The functional role of the pulvinar in discriminating between objective and subjective cognitive impairment in major depressive disorder.

INTRODUCTION: Emotionally driven cognitive complaints represent a major diagnostic challenge for clinicians and indicate the importance of objective confirmation of the accuracy of depressive patients' descriptions of their cognitive symptoms. METHODS: We compared cognitive status and structural and functional brain connectivity changes in the pulvinar and hippocampus between patients with total depression and healthy controls. The depressive group was also classified as "amnestic" or "nonamnestic," based on the members' subjective reports concerning their forgetfulness. We then sought to determine whether these patients would differ in terms of objective neuroimaging and cognitive findings. RESULTS: The right pulvinar exhibited altered connectivity in individuals with depression with objective cognitive impairment, a finding which was not apparent in depressive patients with subjective cognitive impairment. DISCUSSION: The pulvinar may play a role in depression-related cognitive impairments. Connectivity network changes may differ between objective and subjective cognitive impairment in depression and may play a role in the increased risk of dementia in patients with depression.

Infection with COVID-19 is no longer a public emergency: But what about degenerative dementia?

Although no longer considered a public health threat, post-COVID cognitive syndrome continues to impact on a considerable proportion of individuals who were infected with COVID-19. Recent studies have also suggested that COVID may be represent a critical risk factor for the development of Alzheimer's disease (AD). We compared 17 COVID patients with 20 controls and evaluated the effects of COVID-19 on general cognitive performance, hippocampal volume, and connections using structural and seed-based connectivity analysis. We showed that COVID patients exhibited considerably worse cognitive functioning and increased hippocampal connectivity supported by the strong correlation between hippocampal connectivity and cognitive scores. Our findings of higher hippocampal connectivity with no observable hippocampal morphological changes even in mild COVID cases may be represent evidence of a prestructural compensatory mechanism for stimulating additional neuronal resources to combat cognitive dysfunction as recently shown for the prodromal stages of degenerative cognitive disorders. Our findings may be also important in light of recent data showing that other viral infections as well as COVID may constitute a critical risk factor for the development of AD. To our knowledge, this is the first study that investigated network differences in COVID patients, with a particular focus on compensatory hippocampal connectivity.

A structural and resting-state functional connectivity investigation of the pulvinar in elderly individuals and Alzheimer's disease patients.

In Alzheimer's disease (AD), structural and functional changes in the brain may give rise to disruption of specific cognitive functions. The aim of this study is to investigate the functional connectivity alterations in the pulvinar's subdivisions and total pulvinar voxel-based morphometry (VBM) changes in individuals with AD and healthy controls. A seed-based functional connectivity analysis was applied to the anterior, inferior, lateral, and medial pulvinar in each hemisphere. Furthermore, VBM analysis was carried out to compare gray matter (GM) volume differences in the pulvinar and thalamus between the two groups. Connectivity analysis revealed that the pulvinar subdivisions had decreased connectivity in individuals with AD. In addition, the pulvinar and thalamus in each hemisphere were significantly smaller in the AD group. The pulvinar may have a role in AD-related cognitive impairments and the intrinsic connectivity network changes and GM loss in pulvinar subdivisions suggest the cognitive deterioration occurring in those with AD. HIGHLIGHTS: The pulvinar may play a role in pathophysiology of cognitive impairments in those with Alzheimer's disease (AD). Decreased structural volume and functional connectivity were found in patients with AD. The inferior pulvinar is functionally the most affected subdivision by AD compared to the others.

Differentiation of claustrum resting-state functional connectivity in healthy aging, Alzheimer's disease, and Parkinson's disease.

The claustrum is a sheet-like of telencephalic gray matter structure whose function is poorly understood. The claustrum is considered a multimodal computing network due to its reciprocal connections with almost all cortical areas as well as subcortical structures. Although the claustrum has been involved in several neurodegenerative diseases, specific changes in connections of the claustrum remain unclear in Alzheimer's disease (AD), and Parkinson's disease (PD). Resting-state fMRI and T1-weighted structural 3D images from healthy elderly (n = 15), AD (n = 16), and PD (n = 12) subjects were analyzed. Seed-based FC analysis was performed using CONN FC toolbox and T1-weighted images were analyzed with the Computational Anatomy Toolbox for voxel-based morphometry analysis. While we observed a decreased FC between the left claustrum and sensorimotor cortex, auditory association cortex, and cortical regions associated with social cognition in PD compared with the healthy control group (HC), no significant difference was found in alterations in the FC of both claustrum comparing the HC and AD groups. In the AD group, high FC of claustrum with regions of sensorimotor cortex and cortical regions related to cognitive control, including cingulate gyrus, supramarginal gyrus, and insular cortex were demonstrated. In addition, the structural results show significantly decreased volume in bilateral claustrum in AD and PD compared with HC. There were no significant differences in the claustrum volumes between PD and AD groups so the FC may offer more precise findings in distinguishing changes for claustrum in AD and PD.

Geometric morphometric study of anterior branches of external carotid artery and carotid bifurcation by 3D-CT angiography.

PURPOSE: The aim of our study was to determine the variations of the anterior branches of the external carotid artery (ECA) and investigate the morphometric and geometric features of the anterior branches of the ECA and carotid bifurcation (CB). METHODS: A total of 563 ECAs were included from 288 patients in the study. Classification and exit angles of anterior branches of ECA and determination of vertebral levels of CB and anterior branches were performed. RESULTS: The anterior branch variants of the ECA were observed in 8 different subgroups. The most common variations were type Ia 42.3% (n = 120) on the right and type Ib 40.9% (n = 114) on the left. When looking at the vertebral levels, CB was detected at C4 level in 32.9% of total ECAs (n = 185), STA was at C4 level in 33.4% of total ECAs (n = 188), LA was at C3 level in 50.1% of total ECAs (n = 282), and FA was at C2 level in 37.3% of total ECAs. The mean CB angle in all cases was 59.93° ± 16.04. In the anterior branches of the ECA in cases belonging to the Type I group, the widest angle belonged to FA (R = 116.88 ± 27.04°, L = 110.32° ± 25.94). CONCLUSION: In conclusion, a new classification of the variations of the anterior branches of the ECA was made on the basis of the CTA images to gain more practicality in surgical procedures. This study revealed for the first time the angular and level relationship between CB and ECA anterior branches.

Morphometric evaluation of second to fifth metacarpals for retrograde intramedullary headless screw fixation / Evaluación morfométrica del segundo al quinto metacarpianos para la fijación retrógrada con tornillos intramedulares sin cabeza

SUMMARY: Intramedullary headless screw fixation has come to the fore in the treatment of metacarpal fractures in recent years with its advantages. Our aim was to evaluate the metacarpal morphometry for retrograde intramedullary entrance and to determine the optimal entry point. Computed tomography images of 105 patients including 64 men and 41 women, were examined. Distal and proximal metacarpal widths, medullary cavity width, cortex thickness and the measurements of the optimal entry site in volar-dorsal and radio-ulnar directions were measured in both coronal and sagittal planes. In the sagittal plane, the second metacarpal had the widest proximal width (16.29 mm), distal width was greatest in the third metacarpal (14.34 mm) which was significantly different between the sexes (p<0.001). Third metacarpal had the widest medullary cavity width in the sagittal plane (4.12 mm). In the coronal plane, it was the second metarcarpal with the widest proximal (16.14 mm) and distal width (13.92 mm) and was also the longest (66.32 mm). Unlike the sagittal plane, the medullary cavity width in the coronal plane was at the widest (4.06 mm) in fifth metacarpal. The points determined for optimal entry were respectively (4.60 mm; 4.97 mm; 4.55 mm; 4.36 mm) in the dorsal-volar plane, close to the dorsal side. There was no significant difference between the sexes for optimal insertion point in the sagittal planes in all the measured metacarpals. Considering its three dimensional structure, metacarpal bones have irregular morphometric properties and these features differ in sagittal and coronal planes. The optimal entry site is located in the midline in the coronal plane, while it is located in the sagittal plane close to the dorsal part. Knowing these properties can reduce the complication rate by reducing entry attempts and help select the correct material.

RESUMEN: En los últimos años, debido a sus ventajas la fijación intramedular con tornillos sin cabeza ha pasado a primer plano en el tratamiento de las fracturas de los huesos metacarpianos. Nuestro objetivo fue evaluar la morfometría del hueso metacarpiano para la entrada intramedular retrógrada y determinar el punto de entrada óptimo. Se examinaron imágenes de tomografía computarizada de 105 pacientes, incluidos 64 hombres y 41 mujeres. Los anchos de los huesos metacarpianos distal y proximal, el ancho de la cavidad medular, el grosor de la cortical y las medidas del sitio de entrada óptimo en las direcciones palmar-dorsal y radioulnar se midieron en los planos coronal y sagital. En el plano sagital, el segundo hueso metacarpiano presentó el mayor ancho proximal (16,29 mm), el ancho distal fue mayor en el tercer hueso metacarpiano (14,34 mm), lo que fue significativamente diferente entre individuos de ambos sexos (p<0,001). El tercer metacarpiano tenía la cavidad medular más ancha en el plano sagital (4,12 mm). En el plano coronal, era el segundo hueso metarcarpiano con mayor ancho proximal (16,14 mm) y distal (13,92 mm) y también era el más largo (66,32 mm). A diferencia del plano sagital, el ancho de la cavidad medular en el plano coronal era más ancho (4,06 mm) en el quinto hueso metacarpiano. Los puntos determinados para la entrada óptima fueron respectivamente (4,60 mm; 4,97 mm; 4,55 mm; 4,36 mm) en el plano dorsal-volar, próximo del lado dorsal. No hubo diferencia significativa entre ambos sexos para el punto de inserción óptimo en los planos sagitales en todos los huesos metacarpianos medidos. Teniendo en consideración su estructura tridimensional, los huesos metacarpianos tienen propiedades morfométricas irregulares, y estas características difieren en los planos sagital y coronal. El sitio de entrada óptimo se encuentra en la línea mediana en el plano coronal, mientras que se ubica en el plano sagital cerca de la parte dorsal. Conocer estas propiedades puede reducir la tasa de complicaciones al disminuir los intentos de entrada y ayudar a seleccionar el material correcto.

A rare case report: bilateral occipital artery arising from the vertebral artery.

BACKGROUND: Variations of the origin of the occipital artery (OA) can be considered as congenital anomalies that are often asymptomatic and detected incidentally on angiography or during cadaver dissection. While OA normally originates from the posterior aspect of the external carotid artery (ECA), recent evidence also reflects that OA may infrequently originate from the internal carotid artery (ICA); however, OA originating from the vertebral artery (VA) is a highly rare phenomenon. CASE PRESENTATION: In a 54-year-old female patient with the complaint of left hemiparesis, computed tomography (CT) angiography revealed nonstenotic calcified plaques at the beginning of right ICA where common carotid artery (CCA) bifurcates. We also incidentally observed that bilateral OA originated from the VA using maximum intensity projection (MIP) technique. In addition to this rare variation, CT angiography showed the osseous anomaly termed as high-riding VA (HRVA) in the C1/2 vertebral space of the V3 segment of the VA. CONCLUSION: To the best of our knowledge, a case of bilateral OA originating from the VA has not been reported to date. We believe that recognition of this rare variation may contribute to the relevant literature and it is of importance to consider this variation in radiological imaging and surgical procedures involving this region.