Delayed Perceptual Awareness in Rapid Perceptual Decisions

The flourishing of studies on the neural correlates of decision-making calls for an appraisal of the relation between perceptual decisions and conscious perception. By exploiting the long integration time of noisy motion stimuli, and by forcing human observers to make difficult speeded decisions – sometimes a blind guess – about stimulus direction, we traced the temporal buildup of motion discrimination capability and perceptual awareness, as assessed trial by trial through direct rating. We found that both increased gradually with motion coherence and viewing time, but discrimination was systematically leading awareness, reaching a plateau much earlier. Sensitivity and criterion changes contributed jointly to the slow buildup of perceptual awareness. It made no difference whether motion discrimination was accomplished by saccades or verbal responses. These findings suggest that perceptual awareness emerges on the top of a developing or even mature perceptual decision. We argue that the middle temporal (MT) cortical region does not confer us the full phenomenic depth of motion perception, although it may represent a precursor stage in building our subjective sense of visual motion

Mental Imagery Cracked: Direct Monitoring of the Continuous Movements of Covert Visuospatial Attention During Motion Imagery

We sought to provide direct evidence of the attention movements during dynamic mental imagery. Observers extrapolated in imagery the horizontal motion of a target with the gaze in central fixation. We recorded the steady-statevisual- evoked potentials (SSVEP) generated by flickering the left and right sides of the screen at two different frequencies. We found a consistent SSVEP modulation as a function of the imagined target position. Concurrent finger pointing, but not mental training, increased the SSVEP modulation. We conclude that the electrophysiological signature of covert visuospatial attention can be used to reveal non-invasively the continuous spatio-temporal dynamics of mental imagery

Oculomotor behavior (top 4 panels) and contingency strength (bottom panel) in the Detection Task.

<p>The results are grouped in terms of stimulus category (contingent vs. non-contingent trials, different lines, same for all panels) and response type (correct vs. wrong responses, horizontal axis, same for all panels). Bars represent the standard deviation. H = Hits, M = Misses, CR = Correct Rejections, FA = False Alarms.</p

Assessing Self-Awareness through Gaze Agency

<div><p>We define gaze agency as the awareness of the causal effect of one’s own eye movements in gaze-contingent environments, which might soon become a widespread reality with the diffusion of gaze-operated devices. Here we propose a method for measuring gaze agency based on self-monitoring propensity and sensitivity. In one task, naïf observers watched bouncing balls on a computer monitor with the goal of discovering the cause of concurrently presented beeps, which were generated in real-time by their saccades or by other events (Discovery Task). We manipulated observers’ self-awareness by pre-exposing them to a condition in which beeps depended on gaze direction or by focusing their attention to their own eyes. These manipulations increased propensity to agency discovery. In a second task, which served to monitor agency sensitivity at the sensori-motor level, observers were explicitly asked to detect gaze agency (Detection Task). Both tasks turned out to be well suited to measure both increases and decreases of gaze agency. We did not find evident oculomotor correlates of agency discovery or detection. A strength of our approach is that it probes self-monitoring propensity–difficult to evaluate with traditional tasks based on bodily agency. In addition to putting a lens on this novel cognitive function, measuring gaze agency could reveal subtle self-awareness deficits in pathological conditions and during development.</p></div

Who Has Done It? Exploring Gaze Agency in Obsessive-Compulsive Checkers

The sense of agency (SoA) is a multifaceted construct, which can be defined as the ability to understand the causal relationships between our actions and sensory events. Obsessive-Compulsive Disorder (OCD) patients with checking compulsions often report a “lack of action completion” sensations, which has been conceptualized in the so-called “Not Just Right Experiences” construct. An intriguing explanation of this phenomenon comes from Belayachi and Van der Linden (2009, 2010), who suggest that OCD-checking patients are more prone to specify their action in a relatively molecular and inflexible way. Currently, there are no studies in literature which address this issue in OCD patients, except for the one of Gentsch et al. (2012), who suggested an altered SoA in these patients. Here we exploited a novel construct, gaze agency, to evaluate causal attribution capabilities in a group of 21 OCD patients (checkers) and matched healthy controls (HCs). Basically, two tasks targeted observers’ capability to identify their own eye movements as the cause of concurrently presented beeps, which allowed us to measure agency sensitivity as well as subtle agency alterations in an ecological setting. We found a poorer performance in OCD patients as compared to HCs in many parameters of our tasks, suggesting a difficulty with causal attribution possibly due to both a reduced cognitive flexibility and a less functional gaze agency in OCD patients

Assessing Self-Awareness through Gaze Agency - Fig 1

<p>Left panel A, a snapshot of the moving balls display with N = 15. Right panel B, smoothed energy profiles of the balls in the different trials. Energy increases rapidly during the initial part of the trial, when the balls progressively enter the display, whereas it decreases more slowly afterwards, as an effect of the ball bounces. The bounces tend normally to decrease the ball energy, but occasionally they increase it (“squeezing effect”, visible as “bumps” in the curves). N indicates the number of balls in each trial).</p

Detection Task performance.

<p>Detection Task performance.</p

Assessing Self-Awareness through Gaze Agency - Fig 1

<p>Left panel A, a snapshot of the moving balls display with N = 15. Right panel B, smoothed energy profiles of the balls in the different trials. Energy increases rapidly during the initial part of the trial, when the balls progressively enter the display, whereas it decreases more slowly afterwards, as an effect of the ball bounces. The bounces tend normally to decrease the ball energy, but occasionally they increase it (“squeezing effect”, visible as “bumps” in the curves). N indicates the number of balls in each trial).</p