Electroencephalographic Abnormalities in a Patient Suffering from Long-Term Neuropsychological Complications following SARS-CoV-2 Infection.

Introduction: Emotional apathy has recently been identified as a common symptom of long COVID. While recent meta-analyses have demonstrated generalized EEG slowing with the emergence of delta rhythms in patients hospitalized for severe SARS-CoV-2 infection, no EEG study or dopamine transporter scintigraphy (DaTSCAN) has been performed in patients with long COVID presenting with apathy. The objective of this case report was to explore the pathophysiology of neuropsychological symptoms in long COVID. Case Presentation: A 47-year-old patient who developed a long COVID with prominent apathy following an initially clinically mild SARS-CoV-2 infection underwent neuropsychological assessment, cerebral MRI, DaTSCAN, and resting-state high-density EEG 7 months after SARS-CoV-2 infection. The EEG data were compared to those of 21 healthy participants. The patient presented with apathy, cognitive difficulties with dysexecutive syndrome, moderate attentional and verbal episodic memory disturbances, and resolution of premorbid mild gaming disorder, mild mood disturbances, and sleep disturbances. His MRI and DaTSCAN were unremarkable. EEG revealed a complex pattern of oscillatory abnormalities compared to the control group, with a strong increase in whole-scalp delta and beta band activity, as well as a decrease in alpha band activity. Overall, these effects were more prominent in the frontal-central-temporal region. Conclusion: These results suggest widespread changes in EEG oscillatory patterns in a patient with long COVID characterized by neuropsychological complications with prominent apathy. Despite the inherent limitations of a case report, these results suggest dysfunction in the cortical networks involved in motivation and emotion.

Preterm infants show an atypical processing of the mother's voice.

To understand the consequences of prematurity on language perception, it is fundamental to determine how atypical early sensory experience affects brain development. At term equivalent age, ten preterm and ten full-term newborns underwent high-density EEG during mother or stranger speech presentation, in the forward or backward order. A general group effect terms > preterms is evident in the theta frequency band, in the left temporal area, with preterms showing significant activation for strangers' and terms for the mother's voice. A significant group contrast in the low and high theta in the right temporal regions indicates higher activations for the stranger's voice in preterms. Finally, only full terms presented a late gamma band increase for the maternal voice, indicating a more mature brain response. EEG time-frequency analysis demonstrate that preterm infants are selectively responsive to stranger voices in both temporal hemispheres, and that they lack selective brain responses to their mother's forward voice.

Crossed functional specialization between the basal ganglia and cerebellum during vocal emotion decoding: Insights from stroke and Parkinson's disease.

There is growing evidence that both the basal ganglia and the cerebellum play functional roles in emotion processing, either directly or indirectly, through their connections with cortical and subcortical structures. However, the lateralization of this complex processing in emotion recognition remains unclear. To address this issue, we investigated emotional prosody recognition in individuals with Parkinson's disease (model of basal ganglia dysfunction) or cerebellar stroke patients, as well as in matched healthy controls (n = 24 in each group). We analysed performances according to the lateralization of the predominant brain degeneration/lesion. Results showed that a right (basal ganglia and cerebellar) hemispheric dysfunction was likely to induce greater deficits than a left one. Moreover, deficits following left hemispheric dysfunction were only observed in cerebellar stroke patients, and these deficits resembled those observed after degeneration of the right basal ganglia. Additional analyses taking disease duration / time since stroke into consideration revealed a worsening of performances in patients with predominantly right-sided lesions over time. These results point to the differential, but complementary, involvement of the cerebellum and basal ganglia in emotional prosody decoding, with a probable hemispheric specialization according to the level of cognitive integration.

Sensory contribution to vocal emotion deficit in patients with cerebellar stroke.

In recent years, there has been increasing evidence of cerebellar involvement in emotion processing. Difficulties in the recognition of emotion from voices (i.e., emotional prosody) have been observed following cerebellar stroke. However, the interplay between sensory and higher-order cognitive dysfunction in these deficits, as well as possible hemispheric specialization for emotional prosody processing, has yet to be elucidated. We investigated the emotional prosody recognition performances of patients with right versus left cerebellar lesions, as well as of matched controls, entering the acoustic features of the stimuli in our statistical model. We also explored the cerebellar lesion-behavior relationship, using voxel-based lesion-symptom mapping. Results revealed impairment of vocal emotion recognition in both patient subgroups, particularly for neutral or negative prosody, with a higher number of misattributions in patients with right-hemispheric stroke. Voxel-based lesion-symptom mapping showed that some emotional misattributions correlated with lesions in the right Lobules VIIb and VIII and right Crus I and II. Furthermore, a significant proportion of the variance in this misattribution was explained by acoustic features such as pitch, loudness, and spectral aspects. These results point to bilateral posterior cerebellar involvement in both the sensory and cognitive processing of emotions.

Subthalamic nucleus oscillations during vocal emotion processing are dependent of the motor asymmetry of Parkinson's disease.

The subthalamic nucleus (STN) is involved in different aspects of emotional processes and more specifically in emotional prosody recognition. Recent studies on the behavioral effects of deep brain stimulation (DBS) in patients with Parkinson's disease (PD) have uncovered an asymmetry in vocal emotion decoding in PD, with left-onset PD patients showing deficits for the processing of happy voices. Whether and how PD asymmetry affects STN electrophysiological responses to emotional prosody, however, remains unknown. In the current study, local field potential activity was recorded from eight left- and six right-lateralized motor-onset PD patients (LOPD/ROPD) undergoing DBS electrodes implantation, while they listened to angry, happy and neutral voices. Time-frequency decomposition revealed that theta (2-6 Hz), alpha (6-12 Hz) and gamma (60-150 Hz) band responses to emotion were mostly bilateral with a differential pattern of response according to patient's sides-of onset. Conversely, beta-band (12-20 Hz and 20-30 Hz) emotional responses were mostly lateralized in the left STN for both patient groups. Furthermore, STN theta, alpha and gamma band responses to happiness were either absent (theta band) or reduced (alpha and gamma band) in the most affected STN hemisphere (contralateral to the side-of onset), while a late low-beta band left STN happiness-specific response was present in ROPD patients and did not occur in LOPD patients. Altogether, in this study, we demonstrate a complex pattern of oscillatory activity in the human STN in response to emotional voices and reveal a crucial influence of disease laterality on STN low-frequency oscillatory activity.

Dyskinesia-inducing lead contacts optimize outcome of subthalamic stimulation in Parkinson's disease.

BACKGROUND: Acute dyskinesias elicited by STN-DBS, here referred to as stimulation-induced dyskinesias, predict optimal clinical outcome in PD. However, it remains elusive whether stimulation-induced dyskinesias can guide DBS programming. OBJECTIVES: Here, we characterized stimulation-induced dyskinesias clinically and anatomically. We then tested whether dyskinesia-inducing contacts could be effectively programmed using independent current source technology. METHODS: We characterized stimulation-induced dyskinesias with directional and ring stimulation retrospectively in 20 patients. We then localized dyskinesia-inducing contacts by imaging coregistration and eventually programmed those contacts. RESULTS: We elicited dyskinesias in half of our patients. Dyskinesia-inducing contacts were mainly directional and were all located ventrally within the dorsolateral motor STN. When these dyskinesia-inducing contacts were programmed using independent current source technology, dyskinesia disappeared and robust antibradykinetic effects were obtained. CONCLUSION: We confirm that stimulation-induced dyskinesias are helpful clinical observations, which may guide programming of directional STN-DBS in PD. © 2019 International Parkinson and Movement Disorder Society.

Cerebellar contribution to vocal emotion decoding: Insights from stroke and neuroimaging.

While the role of the cerebellum in emotion recognition has been explored with facial expressions, its involvement in the auditory modality (i.e., emotional prosody) remains to be demonstrated. The present study investigated the recognition of emotional prosody in 15 patients with chronic cerebellar ischaemic stroke and 15 matched healthy controls, using a validated task, as well as clinical, motor, neuropsychological, and psychiatric assessments. We explored the cerebellar lesion-behaviour relationship using voxel-based lesion-symptom mapping. Results showed a significant difference between the stroke and healthy control groups, with patients giving erroneous ratings on the Surprise scale when they listened to fearful stimuli. Moreover, voxel-based lesion-symptom mapping revealed that these emotional misattributions correlated with lesions in right Lobules VIIb, VIIIa,b and IX. Interestingly, the posterior cerebellum has previously been found to be involved in affective processing, and Lobule VIIb in rhythm discrimination. These results point to the cerebellum's functional involvement in vocal emotion decoding.

Direct Recordings from Human Anterior Insula Reveal its Leading Role within the Error-Monitoring Network.

The ability to monitor our own errors is mediated by a network that includes dorsomedial prefrontal cortex (dmPFC) and anterior insula (AI). However, the dynamics of the underlying neurophysiological processes remain unclear. In particular, whether AI is on the receiving or driving end of the error-monitoring network is unresolved. Here, we recorded intracerebral electroencephalography signals simultaneously from AI and dmPFC in epileptic patients while they performed a stop-signal task. We found that errors selectively modulated broadband neural activity in human AI. Granger causality estimates revealed that errors were immediately followed by a feedforward influence from AI onto anterior cingulate cortex and, subsequently, onto presupplementary motor area. The reverse pattern of information flow was observed on correct responses. Our findings provide the first direct electrophysiological evidence indicating that the anterior insula rapidly detects and conveys error signals to dmPFC, while the latter might use this input to adapt behavior following inappropriate actions.

Response inhibition rapidly increases single-neuron responses in the subthalamic nucleus of patients with Parkinson's disease.

The subthalamic nucleus (STN) plays a critical role during action inhibition, perhaps by acting like a fast brake on the motor system when inappropriate responses have to be rapidly suppressed. However, the mechanisms involving the STN during motor inhibition are still unclear, particularly because of a relative lack of single-cell responses reported in this structure in humans. In this study, we used extracellular microelectrode recordings during deep brain stimulation surgery in patients with Parkinson's disease (PD) to study STN neurophysiological correlates of inhibitory control during a stop signal task. We found two neuronal subpopulations responding either during motor execution (GO units) or during motor inhibition (STOP units). GO units fired selectively before patients' motor responses whereas STOP units fired selectively when patients successfully withheld their move at a latency preceding the duration of the inhibition process. These results provide electrophysiological evidence for the hypothesized role of the STN in current models of response inhibition.

Subthalamic nucleus activity dissociates proactive and reactive inhibition in patients with Parkinson's disease.

Models of action selection postulate the critical involvement of the subthalamic nucleus (STN), especially in reactive inhibition processes when inappropriate responses to a sudden stimulus must be overridden. The STN could also play a key role during proactive inhibition, when subjects prepare to potentially suppress their actions. Here, we hypothesized that STN responses to reactive and proactive inhibitory control might be driven by different underlying mechanisms with specific temporal profiles. Direct neural recordings in twelve Parkinson's disease patients during a modified stop signal task (SST) revealed a decrease of beta band activity (ßA, 13-35Hz) in the STN during reactive inhibition of smaller amplitude and shorter duration than during motor execution. Crucially, the onset latency of this relative increase of ßA took place before the stop signal reaction time. It could thus be thought of as a "stop" signal inhibiting thalamo-cortical activity that would have supported motor execution. Finally, results also revealed a higher level of ßA in the STN during proactive inhibition, which correlated with patient's inhibitory performances. We propose that ßA in the STN would here participate in the implementation of a "hold your horse" signal to delay motor responses, thus prioritizing accuracy as compared to speed. In brief, our results provide strong electrophysiological support for the hypothesized role of the STN during executive control underlying proactive and reactive response suppression.

Temporal components in the parahippocampal place area revealed by human intracerebral recordings.

Many high-level visual regions exhibit complex patterns of stimulus selectivity that make their responses difficult to explain in terms of a single cognitive mechanism. For example, the parahippocampal place area (PPA) responds maximally to environmental scenes during fMRI studies but also responds strongly to nonscene landmark objects, such as buildings, which have a quite different geometric structure. We hypothesized that PPA responses to scenes and buildings might be driven by different underlying mechanisms with different temporal profiles. To test this, we examined broadband γ (50-150 Hz) responses from human intracerebral electroencephalography recordings, a measure that is closely related to population spiking activity. We found that the PPA distinguished scene from nonscene stimuli in ∼80 ms, suggesting the operation of a bottom-up process that encodes scene-specific visual or geometric features. In contrast, the differential PPA response to buildings versus nonbuildings occurred later (∼170 ms) and may reflect a delayed processing of spatial or semantic features definable for both scenes and objects, perhaps incorporating signals from other cortical regions. Although the response preferences of high-level visual regions are usually interpreted in terms of the operation of a single cognitive mechanism, these results suggest that a more complex picture emerges when the dynamics of recognition are considered.