Covert Shift of Attention Modulates the Ongoing Neural Activity in a Reaching Area of the Macaque Dorsomedial Visual Stream

Background: Attention is used to enhance neural processing of selected parts of a visual scene. It increases neural responses to stimuli near target locations and is usually coupled to eye movements. Covert attention shifts, however, decouple the attentional focus from gaze, allowing to direct the attention to a peripheral location without moving the eyes. We tested whether covert attention shifts modulate ongoing neuronal activity in cortical area V6A, an area that provides a bridge between visual signals and arm-motor control. Methodology/Principal Findings: We performed single cell recordings from 3 Macaca Fascicularis trained to fixate straight-head, while shifting attention outward to a peripheral cue and inward again to the fixation point. We found that neurons in V6A are influenced by spatial attention. The attentional modulation occurs without gaze shifts and cannot be explained by visual stimulations. Visual, motor, and attentional responses can occur in combination in single neurons. Conclusions/Significance: This modulation in an area primarily involved in visuo-motor transformation for reaching may form a neural basis for coupling attention to the preparation of reaching movements. Our results show that cortical processes of attention are related not only to eye-movements, as many studies have shown, but also to arm movements, a finding that has been suggested by some previous behavioral findings. Therefore, the widely-held view that spatial attention is tightly intertwined with - and perhaps directly derived from - motor preparatory processes should be extended to a broader spectrum of motor processes than just eye movements

Extradural Motor Cortex Stimulation might improve episodic and working memory in patients with Parkinson\u2019s disease

Electric Extradural Motor Cortex Stimulation (EMCS) is a neurosurgical procedure suggested for treatment of patients with advanced Parkinson\u2019s disease (PD). We report two PD patients treated by EMCS, who experienced worsening of motor symptoms and cognition 5 years after surgery, when EMCS batteries became discharged. One month after EMCS restoration, they experienced a subjective improvement of motor symptoms and cognition. Neuropsychological assessments were carried out before replacement of batteries (off-EMCS condition) and 6 months afterward (on-EMCS condition). As compared to off-EMCS condition, in on-EMCS condition both patients showed an improvement on tasks of verbal episodic memory and backward spatial short-term/working memory task, and a decline on tasks of selective visual attention and forward spatial short-term memory. These findings suggest that in PD patients EMCS may induce slight beneficial effects on motor symptoms and cognitive processes involved in verbal episodic memory and in active manipulation of information stored in working memory

Event-related alpha suppression in response to facial motion

This article has been made available through the Brunel Open Access Publishing Fund.While biological motion refers to both face and body movements, little is known about the visual perception of facial motion. We therefore examined alpha wave suppression as a reduction in power is thought to reflect visual activity, in addition to attentional reorienting and memory processes. Nineteen neurologically healthy adults were tested on their ability to discriminate between successive facial motion captures. These animations exhibited both rigid and non-rigid facial motion, as well as speech expressions. The structural and surface appearance of these facial animations did not differ, thus participants decisions were based solely on differences in facial movements. Upright, orientation-inverted and luminance-inverted facial stimuli were compared. At occipital and parieto-occipital regions, upright facial motion evoked a transient increase in alpha which was then followed by a significant reduction. This finding is discussed in terms of neural efficiency, gating mechanisms and neural synchronization. Moreover, there was no difference in the amount of alpha suppression evoked by each facial stimulus at occipital regions, suggesting early visual processing remains unaffected by manipulation paradigms. However, upright facial motion evoked greater suppression at parieto-occipital sites, and did so in the shortest latency. Increased activity within this region may reflect higher attentional reorienting to natural facial motion but also involvement of areas associated with the visual control of body effectors. © 2014 Girges et al

Striking Denervation of Neuromuscular Junctions without Lumbar Motoneuron Loss in Geriatric Mouse Muscle

Reasons for the progressive age-related loss of skeletal muscle mass and function, namely sarcopenia, are complex. Few studies describe sarcopenia in mice, although this species is the mammalian model of choice for genetic intervention and development of pharmaceutical interventions for muscle degeneration. One factor, important to sarcopenia-associated neuromuscular change, is myofibre denervation. Here we describe the morphology of the neuromuscular compartment in young (3 month) compared to geriatric (29 month) old female C57Bl/6J mice. There was no significant difference in the size or number of motoneuron cell bodies at the lumbar level (L1–L5) of the spinal cord at 3 and 29 months. However, in geriatric mice, there was a striking increase (by ∼2.5 fold) in the percentage of fully denervated neuromuscular junctions (NMJs) and associated deterioration of Schwann cells in fast extensor digitorum longus (EDL), but not in slow soleus muscles. There were also distinct changes in myofibre composition of lower limb muscles (tibialis anterior (TA) and soleus) with a shift at 29 months to a faster phenotype in fast TA muscle and to a slower phenotype in slow soleus muscle. Overall, we demonstrate complex changes at the NMJ and muscle levels in geriatric mice that occur despite the maintenance of motoneuron cell bodies in the spinal cord. The challenge is to identify which components of the neuromuscular system are primarily responsible for the marked changes within the NMJ and muscle, in order to selectively target future interventions to reduce sarcopenia

ZooMS: a non invasive analysis of global and metameric movement of the lumbar spine.

The assessment of spine mobility is an important parameter to define its functionality. In the last decades a lot of research has been carried out mainly through radiographic investigations; non invasive methods demonstrated not to be sufficiently accurate, not to allow free movement, not to provide metameric assessment and suitable for everyday clinical practice. The aim of this study is the development of a new experimental non invasive protocol, called Zoom on mobility of the spine (ZooMS) to assess the mobility of lumbar spine, from the 11th thoracic to the sacrum bone and the pelvis, with the possibility of identifying the metameric contribution of each rotation around all the axes correlated to the global movement.We developed a dedicated non invasive methodology based on optoelectronic techniques for 3D target recording to be applied to the functional evaluation of the mobility of the lumbar spine in young healthy males. Ten subjects participated in the method validation, performing free rotations (flexion/extension, lateral bending and axial rotation) from standing to the maximum excursion and back.The comparison of the range of motion (RoM) with those presented in literature was satisfactory, although some differences were shown (above all in axial rotation, which however gives the minor contribution to the mobility of the lumbar spine). The validation of the protocol was successful in terms of intraoperator, interoperator and circadian remarking, the 3 factors eventually affecting its repeatability.The RoM of the whole lumbar spine and of each functional unit, together with the pattern of movement may so represent an innovative and important aspect in clinical applications

Evaluation of head-to-trunk control in whiplash patients using digital CranioCorpoGraphy during a stepping test.

Digital-CranioCorpoGraphy (dCCG) has been used to document whiplash effects on head-on-trunk stabilization while subjects walked on the spot (Fukuda test). Twenty-five healthy subjects were compared with 33 whiplash patients. Whiplash patients were classified as chronic (more than 6 months after injury) and recent (less than 6 months after injury). Clear differences between healthy subjects and patients were seen and three different strategies (A, B and C) were detected. Pattern A appeared similar to normals but quantitative analysis showed significant differences with paradoxical head over-stabilization (collar-effect); pattern B decreased head stability; pattern C decreased head stabilization with reduced displacements of the body. Due to the complexity of the data analyzed for each marker, a coefficient of performance (CP) was calculated to simplify the cut-off between normal and pathological tests. CP clearly identified an abnormal stepping pattern. Our findings indicate that firstly dCCG identified a specific vestibular task in whiplash patients, secondly whiplash did not always provoke vestibular involvement and thirdly dCCG could be a tool to discriminate patients with and without vestibular involvement after whiplash