Network level characteristics in the emotion recognition network after unilateral temporal lobe surgery

Neural compensation in manifest neurodegeneration: systems neuroscience evidence from social cognition in frontotemporal dementia

BACKGROUND

It has been argued that symptom onset in neurodegeneration reflects the overload of compensatory mechanisms. The present study aimed to investigate whether neural functional compensation can be observed in the manifest neurodegenerative disease stage, by focusing on a core deficit in frontotemporal dementia, i.e. social cognition, and by combining psychophysical assessment, structural MRI and functional MRI with multidimensional neural markers that allow quantification of neural computations.

METHODS

Nineteen patients with clinically manifest behavioral variant frontotemporal dementia (bvFTD) and 20 controls performed facial expression recognition tasks in the MRI-scanner and offline. Group differences in grey matter volume, neural response amplitude and neural patterns were assessed via a combination of voxel-wise whole-brain, searchlight, and ROI-analyses and these measures were correlated with psychophysical measures of emotion, valence and arousal ratings.

RESULTS

Significant group effects were observed only outside task-relevant regions, converging in the caudate nucleus. This area showed a diagnostic neural pattern as well as hyperactivation and stronger neural representation of facial expressions in the bvFTD sample. Furthermore, response amplitude was associated with behavioral arousal ratings.

CONCLUSIONS

The combined findings reveal converging support for compensatory processes in clinically manifest neurodegeneration, complementing accounts that clinical onset synchronizes with the breakdown of compensatory processes. Furthermore, active compensation may proceed along nodes in intrinsically connected networks, rather than along the more task-specific networks. The findings underscore the potential of distributed multidimensional functional neural characteristics that may provide a novel class of biomarkers with both diagnostic and therapeutic implications, including biomarkers for clinical trials.

Multidimensional Feature in Emotion Recognition Based on Multi-Channel EEG Signals

As a major daily task for the popularization of artificial intelligence technology, more and more attention has been paid to the scientific research of mental state electroencephalogram (EEG) in recent years. To retain the spatial information of EEG signals and fully mine the EEG timing-related information, this paper proposes a novel EEG emotion recognition method. First, to obtain the frequency, spatial, and temporal information of multichannel EEG signals more comprehensively, we choose the multidimensional feature structure as the input of the artificial neural network. Then, a neural network model based on depthwise separable convolution is proposed, extracting the input structure's frequency and spatial features. The network can effectively reduce the computational parameters. Finally, we modeled using the ordered neuronal long short-term memory (ON-LSTM) network, which can automatically learn hierarchical information to extract deep emotional features hidden in EEG time series. The experimental results show that the proposed model can reasonably learn the correlation and temporal dimension information content between EEG multi-channel and improve emotion classification performance. We performed the experimental validation of this paper in two publicly available EEG emotional datasets. In the experiments on the DEAP dataset (a dataset for emotion analysis using EEG, physiological, and video signals), the mean accuracy of emotion recognition for arousal and valence is 95.02% and 94.61%, respectively. In the experiments on the SEED dataset (a dataset collection for various purposes using EEG signals), the average accuracy of emotion recognition is 95.49%.

The neurobiological basis of affect is consistent with psychological construction theory and shares a common neural basis across emotional categories

Affective experience colours everyday perception and cognition, yet its fundamental and neurobiological basis is poorly understood. The current debate essentially centers around the communalities and specificities across individuals, events, and emotional categories like anger, sadness, and happiness. Using fMRI during the experience of these emotions, we critically compare the two dominant conflicting theories on human affect. Basic emotion theory posits emotions as discrete universal entities generated by dedicated emotion category-specific neural circuits, while psychological construction theory claims emotional events as unique, idiosyncratic, and constructed by psychological primitives like core affect and conceptualization, which underlie each emotional event and operate in a predictive framework. Based on the findings of 8 a priori-defined model-specific prediction tests on the neural response amplitudes and patterns, we conclude that the neurobiological basis of affect is primarily characterized by idiosyncratic mechanisms and a common neural basis shared across emotion categories, consistent with psychological construction theory. The findings provide further insight into the organizational principles of the neural basis of affect and brain function in general. Future studies in clinical populations with affective symptoms may reveal the corresponding underlying neural changes from a psychological construction perspective.

Toward social neuropsychology of epilepsy: a meta-analysis on social cognition in epilepsy phenotypes and a critical narrative review on assessment methods

Background

The aim of this review is to (a) characterize social cognition impairments in the domains of emotion recognition (ER) and theory of mind (ToM) in patients with epilepsy and (b) to review assessment tools with a focus on their validity and usability in clinical practice.

Methods

An electronic search for clinical studies investigating social cognition in epilepsy populations vs healthy control subjects (HC) yielded 53 studies for the meta-analysis and descriptive review.

Results

Results suggest that (1) social cognition is significantly impaired in patients with temporal lobe epilepsy (TLE), frontal lobe epilepsy (FLE) and patients with epilepsy not originating within the temporal or frontal lobes including idiopathic generalized epilepsies (eTLE/eFLE); (2) there is no significant difference between eTLE/eFLE and TLE regarding ER, while TLE and FLE patients perform worse than those with eTLE/eFLE, without significant differences between FLE and TLE regarding ToM ability. A descriptive analysis of the most commonly used assessment tools and stimulus material in this field revealed a lack of ecological validity, usability, and economic viability for everyday clinical practice.

Conclusions

Our meta-analysis shows that patients with epilepsy are at a significantly increased risk of deficits in social cognition. However, the underlying multifactorial mechanisms remain unclear. Future research should therefore specifically address the impairment of processing and methodological problems of testing.

Right medial temporal lobe structures particularly impact early stages of affective picture processing

Human vision prioritizes emotional stimuli. This is reflected in stronger electrocortical activation in response to emotional than neutral stimuli, measurable on the surface of the head. Feedback projections from brain structures deep within the medial temporal lobes (mTLs), in particular the amygdala, are thought to give rise to this phenomenon, although causal evidence is rare. Given the many pathways involved in visual processing, the influence of mTL structures could be restricted to specific time windows. Therefore, we delineate the temporal dynamics of the impact of right mTL structures on affective picture processing, investigating event-related potentials (ERPs) in 19 patients (10 female) with right mTL resections and 19 individually matched healthy participants, while they viewed negative and neutral scenes. Groups differed significantly at early- and mid-latency processing stages. Patients with right mTL resection, unlike controls, showed no (P1: 90-140 ms) or marginal (N1: 170-220 ms) emotion modulation. At mid-latency (early posterior negativity: 220-370 ms), emotion modulation over the ipsi-resectional right hemisphere was smaller in patients than in controls, but groups did not differ over the left hemisphere. During late parietal positivities (400-650 ms and 650-900 ms), both groups had similar emotion modulation. Our results demonstrate that right mTL structures attenuate particularly early processing of affectively negative scenes. This is theoretically consistent with an initial amygdala-dependent feedforward sweep in visual emotion processing whose absence is successively compensated. Findings specify the impact of right mTL structures on emotional picture processing and highlight the value of time-resolved measures in affective neuroscience.

Acquired Prosopagnosia with Structurally Intact and Functional Fusiform Face Area and with Face Identity-Specific Configuration Processing Deficits

Prosopagnosia or loss of face perception and recognition is still poorly understood and rare single cases of acquired prosopagnosia can provide a unique window on the behavioural and brain basis of normal face perception. The present study of a new case of acquired prosopagnosia with bilateral occipito-temporal lesions but a structurally intact FFA and OFA investigated whether the lesion overlapped with the face network and whether the structurally intact FFA showed a face selective response. We also investigated the behavioral correlates of the neural findings and assessed configural processing in the context of facial and non-facial identity recognition, expression recognition and memory, also focusing on the face-selectivity of each specific deficit. The findings reveal a face-selective response in the FFA, despite lesions in the face perception network. At the behavioural level, the results showed impaired configural processing for facial identity, but not for other stimulus categories and not for facial expression recognition. These findings challenge a critical role of the FFA for face identity processing and support a domain-specific account of configural processing.

Degeneracy in the nervous system: from neuronal excitability to neural coding

Degeneracy is ubiquitous across biological systems where structurally different elements can yield a similar outcome. Degeneracy is of particular interest in neuroscience too. On the one hand, degeneracy confers robustness to the nervous system and facilitates evolvability: Different elements provide a backup plan for the system in response to any perturbation or disturbance. On the other, a difficulty in the treatment of some neurological disorders such as chronic pain is explained in light of different elements all of which contribute to the pathological behavior of the system. Under these circumstances, targeting a specific element is ineffective because other elements can compensate for this modulation. Understanding degeneracy in the physiological context explains its beneficial role in the robustness of neural circuits. Likewise, understanding degeneracy in the pathological context opens new avenues of discovery to find more effective therapies.

Emotion recognition and theory of mind after temporal lobe epilepsy surgery: A systematic review

In order to navigate in our complex social world successfully, it is crucial to maintain and practice cognitive skills that are dedicated to adaptive social functioning. Emerging evidence suggests that besides deficits in declarative memory, executive functions, and language, impairments in social cognition (SC, e.g., emotion recognition, theory of mind) are also present in temporal lobe epilepsy (TLE). The organic and psycho-social consequences of epilepsy surgery might have additional implications regarding this deficit. Here we qualitatively synthesize longitudinal and cross-sectional findings on SC after TLE surgery. A literature search using PubMed and Scopus identified 275 potential articles. Studies were eligible if they (1) included patients with a diagnosis of TLE, (2) included a healthy comparison group, (3) reported original research, (4) were published in peer-reviewed journals and in English language, (5) reported the intervention of epilepsy surgery. Articles that (1) were case studies, (2) did not focus on SC abilities, (3) used interviews or self-report questionnaires to examine SC functions were excluded. A total of 16 original studies assessing emotion recognition (ER) and/or theory of mind (ToM) matched our criteria. The literature suggests that neither ER nor ToM abilities change after surgery: post-surgery patients show similar impairment patterns to pre-surgery patients. Nevertheless, individual improvement or decline could be masked by group comparisons and results should be considered in light of methodological heterogeneity among studies.

Effects of hyperventilation with face mask on brain network in patients with epilepsy

OBJECTIVES

During the ongoing pandemic of COVID-19, wearing face masks was recommended, including patients with epilepsy doing the hyperventilation (HV) test during electroencephalogram (EEG) examination somewhere. However, evidence was still limited about the effect of HV with face mask on cortical excitability of patients with epilepsy. The motivation of this work is to make use of the graph theory of EEG to characterize the cortical excitability of patients with epilepsy when they did HV under the condition wearing a surgical face mask.

METHODS

We recruited 19 patients with epilepsy and 17 normal controls. All of participants completed two HV experiments, including HV with face mask (HV+) and HV without a mask (HV). The interval was 30 min and the sequence was random. Each experiment consisted of three segments: resting EEG, EEG of HV, and EEG of post-HV. EEG were recorded successively during each experiment. Participants were asked to evaluate the discomfort degree using a questionnaire when every HV is completed.

RESULTS

All of the participants felt more uncomfortable after HV + . Moreover, not only HV decreased small-worldness index in patients with epilepsy, but also HV + significantly increased the clustering coefficient in patients with epilepsy. Importantly, the three-way of Mask*HV*Epilepsy showed interaction in the clustering coefficient in the delta band, as well as in the path length and the small-worldness index in the theta band.

CONCLUSIONS

The results of this study indicated that patients with epilepsy showed the increased excitability of brain network during HV + . We should pay more attention to the adverse effect on brain network excitability caused by HV + in patients with epilepsy. In the clinical practice under the COVID-19 pandemic, it is important that the wearing face mask remain cautious for the individuals with epilepsy when they carried out HV behavior such as exercise (e.g., running, etc.).

Preserving Right Pre-motor and Posterior Prefrontal Cortices Contribute to Maintaining Overall Basic Emotion

Basic emotions such as happiness, sadness, and anger are universal, regardless of the human species, and are governed by specific brain regions. A recent report revealed that mentalizing, which is the ability to estimate other individuals’ emotional states via facial expressions, can be preserved with the help of awake surgery. However, it is still questionable whether we can maintain the ability to understand others’ emotions by preserving the positive mapping sites of intraoperative assessment. Here, we demonstrated the cortical regions related to basic emotions via awake surgery for patients with frontal glioma and investigated the usefulness of functional mapping in preserving basic emotion. Of the 56 consecutive patients with right cerebral hemispheric glioma who underwent awake surgery at our hospital, intraoperative assessment of basic emotion could be successfully performed in 22 patients with frontal glioma and were included in our study. During surgery, positive responses were found in 18 points in 12 patients (54.5%). Of these, 15 points from 11 patients were found at the cortical level, mainly the premotor and posterior part of the prefrontal cortices. Then, we focused on cortical 15 positive mappings with 40 stimulations and investigated the types of emotions that showed errors by every stimulation. There was no specific rule for the region-emotional type, which was beyond our expectations. In the postoperative acute phase, the test score of basic emotion declined in nine patients, and of these, it decreased under the cut-off value (Z-score ≤ −1.65) in three patients. Although the total score declined significantly just after surgery (p = 0.022), it recovered within 3 months postoperatively. Our study revealed that through direct electrical stimulation (DES), the premotor and posterior parts of the prefrontal cortices are related to various kinds of basic emotion, but not a single one. When the region with a positive mapping site is preserved during operation, basic emotion function might be maintained although it declines transiently after surgery.