Selective reaching in macaques: evidence for action-centred attention.

When a monkey selects a piece of food lying on the ground from among other viable objects in the near vicinity, only the desired item governs the particular pattern and direction of the animal's reaching action. It would seem then that selection is an important component controlling the animal's action. But, we may ask, is the selection process in such cases impervious to the presence of other objects that could constitute potential obstacles to or constraints on movement execution? And if it is, in fact, pervious to other objects, do they have a direct influence on the organization of the response? The kinematics of macaques' reaching movements were examined by the current study that analysed some exemplars as they selectively reached to grasp a food item in the absence as well as in the presence of potential obstacles (i.e., stones) that could affect the arm trajectory. Changes in movement parameterization were noted in temporal measures, such as movement time, as well as in spatial ones, such as paths of trajectory. Generally speaking, the presence of stones in the vicinity of the acting hand stalled the reaching movement and affected the arm trajectory as the hand veered away from the stone even when it was not a physical obstacle. We concluded that nearby objects evoke a motor response in macaques, and the attentional mechanisms that allow for a successful action selection are revealed in the reaching path. The data outlined here concur with human studies indicating that potential obstacles are internally represented, a finding implying basic cognitive operations allowing for action selection in macaques.

MUNDUS project: MUltimodal neuroprosthesis for daily upper limb support.

BACKGROUND: MUNDUS is an assistive framework for recovering direct interaction capability of severely motor impaired people based on arm reaching and hand functions. It aims at achieving personalization, modularity and maximization of the user's direct involvement in assistive systems. To this, MUNDUS exploits any residual control of the end-user and can be adapted to the level of severity or to the progression of the disease allowing the user to voluntarily interact with the environment. MUNDUS target pathologies are high-level spinal cord injury (SCI) and neurodegenerative and genetic neuromuscular diseases, such as amyotrophic lateral sclerosis, Friedreich ataxia, and multiple sclerosis (MS). The system can be alternatively driven by residual voluntary muscular activation, head/eye motion, and brain signals. MUNDUS modularly combines an antigravity lightweight and non-cumbersome exoskeleton, closed-loop controlled Neuromuscular Electrical Stimulation for arm and hand motion, and potentially a motorized hand orthosis, for grasping interactive objects. METHODS: The definition of the requirements and of the interaction tasks were designed by a focus group with experts and a questionnaire with 36 potential end-users. RESULTS: The functionality of all modules has been successfully demonstrated. User's intention was detected with a 100% success. Averaging all subjects and tasks, the minimum evaluation score obtained was 1.13 ± 0.99 for the release of the handle during the drinking task, whilst all the other sub-actions achieved a mean value above 1.6. All users, but one, subjectively perceived the usefulness of the assistance and could easily control the system. Donning time ranged from 6 to 65 minutes, scaled on the configuration complexity. CONCLUSIONS: The MUNDUS platform provides functional assistance to daily life activities; the modules integration depends on the user's need, the functionality of the system have been demonstrated for all the possible configurations, and preliminary assessment of usability and acceptance is promising.

LongITools: Dynamic longitudinal exposome trajectories in cardiovascular and metabolic noncommunicable diseases.

The current epidemics of cardiovascular and metabolic noncommunicable diseases have emerged alongside dramatic modifications in lifestyle and living environments. These correspond to changes in our "modern" postwar societies globally characterized by rural-to-urban migration, modernization of agricultural practices, and transportation, climate change, and aging. Evidence suggests that these changes are related to each other, although the social and biological mechanisms as well as their interactions have yet to be uncovered. LongITools, as one of the 9 projects included in the European Human Exposome Network, will tackle this environmental health equation linking multidimensional environmental exposures to the occurrence of cardiovascular and metabolic noncommunicable diseases.

Flexible control of movement in plants.

Although plants are essentially sessile in nature, these organisms are very much in tune with their environment and are capable of a variety of movements. This may come as a surprise to many non-botanists, but not to Charles Darwin, who reported that plants do produce movements. Following Darwin's specific interest on climbing plants, this paper will focus on the attachment mechanisms by the tendrils. We draw attention to an unsolved problem in available literature: whether during the approach phase the tendrils of climbing plants consider the structure of the support they intend to grasp and plan the movement accordingly ahead of time. Here we report the first empirical evidence that this might be the case. The three-dimensional (3D) kinematic analysis of a climbing plant (Pisum sativum L.) demonstrates that the plant not only perceives the support, but it scales the kinematics of tendrils' aperture according to its thickness. When the same support is represented in two-dimensions (2D), and thus unclimbable, there is no evidence for such scaling. In these circumstances the tendrils' kinematics resemble those observed for the condition in which no support was offered. We discuss these data in light of the evidence suggesting that plants are equipped with sensory mechanisms able to provide the necessary information to plan and control a movement.

Mobile Phone and Wearable Sensor-Based mHealth Approaches for Psychiatric Disorders and Symptoms: Systematic Review.

BACKGROUND: Mobile Therapeutic Attention for Patients with Treatment-Resistant Schizophrenia (m-RESIST) is an EU Horizon 2020-funded project aimed at designing and validating an innovative therapeutic program for treatment-resistant schizophrenia. The program exploits information from mobile phones and wearable sensors for behavioral tracking to support intervention administration. OBJECTIVE: To systematically review original studies on sensor-based mHealth apps aimed at uncovering associations between sensor data and symptoms of psychiatric disorders in order to support the m-RESIST approach to assess effectiveness of behavioral monitoring in therapy. METHODS: A systematic review of the English-language literature, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, was performed through Scopus, PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials databases. Studies published between September 1, 2009, and September 30, 2018, were selected. Boolean search operators with an iterative combination of search terms were applied. RESULTS: Studies reporting quantitative information on data collected from mobile use and/or wearable sensors, and where that information was associated with clinical outcomes, were included. A total of 35 studies were identified; most of them investigated bipolar disorders, depression, depression symptoms, stress, and symptoms of stress, while only a few studies addressed persons with schizophrenia. The data from sensors were associated with symptoms of schizophrenia, bipolar disorders, and depression. CONCLUSIONS: Although the data from sensors demonstrated an association with the symptoms of schizophrenia, bipolar disorders, and depression, their usability in clinical settings to support therapeutic intervention is not yet fully assessed and needs to be scrutinized more thoroughly.

Modulation of an optical needle's reflectivity alters the average photon path through scattering media.

We introduce the concept of deliberate placement of absorbers to alter the average path of photons through tissue for a biomedical optical device. By changing the reflectivity of a needle that separates a source and detector, the average photon path through a turbid medium can be changed. Totally reflective needles have photon scattering density functions similar to a point source and detector in an infinite medium. An absorbing needle moves the average photon path of photons that reach the detector away from the needle. Thus, by modulating the reflectivity of the needle, it is possible to modify the sensitive volume, and simple tomography data should be possible. These results are confirmed by Monte Carlo simulations and experiment. Experiments include moving a black target relative to an optical "needle" and measuring the resulting intensity and phase lag of light reaching a detector at the distal end of the needle.

Effects of vasodilation on intrinsic optical signals in the mammalian brain: a phantom study.

Using a broadband spectral technique, we recently showed [J. Biomed. Opt. 10, 064009 (2005)] that during visual stimulation of the cat brain there were not only changes in oxy- and deoxyhemoglobin levels, reminiscent of the optical blood oxygenation level dependence (BOLD) effect reported in humans, but also the apparent water content of the tissue and the optical scattering contribution decreased during stimulation. These relatively fast changes (in seconds) in water tissue content are difficult to explain in physiological terms. We developed a simple model to explain how local vasodilation, which occurs as a result of the stimulation, could cause this apparent change in water content. We show that in a phantom model we can obtain spectral effects similar to those observed in the cat brain such as the apparent decrease of the water spectral component without changing the water content of the bath in which the phantom measurements were performed. Furthermore, using the phantom model, we show that the relative apparent changes in the spectral components due to vasodilation during stimulation are roughly comparable in magnitude to the changes in tissue chromophores due to the optical equivalent of the BOLD effect reported in the literature.

It's all in the type of the task: Dopamine modulates kinematic patterns during competitive vs. cooperative interaction in Parkinson's disease.

Increasing evidence suggests that a dysfunctional dopaminergic system affects the ability to socially interact. Since Parkinson's disease (PD) provides a model for assessing dopaminergic dysfunctions in humans, our study was designed to investigate social interactions in PD patients receiving dopamine replacement therapy (Levodopa=l-Dopa) and in neurologically healthy controls. We focused on the kinematics of one action, reaching to grasp a wooden block, which was performed within the context of two basic modes of social cognition, namely cooperation and competition. During the cooperative tasks, two participants were instructed to reach and grasp their respective objects and to cooperate in forming a specific configuration on the working table. During the competitive tasks, two participants were instructed to compete to place their own object at the bottom of a tower to be built on the working table. PD patients' ability to modulate motor patterning depending on the intention motivating the action they were about to perform was evaluated in both "on" (with l-Dopa) and "off" (without l-Dopa) states. Study results revealed that both the healthy controls and the 'on' PD patients had distinct kinematic patterns for cooperative and competitive actions and that these differed from patterns mirroring similar actions performed by those same participants in non social conditions. The kinematic patterns of the healthy controls and the 'on' patients were highly correlated during the cooperative tasks. The 'off' PD patients were, instead, unable to differentiate between isolated and social conditions. These results support the hypothesis that dopaminergic neurotransmission is involved in shaping the mechanisms underlying social interactions.

Spectrally resolved neurophotonics: a case report of hemodynamics and vascular components in the mammalian brain.

We developed a spectral technique that is independent of the light transport modality (diffusive or nondiffusive) to separate optical changes in scattering and absorption in the cat's brain due to the hemodynamic signal following visual stimulation. We observe changes in oxyhemoglobin and deoxyhemoglobin concentration signals during visual stimulation reminiscent of the functional magnetic resonance imaging (fMRI) blood oxygenation level dependence (BOLD) effect. Repeated measurements at different locations show that the observed changes are local rather than global. We also determine that there is an apparent large decrease in the water concentration and scattering coefficient during stimulation. We model the apparent change in water concentration on the separation of the optical signal from two tissue compartments. One opaque compartment is featureless (black), due to relatively large blood vessels. The other compartment is the rest of the tissue. When blood flow increases due to stimulation, the opaque compartment increases in volume, resulting in an overall decrease of tissue transmission. This increase in baseline absorption changes the apparent relative proportion of all tissue components. However, due to physiological effects, the deoxyhemoglobin is exchanged with oxyhemoglobin resulting in an overall increase in the oxyhemoglobin signal, which is the only component that shows an apparent increase during stimulation.

Optimization of the signal-to-noise ratio of frequency-domain instrumentation for near-infrared spectro-imaging of the human brain.

Frequency-domain near-infrared spectro-imaging offers significant advantages over the continuous-wave method in human brain applications. However, the drawback of existing instruments is a low signal-to-noise ratio for measured phase and modulation depth changes caused by cerebral activation. In this paper we show that in the case of the geometry specific for the activated area in the human brain, the SNR can be significantly improved by increasing the modulation frequency. We present the results of two studies: one performed experimentally using a subnanosecond pulsed light source and a spherical absorbing inhomogeneity immersed in a highly scattering solution, and the other performed numerically using Monte Carlo simulations of light transport in an MRI based digital phantom of the adult human head. We show that changes caused by the absorbing inhomogeneity in both phase and modulation depth increase with frequency and reach maximum values at frequencies between 400 and 1400 MHz, depending on the particular source-detector distance. We also show that for the human head geometry an increase of the modulation frequency from 100 to 500 MHz can increase the phase SNR 2-3 times, and the modulation depth SNR up to 10 times.