Dynamic involvement of premotor and supplementary motor areas in bimanual pinch force control.

Many activities of daily living require quick shifts between symmetric and asymmetric bimanual actions. Bimanual motor control has been mostly studied during continuous repetitive tasks, while little research has been carried out in experimental settings requiring dynamic changes in motor output generated by both hands. Here, we performed functional magnetic resonance imaging (MRI) while healthy volunteers performed a visually guided, bimanual pinch force task.

New insights into cortico-basal-cerebellar connectome: clinical and physiological considerations.

The current model of the basal ganglia system based on the 'direct', 'indirect' and 'hyperdirect' pathways provides striking predictions about basal ganglia function that have been used to develop deep brain stimulation approaches for Parkinson's disease and dystonia. The aim of this review is to challenge this scheme in light of new tract tracing information that has recently become available from the human brain using MRI-based tractography, thus providing a novel perspective on the basal ganglia system. We also explore the implications of additional direct pathways running from cortex to basal ganglia and between basal ganglia and cerebellum in the pathophysiology of movement disorders.

The cortico-rubral and cerebello-rubral pathways are topographically organized within the human red nucleus.

The Red Nucleus (RN) is a large nucleus located in the ventral midbrain: it is subdivided into a small caudal magnocellular part (mRN) and a large rostral parvocellular part (pRN). These distinct structural regions are part of functionally different networks and show distinctive connectivity features: the mRN is connected to the interposed nucleus, whilst the pRN is mainly connected to dentate nucleus, cortex and inferior olivary complex. Despite functional neuroimaging studies suggest RN involvement in complex motor and higher order functions, the pRN and mRN cannot be distinguished using conventional MRI.

Transcranial Magnetic Stimulation of Posterior Parietal Cortex Modulates Line-Length Estimation but Not Illusory Depth Perception.

Transcranial Magnetic Stimulation (TMS) may affect attentional processing when applied to the right posterior parietal cortex (PPC) of healthy participants in line with neuropsychological and neuroimaging evidence on the neural bases of this cognitive function. Specifically, the application of TMS to right PPC induces a rightward attentional bias on line length estimation in healthy participants (i.e.

Structural connectivity-based topography of the human globus pallidus: Implications for therapeutic targeting in movement disorders.

Background: Understanding the topographical organization of the cortico-basal ganglia circuitry is of pivotal importance because of the spreading of techniques such as DBS and, more recently, MR-guided focused ultrasound for the treatment of movement disorders. A growing body of evidence has described both direct cortico- and dento-pallidal connections, although the topographical organization in vivo of these pathways in the human brain has never been reported.

Objective: To investigate the topographical organization of cortico- and dento-pallidal pathways by means of diffusion MRI tractography and connectivity based parcellation.

Endogenous orientation of visual attention in auditory space.

Visuospatial attention is asymmetrically distributed with a leftward bias (i.e. pseudoneglect), while evidence for asymmetries in auditory spatial attention is still controversial.

Is There a Future for Non-invasive Brain Stimulation as a Therapeutic Tool?

Several techniques and protocols of non-invasive transcranial brain stimulation (NIBS), including transcranial magnetic and electrical stimuli, have been developed in the past decades. These techniques can induce long lasting changes in cortical excitability by promoting synaptic plasticity and thus may represent a therapeutic option in neuropsychiatric disorders. On the other hand, despite these techniques have become popular, the fragility and variability of the after effects are the major challenges that non-invasive transcranial brain stimulation currentlyfaces.

White Matter Tissue Quantification at Low -Values Within Constrained Spherical Deconvolution Framework.

In the last decades, a number of Diffusion Weighted Imaging (DWI) based techniques have been developed to study non-invasively human brain tissues, especially white matter (WM). In this context, Constrained Spherical Deconvolution (CSD) is recognized as being able to accurately characterize water molecules displacement, as they emerge from the observation of MR diffusion weighted (MR-DW) images. CSD is suggested to be applied on MR-DW datasets consisting of b-values around 3,000 s/mm and at least 45 unique diffusion weighting directions.

Claustral structural connectivity and cognitive impairment in drug naïve Parkinson's disease.

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.

The Limbic and Sensorimotor Pathways of the Human Amygdala: A Structural Connectivity Study.

The amygdala plays a key role in gathering social cues to context-appropriate responses that require refined motor behavior, involving either direct or indirect connections with sensorimotor-related areas. Although, several studies investigated the structural and functional limbic connectivity of the amygdala both in animals and in humans, less is known about the limbic modulation on sensorimotor-related areas. However, recent evidences suggest the amygdala as a possible cornerstone in the limbic-motor interface.

A Connectomic Analysis of the Human Basal Ganglia Network.

The current model of basal ganglia circuits has been introduced almost two decades ago and has settled the basis for our understanding of basal ganglia physiology and movement disorders. Although many questions are yet to be answered, several efforts have been recently made to shed new light on basal ganglia function. The traditional concept of "direct" and "indirect" pathways, obtained from axonal tracing studies in non-human primates and post-mortem fiber dissection in the human brain, still retains a remarkable appeal but is somehow obsolete.

Does the radiologically isolated syndrome exist? A dual-task cost pilot study.

Simultaneous performance of motor and cognitive tasks may compete for common brain network resources in aging or patients with some neurological diseases, suggesting the occurrence of a cognitive-motor interference. While this phenomenon has been well described for multiple sclerosis (MS) patients, it never has been tested on asymptomatic subject with magnetic resonance imaging (MRI) findings suggestive of demyelinating disease (i.e.

Biased Visuospatial Attention in Cervical Dystonia.

Objectives: There is increasing evidence of non-motor, sensory symptoms, mainly involving the spatial domain, in cervical dystonia (CD). These manifestations are likely driven by dysfunctional overactivity of the parietal cortex during the execution of a sensory task. Few studies also suggest the possibility that visuospatial attention might be specifically affected in patients with CD.

Therapeutic Use of Non-invasive Brain Stimulation in Dystonia.

Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are non-invasive methods for stimulating cortical neurons that have been increasingly used in the neurology realm and in the neurosciences applied to movement disorders. In addition, these tools have the potential to be delivered as clinically therapeutic approach. Despite several studies support this hypothesis, there are several limitations related to the extreme variability of the stimulation protocols, clinical enrolment and variability of rTMS and tDCS after effects that make clinical interpretation very difficult.

Spatial and Temporal High Processing of Visual and Auditory Stimuli in Cervical Dystonia.

Objective: 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.

Background: 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.

Cognitive processess and cognitive reserve in multiple sclerosis.

Multiple Sclerosis (MS) is characterized by motor, cognitive, and neuropsychiatric symptoms, which can occur independently. While MS is traditionally considered an inflammatory disease of the white matter, degeneration of gray matter is increasingly recognized as an important contributor to the progressive cognitive decline. A protective factor against the progression of cognitive dysfunction in MS could be the cognitive reserve, defined as resistance to brain dysfunction.

Perceiving numbers alters time perception.

The representation of time, space and numbers are strictly linked in the primate's cognitive system. Here we show that merely looking at number symbols biases a temporal judgment on their duration depending upon the number's magnitude. In a first experiment, a group of healthy subjects was submitted to a time estimation task, requiring to judge whether the duration of a test stimulus was longer or shorter than that of a previous reference fixed stimulus (digit 5; duration 300 ms).