scholarly journals Dual brain stimulation enhances interpersonal learning through spontaneous movement synchrony

Author(s):  
Yafeng Pan ◽  
Giacomo Novembre ◽  
Bei Song ◽  
Yi Zhu ◽  
Yi Hu

Abstract Social interactive learning denotes the ability to acquire new information from a conspecific—a prerequisite for cultural evolution and survival. As inspired by recent neurophysiological research, here we tested whether social interactive learning can be augmented by exogenously synchronizing oscillatory brain activity across an instructor and a learner engaged in a naturalistic song-learning task. We used a dual brain stimulation protocol entailing the trans-cranial delivery of synchronized electric currents in two individuals simultaneously. When we stimulated inferior frontal brain regions, with 6 Hz alternating currents being in-phase between the instructor and the learner, the dyad exhibited spontaneous and synchronized body movement. Remarkably, this stimulation also led to enhanced learning performance. These effects were both phase- and frequency-specific: 6 Hz anti-phase stimulation or 10 Hz in-phase stimulation, did not yield comparable results. Furthermore, a mediation analysis disclosed that interpersonal movement synchrony acted as a partial mediator of the effect of dual brain stimulation on learning performance, i.e. possibly facilitating the effect of dual brain stimulation on learning. Our results provide a causal demonstration that inter-brain synchronization is a sufficient condition to improve real-time information transfer between pairs of individuals.

2019 ◽  
Author(s):  
Yafeng Pan ◽  
Giacomo Novembre ◽  
Bei Song ◽  
Yi Zhu ◽  
Yi Hu

AbstractSocial interactive learning denotes the ability to acquire new information from a conspecific – a prerequisite for cultural evolution and survival. As inspired by recent neurophysiological research, here we tested whether social interactive learning can be augmented by exogenously synchronizing oscillatory brain activity across an instructor and a learner engaged in a naturalistic song-learning task. We used a dual brain stimulation protocol entailing the trans-cranial delivery of synchronized electric currents in two individuals simultaneously. When we stimulated inferior frontal brain regions, with 6 Hz alternating currents being in-phase between the instructor and the learner, the dyad exhibited spontaneous and synchronized body movement. Remarkably, this stimulation also led to enhanced learning performance. A mediation analysis further disclosed that interpersonal movement synchrony acted as a partial mediator of the effect of dual brain stimulation on learning performance, i.e. possibly facilitating the effect of dual brain stimulation on learning. Our results provide a causal demonstration that inter-brain synchrony is a sufficient condition to improve real-time information transfer between pairs of individuals.SignificanceThe study of social behavior, including but not limited to social learning, is undergoing a paradigm shift moving from single- to multi-person brain research. Yet, nearly all evidence in this area is purely correlational: inter-dependencies between brains’ signals are used to predict success in social behavior. For instance, inter-brain synchrony has been shown to be associated with successful communication, cooperation, and joint attention. Here we took a radically different approach. We stimulated two brains simultaneously, hence manipulating inter-brain synchrony, and measured the resulting effect upon behavior in the context of a social learning task. We report that frequency- and phase-specific dual brain stimulation can lead to the emergence of spontaneous synchronized body movement between an instructor and a learner. Remarkably, this can also augment learning performance.


2021 ◽  
Author(s):  
Julia Pinho ◽  
Vincent T. Cunliffe ◽  
Giovanni Petri ◽  
Rui Oliveira

Group living animals can use social and asocial cues to predict the presence of a reward or a punishment in the environment through associative learning. The degree to which social and asocial learning share the same mechanisms is still a matter of debate, and, so far, studies investigating the neuronal basis of these two types of learning are scarce and have been restricted to primates, including humans, and rodents. Here we have used a Pavlovian fear conditioning paradigm in which a social (fish image) or an asocial (circle image) conditioned stimulus (CS) have been paired with an unconditioned stimulus (US=food), and we have used the expression of the immediate early gene c-fos to map the neural circuits associated with social and asocial learning. Our results show that the learning performance is similar with social (fish image) and asocial (circle image) CSs. However, the brain regions involved in each learning type are distinct. Social learning is associated with an increased expression of c-fos in olfactory bulbs, ventral zone of ventral telencephalic area, ventral habenula and ventromedial thalamus, whereas asocial learning is associated with a decreased expression of c-fos in dorsal habenula and anterior tubercular nucleus. Using egonetworks, we further show that each learning type has an associated pattern of functional connectivity across brain regions. Moreover, a community analysis of the network data reveals four segregated functional submodules, which seem to be associated with different cognitive functions involved in the learning tasks: a generalized attention module, a visual response module, a social stimulus integration module and a learning module. Together, these results suggest that, although there are localized differences in brain activity between social and asocial learning, the two learning types share a common learning module and social learning also recruits a specific social stimulus integration module. Therefore, our results support the occurrence of a common general-purpose learning module, that is differentially modulated by localized activation in social and asocial learning.


2020 ◽  
Author(s):  
Yukitoshi Sakaguchi

Hemispheric brain asymmetries are related to stress coping in both humans and rodents, and imbalanced neural activity between the left and right medial prefrontal cortexes (mPFCs) is observed in depression disorders. Brain stimulation of the PFC is effective to cure depression symptoms. We therefore hypothesized that the imbalanced activity of the mPFCs as well as depression-like behaviors can be induced by chronic stress in rats, and that deep brain stimulation (DBS) can treat such behavior by correcting the asymmetrical activity of the brain regions. Our results indeed show that chronic stress exposure by social isolation (SI) causes depression-like behavior and left/right mPFC activity changes. SI suppressed the activity of both the prelimbic and the infralimbic cortex; however, the extent of the suppression in these regions was oppositely asymmetric. Two weeks of DBS recovered the depression-like behavior and corrected the imbalanced brain activity. In addition, original weight differences between the left and right adrenal glands (AGs) were decreased by SI and recovered by DBS. The integrated index obtained from the mPFCs and AGs asymmetry scores could be useful for estimating the degree of depression. In conclusion, DBS can recover depression-like behavior accompanied by correcting imbalances in both the mPFCs and the AGs.


2019 ◽  
Author(s):  
Gabriel Castrillon ◽  
Nico Sollmann ◽  
Katarzyna Kurcyus ◽  
Adeel Razi ◽  
Sandro M. Krieg ◽  
...  

AbstractNon-invasive brain stimulation reliably modulates brain activity and symptoms of neuropsychiatric disorders. However, stimulation effects substantially vary across individuals and brain regions. We combined transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) to investigate the neuronal basis of inter-individual and inter-areal differences after TMS. We found that stimulating sensory and cognitive areas yielded fundamentally heterogeneous effects. Stimulation of occipital cortex enhanced brain-wide functional connectivity and biophysical modeling identified increased local inhibition and enhanced forward-signaling after TMS. Conversely, frontal stimulation decreased functional connectivity, associated with local disinhibition and disruptions of both feedforward and feedback connections. Finally, we identified brain-wide functional integration as a predictive marker for these heterogeneous stimulation effects in individual subjects. Together, our study suggests that modeling of local and global signaling parameters of a target area will improve the specificity of non-invasive brain stimulation for research and clinical applications.


2020 ◽  
Author(s):  
Brónagh McCoy ◽  
Rebecca P. Lawson ◽  
Jan Theeuwes

ABSTRACTDopamine is known to be involved in several important cognitive processes, most notably in learning from rewards and in the ability to attend to task-relevant aspects of the environment. Both of these features of dopaminergic signalling have been studied separately in research involving Parkinson’s disease (PD) patients, who exhibit diminished levels of dopamine. Here, we tie together some of the commonalities in the effects of dopamine on these aspects of cognition by having PD patients (ON and OFF dopaminergic medication) and healthy controls (HCs) perform two tasks that probe these processes. Within-patient behavioural measures of distractibility, from an attentional capture task, and learning performance, from a probabilistic classification reinforcement learning task, were included in one model to assess the role of distractibility during learning. Dopamine medication state and distractibility level were found to have an interactive effect on learning performance; less distractibility in PD ON was associated with higher accuracy during learning, and this was altered in PD OFF. Functional magnetic resonance imaging (fMRI) data acquired during the learning task furthermore allowed us to assess multivariate patterns of positive and negative outcomes in fronto-striatal and visual brain regions involved in both learning processes and the executive control of attention. Here, we demonstrate that while PD ON show a clearer distinction between outcomes than OFF in dorsolateral prefrontal cortex (DLPFC) and putamen, PD OFF show better distinction of activation patterns in visual regions that respond to the stimuli presented during the task. These results demonstrate that dopamine plays a key role in modulating the interaction between attention and learning at the level of both behaviour and activation patterns in the brain.


Author(s):  
A Vo ◽  
KN Seergobin ◽  
S Jiang ◽  
PA MacDonald

Background: Cognitive impairments are now recognized in Parkinson’s disease. Some of these deficits owe to disease pathology itself whereas others are due to paradoxical effects of dopaminergic medications, such as levodopa. The dopamine overdose hypothesis proposes that dissimilar effects of medication on cognition depend on baseline endogenous dopamine levels in underlying brain regions. We sought to directly test this prevalent theory. Methods: We tested healthy adults, who presumably have optimal endogenous dopamine levels, in two sessions. Participants received 100/25 mg of levodopa/carbidopa in one session and an equal volume of placebo in the other. During each session, participants completed a probabilistic reversal learning task. The number of trials to task completion was used as a behavioural proxy of learning performance. Results: A paired t-test covaried with drug-placebo order revealed that healthy adults learned more poorly on levodopa compared to placebo. Conclusions: Our findings suggest that baseline endogenous dopamine levels are a critical factor determining the effects of dopaminergic medications on cognition, independent of Parkinson’s disease pathology. Partitioning which cognitive functions are helped versus hindered by medication and improving our understanding of the underlying psychopharmacology of these effects is important for improving treatment strategies in Parkinson’s disease.


Author(s):  
Tomáš Paus

This article establishes the concept of a methodological approach to combine brain imaging with brain stimulation. Transcranial magnetic stimulation (TMS) is a tool that allows perturbing neural activity, in time and space, in a noninvasive manner. This approach allows the study of the brain-behaviour relationship. Under certain circumstances, the influence of one region on other, called the effective connectivity, can be measured. Functional connectivity is the extent of correlation in brain activity measured across a number of spatially distinct brain regions. This tool of connectivity can be applied to any dataset acquired with brain-mapping tools. However, its interpretation is complex. Also, the technical complexity of the combined studies needs to be resolved. Future studies may benefit from focusing on neurochemical transmission in specific neural circuits and on temporal dynamics of cortico-cortical interactions.


2019 ◽  
Vol 30 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Mario Rosero Pahi ◽  
Juliana Cavalli ◽  
Frauke Nees ◽  
Herta Flor ◽  
Jamila Andoh

Abstract Many studies have shown that the dorsolateral prefrontal cortex (DLPFC) plays an important role in top-down cognitive control over intentional and deliberate behavior. However, recent studies have reported that DLPFC-mediated top-down control interferes with implicit forms of learning. Here we used continuous theta-burst stimulation (cTBS) combined with electroencephalography to investigate the causal role of DLPFC in implicit contextual memory-guided attention. We aimed to test whether transient disruption of the DLPFC would interfere with implicit learning performance and related electrical brain activity. We applied neuronavigation-guided cTBS to the DLPFC or to the vertex as a control region prior to the performance of an implicit contextual learning task. We found that cTBS applied over the DLPFC significantly improved performance during implicit contextual learning. We also noted that beta-band (13–19 Hz) oscillatory power was reduced at fronto-central channels about 140 to 370 ms after visual stimulus onset in cTBS DLPFC compared with cTBS vertex. Taken together, our results provide evidence that DLPFC-mediated top-down control interferes with contextual memory-guided attention and beta-band oscillatory activity.


2014 ◽  
Vol 28 (3) ◽  
pp. 148-161 ◽  
Author(s):  
David Friedman ◽  
Ray Johnson

A cardinal feature of aging is a decline in episodic memory (EM). Nevertheless, there is evidence that some older adults may be able to “compensate” for failures in recollection-based processing by recruiting brain regions and cognitive processes not normally recruited by the young. We review the evidence suggesting that age-related declines in EM performance and recollection-related brain activity (left-parietal EM effect; LPEM) are due to altered processing at encoding. We describe results from our laboratory on differences in encoding- and retrieval-related activity between young and older adults. We then show that, relative to the young, in older adults brain activity at encoding is reduced over a brain region believed to be crucial for successful semantic elaboration in a 400–1,400-ms interval (left inferior prefrontal cortex, LIPFC; Johnson, Nessler, & Friedman, 2013 ; Nessler, Friedman, Johnson, & Bersick, 2007 ; Nessler, Johnson, Bersick, & Friedman, 2006 ). This reduced brain activity is associated with diminished subsequent recognition-memory performance and the LPEM at retrieval. We provide evidence for this premise by demonstrating that disrupting encoding-related processes during this 400–1,400-ms interval in young adults affords causal support for the hypothesis that the reduction over LIPFC during encoding produces the hallmarks of an age-related EM deficit: normal semantic retrieval at encoding, reduced subsequent episodic recognition accuracy, free recall, and the LPEM. Finally, we show that the reduced LPEM in young adults is associated with “additional” brain activity over similar brain areas as those activated when older adults show deficient retrieval. Hence, rather than supporting the compensation hypothesis, these data are more consistent with the scaffolding hypothesis, in which the recruitment of additional cognitive processes is an adaptive response across the life span in the face of momentary increases in task demand due to poorly-encoded episodic memories.


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