Display omitted
Using an visuo-audio spatial task, a novel version of the Posner task, we support the idea that auditory and visual attentional systems are governed by modality-specific processes and ...provide novel evidence for audiovisual links in endogenous covert spatial attention.
•Facilitation was observed for right-sided auditory stimuli in a new visuo-audio task.•Auditory space has dynamic nature, which adapts to changes in visual space.•Sound localization was enhanced by visual cues.•Crossmodal links in spatial attention were found between audition and vision.•These findings have theoretical and translational implications for future studies.
Visuospatial attention is asymmetrically distributed with a leftward bias (i.e. pseudoneglect), while evidence for asymmetries in auditory spatial attention is still controversial. In the present study, we investigated putative asymmetries in the distribution of auditory spatial attention and the influence that visual information might have on its deployment. A modified version of the Posner task (i.e. the visuo-audio spatial task VAST) was used to investigate spatial processing of auditory targets when endogenous orientation of spatial attention was mediated by visual cues in healthy adults. A line bisection task (LBT) was also administered to assess the presence of a leftward bias in deployment of visuospatial attention. Overall, participants showed rightward and leftward biases in the VAST and the LBT, respectively. In the VAST, sound localization was enhanced by visual cues. Altogether, these findings support the existence of a facilitation effect for auditory targets originating from the right side of space and provide new evidence for crossmodal links in endogenous spatial attention between vision and audition.
Although the olfactory sense has always been considered with less interest than the visual, auditive or somatic senses, it does plays a major role in our ordinary life, with important implication in ...dangerous situations or in social and emotional behaviors. Traditional Diffusion Tensor signal model and related tractography have been used in the past years to reconstruct the cranial nerves, including the olfactory nerve (ON). However, no supplementary information with regard to the pathways of the olfactory network have been provided. Here, by using the more advanced Constrained Spherical Deconvolution (CSD) diffusion model, we show for the first time
and non-invasively that, in healthy humans, the olfactory system has a widely distributed anatomical network to several cortical regions as well as to many subcortical structures. Although the present study focuses on an healthy sample size, a similar approach could be applied in the near future to gain important insights with regard to the early involvement of olfaction in several neurodegenerative disorders.
To differentiate acute central serous chorioretinopathy (CSC) subtypes by multimodal imaging.
The research was designed as a prospective, interventional study. Naive patients with acute CSC were ...followed for 24 months. Overall, 96 CSC patients (96 eyes) and 210 controls (210 eyes) were included. Multimodal imaging allowed the study to classify CSC into retinal pigment epithelium-related CSC (RPE-CSC) and choroidal-related CSC (choroidal-CSC) subtypes. The RPE-CSC type was characterized by normal choroidal thickness (CT) in association with disseminated RPE alterations. The choroidal-CSC type was distinguished by identifying a pachychoroid. All the patients underwent eplerenone or verteporfin photodynamic therapy (PDT). Patients developing macular neovascularization (MNV) underwent anti-VEGF injections. Quantitative measurements included central macular thickness (CMT), choroidal thickness (CT), Sattler layer thickness (SLT) and Haller layer thickness (HLT).
Considering the CSC patients as a whole, baseline BCVA was 0.18 ± 0.25 LogMAR, increasing to 0.13 ± 0.21 LogMAR after 24 months (P < 0.01), whereas baseline CMT improved from 337 ± 126 µm to 244 ± 84 µm after 24 months (P < 0.01). We found the following subdivision of CSC eyes: RPE-CSC type (45%) and choroidal-CSC type (55%). Overall, MNV were detected in 18 eyes (19%), 13 eyes (72%) in the RPE-CSC subgroup and five eyes (28%) in the choroidal-CSC subgroup. Forty eyes responded to eplerenone (57% of RPE-CSC and 47% of choroidal-CSC), whereas 38 eyes required PDT (43% of RPE-CSC and 53% of choroidal-CSC).
Acute CSC includes two main clinical manifestations, displaying differing features concerning retinal and choroidal involvement.
This study identified two clinically different acute CSC subtypes on the basis of quantitative pachychoroid cutoff values.
Introduction
This study aimed to assess quantitative factors associated with treatment response and macular neovascularization (MNV) onset in central serous chorioretinopathy (CSC) through an ...artificial intelligence-based approach.
Methods
The study was designed as an interventional, prospective case series with a planned follow-up of 36 months. We included only eyes demonstrating the first episode of CSC. All the patients underwent eplerenone or photodynamic therapy (PDT) treatment. Eyes developing MNV underwent anti-VEGF injections. We developed an artificial intelligence-based model to assess predictive quantitative structural optical coherence tomography (OCT) factors related to treatment response and onset of MNV. Main outcome measures were best-correct visual acuity (BCVA), central macular thickness (CMT), retinal thickness (RT), retinal pigment epithelium (RPE) thickness, choroidal thickness, Sattler’s layer thickness (SLT), Haller’s layer thickness, retinal and choroidal hyperreflective foci (HF), and MNV.
Results
We included 96 naïve CSC eyes (96 patients). Baseline BCVA was 0.18 ± 0.25 logMAR, which increased to 0.16 ± 0.27 logMAR after 3 years (
p
> 0.05). Baseline CMT was 337 ± 126 µm, which improved to 229 ± 40 µm after 3 years (
p
< 0.01). We observed good response to eplerenone in 40/78 (51%) eyes, whereas 38/78 (49%) eyes underwent PDT. The artificial intelligence model showed choroidal HF and age as determining factors of good response to eplerenone or PDT. RPE thickness < 36 µm, RT < 300 µm, and SLT < 50 µm increased probability of 50% of having MNV.
Conclusions
CSC response to eplerenone or PDT is influenced by choroidal HF and patient age. RPE and SLT represent relevant factors for onset of MNV.
Investigation of spatial and temporal cognitive processing in idiopathic cervical dystonia (CD) by means of specific tasks based on perception in time and space domains of visual and auditory ...stimuli.
Previous psychophysiological studies have investigated temporal and spatial characteristics of neural processing of sensory stimuli (mainly somatosensorial and visual), whereas the definition of such processing at higher cognitive level has not been sufficiently addressed. The impairment of time and space processing is likely driven by basal ganglia dysfunction. However, other cortical and subcortical areas, including cerebellum, may also be involved.
We tested 21 subjects with CD and 22 age-matched healthy controls with 4 recognition tasks exploring visuo-spatial, audio-spatial, visuo-temporal, and audio-temporal processing. Dystonic subjects were subdivided in three groups according to the head movement pattern type (lateral: Laterocollis, rotation: Torticollis) as well as the presence of tremor (Tremor).
We found significant alteration of spatial processing in Laterocollis subgroup compared to controls, whereas impairment of temporal processing was observed in Torticollis subgroup compared to controls.
Our results suggest that dystonia is associated with a dysfunction of temporal and spatial processing for visual and auditory stimuli that could underlie the well-known abnormalities in sequence learning. Moreover, we suggest that different movement pattern type might lead to different dysfunctions at cognitive level within dystonic population.
Introduction
Studies with diffusion tensor imaging (DTI) analysis have produced conflicting information about the involvement of the cerebellar hemispheres in Parkinson’s disease (PD). We, thus, used ...a new approach for the analysis of DTI parameters in order to ascertain the involvement of the cerebellum in PD.
Methods
We performed a fiber tract-based analysis of cerebellar peduncles and cerebellar hemispheres in 16 healthy subjects and in 16 PD patients with more than 5 years duration of disease, using a 3T MRI scanner and a constrained spherical deconvolution (CSD) approach for tractographic reconstructions. In addition, we performed statistical analysis of DTI parameters and fractional anisotropy (FA) XYZ direction samplings.
Results
We found a statistically significant decrement of FA values in PD patients compared to controls (
p
< 0.05). In addition, extrapolating and analyzing FA XYZ direction samplings for each patient and each control, we found that this result was due to a stronger decrement of FA values along the Y axis (antero-posterior direction) (
p
< 0.01); FA changes along X and Z axes were not statistically significant (
p
> 0.05). We confirmed also no statistically significant differences of FA and apparent diffusion coefficient (ADC) for cerebellar peduncles in PD patients compared to healthy controls.
Conclusions
The DTI-based cerebellar abnormalities in PD could constitute an advance in the knowledge of this disease. We demonstrated a statistically significant reduction of FA in cerebellar hemispheres of PD patients compared to healthy controls. Our work also demonstrated that the use of more sophisticated approaches in the DTI parameter analysis could potentially have a clinical relevance.
The claustrum is a thin grey matter structure which is involved in a wide brain network. Previous studies suggested a link between claustrum and Parkinson’s Disease (PD), showing how α-synuclein ...pathology may affect claustral neurons as well as how α-synuclein immunoreactivity may correlate with the onset of cognitive dysfunctions. Our aim is to investigate, via diffusion MRI, claustral structural network changes in drug naïve PD patients, with the goal to understand whether such changes may contribute to cognitive decline in PD. 15 drug naïve PD patients and 15 age-matched controls were enrolled; MR protocol was performed on a 3T scanner. Whole brain probabilistic tractography was obtained using Constrained Spherical Deconvolution (CSD) diffusion model. Connectivity matrices were estimated based on a robust anatomical parcellation of structural T1w images. In PD group, impaired subnetworks were correlated with psychological examinations. We found decreased claustral connectivity in PD patients compared to controls, especially with areas mainly involved in visuomotor and attentional systems. Moreover, we found a positive correlation between MoCA and density of pathways connecting ipsilaterally claustrum to left (
r
= 0.578,
p
= 0.021) and right (
r
= 0.640,
p
= 0.020) Pars Orbitalis. Our results support the hypothesis of claustral involvement in cognitive decline in drug naïve PD patients.
The limbic system is part of an intricate network which is involved in several functions like memory and emotion. Traditionally the role of the cerebellum was considered mainly associated to motion ...control; however several evidences are raising about a role of the cerebellum in learning skills, emotions control, mnemonic and behavioral processes involving also connections with limbic system. In 15 normal subjects we studied limbic connections by probabilistic Constrained Spherical Deconvolution (CSD) tractography. The main result of our work was to prove for the first time in human brain the existence of a direct cerebello-limbic pathway which was previously hypothesized but never demonstrated. We also extended our analysis to the other limbic connections including cingulate fasciculus, inferior longitudinal fasciculus, uncinated fasciculus, anterior thalamic connections and fornix. Although these pathways have been already described in the tractographic literature we provided reconstruction, quantitative analysis and Fractional Anisotropy (FA) right-left symmetry comparison using probabilistic CSD tractography that is known to provide a potential improvement compared to previously used Diffusion Tensor Imaging (DTI) techniques. The demonstration of the existence of cerebello-limbic pathway could constitute an important step in the knowledge of the anatomic substrate of non-motor cerebellar functions. Finally the CSD statistical data about limbic connections in healthy subjects could be potentially useful in the diagnosis of pathological disorders damaging this system.
We evaluated, by means of a non-invasive procedure based on MRI, the masticatory muscular microstructure in a 55-year-old-female patient affected by bruxism. The patient underwent MR examination ...before and after 1 month of splint therapy, when she mentioned the complete disappearance of all symptoms. By means of diffusion tensor imaging we observed changes at microstructural level of masticatory muscular complex. We conclude that diffusion tensor imaging may be a useful instrument both to perform panoramic reconstruction of the masticatory muscle complex and to investigate microstructural modifications related to the pain relief in bruxism.
PDF
