Lateral head turning affects temporal memory

Evidence of abnormal scalar timing property in alexithymia

Evidence suggests that incidental modulation of affective states affects the ability to keep track of time. Alexithymia represents an ideal condition to further address the emotion-time processing link, as it refers to a trait characterized by a deficit of affective processing. 31 healthy participants completed an online version of the TAS-20 scale, which measures alexithymia, and a time reproduction task of visual stimuli related to positive (i.e., happiness) and negative (i.e., anger) facial expressions. Results documented a positive correlation between TAS-20 score and the variability in reproducing sub-second durations of the anger expression stimuli We also found an overestimation of sub-second durations of non-affective expressions in borderline/alexithymic participants. Finally, in line with the literature, we confirmed the overall tendency to overestimate the duration of anger expression stimuli. These findings, which can be interpreted in terms of abnormal scalar timing property in alexithymia, expand previous investigations linking this personality trait with abnormal processing of negative emotions. The evidence that alexithymia predicts the reproduction variability of sub-second durations of negative affective stimuli corroborates previous neuroimaging studies documenting cerebellar deficits in these individuals.

Alexithymia Is Linked with a Negative Bias for Past and Current Events in Healthy Humans

Although research provides a rich literature about the influence of emotional states on temporal cognition, evidence about the influence of the style of emotion processing, as a personality trait, on temporal cognition is extremely limited. We provide a novel contribution to the field by exploring the relationship between difficulties of identifying and describing feelings and emotions (alexithymia) and time perspective. One hundred and forty-two healthy participants completed an online version of the TAS-20 scale, which measures alexithymia, and the Zimbardo Time Perspective Inventory, which monitors individual differences in time-orientation regarding the past, present, and future. The results show greater attention to past negative aspects in participants whose TAS-20 score was indicating borderline or manifest alexithymia, as compared to non-alexithymic individuals. Moreover, the higher the TAS-20 score, the higher the tendency was to focus on negative aspects of the past and interpret the present fatalistically. These results suggest that difficulties in identifying and describing feelings and emotions are associated with a negative bias for past and present events. Theoretical and clinical implications of this finding are discussed.

No Evidence of Perceptual Pseudoneglect in Alexithymia

Neuroscience research links alexithymia, the difficulty in identifying and describing feelings and emotions, with left hemisphere dominance and/or right hemisphere deficit. To provide behavioral evidence for this neuroscientific hypothesis, we explored the relationship between alexithymia and performance in a line bisection task, a standard method for evaluating visuospatial processing in relation to right hemisphere functioning. We enrolled 222 healthy participants who completed a version of the 20-item Toronto Alexithymia Scale (TAS-20), which measures alexithymia, and were asked to mark (bisect) the center of a 10-cm horizontal segment. The results document a significant rightward shift in the center of the line in participants with borderline and manifest alexithymia compared with non-alexithymic individuals. The higher the TAS-20 score, the greater the rightward shift in the line bisection task. This finding supports the right hemisphere deficit hypothesis in alexithymia and suggests that visuospatial abnormalities may be an important component of this mental condition.

Time Processing, Interoception, and Insula Activation: A Mini-Review on Clinical Disorders

Time processing is a multifaceted skill crucial for managing different aspects of life. In the current work, we explored the relationship between interoception and time processing by examining research on clinical models. We investigated whether time processing deficits are associated with dysfunction of the interoceptive system and/or insular cortex activity, which is crucial in decoding internal body signaling. Furthermore, we explored whether insular activation predicts the subjective experience of time (i.e., the subjective duration of a target stimulus to be timed). Overall, our work suggests that alteration of the interoceptive system could be a common psychophysiological hallmark of mental disorders affected by time processing deficits.

Number is special: time, space, and number interact in a temporal reproduction task

Space, time, and number are among fundamental aspects of behavior and reasoning about the environment. Recent studies have shown that these dimensions highly interact with each other. To explain such interaction, two theories have been proposed: A Theory of Magnitude (ATOM), which posits the existence of a common magnitude system, and Conceptual Metaphor Theory (CMT), which proposes abstract domains such as time and number are mapped through more concrete domains such as space. The present study investigates the interaction of number, time and space in a single experimental paradigm using a temporal reproduction task with a visuospatial component. We also investigated whether mathematical education and continuous involvement with calculations and numbers change the processing precision related to number, time, and space. Two groups of students in mathematics (n = 28) and Persian literature (n = 28) participated in a time reproduction task. The stimuli included Arabic numbers 1, 2, 8, and 9, which were presented to the participants over short (300, 400, 500 ms) and long durations (1000, 1100, 1200 ms) on both sides (left and right) of the monitor. The interaction effect of spatialـnumerical and temporal-numerical was found to be significant. There was no overall time-space interaction, but the triple interaction effect between number, time, and space was significant suggesting the existence of a common representational system. This main result was slightly in line with recent proposed theories. Furthermore, the results showed that the main effect of group was not significant. In addition, we found that among the three factors (number, time, and space) the effect of number is more prominent, i.e., when number disappeared the interaction effect was not observed. The results also suggest that the nature of interactions between these factors is not influenced by cognitive and educational factors. The findings of the study are finally discussed in terms of symmetrical or asymmetrical cross-dimensional influences within the frameworks of ATOM and CMT theories.

Time is overestimated in obesity: A cohort study

Food addiction and high impulsivity are common traits in obesity. In accordance with the evidence that time is overestimated in patients with a history of impulsivity and/or drug addiction, we tested the hypothesis that duration is overestimated in obesity. A total of 92 obese participants and 182 healthy controls completed a timing task of visual stimuli. In line with our prediction, obese participants overestimated the duration of the displayed visual stimuli than controls. Our result has potential clinical implications in the field of obesity, as it suggests a potential contribution of this cognitive dysfunction in the emergence and maintenance of obesity-related behaviour.

Group membership and racial bias modulate the temporal estimation of in-group/out-group body movements

Social group categorization has been mainly studied in relation to ownership manipulations involving highly-salient multisensory cues. Here, we propose a novel paradigm that can implicitly activate the embodiment process in the presence of group affiliation information, whilst participants complete a task irrelevant to social categorization. Ethnically White participants watched videos of White- and Black-skinned models writing a proverb. The writing was interrupted 7, 4 or 1 s before completion. Participants were tasked with estimating the residual duration following interruption. A video showing only hand kinematic traces acted as a control condition. Residual duration estimates for out-group and control videos were significantly lower than those for in-group videos only for the longest duration. Moreover, stronger implicit racial bias was negatively correlated to estimates of residual duration for out-group videos. The underestimation bias for the out-group condition might be mediated by implicit embodiment, affective and attentional processes, and finalized to a rapid out-group categorization.

Slower Time estimation in Post-Traumatic Stress Disorder

Cognitive deficits in Posttraumatic Stress Disorder (PTSD) and dissociative symptoms suggest there may be an underlying and persistent problem with temporal processing in PTSD, but this question has not been systematically examined. We investigated the ability of a group of PTSD participants in estimating the duration of supra-second visual stimuli relative to healthy controls. The data of 59 participants with PTSD and 62 healthy controls, collected from the BRID database, have been examined. Overall, our results indicate that PTSD patients overestimate the duration of the displayed stimuli. Moreover, we found that PTSD are more variable in the time estimation compared to the control group. Finally, we found evidence that working memory and attention impairments were associated with time overestimation in PTSD. The finding of time overestimation in PTSD accords with previous reports of time overestimation during stressful experiences associated with fear and arousal, but extends findings to suggest it remains in chronic PTSD populations processing non-emotional stimuli. The evidence of time overestimation in PTSD suggests the potential relevance of this factor as a cognitive marker in assessing the neuropsychological profile of this clinical population.

The Perception of Time Is Underestimated in Adolescents With Anorexia Nervosa

Research has revealed reduced temporal discounting (i.e., increased capacity to delay reward) and altered interoceptive awareness in anorexia nervosa (AN). In line with the research linking temporal underestimation with a reduced tendency to devalue a reward and reduced interoceptive awareness, we tested the hypothesis that time duration might be underestimated in AN. Our findings revealed that patients with AN displayed lower timing accuracy in the form of timing underestimation compared with controls. These results were not predicted by clinical, demographic factors, attention, and working memory performance of the participants. The evidence of a temporal underestimation bias in AN might be clinically relevant to explain their abnormal motivation in pursuing a long-term restrictive diet, in line with the evidence that increasing the subjective temporal proximity of remote future goals can boost motivation and the actual behavior to reach them.

Rightward and leftward biases in temporal reproduction of objects represented in central and peripheral spaces

The basis for how we represent temporal intervals in memory remains unclear. One proposal, the mental time line theory (MTL), posits that our representation of temporal duration depends on a horizontal mental time line, thus suggesting that the representation of time has an underlying spatial component. Recent work suggests that the MTL is a learned strategy, prompting new questions of when and why MTL is used to represent temporal duration, and whether time is always represented spatially. The current study examines the hypothesis that the MTL may be a time processing strategy specific to centrally-located stimuli. In two experiments (visual eccentricity and prismatic adaptation procedures), we investigated the magnitude of the rightward bias, an index of the MTL, in central and peripheral space. When participants performed a supra-second temporal interval reproduction task, we observed a rightward bias only in central vision (within 3° visual angle), but not in the peripheral space (approximately 6-8° visual angle). Instead, in the periphery, we observed a leftward bias. The results suggest that the MTL may be a learned strategy specific to central space and that strategies for temporal interval estimation that do not depend on MTL may exist for stimuli perceived peripherally.

Salivary secretion and disgust: A pilot study

Although a direct link has been established between self-experienced disgust and salivary secretion, it is unclear whether this physiological index is modulated by the social experience of disgust (i.e., exposure to the facial expression of disgust). We tested this issue in a pilot study by collecting salivary samples in a group of 20 healthy humans watching pictures of faces expressing disgust. Moreover, we tried to replicate previous evidence by testing saliva secretion in response to pictures of unpalatable (i.e., rotten) food and non-gustatory disgusting stimuli (i.e., disgusting insects). Overall, our analysis shows a general reduction of saliva secretion in response to disgust stimuli, compared to their positive counterparts, although further analyses for specific stimulus categories indicated that this difference was statistically significant only for food pictures. The non-significance of the face and insect categories might be due to insufficient power of our small sample. Overall, a general reduction of saliva secretion for different disgust-related stimuli suggests a shared mechanism of encoding, in line with theories of neural reuse.

Core, social and moral disgust are bounded: A review on behavioral and neural bases of repugnance in clinical disorders

Disgust is a multifaceted experience that might affect several aspects of life. Here, we reviewed research on neurological and psychiatric disorders that are characterized by abnormal disgust processing to test the hypothesis of a shared neurocognitive architecture in the representation of three disgust domains: i) personal experience of 'core disgust'; ii) social disgust, i.e., sensitivity to others' expressions of disgust; iii) moral disgust, i.e., sensitivity to ethical violations. Our review provides some support to the shared neurocognitive hypothesis and suggests that the insula might be the "hub" structure linking the three domains of disgust sensitivity, while other brain regions may subserve specific facets of the multidimensional experience. Our review also suggests a role of serotonin core and moral disgust, supporting "neo-sentimentalist" theories of morality, which posit a causal role of affect in moral judgment.

Motor activity improves temporal expectancy

Certain brain areas involved in interval timing are also important in motor activity. This raises the possibility that motor activity might influence interval timing. To test this hypothesis, we assessed interval timing in healthy adults following different types of training. The pre- and post-training tasks consisted of a button press in response to the presentation of a rhythmic visual stimulus. Alterations in temporal expectancy were evaluated by measuring response times. Training consisted of responding to the visual presentation of regularly appearing stimuli by either: (1) pointing with a whole-body movement, (2) pointing only with the arm, (3) imagining pointing with a whole-body movement, (4) simply watching the stimulus presentation, (5) pointing with a whole-body movement in response to a target that appeared at irregular intervals (6) reading a newspaper. Participants performing a motor activity in response to the regular target showed significant improvements in judgment times compared to individuals with no associated motor activity. Individuals who only imagined pointing with a whole-body movement also showed significant improvements. No improvements were observed in the group that trained with a motor response to an irregular stimulus, hence eliminating the explanation that the improved temporal expectations of the other motor training groups was purely due to an improved motor capacity to press the response button. All groups performed a secondary task equally well, hence indicating that our results could not simply be attributed to differences in attention between the groups. Our results show that motor activity, even when it does not play a causal or corrective role, can lead to improved interval timing judgments.

Timing recalibration in childhood Tourette syndrome associated with persistent pimozide treatment

In this study, we have tested the effects of the dopamine D2 receptor blocker pimozide on timing performance in patients with Tourette syndrome (TS). Nine children with TS were tested off-medication and following 3 months of daily treatment with pimozide. Subjects completed a time reproduction and a time production task using supra-second temporal intervals. We show that pimozide improves motor timing performance by reducing the patients' variability in reproducing the duration of visual stimuli. On the other hand, this medication has no effect on the reproduction accuracy and on both variability and accuracy of the performance on the time production task. Our results suggest that pimozide might have improved motor timing variability as a result of its beneficial side effect on endogenous dopamine levels (i.e., normalization).

Temporal accuracy and variability in the left and right posterior parietal cortex

Several brain-imaging and lesion studies have suggested a role for the posterior parietal cortex (PPC) in computing interval-timing tasks. PPC also seems to have a key role in modulating visuospatial mechanisms, which are known to affect temporal performance. By applying transcranial direct current stimulation (tDCS) over the left and right PPC, we aimed to modulate timing ability performance in healthy humans performing a cognitively controlled timing task. In two separate experiments we compared time-processing abilities of two groups of healthy adults submitted to anodal, cathodal or sham tDCS over right or left PPC, by employing a supra-second time reproduction task. Cathodal stimulation over the right PPC affected temporal accuracy by leading participants to overestimate time intervals. Moreover, when applied to the left PPC, it reduced variability in reproducing temporal intervals. No effect was reported for anodal stimulation. These results expand current knowledge on the role of the parietal cortex on temporal processing. We provide evidence that the parietal cortex of both hemispheres is involved in temporal processing by acting on distinct components of timing performance such as accuracy and variability.

Temporal abnormalities in children with developmental dyscalculia

Recent imaging studies have associated Developmental dyscalculia (DD) to structural and functional alterations corresponding Parietal and the Prefrontal cortex (PFC). Since these areas were shown also to be involved in timing abilities, we hypothesized that time processing is abnormal in DD. We compared time processing abilities between 10 children with pure DD (8 years old) and 11 age-matched healthy children. Results show that the DD group underestimated duration of a sub-second scale when asked to perform a time comparison task. The timing abnormality observed in our DD participants is consistent with evidence of a shared fronto-parietal neural network for representing time and quantity.

Left hand dominance affects supra-second time processing

Previous studies exploring specific brain functions of left- and right-handed subjects have shown variances in spatial and motor abilities that might be explained according to consistent structural and functional differences. Given the role of both spatial and motor information in the processing of temporal intervals, we designed a study aimed at investigating timing abilities in left-handed subjects. To this purpose both left- and right-handed subjects were asked to perform a time reproduction of sub-second vs. supra-second time intervals with their left and right hand. Our results show that during processing of the supra-second intervals left-handed participants sub-estimated the duration of the intervals, independently of the hand used to perform the task, while no differences were reported for the sub-second intervals. These results are discussed on the basis of recent findings on supra-second motor timing, as well as emerging evidence that suggests a linear representation of time with a left-to-right displacement.