the vacuolation was most severe in laminae II/III and the glial cell reaction in laminae V/VI. Surviving neurons were most abundant in laminae II/III while PrP deposition either affected all laminae equally or was maximal in lamina II/III. In vCJD, the vacuoles and diffuse PrP deposits were distributed relatively uniformly parallel to the pia mater while the florid deposits were consistently distributed in regular clusters. Across V1, the vacuoles either exhibited a bimodal distribution or were uniformly distributed. The diffuse PrP deposits occurred most frequently in laminae II/III while the florid deposits were more generally distributed. The data suggest that in both sCJD and vCJD, pathological changes in area V1 may affect the processing of visual information in laminae II/III and its transmission from V1 to V2 and to subcortical visual areas. In addition, the data suggest an association in sCJD between the developing pathology and the functional domains of V1 while in vCJD the pathology is more uniformly distributed. These changes could be a factor in the development of poor visual acuity, visual field defects, cortical blindness, diplopia, and vertical gaze palsy that have been observed in Creutzfeldt-Jakob syndrome.

Neuropathological changes in striate and extrastriate visual cortex in variant Creutzfeldt-Jakob disease (vCJD)

Pathological changes in striate (B17, V1) and extrastriate (B18, V2) visual cortex were studied in variant Creutzfeldt-Jakob disease (vCJD). No differences in densities of vacuoles or surviving neurons were observed in B17 and B18 but densities of glial cell nuclei and deposits of prion protein (PrP) were greater in B18. PrP deposit densities in B17 and B18 were positively correlated. Diffuse deposit density in B17 was negatively correlated with the density of surviving neurons in B18. The vacuoles either exhibited a density peak in laminae II/III and V/VI or were more uniformly distributed across the laminae. Diffuse deposits were most frequent in laminae II/III and florid deposits more generally distributed. In B18, the surviving neurons were more consistently bimodally distributed and the glial cell nuclei most abundant in laminae V/VI than in B17. Hence, both striate and extrastriate visual cortex is affected by the pathology of vCJD, the pathological changes being most severe in B18. Neuronal degeneration in B18 appears to be associated with diffuse PrP deposit formation in B17. These data suggest that the short cortico-cortical connections between B17 and B18 and the pathways to subcortical visual areas are compromised in vCJD.

A quantitative study of the pathological lesions in the neocortex and hippocampus of twelve patients with corticobasal degeneration

The density of ballooned neurons (BN), tau-positive neurons with inclusion bodies (tau+ neurons), and tau-positive plaques (tau+ plaques) was determined in sections of the frontal, parietal, and temporal lobe in 12 patients with corticobasal degeneration (CBD). No significant differences in the mean density of BN and tau+ neurons were observed between neocortical regions. In the hippocampus, the densities of BN were significantly lower than in the neocortex, and densities of tau+ neurons were greater in sectors CA1 and CA2, compared with CA3 and CA4. Tau+ plaques were present in one or more brain regions in six patients. Significantly more BN were recorded in the lower (laminae V/VI) compared with the upper cortex (laminae I/II/III) but tau+ neurons were equally frequent in the upper and lower cortex. No significant correlations were observed between the densities of BN and tau+ neurons, but the densities of BN in the superior temporal gyrus and tau+ plaques in the frontal cortex were positively correlated with age. A principal components analysis (PCA) suggested that differences in the density of tau+ neurons in the frontal and motor cortex were the most important sources of variation between patients. In addition, one patient with a particularly high density of tau+ neurons in the hippocampus appeared to be atypical of the patient group studied. The data support the hypothesis that, although clinically heterogeneous, CBD is a pathologically distinct disorder. (C) 2000 Academic Press.

Clustering and spatial correlations of the neuronal cytoplasmic inclusions, astrocytic plaques and ballooned neurons in corticobasal degeneration

This study tested three hypotheses: (1) that there is clustering of the neuronal cytoplasmic inclusions (NCI), astrocytic plaques (AP) and ballooned neurons (BN) in corticobasal degeneration (CBD), (2) that the clusters of NCI and BN are not spatially correlated, and (3) that the lesions are correlated with disease ‘stage’. In 50% of the regions, clusters of lesions were 400–800 µm in diameter and regularly distributed parallel to the tissue boundary. Clusters of NCI and BN were larger in laminae II/III and V/VI, respectively. In a third of regions, the clusters of BN and NCI were negatively spatially correlated. Cluster size of the BN in the parahippocampal gyrus (PHG) was positively correlated with disease ‘stage’. The data suggest the following: (1) degeneration of the cortico-cortical pathways in CBD, (2) clusters of NCI and BN may affect different anatomical pathways and (3) BN may develop after the NCI in the PHG.

Classic beta-amyloid deposits cluster around large diameter blood vessels rather than capillaries in sporadic Alzheimer's disease

Various hypotheses could explain the relationship between beta-amyloid (Abeta) deposition and the vasculature in Alzheimer's disease (AD). Amyloid deposition may reduce capillary density, affect endothelial cells of blood vessels, result in diffusion from blood vessels, or interfere with the perivascular clearance mechanism. Hence, the spatial pattern of the classic ('cored') type of Abeta deposit was studied in the upper laminae (I,II/III) of the superior frontal gyrus in nine cases of sporadic AD (SAD). Sections were immunostained with antibodies against Abeta and with collagen IV to study the relationships between the spatial distribution of the classic deposits and the blood vessel profiles. Both the classic deposits and blood vessel profiles were distributed in clusters. In all cases, there was a positive spatial correlation between the clusters of the classic deposits and the larger diameter (>10 microm) blood vessel profiles and especially the vertically penetrating arterioles. In only 1 case, was there a significant spatial correlation between the clusters of the classic deposits and the smaller diameter (<10 microm) capillaries. There were no negative correlations between the density of Abeta deposits and the smaller diameter capillaries. In 9/11 cases, the clusters of the classic deposits were significantly larger than those of the clusters of the larger blood vessel profiles. In addition, the density of the classic deposits declined as a negative exponential function with distance from a vertically penetrating arteriole. These results suggest that the classic Abeta deposits cluster around the larger blood vessels in the upper laminae of the frontal cortex. This aggregation could result from diffusion of proteins from blood vessels or from overloading the system of perivascular clearance from the brain.

Neuropathological changes in ten cases of neuronal intermediate filament inclusion disease (NIFID):A study using α-internexin immunohistochemistry and principal components analysis (PCA)

Ten cases of neuronal intermediate filament inclusion disease (NIFID) were studied quantitatively. The α-internexin positive neurofilament inclusions (NI) were most abundant in the motor cortex and CA sectors of the hippocampus. The densities of the NI and the swollen achromatic neurons (SN) were similar in laminae II/III and V/VI but glial cell density was greater in V/VI. The density of the NI was positively correlated with the SN and the glial cells. Principal components analysis (PCA) suggested that PC1 was associated with variation in neuronal loss in the frontal/temporal lobes and PC2 with neuronal loss in the frontal lobe and NI density in the parahippocampal gyrus. The data suggest: 1) frontal and temporal lobe degeneration in NIFID is associated with the widespread formation of NI and SN, 2) NI and SN affect cortical laminae II/III and V/VI, 3) the NI and SN affect closely related neuronal populations, and 4) variations in neuronal loss and in the density of NI were the most important sources of pathological heterogeneity. © Springer-Verlag 2005.

Quantification of the pathological changes in the temporal lobe of patients with a novel neurofilamentopathy: neurofilament inclusion disease (NID)

Objective: To quantify the densities of neurofilament inclusions (NI), swollen achromatic neurons, surviving neurons and glial cells in a novel neurofilamentopathy neurofilament inclusion disease (NID). Material: Sectionsof temporal lobe from 4 cases of NID stained with an antibody raised to neurofilament proteins. Method: Densities of the pathological changes were estimated in the various gyri of the temporal lobe, hippocampus and dentate gyrus. Results: Densities of the NI and swollen achromatic neurons (SN) were greater in the cerebral cortical gyri than in the hippocampus and dentate gyrus. Lesion density was relatively constant between gyri and between the CA sectors of the hippocampus. In cortical gyri, the density of the NI, SN and glial cell nuclei was greater in laminae II/III than laminae V/VI. Densities of the NI were negatively correlated with the surviving neurons and positively correlated with the glial cell nuclei. The density of the SN was positively correlated with that of the surviving neurons. Conclusion: The pathology of NID morphologically resembles that of Pick's disease (PD) and corticobasal degeneration (CBD), but there are distinct differences between NID and these disorders supporting the hypothesis that NID is a novel and unique type of neurodegenerative disease.

Sulphide ore minerals:surface chemical properties

The surfaces of iron-containing sulphide minerals were oxidised by a range of inorganic oxidants, and the resultant surface alteration products studied using various spectroscopic techniques. The characterisation of surface oxidation is relevant to the alteration of ores in nature and their behaviour during flotation and leaching, of importance to the metallurgical industry. The sulphides investigated included pyrite (FeS2), hexagonal pyrrhotine (Fe9S10), monoclinic pyrrhotine (Fe7Se), violarite (FeNi2S4), pentlandite ((FeiNi)9Se), chalcopyrite (CuFeS2) and arsenopyrite (FeAsS). The surfaces were oxidised by various methods including acid (sulphuric), alkali (ammonium hydroxide), hydrogen peroxide, steam, electrochemical and air/oxygen (in a low-temperature (150ºC) furnace), The surfaces were examined using surface sensitive chemical spectroscopic methods including x-ray photoelectron spectroscopy (ms), Auger electron spectroscopy (LES) and conversion electron Mössbauer spectroscopy (CEKS). Physical characterisation of the surfaces was undertaken using scanning electron microscopy (SM), spectral reflectance measurements and optical microscopy. Bulk characterisation of the sulphide minerals was undertaken using x-ray diffraction and electron microprobe techniques. Observed phases suggested to form in most of the sulphide surfaces include Fe204, Fe1-x0, Fe202, Fe00H, Fe(OH)3, with iron II & III oxy-sulphates. The iron sulphides show variable extents of oxidation, indicating pyrite to be the most stable. Violarite shows stability to oxidation, suggested to result from both its stable spinel crystal structure, and from the rapid formation of sulphur at the surface protecting the sub-surface from further oxidation. The phenomenon of sub-surface enrichment (in metals), forming secondary sulphides, is exhibited by pentlandite and chalcopyrite, forming violarite and copper sulphides respectively. The consequences of this enrichment with regard to processing and leaching are discussed. Arsenopyrite, often a hindrance in ore processing, exhibits the formation of arsenic compounds at the surface, the dissolution of which is discussed in view of the possible environmental hazard caused by the local pollution of water systems. The results obtained allow a characterisation of the sulphides in terms of their relative stability to oxidation, and an order of stability of the sulphide surfaces is proposed. Models were constructed to explain the chemical compositions of the surfaces, and the inter-relationships between the phases determined at the surface and in the sub-surface. These were compared to the thermo-chemically predicted phases shown in Eh/pH and partial pressure diagrams! The results are discussed, both in terms of the mineralogy and geochemistry of natural ores, and the implications for extraction and processing of these ore minerals.

A quantitative study of the pathological changes in the cortical white matter in variant Creutzfeldt-Jakob disease (vCJD)

The objective of this study was to determine the degree of white matter pathology in the cerebral cortex in cases of variant Creutzfeldt-Jakob disease (vCJD) and to study the relationships between the white matter and grey matter pathologies. Hence, the pathological changes in cortical white matter were studied in individual gyri of the frontal, parietal, occipital, and temporal cortex in eleven cases of vCJD. Vacuolation (‘spongiform change’), deposition of the disease form of prion protein (PrPsc) in the form of discrete PrP deposits, and gliosis were observed in the white matter of virtually all cortical regions studied. Mean density of the vacuoles in the white matter was greater in the parietal lobe compared with the frontal, occipital, and temporal lobes but there were fewer glial cells in the occipital lobe compared with the other cortical regions. In the white matter of the frontal cortex, vacuole density was negatively correlated with the density of both glial cell nuclei and the PrP deposits. In addition, the densities of glial cells and PrP deposits were positively correlated in the frontal and parietal cortex. In the white matter of the frontal cortex and inferior temporal gyrus, there was a negative correlation between the densities of the vacuoles and the number of surviving neurons in laminae V/VI of the adjacent grey matter. In addition, in the frontal cortex, vacuole density in the white matter was negatively correlated with the density of the diffuse PrP deposits in laminae II/III and V/VI of the adjacent grey matter. The densities of PrP deposits in the white matter of the frontal cortex were positively correlated with the density of the diffuse PrP deposits in laminae II/III and V/V1 and with the number of surviving neurons in laminae V/V1. The data suggest that in the white matter in vCJD, gliosis is associated with the development of PrP deposits while the appearance of the vacuolation is a later development. In addition, neuronal loss and PrP deposition in the lower cortical laminae of the grey matter may be a consequence of axonal degeneration within the white matter.

A quantitative study of the pathological changes in the cortical white matter in variant Creutzfeldt-Jakob disease (vCJD).

Objective: To quantify cortical white matter pathology in variant Creutzfeldt-Jakob disease (vCJD) and to correlate white and grey matter pathologies. Methods: Pathological changes were studied in immunolabeled sections of the frontal, parietal, occipital, and temporal cortex of eleven cases of vCJD. Results: Vacuolation ("spongiform change"), deposition of the disease form of prion protein (PrPsc), and a glial cell reaction were observed in the white matter. The density of the vacuoles was greatest in the white matter of the occipital cortex and glial cell density in the inferior temporal gyrus (ITG). Florid-type PrPsc deposits were present in approximately 50% of white matter regions studied. In the white matter of the frontal cortex (FC), vacuole density was negatively correlated with the densities of both glial cell nuclei and PrPsc deposits. In addition, in the frontal and parietal cortices the densities of glial cells and PrPsc deposits were positively correlated. In the FC and ITG, there was a negative correlation between the densities of the vacuoles in the white matter and the number of surviving neurons in laminae V/VI of the adjacent grey matter. In the FC, vacuole density in the white matter was negatively correlated with the density of the diffuse PrPsc deposits in laminae II/III and V/VI of the adjacent grey matter. In addition, the densities of PrPsc deposits in the white matter of the FC were positively correlated with the density of the diffuse PrPsc deposits in laminae II/III and V/VI and with the number of surviving neurons in laminae V/VI. Conclusion: The data suggest significant degeneration of cortical white matter in vCJD; the vacuolation being related to neuronal loss in the lower cortical laminae of adjacent grey matter, PrPsc deposits the result of leakage from damaged axons, and gliosis a reaction to these changes.

Laterality differences in memory and attention

A critical review of the auditory selective attention literature is presented, particular reference is made to methodological issues arising from the asymmetrical hemispheric representation of language in the context of the dominant research technique dichotic shadowing. Subsequently the concept of cerebral localization is introduced, and the experimental literature with reference to models of laterality effects in speech and audition discussed. The review indicated the importance of hemispheric asymmetries insofar as they might influence the results of dichotic shadowing tasks. It is suggested that there is a potential overlap between models of selective attention and hemispheric differences. In Experiment I, ~ a key experiment in auditory selective attention is replicated and by exercising control over possible laterality effects some of the conflicting results of earlier studies were reconciled. The three subsequent experiments, II, III and IV, are concerned with the recall of verbally shadowed inputs. A highly significant and consistent effect of ear of arrival upon the serial position of items recalled is reported. Experiment V is directed towards an analysis of the effect that the processing of unattended inputs has upon the serial position of attended items that are recalled. A significant effect of the type of unattended material upon the recall of attended items was found to be influenced by the ear of arrival of inputs. In Experiment VI, differences between the two ears as attended and unattended input channels were clarified. Two main conclusions were drawn from this work. First, that the dichotic shadowing technique cannot control attention. Instead the task aprocessing both channels of dichotic inputs is unevenly shared bet\'reen the hemispheres as a function of the ear shadowed. Consequently, evidence for the processing of unattended information is considered in terms of constraints imposed by asymmetries in the functional organization of language, not in terms of a limited processing capacity model. The second conclusion to be drawn is that laterality differences can be effectively examined using the dichotic shadowing technique, a new model of laterality differences is proposed and discussed.

The neuropathology of the occipital cortex and its significance in the visual problems of patients with variant Creutzfeldt-Jakob disease (vCJD)

The occipital lobe is one of the cortical areas most affected by the pathology of variant Creutzfeldt-Jakob disease (vCJD). To understand the visual problems of vCJD patients, neuropathological changes were studied in striate (B17, V1) and extrastriate (B18, V2) regions of the occipital cortex in eleven cases of vCJD. No differences in the density of vacuoles or surviving neurons were observed in B17 and B18 but densities of glial cell nuclei and deposits of the protease resistant form of prion protein (PrPsc) were greater in B18. The density of PrPsc deposits in B17 was positively correlated with their density in B18. The density of the diffuse PrPsc deposits in B17 was negatively correlated with the density of the surviving neurons in B18. In B17 and B18, the vacuoles either exhibited density peaks in laminae II/III and V/VI or were more uniformly distributed across the laminae. Diffuse PrPsc deposits were most frequent in laminae II/III and florid PrPsc deposits more generally distributed. In B18, the surviving neurons were more consistently bimodally distributed and the glial cell nuclei most abundant in laminae V/VI compared with B17. Hence, both striate and extrastriate areas of the occipital cortex are affected by the pathology of vCJD, the pathological changes being most severe in B18. Neuronal degeneration in B18 may be associated with the development of diffuse PrPsc deposits in B17. These data suggest that the short cortico-cortical connections between B17 and B18 and the pathways to subcortical visual areas are compromised in vCJD. Pathological changes in striate and extrastriate regions of the occipital cortex may contribute to several of the visual problems identified in patients with vCJD including oculomotor and visuo-spatial function.

The visual cortex in Alzheimer disease:laminar distribution of the pathological changes in visual areas V1 and V2

Alzheimer’s disease (AD) is an important neurodegenerative disorder causing visual problems in the elderly population. The pathology of AD includes the deposition in the brain of abnormal aggregates of ?-amyloid (A?) in the form of senile plaques (SP) and abnormally phosphorylated tau in the form of neurofibrillary tangles (NFT). A variety of visual problems have been reported in patients with AD including loss of visual acuity (VA), colour vision and visual fields; changes in pupillary responses to mydriatics, defects in fixation and in smooth and saccadic eye movements; changes in contrast sensitivity and in visual evoked potentials (VEP); and disturbances in complex visual tasks such as reading, visuospatial function, and in the naming and identification of objects. In addition, pathological changes have been observed to affect the eye, visual pathway, and visual cortex in AD. To better understand degeneration of the visual cortex in AD, the laminar distribution of the SP and NFT was studied in visual areas V1 and V2 in 18 cases of AD which varied in disease onset and duration. In area V1, the mean density of SP and NFT reached a maximum in lamina III and in laminae II and III respectively. In V2, mean SP density was maximal in laminae III and IV and NFT density in laminae II and III. The densities of SP in laminae I of V1 and NFT in lamina IV of V2 were negatively correlated with patient age. No significant correlations were observed in any cortical lamina between the density of NFT and disease onset or duration. However, in area V2, the densities of SP in lamina II and lamina V were negatively correlated with disease duration and disease onset respectively. In addition, there were several positive correlations between the densities of SP and NFT in V1 with those in area V2. The data suggest: (1) NFT pathology is greater in area V2 than V1, (2) laminae II/III of V1 and V2 are most affected by the pathology, (3) the formation of SP and NFT in V1 and V2 are interconnected, and (4) the pathology may spread between visual areas via the feed-forward short cortico-cortical connections.

The neuropathology of the occipital cortex and its significance in the visual problems of patients with variant Creutzfeldt-Jakob Disease (vCJD)

The occipital lobe is one of the cortical areas most affected by the pathology of variant Creutzfeldt-Jakob disease (vCJD). To understand the visual problems of vCJD patients, neuropathological changes were studied in striate (B17, V1) and extrastriate (B18, V2) regions of the occipital cortex in eleven cases of vCJD. No differences in the density of vacuoles or surviving neurons were observed in B17 and B18 but densities of glial cell nuclei and deposits of the protease resistant form of prion protein (PrPsc) were greater in B18. The density of PrPsc deposits in B17 was positively correlated with their density in B18. The density of the diffuse PrPsc deposits in B17 was negatively correlated with the density of the surviving neurons in B18. In B17 and B18, the vacuoles either exhibited density peaks in laminae II/III and V/VI or were more uniformly distributed across the laminae. Diffuse PrPsc deposits were most frequent in laminae II/III and florid PrPsc deposits more generally distributed. In B18, the surviving neurons were more consistently bimodally distributed and the glial cell nuclei most abundant in laminae V/VI compared with B17. Hence, both striate and extrastriate areas of the occipital cortex are affected by the pathology of vCJD, the pathological changes being most severe in B18. Neuronal degeneration in B18 may be associated with the development of diffuse PrPsc deposits in B17. These data suggest that the short cortico-cortical connections between B17 and B18 and the pathways to subcortical visual areas are compromised in vCJD. Pathological changes in striate and extrastriate regions of the occipital cortex may contribute to several of the visual problems identified in patients with vCJD including oculomotor and visuo-spatial function. © 2012 Nova Science Publishers, Inc. All rights reserved.

A quantitative study of the pathological changes in the cortical white matter in variant Creutzfeld-Jakob disease (vCJD)

The objective of this study was to determine the degree of white matter pathology in the cerebral cortex in cases of variant Creutzfeldt-Jakob disease (vCJD) and to study the relationships between the white matter and grey matter pathologies. Hence, the pathological changes in cortical white matter were studied in individual gyri of the frontal, parietal, occipital, and temporal cortex in eleven cases of vCJD. Vacuolation (‘spongiform change’), deposition of the disease form of prion protein (PrPsc) in the form of discrete PrP deposits, and gliosis were observed in the white matter of virtually all cortical regions studied. Mean density of the vacuoles in the white matter was greater in the parietal lobe compared with the frontal, occipital, and temporal lobes but there were fewer glial cells in the occipital lobe compared with the other cortical regions. In the white matter of the frontal cortex, vacuole density was negatively correlated with the density of both glial cell nuclei and the PrP deposits. In addition, the densities of glial cells and PrP deposits were positively correlated in the frontal and parietal cortex. In the white matter of the frontal cortex and inferior temporal gyrus, there was a negative correlation between the densities of the vacuoles and the number of surviving neurons in laminae V/VI of the adjacent grey matter. In addition, in the frontal cortex, vacuole density in the white matter was negatively correlated with the density of the diffuse PrP deposits in laminae II/III and V/VI of the adjacent grey matter. The densities of PrP deposits in the white matter of the frontal cortex were positively correlated with the density of the diffuse PrP deposits in laminae II/III and V/V1 and with the number of surviving neurons in laminae V/V1. The data suggest that in the white matter in vCJD, gliosis is associated with the development of PrP deposits while the appearance of the vacuolation is a later development. In addition, neuronal loss and PrP deposition in the lower cortical laminae of the grey matter may be a consequence of axonal degeneration within the white matter.