Inhibition of Return in children with Tourette's syndrome and comorbid forms: A Preliminary Study

Background: This study investigated the nature and functioning of the visual-spatial inhibition of return (IOR) phenomenon in children with “pure” Tourette's syndrome (TS), and those with comorbid forms of TS. Method: Children with TS-only and “TS + comorbid” (TS + ADHD +/- OCD) and matched controls performed the inhibition of return (IOR) task, which involved responding to left and right visual targets appearing on a computer screen that were preceded by congruent or incongruent exogenous visual cues. Results: The TS-only group performed similarly on the IOR task to the controls. When the TS-only group was subdivided into children with mild and severe TS symptoms, a post hoc comparison between the controls and severe TS symptom children revealed that these TS children had a reduced magnitude of IOR for targets appearing in the right visual field. The comparison between the TS + comorbid and controls revealed an atypical IOR pattern for the TS + comorbid group. They displayed a loss of normal facilitatory and inhibitory effects for right visual field targets. Conclusions: The findings suggest abnormalities in attentional “disengage” and “move” mechanisms in TS when directing attention to the right visual field, which may reflect left posterior parietal, superior colliculus, and midbrain pathology.     

Progressive age-related changes in the attentional blink paradigm

Previous studies on aging and attention typically examine group differences between younger and older adults, rather than seeing aging as a continuous process. Using correlational analyses, this study examined progressive changes in the magnitude of the attentional blink (AB) associated with aging. Increased age was found to be significantly associated with the ability to detect the second target (T2), whereby older age was correlated with the production of a longer and more pronounced AB; this supports the proposition that aging is associated with reduced inhibitory processes and selective attention. It was also found that AB performance somewhat improves between ages 18-39 years, but tends to decline from 40 years of age onward, providing an interesting and novel finding that AB effects may become more sensitive at this point in time. The AB task may prove useful in the assessment of selective attention in normal healthy adults, as well as changes associated with pathological aging.     

Functional and connectivity changes during working memory in Huntington’s disease: 18 month longitudinal data from the IMAGE-HD study

Background

This study aimed to characterize, for the first time, 18 month longitudinal changes in both functional activation and functional connectivity during working memory in premanifest Huntington’s disease (pre-HD) and symptomatic HD (symp-HD).

Methods

Functional magnetic resonance imaging (fMRI) was used to investigate longitudinal changes in neuronal activity during working memory performance via an N-BACK task (0-BACK and 1-BACK) in 27 pre-HD, 17 symp-HD, and 23 control participants. Whole-brain analysis of activation and region-of-interest analysis of functional connectivity was applied to longitudinal fMRI data collected at baseline and 18 months follow-up.

Results

Compared with controls, the pre-HD group showed significantly increased activation longitudinally during 1-BACK versus 0-BACK in the lateral and medial prefrontal, anterior cingulate, primary motor, and temporal areas cortically, and caudate and putamen subcortically. Pre-HD far from onset, compared with controls, showed further longitudinal increases in the right and left dorsolateral prefrontal cortex (DLPFC). Longitudinal increased activation in anterior cingulate and medial primary motor areas were associated with disease burden in the pre-HD group. Moreover, in pre-HD increased activation over time in primary motor and putamen regions were associated with average response time during 1-BACK performance. During 1-BACK, functional connectivity between the right DLPFC and posterior parietal, anterior cingulate, and caudate was significantly reduced over 18 months only in the pre-HD group.

Conclusions

Longitudinal reductions in connectivity over 18 months may represent an early signature of cortico-cortical and cortico-striatal functional disconnectivity in pre-HD, whereas the concomitant increased cortical and subcortical activation may reflect a compensatory response to the demands for cognitive resources required during task performance. Our findings demonstrate that functional imaging modalities have the potential to serve as sensitive methods for the assessment of cortical and subcortical responses to future treatment measures.     

Linguistic authority and convention in a speech act analysis of pornography

Recently, several philosophers have recast feminist arguments against pornography in terms of Speech Act Theory. In particular, they have considered the ways in which the illocutionary force of pornographic speech serves to set the conventions of sexual discourse while simultaneously silencing the speech of women, especially during unwanted sexual encounters. Yet, this raises serious questions as to how pornographers could (i) be authorities in the language game of sex, and (ii) set the conventions for sexual discourse—questions which these speech act-theoretic arguments against pornography have thus far failed to adequately answer. I fill in this gap of the argumentation by demonstrating that there are fairly weak standards for who counts as an authority or convention-setter in sexual discourse. With this analysis of the underpinnings of a speech act analysis of pornography in mind, I discuss a range of possible objections. I conclude that (i) the endorsement of censorship by a speech act analysis of pornography competes with its commitment to the conventionality of speech acts, and, more damningly, that (ii), recasting anti-pornography arguments in terms of linguistic conventions risks an unwitting defence of a rapist's lack of mens rea—an intolerable result; and yet resisting this conclusion requires that one back away from the original claim to women's voices being ‘silenced’.     

Enhanced corticospinal response to observed pain in pain synesthetes

Observing noxious injury to another’s hand is known to induce corticospinal inhibition that can be measured in the observer’s corresponding muscle. Here, we investigated whether acquired pain synesthetes, individuals who experience actual pain when observing injury to another, demonstrate less corticospinal inhibition than do controls during pain observation, as a potential mechanism for the experience of vicarious pain. We recorded motor-evoked potentials (MEPs) induced at two time points through transcranial magnetic stimulation while participants observed videos of a hand at rest, a hypodermic needle penetrating the skin, a Q-tip touching the skin, and a hypodermic needle penetrating an apple. We compared MEPs in three groups: 7 amputees who experience pain synesthesia, 11 nonsynesthete amputees who experience phantom limb pain, and 10 healthy controls. Results indicated that the pain synesthete group demonstrated significantly enhanced MEP response to the needle penetrating the hand, relative to the needle not having yet penetrated the hand, as compared with controls. This effect was not observed exclusively in the same muscle where noxious stimulation was applied. We speculate that our findings reflect a generalized response to pain observation arising from hyperactivity of motor mirror neurons not involved in direct one-to-one simulation but, rather, in the representation of another’s experience.     

Engagement with beauty: appreciating natural, artistic, and moral beauty

The Engagement With Beauty Scale (EBS), designed from the aesthetics of I. Kant (1790/1987), G. W. F. Hegel (ca. 1835/1993), and T. Aquinas (ca. 1260/1947) and the psychological work of J. Haidt (J. Haidt & D. Keltner, 2004), measures engagement with natural, artistic, and moral beauty. In Studies 1 and 2, the authors describe scale construction, exploratory factor analysis, confirmatory factor analysis, internal consistency, and temporal stability. In Studies 1 and 2, the authors also establish concurrent validity with the Appreciation of Beauty and Excellence subscale of the Values in Action Inventory of Strengths (C. Peterson & M. E. P. Seligman, 2004), the Gratitude, Resentment, and Appreciation Test (P. C. Watkins, K. Woodward, T. Stone, & R. L. Kolts, 2003), and the Spiritual Transcendence Scale (R. L. Piedmont, 2004). In Study 3, the authors used the EBS Artistic Beauty subscale to differentiate students engaged in the arts from those who were not.     

Local-global processing in obsessive-compulsive disorder and comorbid Tourette's syndrome

Neuropsychological and neuroimaging studies implicate attentional difficulties in obsessive-compulsive disorder (OCD), but results are inconsistent due possibly to sample heterogeneity and lack of control of comorbid disorders, such as Tourette's syndrome (TS). Nevertheless, it has been suggested that OCD symptomatology may be a result of over-focused attention at a local level. Therefore, this study aimed to examine the ability of OCD patients (pure and comorbid OCD + TS) to process local and global stimuli. Using a local-global paradigm, participants were required to respond to the directed level (local or global) of various stimuli. Results indicate that pure OCD participants were impaired on the global task, whereas comorbid OCD + TS participants had difficulty processing local information. Results are consistent with previously reported lateralisation anomalies and suggest that OCD negatively affects the ability to process hierarchically presented stimuli.     

Ouch! My phantom leg jumps/hurts when you stab "my" virtual hand

Pain synaesthetes experience pain in a presensitised region when observing or imagining another person in pain. We conducted an upper-limb embodiment study using a modified rubber-hand illusion in which lower-limb amputees originally participated as control subjects for the upper-limb amputees. While we found all subjects experienced topographic illusory sensations, we also serendipitously found that lower-limb amputee pain synaesthetes experienced pain or a motor response in their phantom leg when the embodied hand was threatened (e.g., with a retractable knife, mousetrap, or syringe) or submitted to high-frequency stimulation (e.g., vibration). Embodiment illusions were brought about by touching, manipulating, or threatening a rubber or real hand which was observed through a mirror so that it was superimposed upon the target hand (phantom hand for upper-limb amputees, or real hand in others). Participants included eight pain synaesthetes (six lower-limb amputees, one upper-limb amputee, and one nonamputee), and thirty-one controls (eight lower-limb amputees, twelve upper-limb amputees, and eleven nonamputees). We documented participant's subjective reports, together with quantitative measures including the Questionnaire Measure of Emotional Empathy. We found no association between pain synaesthesia and empathy scores. On the basis of related literature we suggest that pain synaesthetes likely experienced phantom-leg pain because (a) the motor system was already engaged during visual capture; (b) threatening stimuli, to which they are hyper-vigilant, triggered avoidance or 'escape' motor schemata; and (c) there could be no feedback confirming that initiated motor schemata for the phantom limb were successfully performed. Ultimately, we have further defined this new condition, synaesthesia for pain, as not only having a sensory pain component, but also a key motor component, manifesting itself in avoidance, contraction, and withdrawal 'actions'.