rTMS of the superior parietal lobule improves contrast discrimination but has no effect on the perception of distance between stimuli in the image plane.

The superior parietal lobule (SPL) is a region of the brain that has been associated with a diverse range of high-level visual and cognitive functions. This suggested the possibility that it supports a lower-level function that is engaged by a wide range of experimental tasks. Analysis of tasks used in previous studies suggests that one such lower-level function might be the perception of the distance between stimuli in the image plane. In this study, we applied online high-frequency repetitive transcranial magnetic stimulation (rTMS) over the left SPL or the vertex in order to further investigate the role played by this region in the perceived visual separation between points. As a control task, we asked participants to detect the difference in contrast between two Gabor patches. The results failed to support the main hypothesis, but we unexpectedly found that rTMS to left SPL improved peripheral contrast discrimination. Previous studies have found that rTMS to the right frontal eye field, which has strong functional connectivity with the SPL, has the same effect, suggesting the two areas work together to influence early visual areas.

Just let me check: The role of individual differences in self-reported anxiety and obsessive-compulsive features on subjective, behavioural, and physiological indices during a checking task.

Checking behaviour has been described as a form of preventative behaviour used by an individual to establish control over the environment and avoid future misfortune. However, when compulsive, checking behaviours can become disabling and distressing and have been linked to the maintenance of anxiety and obsessive-compulsive disorders. Despite this, there is limited literature across the field that has assessed the impact of dimensional measures of anxiety and obsessive-compulsive features (i.e., negative affect, uncertainty, and perfectionism) in driving checking behaviour. As such, the present study examined the impact of individual differences in self-reported anxiety and obsessive-compulsive features on subjective, behavioural, and physiological indices during a visual discrimination and checking task (n = 87). Higher self-reported anxiety and obsessive-compulsive features were associated with higher subjective ratings of unpleasantness and the urge to check during the task. Moreover, higher self-reported anxiety and obsessive-compulsive features related to general negative affect, uncertainty, and perfectionism were associated with greater checking frequency during the task. Lastly, stronger obsessional beliefs about perfectionism and the need for certainty were found to predict poorer accuracy, slower reaction times, and higher engagement of the corrugator supercilii during the task. In sum, these findings demonstrate how different anxiety and obsessive-compulsive features, in particular perfectionism and the need for certainty, may relate to and maintain checking behaviour in low threat contexts, which likely has implications for models of excessive and persistent checking in anxiety and obsessive-compulsive disorders.

Intolerance of uncertainty is associated with heightened responding in the prefrontal cortex during cue-signalled uncertainty of threat.

Heightened responding to uncertain threat is considered a hallmark of anxiety disorder pathology. We sought to determine whether individual differences in self-reported intolerance of uncertainty (IU), a key transdiagnostic dimension in anxiety-related pathology, underlies differential recruitment of neural circuitry during cue-signalled uncertainty of threat (n = 42). In an instructed threat of shock task, cues signalled uncertain threat of shock (50%) or certain safety from shock. Ratings of arousal and valence, skin conductance response (SCR), and functional magnetic resonance imaging were acquired. Overall, participants displayed greater ratings of arousal and negative valence, SCR, and amygdala activation to uncertain threat versus safe cues. IU was not associated with greater arousal ratings, SCR, or amygdala activation to uncertain threat versus safe cues. However, we found that high IU was associated with greater ratings of negative valence and greater activity in the medial prefrontal cortex and dorsomedial rostral prefrontal cortex to uncertain threat versus safe cues. These findings suggest that during cue-signalled uncertainty of threat, individuals high in IU rate uncertain threat as aversive and engage prefrontal cortical regions known to be involved in safety-signalling and conscious threat appraisal. Taken together, these findings highlight the potential of IU in modulating safety-signalling and conscious appraisal mechanisms in situations with cue-signalled uncertainty of threat, which may be relevant to models of anxiety-related pathology.

Intolerance of uncertainty and physiological responses during instructed uncertain threat: A multi-lab investigation.

Individuals with high self-reported Intolerance of uncertainty (IU) tend to interpret uncertainty negatively. Recent research has been inconclusive on evidence of an association between IU and physiological responses during instructed uncertain threat. To address this gap, we conducted secondary analyses of IU and physiology data recorded during instructed uncertain threat tasks from two lab sites (Wisconsin-Madison; n = 128; Yale, n = 95). No IU-related effects were observed for orbicularis oculi activity (auditory startle-reflex). Higher IU was associated with: (1) greater corrugator supercilii activity to predictable and unpredictable threat of shock, compared to the safety from shock, and (2) poorer discriminatory skin conductance response between the unpredictable threat of shock, relative to the safety from shock. These findings suggest that IU-related biases may be captured differently depending on the physiological measure during instructed uncertain threat. Implications of these findings for neurobiological models of uncertainty and anticipation in anxiety are discussed.

The role of intolerance of uncertainty in the acquisition and extinction of reward.

Individuals, who score high in self-reported intolerance of uncertainty (IU), tend to find uncertainty anxiety-provoking. IU has been reliably associated with disrupted threat extinction. However, it is unclear whether IU would be related to disrupted extinction to other arousing stimuli that are not threatening (i.e., rewarding). We addressed this question by conducting a Pavlovian reward conditioning task with acquisition and extinction training phases (n = 58). In the Pavlovian reward conditioning task, we recorded liking ratings, skin conductance response (SCR), and corrugator supercilii activity (i.e., brow muscle indicative or negative and positive affect) to learned reward (CS+) and neutral (CS-) cues. Typical patterns of reward acquisition and extinction training were observed for liking ratings. There was evidence for conditioning in SCR during the extinction training phase but not the acquisition training phase. However, no evidence of conditioning in either the acquisition or extinction training phase was observed for the corrugator supercilii. IU was not related to any measures during the acquisition or extinction training phases. Taken together, these results suggest that the current Pavlovian reward conditioning task was not sufficient for eliciting a reliable conditioned reward response, and therefore, further research with optimized reward conditioning designs are required to test whether IU-related deficits occur during the extinction of reward.

Your guess is as good as mine: A registered report assessing physiological markers of fear and anxiety to the unknown in individuals with varying levels of intolerance of uncertainty.

Individuals who score high in Intolerance of Uncertainty (IU) have a tendency to find uncertainty and the unknown aversive. However, there is a dearth of literature on the extent to which the known vs. the unknown during threatening contexts induce fear and anxiety in individuals with high IU. In the following registered report we attempted to address this question by manipulating the known and unknown in the threat of predictable and unpredictable aversive events task. Throughout the task, we measured a variety of self-report (ratings of valence and arousal) and physiological indices (skin conductance, pupil dilation, orbicularis oculi, corrugator supercilii). We collected data from 93 participants. Higher IU, relative to lower IU was associated with: (1) less discriminatory orbicularis oculi activity between cue and interstimulus interval periods across conditions, and (2) larger corrugator supercilii activity to the known predictable shock condition and smaller corrugator supercilii activity to the known unpredictable shock condition, compared to the other conditions. These findings provide evidence that IU-related biases manifest differently depending on the physiological marker of fear and anxiety and the type of known-unknown threat i.e. orbicularis oculi activity was related to generalisation across conditions, whilse corrugator supercilii activity reflected distress/relief during conditions with known threat. Ultimately, this research will inform future models of IU in relation to anxiety and stress disorders.

The role of the ventral intraparietal area (VIP/pVIP) in the perception of object-motion and self-motion.

Retinal image motion is a composite signal that contains information about two behaviourally significant factors: self-motion and the movement of environmental objects. It is thought that the brain separates the two relevant signals, and although multiple brain regions have been identified that respond selectively to the composite optic flow signal, which brain region(s) perform the parsing process remains unknown. Here, we present original evidence that the putative human ventral intraparietal area (pVIP), a region known to receive optic flow signals as well as independent self-motion signals from other sensory modalities, plays a critical role in the parsing process and acts to isolate object-motion. We localised pVIP using its multisensory response profile, and then tested its relative responses to simulated object-motion and self-motion stimuli; results indicated that responses were much stronger in pVIP to stimuli that specified object-motion. We report two further observations that will be significant for the future direction of research in this area; firstly, activation in pVIP was suppressed by distant stationary objects compared to the absence of objects or closer objects. Secondly, we describe several other brain regions that share with pVIP selectivity for visual object-motion over visual self-motion as well as a multisensory response.