A Multisensory Deficit in the Perception of Pleasantness in Parkinson’s Disease

Background: There is growing interest in non-motor symptoms in Parkinson’s disease (PD), due to the impact on quality of life. Anhedonia, the inability to experience joy and lust, has a prevalence of up to 46% in PD. The perception of pleasantness of an odor is reduced in anhedonia without PD. We previously showed a reduced hedonic olfactory perception in PD, i.e., patients evaluated odors as less pleasant or unpleasant compared to controls. This deficit correlated with anhedonia. Objective: We aimed to confirm these findings. Moreover, we hypothesized that the perception of pleasantness in PD is affected on a multisensory level and correlates with anhedonia. Therefore, we assessed olfactory, visual and acoustic evaluation of pleasantness in PD and healthy individuals. Methods: Participants had to rate the pleasantness of 22 odors, pictures, and sounds on a nine-point Likert scale. Depression, anhedonia, and apathy were assessed by means of questionnaires. Results of the pleasantness-rating were compared between groups and correlated to scores of the questionnaires. Results: In particular pleasant and unpleasant stimuli across all three modalities are perceived less intense in PD, suggesting that a reduced range of perception of pleasantness is a multisensory phenomenon. However, only a reduction of visual hedonic perception correlated with anhedonia in PD. A correlation of reduced perception of pleasantness with apathy or depression was not present. Conclusion: We provide evidence for a multisensory deficit in the perception of pleasantness. Further studies should delineate the underlying neural circuity and the diagnostic value to detect neuropsychiatric symptoms in PD.

Reactivity of Judgments of Learning in a Levels-of-Processing Paradigm

Recent studies have shown that judgments of learning (JOLs) are reactive measures in paired-associate learning paradigms. However, evidence is scarce concerning whether JOLs are reactive in other paradigms. In old/new recognition experiments, we investigated the reactivity effects of JOLs in a levels-of-processing (LOP) paradigm. In Experiments 1 and 2, for each word, subjects saw a yes/no orienting question followed by the target word and a response. Then, they either did or did not make a JOL. The yes/no questions were about target words’ appearances, rhyming properties, or category memberships. In Experiment 3, for each word, subjects gave a pleasantness rating or counted the letter “e ”. Our results revealed that JOLs enhanced recognition across all orienting tasks in Experiments 1 and 2, and for the e-counting task in Experiment 3. This reactive effect was salient for shallow tasks, attenuating – but not eliminating – the LOP effect after making JOLs. We conclude that JOLs are reactive in LOP paradigms and subjects encode words more effectively when providing JOLs.

Reproducibility of a food menu to measure energy and macronutrient intakes in a laboratory and under real-life conditions

Given the limitations associated with the measurement of food intake, we aimed to determine the reliability of a food menu to measure energy intake (EI) and macronutrient intake within the laboratory and under free-living conditions. A total of eight men and eight women (age 25·74 (sd5·9) years, BMI 23·7 (sd2·7) kg/m2) completed three identical in-laboratory sessions (ILS) and three out-of-laboratory sessions (OLS). During the ILS, participants hadad libitumaccess to a variety of foods, which they chose from a menu every hour, for 5 h. For the OLS, the foods were chosen from the menu at the start of the day and packed into containers to bring home. There were no significant differences in total EI (6118·6 (sd2691·2), 6678·8 (sd2371·3), 6489·5 (sd2742·9) kJ; NS) between the three ILS and three OLS (6816·0 (sd2713·2), 6553·5 (sd2364·5), 6456·4 (sd3066·8) kJ; NS). Significant intraclass correlations (ICC) for total energy (r0·77,P < 0·0001), carbohydrate (r0·81,P < 0·0001), dietary fat (r0·54,P < 0·0001) and protein (r0·81,P < 0·0001) intakes for the ILS and significant ICC for total energy (r0·85,P < 0·0001), carbohydrate (0·85,P < 0·0001), dietary fat (0·72P < 0·0001) and protein (0·80,P < 0·0001) intakes for the OLS were noted. The average within-subject CV for total EI was 18·3 (sd10·0) and 16·1 (sd10·3) % for the ILS and OLS, respectively, with a pleasantness rating for foods consumed of 124 (sd14) mm out of 150 mm (83 %). Overall, the food menu produces a relatively reliable measure of EI inside and outside the laboratory. The results also underscore the difficulties in capturing a representative image of food intake given the relatively high day-to-day variation in the amount and composition of foods consumed.

Form Pleasantness: Arousal Processing or Arousal Pick-up?

In what way is physiological arousal implicated in form pleasantness? Does form pleasantness necessarily imply cognitive processing of the arousal response to the visual stimuli? Or can the physiological arousal response also have a direct effect on it? This problem has scientific relevance since it contributes to the settlement of two debates of a similar nature: one between two rival theories of perception and one between two rival theories of emotion. The two theories of perception are the indirect information-processing one as stated by Fodor and Pylyshyn in 1981 versus the direct information pick-up viewpoint as stated by Turvey, Shaw, Reed, and Mace in 1981. The two theories of emotion are the indirect cognition-arousal theory which begins with Schachter in 1964 versus the view that emotions can be the direct result of purely somatic arousal and emotion patterns as stated both by Zajonc and Leventhal in 1984. This is explained in the first part of the article. The second part describes an experiment on the conflicting consequences of these two approaches (the indirect, cognitive and the direct sensory-motor). An inverted U-shaped relation between the arousal potential of visual stimuli and the pleasantness rating of those stimuli is usually found. If the supporters of the direct theories are right, this will always be so however much one tries to manipulate arousal processing. If, on the other hand the cognitivists are right, it would be indeed possible to manipulate the curve. This can be done, for example, by giving the subject bogus feedback relating to his physiological arousal in response to the visual stimuli, under well controlled conditions. This is a much used procedure in the cognitive-arousal theory of emotion. According to the results of the present experiment, this manipulation does not affect the inverted U-shaped relation between the arousal potential of visual stimuli and their pleasantness rating. A direct effect of physiological arousal on form pleasantness appears plausible.