Abnormal visual scanning of emotionally evocative natural scenes in Huntington's disease

Huntington’s disease (HD) is a neurodegenerative movement disorder associated with deficits in the processing of emotional stimuli, including alterations in the self-reported subjective experience of emotion when presented with pictures of emotional scenes. The aim of this study was to determine whether individuals with HD, compared to unaffected controls, display abnormal visual scanning of emotionally evocative natural scenes. Using eye-tracking, we recorded eye-movements of 25 HD participants (advanced pre-symptomatic and early symptomatic) and 25 age-matched unaffected control participants during a picture viewing task. Participants viewed pictures of natural scenes associated with different emotions: anger, fear, disgust, happiness, or neutral, and evaluated those pictures on a valence rating scale. Individuals with HD displayed abnormal visual scanning patterns, but did not differ from controls with respect to their valence ratings. Specifically, compared to controls, HD participants spent less time fixating on the pictures and made longer scan paths. This finding highlights the importance of taking visual scanning behavior into account when investigating emotion processing in HD. The visual scanning patterns displayed by HD participants could reflect a heightened, but possibly unfocussed, search for information, and might be linked to attentional deficits or to altered subjective emotional experiences in HD. Another possibility is that HD participants may have found it more difficult than controls to evaluate the emotional valence of the scenes, and the heightened search for information was employed as a compensatory strategy

Modulation of Habit Formation by Levodopa in Parkinson's Disease

Dopamine promotes the execution of positively reinforced actions, but its role for the formation of behaviour when feedback is unavailable remains open. To study this issue, the performance of treated/untreated patients with Parkinson's disease and controls was analysed in an implicit learning task, hypothesising dopamine-dependent adherence to hidden task rules. Sixteen patients on/off levodopa and fourteen healthy subjects engaged in a Go/NoGo paradigm comprising four equiprobable stimuli. One of the stimuli was defined as target which was first consistently preceded by one of the three non-target stimuli (conditioning), whereas this coupling was dissolved thereafter (deconditioning). Two task versions were presented: in a ‘Go version’, only the target cue required the execution of a button press, whereas non-target stimuli were not instructive of a response; in a ‘NoGo version’, only the target cue demanded the inhibition of the button press which was demanded upon any non-target stimulus. Levodopa influenced in which task version errors grew from conditioning to deconditioning: in unmedicated patients just as controls errors only rose in the NoGo version with an increase of incorrect responses to target cues. Contrarily, in medicated patients errors went up only in the Go version with an increase of response omissions to target cues. The error increases during deconditioning can be understood as a perpetuation of reaction tendencies acquired during conditioning. The levodopa-mediated modulation of this carry-over effect suggests that dopamine supports habit conditioning under the task demand of response execution, but dampens it when inhibition is required. However, other than in reinforcement learning, supporting dopaminergic actions referred to the most frequent, i. e., non-target behaviour. Since this is passive whenever selective actions are executed against an inactive background, dopaminergic treatment could in according scenarios contribute to passive behaviour in patients with Parkinson's disease

Efecto de la carga de sulfito de sodio en el pulpaje NSSC de E. Globulus

El presente trabajo tuvo como principal objetivo determinar el efecto de la adición de una alta carga de sulfito de sodio (Na2SO3) para la sustitución de otras fuentes alcalinas (Na2CO3 o NaOH) sobre el pulpaje de alto rendimiento al sulfito neutro. En la etapa química se utilizó sólo sulfito de sodio (Na2SO3) como agente deslignificante y en la etapa mecánica un refinador Bauer de 12”. Se obtuvieron pulpas con rendimientos variables entre 70 y 90 % y se verificó que las propiedades físico-mecánicas de las pulpas aumentan considerablemente a medida que el rendimiento baja. Al mismo tiempo disminuyeron, notablemente, el consumo energético de desfibración y el de refinación. Pulpas con rendimientos cercanos al 80%, fabricada con una alta dosis de sulfito de sodio presentaron propiedades físico-mecánicas similares a una pulpa química. La mayor carga de sulfito no significó un aumento considerable del consumo de reactivos, especialmente a altos rendimientos. El buen desarrollo de propiedades físicomecánicas se debe, probablemente, a la alta proporción de hemicelulosas que presenta la pulpa y a la selectividad del proceso para remover lignina desde la lámina media, lo que favorece la obtención de fibras íntegras y con un menor esfuerzo mecánico. AbstractThis paper presents experimental results on the effect of adding high doses of sodium sulphite (Na2SO3) to replace other sources of alkali, such as Na2CO3 or NaOH, in high-yield Neutral Semichemical Pulping (NSSC) process. Sodium sulfite (Na2SO3) was used as delignification agent in the chemical stage of eucalyptus globulus pulping. A 12” Bauer refiner was employed in the mechanical stage. Pulp yields ranged within 70-90% and, results show that physical and mechanical properties increased significantly as yields decreased. Moreover, the defibration energy consumption and beatings energy also showed a significant decrease.Those pulps featuring yields near 80%, obtained with high sodium sulfite loads, presented similar physical and mechanical properties as chemical pulps. At the largest sulfide dose used here, no significant increase in chemical consumption was observed, especially at high yields. This study shows that physical and chemical properties are enhanced by high hemicelluloses content, and process selectivity to remove lignin from the middle lamella, which leads to a fiber integrity and reduced mechanical stress

Multidisciplinary rehabilitation reduces hypothalamic grey matter volume loss in individuals with preclinical Huntington's disease: A nine-month pilot study

Background: Hypothalamic pathology is a well-documented feature of Huntington's disease (HD) and is believed to contribute to circadian rhythm and habitual sleep disturbances. Currently, no therapies exist to combat hypothalamic changes, nor circadian rhythm and habitual sleep disturbances in HD. Objective: To evaluate the effects of multidisciplinary rehabilitation on hypothalamic volume, brain-derived neurotrophic factor (BDNF), circadian rhythm and habitual sleep in individuals with preclinical HD. Methods: Eighteen individuals with HD (ten premanifest and eight prodromal) undertook a nine-month multidisciplinary rehabilitation intervention (intervention group), which included exercise, cognitive and dual task training and social events, and were compared to a community sample of eleven individuals with premanifest HD receiving no intervention (control group). Hypothalamic volume, serum BDNF, salivary cortisol and melatonin concentrations, subjective sleep quality, daytime somnolence, habitual sleep-wake patterns, stress and anxiety and depression symptomatology were evaluated. Results: Hypothalamus grey matter volume loss was significantly attenuated in the intervention group compared to the control group after controlling for age, gender, Unified Huntington's Disease Rating Scale-Total Motor Score and number of cytosine-adenine-guanine repeats. Serum BDNF levels were maintained in the intervention group, but decreased in the control group following the study period. Both groups exhibited decreases in cortisol and melatonin concentrations. No changes were observed in sleep or mood outcomes. Conclusions: This exploratory study provides evidence that multidisciplinary rehabilitation can reduce hypothalamic volume loss and maintain peripheral BDNF levels in individuals with preclinical HD but may not impact on circadian rhythm. Larger, randomised controlled trials are required to confirm these findings

A sensorimotor control framework for understanding emotional communication and regulation

JHGW and CFH are supported by the Northwood Trust. TEVR was supported by a National Health and Medical Research Council (NHMRC) Early Career Fellowship (1088785). RP and MW were supported by the the Australian Research Council (ARC) Centre of Excellence for Cognition and its Disorders (CE110001021)Peer reviewedPublisher PD

An Investigation of Emotion Processing Impairments in Huntington’s Disease

Huntington's disease (HD) is a neurodegenerative disorder associated with altered processing of emotional stimuli. Altered emotion processing in HD includes a well-established deficit in the ability to recognize emotions from facial expressions. Subjective experience of emotion is also altered, although previous studies have indicated both diminished and exaggerated subjective experiences. The overarching purpose of this thesis was to improve current knowledge on the processing of emotional stimuli in HD, by answering three research questions, which are addressed in three papers. For the thesis, data were collected from 25 participants with the gene-expansion for HD (late pre-manifest and early diagnosed) and 25 HD gene-negative healthy control participants. <br>     <br>    The first paper addressed the question of whether individuals with HD, compared to controls, show altered facial muscle responses to emotionally-evocative scenes and emotionally-expressive faces. Using electromyography (EMG) to examine facial muscles activity, we found that HD participants displayed lower activation of the <i>levator labii</i> muscle when viewing disgusting scenes than control participants, providing evidence for reduced disgust experience in HD. HD participants also displayed lower EMG responses of the <i>zygomaticus major</i> and <i>orbicularis</i> <i>oculi</i> muscles in reaction to happy faces and of the <i>frontalis</i> muscle in reaction to fearful faces. The finding of diminished responsivity to disgust is relevant to current controversies regarding whether disgust processing is affected in HD, and the reduced responsivity to happy stimuli may have implications for social functioning in HD. <br>     <br>    The second paper addressed the question of whether individuals with HD visually scan emotionally-evocative natural scenes differently than healthy controls. We found that HD participants fixated for a smaller portion of picture viewing time, and that their scan paths were longer than those of controls. These findings suggest an enhanced, but unfocussed search for information in HD. This search for information may constitute a strategy used by HD participants to compensate for difficulties in evaluating the stimuli, perhaps due to difficulties with self-reflection. <br>     <br>    The third paper addressed the question of whether individuals with HD display reduced visual scanning of the emotionally most informative features of human faces than healthy controls. We found that, relative to the scanning of the whole pictures, the HD participants made a lower number of fixations on the eye and nose/mouth regions and spent less time looking at these regions. Further, visual scanning of the eye region was associated with emotion recognition performance in the HD group, raising the possibility that scanning of the eyes is insufficient for accurate emotion recognition in HD. Alternatively, people with HD may show reduced scanning of the eyes because they are less emotionally engaged with other people, in line with the significance of eye-contact in social interactions. <br>     <br>    Taken together, findings from this research project yielded several new insights into how individuals with HD process emotion-related visual stimuli differently than healthy control participants. Some of the effects observed in HD may be related to similar underlying processes, but overall the findings suggest that alterations in emotion processing in HD are nuanced and complex

Efecto de la carga de sulfito de sodio en el pulpaje NSSC de "E. globulus"

This paper presents experimental results on the effect of adding high doses of sodium sulphite (Na2SO3)to replace other sources of alkali, such as Na2CO3 or NaOH, in high-yield Neutral Semichemical Pulping(NSSC) process. Sodium sulfite (Na2SO3) was used as delignification agent in the chemical stage ofeucalyptus globulus pulping. A 12� Bauer refiner was employed in the mechanical stage. Pulp yieldsranged within 70-90% and, results show that physical and mechanical properties increased significantlyas yields decreased. Moreover, the defibration energy consumption and beatings energy also showed asignificant decrease.Those pulps featuring yields near 80%, obtained with high sodium sulfite loads, presented similarphysical and mechanical properties as chemical pulps. At the largest sulfide dose used here, no significantincrease in chemical consumption was observed, especially at high yields. This study shows that physicaland chemical properties are enhanced by high hemicelluloses content, and process selectivity to removelignin from the middle lamella, which leads to a fiber integrity and reduced mechanical stress

Efecto de la carga de sulfito de sodio en el pulpaje NSSC de E. globulus

El presente trabajo tuvo como principal objetivo determinar el efecto de la adición de una alta carga de sulfito de sodio (Na2SO3) para la sustitución de otras fuentes alcalinas (Na2CO3 o NaOH) sobre el pulpaje de alto rendimiento al sulfito neutro. En la etapa química se utilizó sólo sulfito de sodio (Na2SO3) como agente deslignificante y en la etapa mecánica un refinador Bauer de 12". Se obtuvieron pulpas con rendimientos variables entre 70 y 90 % y se verificó que las propiedades físico-mecánicas de las pulpas aumentan considerablemente a medida que el rendimiento baja. Al mismo tiempo disminuyeron, notablemente, el consumo energético de desfibración y el de refinación. Pulpas con rendimientos cercanos al 80%, fabricada con una alta dosis de sulfito de sodio presentaron propiedades físico-mecánicas similares a una pulpa química. La mayor carga de sulfito no significó un aumento considerable del consumo de reactivos, especialmente a altos rendimientos. El buen desarrollo de propiedades físico-mecánicas se debe, probablemente, a la alta proporción de hemicelulosas que presenta la pulpa y a la selectividad del proceso para remover lignina desde la lámina media, lo que favorece la obtención de fibras íntegras y con un menor esfuerzo mecánico