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  • Multisensory interactions in the depth plane in front and rear space: a review.

    6 December 2017

    In this review, we evaluate the neurophysiological, neuropsychological, and psychophysical evidence relevant to the claim that multisensory information is processed differently depending on the region of space in which it happens to be presented. We discuss how the majority of studies of multisensory interactions in the depth plane that have been conducted to date have focused on visuotactile and audiotactile interactions in frontal peripersonal space and underline the importance of such multisensory interactions in defining peripersonal space. Based on our review of studies of multisensory interactions in depth, we question the extent to which peri- and extra-personal space (both frontal and rear) are characterized by differences in multisensory interactions (as evidenced by multisensory stimuli producing a different behavioral outcome as compared to unisensory stimulation). In addition to providing an overview of studies of multisensory interactions in different regions of space, our goal in writing this review has been to demonstrate that the various kinds of multisensory interactions that have been documented may follow very similar organizing principles. Multisensory interactions in depth that involve tactile stimuli are constrained by the fact that such stimuli typically need to contact the skin surface. Therefore, depth-related preferences of multisensory interactions involving touch can largely be explained in terms of their spatial alignment in depth and their alignment with the body. As yet, no such depth-related asymmetry has been observed in the case of audiovisual interactions. We therefore suggest that the spatial boundary of peripersonal space and the enhanced audiotactile and visuotactile interactions that occur in peripersonal space can be explained in terms of the particular spatial alignment of stimuli from different modalities with the body and that they likely reflect the result of prior multisensory experience.

  • That Sounds Sweet: Using Cross-Modal Correspondences to Communicate Gustatory Attributes

    28 November 2017

    © 2014 Wiley Periodicals, Inc. Building on existing research into sound symbolism and cross-modal correspondences, this article proposes that cross-modal correspondences-systematic mappings between different sensory modalities-can be used to communicate nonmusical, low-level sensory properties such as basic tastes through music. A series of three experiments demonstrates that cross-modal correspondences enable people to systematically encode basic taste properties into parameters in musical space (Experiment 1), and that they are able to correctly decode basic taste information embedded in complex musical compositions (Experiments 2 and 3). The results also suggest some culture-specificity to these mappings, given that decoding performance, while still above chance levels, was lower in Indian participants than in those from the United States (Experiment 3). Implications and potential applications of these findings are discussed.

  • Dopamine-associated cached values are not sufficient as the basis for action selection.

    30 November 2017

    Phasic dopamine transmission is posited to act as a critical teaching signal that updates the stored (or "cached") values assigned to reward-predictive stimuli and actions. It is widely hypothesized that these cached values determine the selection among multiple courses of action, a premise that has provided a foundation for contemporary theories of decision making. In the current work we used fast-scan cyclic voltammetry to probe dopamine-associated cached values from cue-evoked dopamine release in the nucleus accumbens of rats performing cost-benefit decision-making paradigms to evaluate critically the relationship between dopamine-associated cached values and preferences. By manipulating the amount of effort required to obtain rewards of different sizes, we were able to bias rats toward preferring an option yielding a high-value reward in some sessions and toward instead preferring an option yielding a low-value reward in others. Therefore, this approach permitted the investigation of dopamine-associated cached values in a context in which reward magnitude and subjective preference were dissociated. We observed greater cue-evoked mesolimbic dopamine release to options yielding the high-value reward even when rats preferred the option yielding the low-value reward. This result identifies a clear mismatch between the ordinal utility of the available options and the rank ordering of their cached values, thereby providing robust evidence that dopamine-associated cached values cannot be the sole determinant of choices in simple economic decision making.

  • The experience of traumatic events disrupts the measurement invariance of a posttraumatic stress scale.

    4 December 2017

    Studies that include multiple assessments of a particular instrument within the same population are based on the presumption that this instrument measures the same construct over time. But what if the meaning of the construct changes over time due to one's experiences? For example, the experience of a traumatic event can influence one's view of the world, others, and self, and may disrupt the stability of a questionnaire measuring posttraumatic stress symptoms (i.e., it may affect the interpretation of items). Nevertheless, assessments before and after such a traumatic event are crucial to study longitudinal development of posttraumatic stress symptoms. In this study, we examined measurement invariance of posttraumatic stress symptoms in a sample of Dutch soldiers before and after they went on deployment to Afghanistan (N = 249). Results showed that the underlying measurement model before deployment was different from the measurement model after deployment due to invariant item thresholds. These results were replicated in a sample of soldiers deployed to Iraq (N = 305). Since the lack of measurement invariance was due to instability of the majority of the items, it seems reasonable to conclude that the underlying construct of PSS is unstable over time if war-zone related traumatic events occur in between measurements. From a statistical point of view, the scores over time cannot be compared when there is a lack of measurement invariance. The main message of this paper is that researchers working with posttraumatic stress questionnaires in longitudinal studies should not take measurement invariance for granted, but should use pre- and post-symptom scores as different constructs for each time point in the analysis.

  • Anger: Cause or Consequence of Posttraumatic Stress? A Prospective Study of Dutch Soldiers

    27 October 2017

    Many studies have shown that individuals with posttraumatic stress disorder (PTSD) experience more anger over time and across situations (i.e., trait anger) than trauma-exposed individuals without PTSD. There is a lack of prospective research, however, that considers anger levels before trauma exposure. The aim of this study was to prospectively assess the relationship between trait anger and PTSD symptoms, with several known risk factors, including baseline symptoms, neuroticism, and stressor severity in the model. Participants were 249 Dutch soldiers tested approximately 2 months before and approximately 2 months and 9 months after their deployment to Afghanistan. Trait anger and PTSD symptom severity were measured at all assessments. Structural equation modeling including cross-lagged effects showed that higher trait anger before deployment predicted higher PTSD symptoms 2 months after deployment (β = .36), with stressor severity and baseline symptoms in the model, but not with neuroticism in the model. Trait anger at 2 months postdeployment did not predict PTSD symptom severity at 9 months, and PTSD symptom severity 2 months postdeployment did not predict subsequent trait anger scores. Findings suggest that trait anger may be a pretrauma vulnerability factor for PTSD symptoms, but does not add variance beyond the effect of neuroticism. © 2014 International Society for Traumatic Stress Studies.

  • Common and dissociated mechanisms for estimating large and small dot arrays: Value-specific fMRI adaptation

    17 November 2017

    An fMRI pair-adaptation paradigm was used to identify the brain regions linked to the apprehension of small and large numbers of items. Participants classified stimuli on the basis of their numerosities (fewer or more than five dots). We manipulated the type of repetition within pairs of dot arrays. Overall processing of pairs with small as opposed to large quantities was associated with a decreased BOLD response in the midline structures and inferior parietal cortex. The opposite pattern was observed in middle cingulate cortex. Pairs in which the same numerosity category was repeated, were associated with a decreased signal in the left prefrontal and the left inferior parietal cortices, compared with when numerosities changed. Repetitions of exact numerosities irrespective of sample size were associated with decreased responses in bi-lateral prefrontal, sensory-motor regions, posterior occipital and left intraparietal sulcus (IPS). More importantly, we found value-specific adaptation specific to repeated small quantity in the left lateral occipito-temporal cortex, irrespective of whether the exact same stimulus pattern repeated. Our results indicate that a large network of regions (including the IPS) support visual quantity processing independent of the number of items present; however assimilation of small quantities is associated with additional support from regions within the left occipito-temporal cortex. We propose that processing of small quantities is aided by a subitizing-specific network. This network may account for the increased processing efficiency often reported for numerosities in the subitizing range. © 2014 Wiley Periodicals, Inc.

  • Understanding developmental language disorders: From theory to practice

    27 October 2017

    © 2008 Psychology Press. All rights reserved. Developmental language disorders (DLD) occur when a child fails to develop his or her native language often for no apparent reason. Delayed development of speech and/or language is one of the most common reasons for parents of preschool children to seek the advice of their family doctor. Although some children rapidly improve, others have more persistent language difficulties. These long-term deficits can adversely affect academic progress, social relationships and mental well-being. Although DLDs are common, we are still a long way from understanding what causes them and how best to intervene. Understanding Developmental Language Disorders summarises the recent research developments in genetics and neuroimaging studies, assessment techniques and treatment studies to provide an overview of all aspects of DLD. The book investigates the possible genetic and biological causes of the disorder, how best to assess children's language skills to identify when and where communication breakdown occurs, what the long-term outcomes are for children who grow up with DLD, overlaps between DLD and other childhood disorders such as dyslexia and autism and how best to treat children with the disorder. Each chapter is written by a leading authority in the field in a format accessible to researchers, clinicians and families alike. This book, with its focus on both theory and practice, will be invaluable to students and researchers of speech-language pathology, psychology, psychiatry, linguistics and education. It will also be of interest to practicing speech-language pathologists, clinical psychologists, psychiatrists, educational psychologists, and teachers and parents of children with developmental language disorders.