Exogenous capture accounts for fundamental differences between prosaccade and antisaccade performance

Oculomotor circuits generate eye movements based on the physical salience of objects and current behavioral goals, exogenous and endogenous influences, respectively. However, the interactions between exogenous and endogenous mechanisms and their dynamic contributions to target selection have been difficult to resolve because they evolve extremely rapidly. In a recent study (Salinas et al., 2019), we achieved the necessary temporal precision using an urgent variant of the antisaccade task wherein motor plans are initiated early and choice accuracy depends sharply on when exactly the visual cue information becomes available. Empirical and modeling results indicated that the exogenous signal arrives ~80 ms after cue onset and rapidly accelerates the (incorrect) plan toward the cue, whereas the informed endogenous signal arrives ~25 ms later to favor the (correct) plan away from the cue. Here, we scrutinize a key mechanistic hypothesis about this dynamic, that the exogenous and endogenous signals act at different times and independently of each other. We test quantitative model predictions by comparing the performance of human participants instructed to look toward a visual cue versus away from it under high urgency. We find that, indeed, the exogenous response is largely impervious to task instructions; it simply flips its sign relative to the correct choice, and this largely explains the drastic differences in psychometric performance between the two tasks. Thus, saccadic choices are strongly dictated by the alignment between salience and behavioral goals.

Bullous Parametric Response Map for Functional Localization of COPD

Advanced bronchoscopic lung volume reduction treatment (BLVR) is now a routine care option for treating patients with severe emphysema. Patterns of low attenuation clusters indicating emphysema and functional small airway disease (fSAD) on paired CT, which may provide additional insights to the target selection of the segmental or subsegmental lobe of the treatments, require further investigation. The low attenuation clusters (LACS) were segmented to identify the scalar and spatial distribution of the lung destructions, in terms of 10 fractions scales of low attenuation density (LAD) located in upper lobes and lower lobes. The LACs of functional small airway disease (fSAD) were delineated by applying the technique of parametric response map (PRM) on the co-registered CT image data. Both emphysematous LACs of inspiratory CT and fSAD LACs on expiratory CT were used to derive the coefficients of the predictive model for estimating the airflow limitation. The voxel-wise severity is then predicted using the regional LACs on the co-registered CT to indicate the functional localization, namely, the bullous parametric response map (BPRM). A total of 100 subjects, 88 patients with mild to very severe COPD and 12 control participants with normal lung functions (FEV1/FVC % > 70%), were evaluated. Pearson’s correlations between FEV1/FVC% and LAV%HU-950 of severe emphysema are − 0.55 comparing to − 0.67 and − 0.62 of LAV%HU-856 of air-trapping and LAV%fSAD respectively. Pearson’s correlation between FEV1/FVC% and FEV1/FVC% predicted by the proposed model using LAD% of HU-950 and fSAD on BPRM is 0.82 (p < 0.01). The result of the Bullous Parametric Response Map (BPRM) is capable of identifying the less functional area of the lung, where the BLVR treatment is aimed at removing from a hyperinflated area of emphysematous regions.

Computing Touch-Point Ambiguity on Mobile Touchscreens for Modeling Target Selection Times

Finger-Fitts law (FFitts law) is a model to predict touch-pointing times, modified from Fitts' law. It considers the absolute touch-point precision, or a finger tremor factor σa, to decrease the admissible target area and thus increase the task difficulty. Among choices such as running an independent task or performing parameter optimization, there is no consensus on the best methodology to measure σa. This inconsistency could be detrimental to HCI studies such as pointing technique evaluations and user group comparisons. By integrating the results of our 1D and 2D touch-pointing experiments and reanalyses of previous studies' data, we examined the advantages and disadvantages of each approach to compute σa. We found that the parameter optimization method is a suboptimal choice for predicting the performance.

Visual, delay and oculomotor timing and tuning in macaque dorsal pulvinar during instructed and free choice memory saccades

Causal perturbation studies suggest that the primate dorsal pulvinar (dPul) plays a crucial role in target selection and saccade planning, but many of its basic visuomotor neuronal properties are unclear. While some functional aspects of dPul and interconnected frontoparietal areas - such as ipsilesional choice bias after inactivation - are similar, it is not known if dPul neurons share oculomotor response properties of cortical circuitry. In particular, the delay period and choice-related activity have not been explored. Here we investigated visuomotor timing and tuning in macaque dPul during instructed and free choice memory saccades using electrophysiological recordings. Most units (80%) showed significant visual (16%), visuomotor (29%) or motor-related (35%) responses. Visual cue responses were mainly contralaterally-tuned; motor responses showed weak contralateral bias. Saccade-related responses (enhancement and suppression) were more common (64%) than cue-driven responses (45%). Pre-saccadic enhancement was less frequent (9-15% depending on the definition), and only few units exhibited classical visuomotor patterns such as a combination of cue and continuous delay period activity up to the saccade onset, or pre-saccadic ramping. Instead, activity was often suppressed during movement planning (30%) and execution phases (19%). Interestingly, most spatially-selective neurons did not encode the upcoming decision during the delay in free choice trials. Thus, in absence of a visible goal, the dorsal pulvinar has only a limited role in the prospective motor planning, with response patterns partially complementary to its frontoparietal cortical partners. Conversely, prevalent cue and post-saccadic responses imply that the dorsal pulvinar participates in integrating spatial goals with processing across saccades.

A Decisive Review to Understand the Basic Fundamentals of Novel Corona Viruse Disease

With the development and spread of 2019 novel coronavirus (2019-nCoV), also known as the severe acute respiratory syndrome coronavirus 2, a new public health disaster is threatening the world (SARS-CoV-2). In December 2019, the virus was discovered in bats and transmitted to humans via unidentified intermediary species in Wuhan, Hubei Province, China. To date (05/03/2020), there have been roughly 96,000 recorded cases of coronavirus disease 2019 (COVID-2019) and 3300 documented deaths. The disease is spread through inhalation or contact with contaminated droplets, with a 2 to 14-day incubation period. Fever, cough, sore throat, dyspnea, weariness, and malaise are common symptoms. The disease is mild in most people; in some (usually the elderly and those with comorbidities), it can lead to pneumonia, ARDS (acute respiratory distress syndrome), and multi-organ failure. A large number of persons are asymptomatic. The case fatality rate is expected to be between 2 and 3%. Specimen collection, assay collection, serology, nucleic acid testing or molecular testing, and target selection for RT-PCR are all examples of laboratory diagnosis. Home isolation of suspected cases and those with mild illnesses, as well as tight infection control measures in hospitals, including contact and droplet precautions, are all part of the prevention strategy. The virus has a lower fatality rate than its two ancestors, SARS-CoV and Middle East respiratory sickness coronavirus (MERS-CoV). The global consequences of this new epidemic are still unknown.

Investigation of Input Modalities Based on a Spatial Region Array for Hand-Gesture Interfaces

To improve the efficiency of computer input, extensive research has been conducted on hand movement in a spatial region. Most of it has focused on the technologies but not the users’ spatial controllability. To assess this, we analyze a users’ common operational area through partitioning, including a layered array of one dimension and a spatial region array of two dimensions. In addition, to determine the difference in spatial controllability between a sighted person and a visually impaired person, we designed two experiments: target selection under a visual and under a non-visual scenario. Furthermore, we explored two factors: the size and the position of the target. Results showed the following: the 5 × 5 target blocks, which were 60.8 mm × 48 mm, could be easily controlled by both the sighted and the visually impaired person; the sighted person could easily select the bottom-right area; however, for the visually impaired person, the easiest selected area was the upper right. Based on the results of the users’ spatial controllability, we propose two interaction techniques (non-visual selection and a spatial gesture recognition technique for surgery) and four spatial partitioning strategies for human-computer interaction designers, which can improve the users spatial controllability.