Compensatory premotor activity during affective face processing in subclinical carriers of a single mutant Parkin allele

Patients with Parkinson's disease suffer from significant motor impairments and accompanying cognitive and affective dysfunction due to progressive disturbances of basal ganglia–cortical gating loops. Parkinson's disease has a long presymptomatic stage, which indicates a substantial capacity of the human brain to compensate for dopaminergic nerve degeneration before clinical manifestation of the disease. Neuroimaging studies provide evidence that increased motor-related cortical activity can compensate for progressive dopaminergic nerve degeneration in carriers of a single mutant Parkin or PINK1 gene, who show a mild but significant reduction of dopamine metabolism in the basal ganglia in the complete absence of clinical motor signs. However, it is currently unknown whether similar compensatory mechanisms are effective in non-motor basal ganglia–cortical gating loops. Here, we ask whether asymptomatic Parkin mutation carriers show altered patterns of brain activity during processing of facial gestures, and whether this might compensate for latent facial emotion recognition deficits. Current theories in social neuroscience assume that execution and perception of facial gestures are linked by a special class of visuomotor neurons (‘mirror neurons’) in the ventrolateral premotor cortex/pars opercularis of the inferior frontal gyrus (Brodmann area 44/6). We hypothesized that asymptomatic Parkin mutation carriers would show increased activity in this area during processing of affective facial gestures, replicating the compensatory motor effects that have previously been observed in these individuals. Additionally, Parkin mutation carriers might show altered activity in other basal ganglia–cortical gating loops. Eight asymptomatic heterozygous Parkin mutation carriers and eight matched controls underwent functional magnetic resonance imaging and a subsequent facial emotion recognition task. As predicted, Parkin mutation carriers showed significantly stronger activity in the right ventrolateral premotor cortex during execution and perception of affective facial gestures than healthy controls. Furthermore, Parkin mutation carriers showed a slightly reduced ability to recognize facial emotions that was least severe in individuals who showed the strongest increase of ventrolateral premotor activity. In addition, Parkin mutation carriers showed a significantly weaker than normal increase of activity in the left lateral orbitofrontal cortex (inferior frontal gyrus pars orbitalis, Brodmann area 47), which was unrelated to facial emotion recognition ability. These findings are consistent with the hypothesis that compensatory activity in the ventrolateral premotor cortex during processing of affective facial gestures can reduce impairments in facial emotion recognition in subclinical Parkin mutation carriers. A breakdown of this compensatory mechanism might lead to the impairment of facial expressivity and facial emotion recognition observed in manifest Parkinson's disease

A Perfusion MRI Study of Emotional Valence and Arousal in Parkinson's Disease

Background. Brain regions subserving emotion have mostly been studied using functional magnetic resonance imaging (fMRI) during emotion provocation procedures in healthy participants. Objective. To identify neuroanatomical regions associated with spontaneous changes in emotional state over time. Methods. Self-rated emotional valence and arousal scores, and regional cerebral blood flow (rCBF) measured by perfusion MRI, were measured 4 or 8 times spanning at least 2 weeks in each of 21 subjects with Parkinson's disease (PD). A random-effects SPM analysis, corrected for multiple comparisons, identified significant clusters of contiguous voxels in which rCBF varied with valence or arousal. Results. Emotional valence correlated positively with rCBF in several brain regions, including medial globus pallidus, orbital prefrontal cortex (PFC), and white matter near putamen, thalamus, insula, and medial PFC. Valence correlated negatively with rCBF in striatum, subgenual cingulate cortex, ventrolateral PFC, and precuneus—posterior cingulate cortex (PCC). Arousal correlated positively with rCBF in clusters including claustrum-thalamus-ventral striatum and inferior parietal lobule and correlated negatively in clusters including posterior insula—mediodorsal thalamus and midbrain. Conclusion. This study demonstrates that the temporal stability of perfusion MRI allows within-subject investigations of spontaneous fluctuations in mental state, such as mood, over relatively long-time intervals

On the analysis of EEG power, frequency and asymmetry in Parkinson's disease during emotion processing

Objective: While Parkinson’s disease (PD) has traditionally been described as a movement disorder, there is growing evidence of disruption in emotion information processing associated with the disease. The aim of this study was to investigate whether there are specific electroencephalographic (EEG) characteristics that discriminate PD patients and normal controls during emotion information processing. Method: EEG recordings from 14 scalp sites were collected from 20 PD patients and 30 age-matched normal controls. Multimodal (audio-visual) stimuli were presented to evoke specific targeted emotional states such as happiness, sadness, fear, anger, surprise and disgust. Absolute and relative power, frequency and asymmetry measures derived from spectrally analyzed EEGs were subjected to repeated ANOVA measures for group comparisons as well as to discriminate function analysis to examine their utility as classification indices. In addition, subjective ratings were obtained for the used emotional stimuli. Results: Behaviorally, PD patients showed no impairments in emotion recognition as measured by subjective ratings. Compared with normal controls, PD patients evidenced smaller overall relative delta, theta, alpha and beta power, and at bilateral anterior regions smaller absolute theta, alpha, and beta power and higher mean total spectrum frequency across different emotional states. Inter-hemispheric theta, alpha, and beta power asymmetry index differences were noted, with controls exhibiting greater right than left hemisphere activation. Whereas intra-hemispheric alpha power asymmetry reduction was exhibited in patients bilaterally at all regions. Discriminant analysis correctly classified 95.0% of the patients and controls during emotional stimuli. Conclusion: These distributed spectral powers in different frequency bands might provide meaningful information about emotional processing in PD patients

Effects of Dopamine on Sensitivity to Social Bias in Parkinson's Disease

Patients with Parkinson's disease (PD) sometimes develop impulsive compulsive behaviours (ICBs) due to their dopaminergic medication. We compared 26 impulsive and 27 non-impulsive patients with PD, both on and off medication, on a task that examined emotion bias in decision making. No group differences were detected, but patients on medication were less biased by emotions than patients off medication and the strongest effects were seen in patients with ICBs. PD patients with ICBs on medication also showed more learning from negative feedback and less from positive feedback, whereas off medication they showed the opposite effect

Inter-hemispheric EEG coherence analysis in Parkinson's disease : Assessing brain activity during emotion processing

Parkinson’s disease (PD) is not only characterized by its prominent motor symptoms but also associated with disturbances in cognitive and emotional functioning. The objective of the present study was to investigate the influence of emotion processing on inter-hemispheric electroencephalography (EEG) coherence in PD. Multimodal emotional stimuli (happiness, sadness, fear, anger, surprise, and disgust) were presented to 20 PD patients and 30 age-, education level-, and gender-matched healthy controls (HC) while EEG was recorded. Inter-hemispheric coherence was computed from seven homologous EEG electrode pairs (AF3–AF4, F7–F8, F3–F4, FC5–FC6, T7–T8, P7–P8, and O1–O2) for delta, theta, alpha, beta, and gamma frequency bands. In addition, subjective ratings were obtained for a representative of emotional stimuli. Interhemispherically, PD patients showed significantly lower coherence in theta, alpha, beta, and gamma frequency bands than HC during emotion processing. No significant changes were found in the delta frequency band coherence. We also found that PD patients were more impaired in recognizing negative emotions (sadness, fear, anger, and disgust) than relatively positive emotions (happiness and surprise). Behaviorally, PD patients did not show impairment in emotion recognition as measured by subjective ratings. These findings suggest that PD patients may have an impairment of inter-hemispheric functional connectivity (i.e., a decline in cortical connectivity) during emotion processing. This study may increase the awareness of EEG emotional response studies in clinical practice to uncover potential neurophysiologic abnormalities

Perception of Communicative and Non-communicative Motion-Defined Gestures in Parkinson’s Disease

Objectives: Parkinson’s disease (PD) is associated with deficits in social cognition and visual perception, but little is known about how the disease affects perception of socially complex biological motion, specifically motion-defined communicative and non-communicative gestures. We predicted that individuals with PD would perform more poorly than normal control (NC) participants in discriminating between communicative and non-communicative gestures, and in describing communicative gestures. We related the results to the participants’ gender, as there are gender differences in social cognition in PD. Methods: The study included 23 individuals with PD (10 men) and 24 NC participants (10 men) matched for age and education level. Participants viewed point-light human figures that conveyed communicative and non-communicative gestures and were asked to describe each gesture while discriminating between the two gesture types. Results: PD as a group were less accurate than NC in describing non-communicative but not communicative gestures. Men with PD were impaired in describing and discriminating between communicative as well as non-communicative gestures. Conclusions: The present study demonstrated PD-related impairments in perceiving and inferring the meaning of biological motion gestures. Men with PD may have particular difficulty in understanding the communicative gestures of others in interpersonal exchanges

Impaired perception of biological motion in Parkinson’s disease

OBJECTIVE: We examined biological motion perception in Parkinson’s disease (PD). Biological motion perception is related to one’s own motor function and depends on the integrity of brain areas affected in PD, including posterior superior temporal sulcus. If deficits in biological motion perception exist, they may be specific to perceiving natural/fast walking patterns that individuals with PD can no longer perform, and may correlate with disease-related motor dysfunction. METHOD: Twenty-six nondemented individuals with PD and 24 control participants viewed videos of point-light walkers and scrambled versions that served as foils, and indicated whether each video depicted a human walking. Point-light walkers varied by gait type (natural, parkinsonian) and speed (0.5, 1.0, 1.5 m/s). Participants also completed control tasks (object motion, coherent motion perception), a contrast sensitivity assessment, and a walking assessment. RESULTS: The PD group demonstrated significantly less sensitivity to biological motion than the control group (p < .001, Cohen’s d = 1.22), regardless of stimulus gait type or speed, with a less substantial deficit in object motion perception (p = .02, Cohen’s d = .68). There was no group difference in coherent motion perception. Although individuals with PD had slower walking speed and shorter stride length than control participants, gait parameters did not correlate with biological motion perception. Contrast sensitivity and coherent motion perception also did not correlate with biological motion perception. CONCLUSION: PD leads to a deficit in perceiving biological motion, which is independent of gait dysfunction and low-level vision changes, and may therefore arise from difficulty perceptually integrating form and motion cues in posterior superior temporal sulcus.Published versio

Effects of dance therapy on balance, gait and neuro-psychological performances in patients with Parkinson's disease and postural instability

Postural Instability (PI) is a core feature of Parkinson’s Disease (PD) and a major cause of falls and disabilities. Impairment of executive functions has been called as an aggravating factor on motor performances. Dance therapy has been shown effective for improving gait and has been suggested as an alternative rehabilitative method. To evaluate gait performance, spatial-temporal (S-T) gait parameters and cognitive performances in a cohort of patients with PD and PI modifications in balance after a cycle of dance therapy

Biological motion perception in Parkinson's disease

Parkinson’s disease (PD) disrupts many aspects of visual perception, which has negative functional consequences. How PD affects perception of moving human bodies, or biological motion, is unknown. The ability to accurately perceive others’ motion is related to one’s own motor ability and depends on the integrity of brain areas affected in PD, including superior temporal sulcus and premotor cortex. Biological motion perception may therefore be compromised in PD but also provide a target for intervention, with perceptual training potentially improving motor function. Experiment 1 investigated whether perception of biological motion was impaired in PD (N=26) relative to neurologically-healthy control (NC; N=24) individuals. Participants viewed videos of point-light human figures and judged whether or not they depicted walking. As predicted, PD were less sensitive to biological motion than NC. This deficit was not associated with participants’ own walking difficulties or with other perceptual deficits (contrast sensitivity, coherent motion perception). Experiment 2 evaluated the hypothesis that PD deficits would extend to more socially-complex biological motion. PD (N=23) and NC (N=24) viewed point-light figures depicting communicative and non-communicative (object-oriented) gestures. The PD group was less accurate than NC in describing non-communicative gestures, an effect driven by PD men, who also had difficulty perceiving communicative gestures. Experiment 3 tested the efficacy of perceptual training for PD. Because biological motion perception is associated with motor function, it was hypothesized that perceptual training would improve walking. Individuals with PD were randomized to Gait Observation (N=13; viewing videos of healthy and unhealthy gait) or Landscape Observation (N=10; viewing videos of moving water) and trained daily for one week while gait data were collected with accelerometers. Post-training, only the Gait Observation group self-reported increased mobility, though improvements were not seen in objective gait data (daily activity, walking speed, stride length, stride frequency, leg swing time, gait asymmetry). These studies demonstrate that individuals with PD have difficulty perceiving biological motion (walking and socially-complex gestures). Improving biological motion perception led to enhancement in self-perceived walking ability. Perceptual training that incorporates more explicit learning over a longer time period may be required to effect objective improvements in walking.2018-12-06T00:00:00

Correlati neurali delle alterazioni emotive in pazienti con Parkinson: una meta-analisi

Evidenze in letteratura mostrano la presenza di alterazioni del funzionamento emotivo in pazienti affetti da malattia di Parkinson. É stata quindi effettuata una revisione sistematica della letteratura a riguardo e una meta-analisi (ALE), selezionando studi svolti con fMRI in cui fosse presente un confronto diretto tra le prestazioni di controlli sani e pazienti con Parkinson nel medesimo compito di natura emotiva. I risultati ottenuti dalla meta-analisi mostrano una diminuzione dell'attività dei nuclei della base dell'emisfero sinistro nei pazienti rispetto ai controlli sani. Evidenze presenti in letteratura suggeriscono come alterazioni nell'attivazione dei nuclei della base possono essere legate a disfunzioni non solo di natura motoria, manifeste con il progredire della malattia di Parkinson, anche emotiva.Evidences in literature show the presence of alterations in emotional functioning in patients with Parkinson's disease. It was therefore carried out a systematic review and a meta-analysis (ALE), selecting fMRI studies in which there was a direct comparison between the performance of healthy controls and patients with Parkinson's disease in the same emotional task. The results obtained from the meta-analysis show a decrease in the activity of the basal nuclei of the left hemisphere in patients compared to healthy controls. Evidence in the literature suggests that alterations in the activation of the basal nuclei can be linked not only to motor dysfunction, shown with the progression of Parkinson's disease, also to emotional dysfunction