Doctor of Philosophy, Ben Gurion University Of The Negev (2016)
Master of Arts, Ben Gurion University Of The Negev (2012)
Bachelor of Science, Tel-Aviv University (2010)
I am interested in the neurocognitive mechanisms and decision-making processes that characterize or underlie obsessive-compulsive and related disorders, mainly obsessive-compulsive disorder (OCD) and hoarding disorder.
I am also fascinated by the relations of these mechanisms to the different elements of treatments for these disorders.
I study these mechanisms using both behavioral tasks and neuroimaging in patients as well as in healthy controls.
Hoarding disorder is characterized by difficulty parting with possessions and by clutter that impairs the functionality of living spaces. Cognitive behavioral therapy conducted by a therapist (individual or in a group) for hoarding symptoms has shown promise. For those who cannot afford or access the services of a therapist, one alternative is an evidence-based, highly structured, short-term, skills-based group using CBT principles but led by non-professional facilitators (the Buried in Treasures [BIT] Workshop). BIT has achieved improvement rates similar to those of psychologist-led CBT. Regardless of modality, however, clinically relevant symptoms remain after treatment, and new approaches to augment existing treatments are needed. Based on two recent studies - one reporting that personalized care and accountability made treatments more acceptable to individuals with hoarding disorder and another reporting that greater number of home sessions were associated with better clinical outcomes, we tested the feasibility and effectiveness of adding personalized, in-home uncluttering sessions to the final weeks of BIT. Participants (n = 5) had 15 sessions of BIT and up to 20 hours of in-home uncluttering. Reductions in hoarding symptoms, clutter, and impairment of daily activities were observed. Treatment response rate was comparable to rates in other BIT studies, with continued improvement in clutter level after in-home uncluttering sessions. This small study suggests that adding in-home uncluttering sessions to BIT is feasible and effective.
View details for DOI 10.1016/j.jpsychires.2018.10.001
View details for PubMedID 30419524
Voelker et al. (this issue) discuss how training improves task speed. They suggest two constraints when exploring how training changes cognition through transfer: (1) a link between improved connectivity and response speed and (2) the transfer task should use pathways altered by training. Looking at the literature on aging, we believe the latter constraint should be reconsidered. We discuss evidence from developmental aging, questioning whether the transfer task necessarily requires using training task pathways. Additionally, we expand the discussion of state training to research on aging-specifically, the link between resting state network activity, mindfulness training, and executive functioning.
View details for DOI 10.1080/17588928.2016.1206874
View details for PubMedID 27448162
Repeated checking is a common ritual in obsessive-compulsive disorder (OCD). van den Hout and Kindt (2003b) devised a task demonstrating paradoxical reductions in memory confidence following repeated checking. This effect was later found to be contingent upon response inhibition. The current study aims to (1) test an alternative interpretation, whereby repeated-checking effects are caused by viewing multiple exemplars, and (2) test whether repeated checking affects response inhibition.132 students participated in two experiments (66 in Experiment 1 and 66 in Experiment 2). Participants were randomly allocated to a repeated-checking task or a simple-action task that featured similar multiple exemplars without the need for checking. Both tasks were followed by a stop-signal task, measuring response inhibition. Experiment 1 featured a stop-signal task with neutral go-signals while Experiment 2 incorporated familiar and unfamiliar stimuli from the previous task as go-signals.In both experiments, the repeated-checking group exhibited reduced memory confidence compared to the simple-action group. Groups did not differ in their response inhibition for neutral stimuli (Experiment 1), while familiar go-signals had a detrimental effect on response inhibition (Experiment 2).Our results examine the association between checking and response inhibition in healthy participants without attention deficit hyperactivity disorder and dyslexia. Replication with clinical samples awaits future studies.Repeated checking impairs memory confidence. Increased familiarity of stimuli shortens the time it takes to respond to them while it impairs inhibition response to them. These effects possibly provide initial evidence for the hypothesized role of response inhibition in the maintenance of OCD.
View details for DOI 10.1016/j.jbtep.2014.12.007
View details for Web of Science ID 000383731600012
View details for PubMedID 25666207
Numerous studies have investigated response inhibition (RI) in obsessive-compulsive disorder (OCD), with many reporting that OCD patients demonstrate deficits in RI as compared to controls. However, reported effect sizes tend to be modest and results have been inconsistent, with some studies finding intact RI in OCD. To date, no study has examined the effect of medications on RI in OCD patients.We analyzed results from a stop-signal task to probe RI in 65 OCD patients (32 of whom were medicated) and 58 healthy controls (HCs).There was no statistically significant difference in stop-signal reaction time between the OCD group and the HC group, or between the medicated and unmedicated OCD patients. However, variability was significantly greater in the medicated OCD group compared to the unmedicated group.These results indicate that some samples of OCD patients do not have deficits in RI, making it unlikely that deficient RI underlies repetitive behaviors in all OCD patients. Future research is needed to fully elucidate the impact of medication use on stop-signal performance. Implications for future research on the cognitive processes underlying repetitive thoughts and behaviors are discussed.
View details for DOI 10.1002/da.22492
View details for PubMedID 26990215
Uncertainty affects performance in many cognitive tasks, including the visual-search task, and individual differences in the experience of uncertainty may contribute to several psychological disorders. Despite the importance of uncertainty, to date, no study has explained the basic mechanisms underlying individual differences in the experience of uncertainty. However, it has been suggested that inhibition, a cognitive mechanism aimed at suppressing unwanted thoughts or actions, may affect the development of uncertainty. In the current study, we investigated the relationship between inhibition and behavioral responses to uncertainty in the visual-search task. To accomplish this goal, forty six university students completed a novel combined visual-search and stop-signal task, in which we manipulated the degree to which the inhibitory control system was activated by varying the proportions of stop signals in separate blocks. We utilized target-absent trials in the visual-search task as a behavioral probe of responses to uncertainty. We found that activating higher levels of inhibitory control resulted in faster responses to target-absent visual-search trials, while not affecting target-present trials. These findings suggest that activation of inhibitory control may causally affect behavioral responses to uncertainty. Thus, individual differences in inhibitory control may influence the ability to rely on internal-ambiguous cues which are common in visual-search and other cognitive tasks. Clinical implications for obsessive-compulsive disorder (OCD) and other disorders involving deficient inhibitory control and difficulty with uncertainty are discussed.
View details for DOI 10.1016/j.neuropsychologia.2015.11.020
View details for PubMedID 26631539
Since mirror neurons were introduced to the neuroscientific community more than 20 years ago, they have become an elegant and intuitive account for different cognitive mechanisms (e.g., empathy, goal understanding) and conditions (e.g., autism spectrum disorders). Recently, mirror neurons were suggested to be the mechanism underlying a specific type of synesthesia. Mirror-touch synesthesia is a phenomenon in which individuals experience somatosensory sensations when seeing someone else being touched. Appealing as it is, careful delineation is required when applying this mechanism. Using the mirror-touch synesthesia case, we put forward theoretical and methodological issues that should be addressed before relying on the mirror-neurons account.
View details for DOI 10.1177/1073858416652079
View details for PubMedID 27242280
In musical-space synesthesia, musical pitches are perceived as having a spatially defined array. Previous studies showed that symbolic inducers (e.g., numbers, months) can modulate response according to the inducer's relative position on the synesthetic spatial form. In the current study we tested two musical-space synesthetes and a group of matched controls on three different tasks: musical-space mapping, spatial cue detection and a spatial Stroop-like task. In the free mapping task, both synesthetes exhibited a diagonal organization of musical pitch tones rising from bottom left to the top right. This organization was found to be consistent over time. In the subsequent tasks, synesthetes were asked to ignore an auditory or visually presented musical pitch (irrelevant information) and respond to a visual target (i.e., an asterisk) on the screen (relevant information). Compatibility between musical pitch and the target's spatial location was manipulated to be compatible or incompatible with the synesthetes' spatial representations. In the spatial cue detection task participants had to press the space key immediately upon detecting the target. In the Stroop-like task, they had to reach the target by using a mouse cursor. In both tasks, synesthetes' performance was modulated by the compatibility between irrelevant and relevant spatial information. Specifically, the target's spatial location conflicted with the spatial information triggered by the irrelevant musical stimulus. These results reveal that for musical-space synesthetes, musical information automatically orients attention according to their specific spatial musical-forms. The present study demonstrates the genuineness of musical-space synesthesia by revealing its two hallmarks-automaticity and consistency. In addition, our results challenge previous findings regarding an implicit vertical representation for pitch tones in non-synesthete musicians.
View details for DOI 10.1016/j.concog.2014.06.001
View details for Web of Science ID 000340807700002
View details for PubMedID 25023138
Obsessive-compulsive disorder (OCD) is an anxiety disorder characterized by compulsions aimed at reducing anxiety associated with intrusive cognitions. However, compulsive behaviors such as repeated checking were found to increase rather than decrease uncertainty related to obsessive thoughts (e.g., whether the gas stove was turned off). Some recent studies illustrate that OCD patients and their family members have inhibitory deficits, often demonstrated by the stop-signal task. The current study aims to investigate relations between inhibitory control and effects of repeated checking.Fifty-five healthy participants carried out a stop-signal task followed by a repeated-checking task. Additionally, participants were asked to complete self-report questionnaires measuring OCD, anxiety and depression symptoms.Confirming our hypothesis, participants with poor inhibitory capabilities demonstrated greater uncertainty and memory distrust as a consequence of repeated checking than participants with good inhibitory control.Our findings concern an initial investigation on a sample of healthy participants and should be replicated and extended to clinical populations.These results suggest that deficits in inhibitory control may underlie cognitive vulnerability in OCD. An updated model integrating neuropsychological findings with current OCD models is suggested.
View details for DOI 10.1016/j.jbtep.2012.07.002
View details for Web of Science ID 000311978800005
View details for PubMedID 22863450
In spatial-sequence synesthesia, ordinal sequences are visualized in explicit spatial locations. We examined a recently documented subtype in which musical notes are represented in spatial configurations, to verify consistency and automaticity of musical pitch-space (M-S) synesthesia. An M-S synesthete performed a mapping pre-task (Exp. 1) used to indicate the locations of 7 auditory or visually presented notes, in 2 sessions a month apart. Results revealed strong correlations between sessions, suggesting the synesthete's musical forms were consistent over time. Experiment 2 assessed automaticity of M-S synesthesia. The same synesthete and matched controls preformed a spatial Stroop-like task. Participants were presented with an auditory or visual musical note and then had to reach for an asterisk (target) with a mouse cursor. The target appeared in a compatible or incompatible location (according to the synesthete's spatial representation). A compatibility effect was found for the synesthete but not for controls. The synesthete was significantly faster when the target appeared in compatible locations than in incompatible ones. Our findings show that for synesthetes, auditory and visually presented notes automatically trigger attention to specific spatial locations according to their specific M-S associations.
View details for DOI 10.1007/s10339-012-0498-0
View details for Web of Science ID 000308824700292
View details for PubMedID 22806677