Ameliorating Emotional Attention through Modulation of Neural Oscillations with Transcranial Alternating Current Stimulation

AbstractBackgroundNumerous clinical reports suggest that psychopathy like schizophrenia, anxiety and depressive disorder is accompanied by early attentional abnormalities in emotional information processing. In the past decade, the efficacy of transcranial alternating current stimulation (tACS) in changing emotional functioning has been repeatedly observed and has demonstrated a causal relationship between endogenous oscillations and emotional processing. However, tACS effects on emotional attention have not yet been tested.MethodsA total of 53 healthy participants were randomized to 2 groups, and they were subjected to active or sham tACS at individual alpha frequency (IAF) in the bilaterally dorsolateral prefrontal cortex (dlPFC). Participants and received this treatment for 20 min durations daily for 7 consecutive days. On days 1 and 7, electroencephalogram (EEG) recording of 8 minute resting with eyes open and closed. Responses to a facial emotion identification task were also recorded to measure alpha changes and event-related potential (ERP) alterations.ResultsOn day 7 after tACS, the active group showed a more clear elevation in alpha power at rest, especially in open state around stimulation area, compared to the sham group. ERPs revealed a significant larger P200 amplitude after active stimulation (p < 0.05), indicating attentional improvement in facial emotion processing. Additionally, a notable positive correlation (p < 0.05) between alpha power and P200 amplitude was found, providing an electrophysiological interpretation regarding the role of tACS in emotional attention modulation. In addition, the IAF-tACS showed an obvious advantage in alpha entrainment compared to an additional 10 Hz-tACS.ConclusionsThese results support a seminal outcome for the effect of IAF-tACS on emotional attention modulation, demonstrating a feasible and individual-specific therapy for neuropsychiatric disorders related to emotion processing, especially regarding oscillatory disturbances.

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An ERP study on facial emotion processing in young people with subjective memory complaints

Scientific Reports ◽

10.1038/s41598-021-90861-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Vanesa Perez ◽

Ruth Garrido-Chaves ◽

Mario Perez-Alarcón ◽

Tiago O. Paiva ◽

Matias M. Pulopulos ◽

...

Keyword(s):

Young People ◽

Early Stage ◽

Emotion Processing ◽

Affective State ◽

Event Related Potential ◽

Facial Emotion ◽

Subjective Memory Complaints ◽

Subjective Memory ◽

Memory Complaints ◽

Facial Emotion Processing

AbstractSubjective memory complaints (SMCs) are commonly related to aging, but they are also presented by young adults. Their neurophysiological mechanisms are not thoroughly understood, although some aspects related to affective state have been mentioned. Here, we investigated whether facial emotion processing is different in young people with (n = 41) and without (n = 39) SMCs who were exposed to positive, negative, and neutral faces, by recording the event-related potential (ERP) activity. From the ERP activity, the N170 (an index of face processing) and the LPP (an index of motivated attention) components were extracted. Regarding the N170, results showed less amplitude for positive and neutral faces in the participants with SMCs than in those without SMCs. Moreover, women with SMCs displayed longer latencies for neutral faces than women without SMCs. No significant differences were found between the groups in the LPP component. Together, our findings suggest deficits in an early stage of facial emotion processing in young people with SMCs, and they emphasize the importance of further examining affective dimensions.

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Facial Emotion Processing and Language During Middle Childhood: An Event Related Potential Study

10.31234/osf.io/bacz5 ◽

2021 ◽

Author(s):

Felicity J Bigelow ◽

Gillian M Clark ◽

Jarrad Lum ◽

Peter Gregory Enticott

Keyword(s):

Middle Childhood ◽

Cognitive Skills ◽

Social Cognitive ◽

Emotion Processing ◽

Event Related Potentials ◽

Event Related Potential ◽

Facial Emotion ◽

Physiological Indicators ◽

Facial Emotion Processing ◽

Related Potentials

Facial emotion processing (FEP) is critical to social cognitive ability. Developmentally, FEP rapidly improves in early childhood and continues to be fine-tuned throughout middle childhood and into adolescence. Previous research has suggested that language plays a role in the development of social cognitive skills, including non-verbal emotion recognition tasks. Here we investigated whether language is associated with specific neurophysiological indicators of FEP. One hundred and fourteen children (4-12 years) completed a language assessment and a FEP task including stimuli depicting anger, happiness, fear, and neutrality. EEG was used to record key event related potentials (ERPs; P100, N170, LPP at occipital and parietal sites separately) previously shown to be sensitive to faces and facial emotion. While there were no main effects of language, the P100 latency to negative expressions appeared to increase with language, while LPP amplitude increased with language for negative and neutral expressions. These findings suggest that language is linked to some early physiological indicators of FEP, but this is dependent on the facial expression. Future studies should explore the role of language in later stages of neural processing, with a focus on processes localised to ventromedial prefrontal regions.

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Local network-level integration mediates effects of transcranial Alternating Current Stimulation

10.1101/216176 ◽

2017 ◽

Author(s):

Marco Fuscà ◽

Philipp Ruhnau ◽

Toralf Neuling ◽

Nathan Weisz

Keyword(s):

Occipital Cortex ◽

Alternating Current ◽

Functional Network ◽

Local Network ◽

Oscillatory Activity ◽

Alpha Power ◽

State Dependency ◽

External Stimulation ◽

Posterior Cingulate ◽

Transcranial Alternating Current Stimulation

AbstractTranscranial alternating current stimulation (tACS) has been proposed as a tool to draw causal inferences on the role of oscillatory activity in cognitive functioning and has the potential to induce long-term changes in cerebral networks. However, the mechanisms of action of tACS are not yet clear, though previous modeling works have suggested that variability may be mediated by local and network-level brain states. We used magnetoencephalography (MEG) to record brain activity from 17 healthy participants as they kept their eyes open (EO) or closed (EC) while being stimulated either with sham, weak, or strong alpha-tACS using a montage commonly assumed to target occipital areas. We reconstructed the activity of sources in all stimulation conditions by means of beamforming. The analysis of resting-state data revealed an interaction of the external stimulation with the endogenous alpha power difference between EO and EC in the posterior cingulate. This region is remote from occipital cortex, which showed strongest EC vs. EO alpha modulation, thus suggesting state-dependency long-range effects of tACS. In a follow-up analysis of this online-tACS effect, we find evidence that this dependency effect could be mediated by functional network changes: connection strength from the precuneus, a region adjusting for a measure of network integration in the two states (EC vs. EO during no-tACS), was significantly correlated with the state-dependency effect in the posterior cingulate (during tACS). No analogous correlation could be found for alpha power modulations in occipital cortex. Altogether, this is the first strong evidence to illustrate how functional network architectures can shape tACS effects.

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Removal of Gross Artifacts of Transcranial Alternating Current Stimulation in Simultaneous EEG Monitoring

Sensors ◽

10.3390/s19010190 ◽

2019 ◽

Vol 19 (1) ◽

pp. 190 ◽

Cited By ~ 14

Author(s):

Siddharth Kohli ◽

Alexander J. Casson

Keyword(s):

Large Scale ◽

Alternating Current ◽

Event Related Potential ◽

Transcranial Electrical Stimulation ◽

Trade Offs ◽

Multi Stage ◽

Before And After ◽

Transcranial Alternating Current Stimulation ◽

Eeg Recordings ◽

The Time Domain

Transcranial electrical stimulation is a widely used non-invasive brain stimulation approach. To date, EEG has been used to evaluate the effect of transcranial Direct Current Stimulation (tDCS) and transcranial Alternating Current Stimulation (tACS), but most studies have been limited to exploring changes in EEG before and after stimulation due to the presence of stimulation artifacts in the EEG data. This paper presents two different algorithms for removing the gross tACS artifact from simultaneous EEG recordings. These give different trade-offs in removal performance, in the amount of data required, and in their suitability for closed loop systems. Superposition of Moving Averages and Adaptive Filtering techniques are investigated, with significant emphasis on verification. We present head phantom testing results for controlled analysis, together with on-person EEG recordings in the time domain, frequency domain, and Event Related Potential (ERP) domain. The results show that EEG during tACS can be recovered free of large scale stimulation artifacts. Previous studies have not quantified the performance of the tACS artifact removal procedures, instead focusing on the removal of second order artifacts such as respiration related oscillations. We focus on the unresolved challenge of removing the first order stimulation artifact, presented with a new multi-stage validation strategy.

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The functional neuroanatomy of emotion processing in frontotemporal dementias

Brain ◽

10.1093/brain/awz204 ◽

2019 ◽

Vol 142 (9) ◽

pp. 2873-2887 ◽

Cited By ~ 9

Author(s):

Charles R Marshall ◽

Christopher J D Hardy ◽

Lucy L Russell ◽

Rebecca L Bond ◽

Harri Sivasathiaseelan ◽

...

Keyword(s):

Frontotemporal Dementia ◽

Functional Mri ◽

Facial Expressions ◽

Emotion Processing ◽

Primary Progressive Aphasia ◽

Facial Emotion ◽

Healthy Controls ◽

Emotion Identification ◽

Patient Groups ◽

Semantic Variant

Abstract Impaired processing of emotional signals is a core feature of frontotemporal dementia syndromes, but the underlying neural mechanisms have proved challenging to characterize and measure. Progress in this field may depend on detecting functional changes in the working brain, and disentangling components of emotion processing that include sensory decoding, emotion categorization and emotional contagion. We addressed this using functional MRI of naturalistic, dynamic facial emotion processing with concurrent indices of autonomic arousal, in a cohort of patients representing all major frontotemporal dementia syndromes relative to healthy age-matched individuals. Seventeen patients with behavioural variant frontotemporal dementia [four female; mean (standard deviation) age 64.8 (6.8) years], 12 with semantic variant primary progressive aphasia [four female; 66.9 (7.0) years], nine with non-fluent variant primary progressive aphasia [five female; 67.4 (8.1) years] and 22 healthy controls [12 female; 68.6 (6.8) years] passively viewed videos of universal facial expressions during functional MRI acquisition, with simultaneous heart rate and pupillometric recordings; emotion identification accuracy was assessed in a post-scan behavioural task. Relative to healthy controls, patient groups showed significant impairments (analysis of variance models, all P < 0.05) of facial emotion identification (all syndromes) and cardiac (all syndromes) and pupillary (non-fluent variant only) reactivity. Group-level functional neuroanatomical changes were assessed using statistical parametric mapping, thresholded at P < 0.05 after correction for multiple comparisons over the whole brain or within pre-specified regions of interest. In response to viewing facial expressions, all participant groups showed comparable activation of primary visual cortex while patient groups showed differential hypo-activation of fusiform and posterior temporo-occipital junctional cortices. Bi-hemispheric, syndrome-specific activations predicting facial emotion identification performance were identified (behavioural variant, anterior insula and caudate; semantic variant, anterior temporal cortex; non-fluent variant, frontal operculum). The semantic and non-fluent variant groups additionally showed complex profiles of central parasympathetic and sympathetic autonomic involvement that overlapped signatures of emotional visual and categorization processing and extended (in the non-fluent group) to brainstem effector pathways. These findings open a window on the functional cerebral mechanisms underpinning complex socio-emotional phenotypes of frontotemporal dementia, with implications for novel physiological biomarker development.

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A Comparison of Closed Loop vs. Fixed Frequency tACS on Modulating Brain Oscillations and Visual Detection

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2021.661432 ◽

2021 ◽

Vol 15 ◽

Author(s):

Heiko I. Stecher ◽

Annika Notbohm ◽

Florian H. Kasten ◽

Christoph S. Herrmann

Keyword(s):

Closed Loop ◽

Alternating Current ◽

Alpha Activity ◽

Stimulation Frequency ◽

Alpha Power ◽

Brain Oscillations ◽

Stimulation Protocol ◽

Fixed Frequency ◽

Transcranial Alternating Current Stimulation ◽

Synaptic Changes

Transcranial alternating current stimulation has emerged as an effective tool for the exploration of brain oscillations. By applying a weak alternating current between electrodes placed on the scalp matched to the endogenous frequency, tACS enables the specific modulation of targeted brain oscillations This results in alterations in cognitive functions or persistent physiological changes. Most studies that utilize tACS determine a fixed stimulation frequency prior to the stimulation that is kept constant throughout the experiment. Yet it is known that brain rhythms can encounter shifts in their endogenous frequency. This could potentially move the ongoing brain oscillations into a frequency region where it is no longer affected by the stimulation, thereby decreasing or negating the effect of tACS. Such an effect of a mismatch between stimulation frequency and endogenous frequency on the outcome of stimulation has been shown before for the parietal alpha-activity. In this study, we employed an intermittent closed loop stimulation protocol, where the stimulation is divided into short epochs, between which an EEG is recorded and rapidly analyzed to determine a new stimulation frequency for the next stimulation epoch. This stimulation protocol was tested in a three-group study against a classical fixed stimulation protocol and a sham-treatment. We targeted the parietal alpha rhythm and hypothesized that this setup will ensure a constant close match between the frequencies of tACS and alpha activity. This closer match should lead to an increased modulation of detection of visual luminance changes depending on the phase of the tACS and an increased rise in alpha peak power post stimulation when compared to a protocol with fixed pre-determined stimulation frequency. Contrary to our hypothesis, our results show that only a fixed stimulation protocol leads to a persistent increase in post-stimulation alpha power as compared to sham. Furthermore, in none of the stimulated groups significant modulation of detection performance occurred. While the lack of behavioral effects is inconclusive due to the short selection of different phase bins and trials, the physiological results suggest that a constant stimulation with a fixed frequency is actually beneficial, when the goal is to produce persistent synaptic changes.

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