Handedness and Graspability Modify Shifts of Visuospatial Attention to Near-Hand Objects

Standing and Walking Attention Visual Field (SWAVF) task: A new method to assess visuospatial attention during walking

Visuospatial attention during walking has been associated with pedestrian safety and fall risks. However, visuospatial attention measures during walking remained under-explored. Current studies introduced a newly-developed Standing and Walking Visual Attention Field (SWAVF) task to assess visuospatial attention during walking and examined its reliability, validity, and stability. Thirty young adults completed a traditional computerized Attention Visual Field (AVF) task while sitting, and the SWAVF task under walking and standing settings. Nine participants also performed the SWAVF task under additional distraction conditions. Results showed good split-half reliability during standing (r = 0.70) and walking (r = 0.69), moderate concurrent validity with the sitting AVF task (r = 0.42), moderate convergent validity between the standing and walking settings (r = 0.69), good construct validity, and moderate rank-order stability (r = 0.53). Overall, the SWAVF task showed good psychometric properties. Potential applications to the evaluation of prosthetic and other exoskeleton devices, smart glasses, and ground-level traffic lights or signs were discussed.

Perspective Taking and Avatar-Self Merging

Today, avatars often represent users in digital worlds such as in video games or workplace applications. Avatars embody the user and perform their actions in these artificial environments. As a result, users sometimes develop the feeling that their self merges with their avatar. The user realizes that they are the avatar, but the avatar is also the user-meaning that avatar's appearance, character, and actions also affect their self. In the present paper, we first introduce the event-coding approach of the self and then argue based on the reviewed literature on human-avatar interaction that a self-controlled avatar can lead to avatar-self merging: the user sets their own goals in the virtual environment, plans and executes the avatar's actions, and compares the predicted with the actual motion outcomes of the avatar. This makes the user feel body ownership and agency over the avatar's action. Following the event-coding account, avatar-self merging should not be seen as an all-or-nothing process, but rather as a continuous process to which various factors contribute, including successfully taking the perspective of the avatar. Against this background, we discuss affective, cognitive, and visuo-spatial perspective taking of the avatar. As evidence for avatar-self merging, we present findings showing that when users take the avatar's perspective, they can show spontaneous behavioral tendencies that run counter to their own.

Visual attention around a hand location localized by proprioceptive information

Facilitation of visual processing has been reported in the space near the hand. To understand the underlying mechanism of hand proximity attention, we conducted experiments that isolated hand-related effects from top–down attention, proprioceptive information from visual information, the position effect from the influence of action, and the distance effect from the peripersonal effect. The flash-lag effect was used as an index of attentional modulation. Because the results showed that the flash-lag effect was smaller at locations near the hand, we concluded that there was a facilitation effect of the visual stimuli around the hand location identified through proprioceptive information. This was confirmed by conventional reaction time measures. We also measured steady-state visual evoked potential (SSVEP) in order to investigate the spatial properties of hand proximity attention and top–down attention. The results showed that SSVEP reflects the effect of top–down attention but not that of hand proximity attention. This suggests that the site of hand proximity attention is at a later stage of visual processing, assuming that SSVEP responds to neural activities at the early stages. The results of left-handers differed from those of right-handers, and this is discussed in relation to handedness variation.

Interhemispheric Parietal-Frontal Connectivity Predicts the Ability to Acquire a Nondominant Hand Skill

Introduction: After chronic impairment of the right dominant hand, some individuals are able to compensate with increased performance with the intact left nondominant hand. This process may depend on the nondominant (right) hemisphere's ability to access dominant (left) hemisphere mechanisms. To predict or modulate patients' ability to compensate with the left hand, we must understand the neural mechanisms and connections that underpin this process. Methods: We studied 17 right-handed healthy adults who underwent resting-state functional connectivity (FC) magnetic resonance imaging scans before 10 days of training on a left-hand precision drawing task. We sought to identify right-hemisphere areas where FC from left-hemisphere seeds (primary motor cortex, intraparietal sulcus [IPS], inferior parietal lobule) would predict left-hand skill learning or magnitude. Results: Left-hand skill learning was predicted by convergent FC from left primary motor cortex and left IPS onto the same small region (0.31 cm3) in the right superior parietal lobule (SPL). Discussion: For patients who must compensate with the left hand, the right SPL may play a key role in integrating left-hemisphere mechanisms that typically control the right hand. Our study provides the first model of how interhemispheric functional connections in the human brain may support compensation after chronic injury to the right hand.

Space, time and number: common coding mechanisms and interactions between domains

Space, time and number are key dimensions that underlie how we perceive, identify and act within the environment. They are interconnected in our behaviour and brain. In this study, we examined interdependencies between these dimensions. To this end, left- and right-handed participants performed an object collision task that required space–time processing and arithmetic tests that involved number processing. Handedness of the participants influenced collision detection with left-handers being more accurate than right-handers, which is in line with the premise that hand preference guides individual differences as a result of sensorimotor experiences and distinct interhemispheric integration patterns. The data further showed that successful collision detection was a predictor for arithmetic achievement, at least in right-handers. These findings suggest that handedness plays a mediating role in binding information processing across domains, likely due to selective connectivity properties within the sensorimotor system that is guided by hemispheric lateralisation patterns.

Where is an emotion? Using targeted visceroception as a method of improving emotion regulation in healthy participants to inform suicide prevention initiatives: a randomised controlled trial

BACKGROUND

William James' 1884 paper "What is an emotion?" has generated much recent interest in affective science regarding somatic contributions to emotion. Studies of interoception ("sensing the physiological condition of the body") suggest that sensing specific parts of the body contributes to the production of emotion, namely when sensing the viscera (i.e. "visceroception" of the heart, gut or lungs). Improved visceroception has, for instance, been linked to increased emotional intensity, suggesting a role for interoception in emotion regulation that may pertain specifically to visceral bodily locations. Thus, in addition to asking James' question, "What is an emotion?", we ask, "Where is an emotion?". Further, there is an evidence base pointing to the connections between emotion regulation and suicide, and between interoception and suicide. This is a preliminary trial investigating whether targeted interoception/visceroception improves emotion regulation. Ultimately, the overall project aims to inform suicide prevention efforts.

METHODS

The trial utilises a pre-test/post-test control group design, with two experimental groups undergoing visceroceptive interventions (focussing on areas pertaining to the gut or heart) and a control group. The interventions will run for 8 weeks. A spatial cueing task will measure reaction times to bodily changes relating to lower abdomen or chest focus. A stop/signal task will measure emotional inhibition, which is hypothesised to obscure awareness of active bodily locations. Visceroceptive ability will be tracked using a heartbeat estimation task, a water load test, and by self-report questionnaire. The sample will consist of healthcare professionals and healthcare students. Despite these being groups that represent a relatively high suicide risk among professional and student groups, all participants will be healthy, given the preliminary nature of this trial.

DISCUSSION

To our knowledge, this will be the first project to address whether emotional feeling presents as a localised bodily phenomenon and whether trained awareness of emotional localisation can improve emotion regulation. It will also be the first to investigate relationships between interoception and emotional inhibition (i.e. whether a sustained interoceptive practice leads to the disinhibition of bodily emotional sensations, which can positively contribute to emotion regulation). These empirical findings on emotion regulation from a healthy sample will be used to inform a desk-based enquiry into the role of embodied emotion in suicide prevention, which may make a significant contribution to a growing evidence base on interoception and suicide.

TRIAL REGISTRATION

ACTR N12619000324112 . Registered on 4 March 2019. Universal Trial Number (UTN): U1111-1221-0201.

Faster recognition of graspable targets defined by orientation in a visual search task

Peri-hand space is the area surrounding the hand. Objects within this space may be subject to increased visuospatial perception, increased attentional prioritization, and slower attentional disengagement compared to more distal objects. This may result from kinesthetic and visual feedback about the location of the hand that projects from the reach and grasp networks of the dorsal visual stream back to occipital visual areas, which in turn, refines cortical visual processing that can subsequently guide skilled motor actions. Thus, we hypothesized that visual stimuli that afford action, which are known to potentiate activity in the dorsal visual stream, would be associated with greater alterations in visual processing when presented near the hand. To test this, participants held their right hand near or far from a touchscreen that presented a visual array containing a single target object that differed from 11 distractor objects by orientation only. The target objects and their accompanying distractors either strongly afforded grasping or did not. Participants identified the target among the distractors by reaching out and touching it with their left index finger while eye-tracking was used to measure visual search times, target recognition times, and search accuracy. The results failed to support the theory of enhanced visual processing of graspable objects near the hand as participants were faster at recognizing graspable compared to non-graspable targets, regardless of the position of the right hand. The results are discussed in relation to the idea that, in addition to potentiating appropriate motor responses, object affordances may also potentiate early visual processes necessary for object recognition.

The Fragility of the Near-Hand Effect

Recent literature has demonstrated that hand position can affect visual processing, a set of phenomena termed Near Hand Effects (NHEs). Across four studies we looked for single-hand NHEs on a large screen when participants were asked to discriminate stimuli based on size, colour, and orientation (Study 1), to detect stimuli after a manipulation of hand shaping (Study 2), to detect stimuli after the introduction of a peripheral cue (Study 3), and finally to detect stimuli after a manipulation of screen orientation (Study 4). Each study failed to find a NHE. Further examination of the pooled data using a Bayesian analysis also failed to reveal positive evidence for faster responses or larger cueing effects near a hand. These findings suggest that at least some NHEs may be surprisingly fragile, which dovetails with the recent proposition that NHEs may not form a unitary set of phenomena (Gozli & Deng, 2018). The implication is that visual processing may be less sensitive to hand position across measurement techniques than previously thought, and points to a need for well-powered, methodologically rigorous studies on this topic in the future.