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1.
Transl Psychiatry ; 14(1): 206, 2024 May 23.
Article in English | MEDLINE | ID: mdl-38782961

ABSTRACT

Interoception is the perception of afferent information that arises from anywhere and everywhere within the body. Recently, interoceptive accuracy could be enhanced by cognitive training. Given that the anterior insula cortex (AIC) is a key node of interoception, we hypothesized that resting functional connectivity (RSFC) from AIC was involved in an effect of interoceptive training. To address this issue, we conducted a longitudinal intervention study using interoceptive training and obtained RSFC using fMRI before and after the intervention. A heartbeat perception task evaluated interoceptive accuracy. Twenty-two healthy volunteers (15 females, age 19.9 ± 2.0 years) participated. After the intervention, interoceptive accuracy was enhanced, and anxiety levels and somatic symptoms were reduced. Also, RSFC from AIC to the dorsolateral prefrontal cortex (DLPFC), superior marginal gyrus (SMG), anterior cingulate cortex (ACC), and brain stem, including nucleus tractus solitarius (NTS) were enhanced, and those from AIC to the visual cortex (VC) were decreased according to enhanced interoceptive accuracy. The neural circuit of AIC, ACC, and NTS is involved in the bottom-up process of interoception. The neural circuit of AIC, DLPFC, and SMG is involved in the top-down process of interoception, which was thought to represent the cognitive control of emotion. The findings provided a better understanding of neural underpinnings of the effect of interoceptive training on somatic symptoms and anxiety levels by enhancing both bottom-up and top-down processes of interoception, which has a potential contribution to the structure of psychotherapies based on the neural mechanism of psychosomatics.


Subject(s)
Insular Cortex , Interoception , Magnetic Resonance Imaging , Humans , Female , Interoception/physiology , Male , Insular Cortex/physiology , Insular Cortex/diagnostic imaging , Young Adult , Adult , Anxiety/physiopathology , Longitudinal Studies , Neural Pathways/physiology , Cerebral Cortex/physiology , Cerebral Cortex/diagnostic imaging , Gyrus Cinguli/physiology , Gyrus Cinguli/diagnostic imaging
2.
Hum Brain Mapp ; 45(6): e26643, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38664992

ABSTRACT

Coping with distracting inputs during goal-directed behavior is a common challenge, especially when stopping ongoing responses. The neural basis for this remains debated. Our study explores this using a conflict-modulation Stop Signal task, integrating group independent component analysis (group-ICA), multivariate pattern analysis (MVPA), and EEG source localization analysis. Consistent with previous findings, we show that stopping performance is better in congruent (nonconflicting) trials than in incongruent (conflicting) trials. Conflict effects in incongruent trials compromise stopping more due to the need for the reconfiguration of stimulus-response (S-R) mappings. These cognitive dynamics are reflected by four independent neural activity patterns (ICA), each coding representational content (MVPA). It is shown that each component was equally important in predicting behavioral outcomes. The data support an emerging idea that perception-action integration in action-stopping involves multiple independent neural activity patterns. One pattern relates to the precuneus (BA 7) and is involved in attention and early S-R processes. Of note, three other independent neural activity patterns were associated with the insular cortex (BA13) in distinct time windows. These patterns reflect a role in early attentional selection but also show the reiterated processing of representational content relevant for stopping in different S-R mapping contexts. Moreover, the insular cortex's role in automatic versus complex response selection in relation to stopping processes is shown. Overall, the insular cortex is depicted as a brain hub, crucial for response selection and cancellation across both straightforward (automatic) and complex (conditional) S-R mappings, providing a neural basis for general cognitive accounts on action control.


Subject(s)
Conflict, Psychological , Electroencephalography , Inhibition, Psychological , Insular Cortex , Humans , Male , Female , Adult , Young Adult , Insular Cortex/physiology , Insular Cortex/diagnostic imaging , Brain Mapping , Attention/physiology , Psychomotor Performance/physiology , Cerebral Cortex/physiology , Cerebral Cortex/diagnostic imaging
3.
PLoS One ; 19(4): e0298740, 2024.
Article in English | MEDLINE | ID: mdl-38669282

ABSTRACT

In this research, we employed functional magnetic resonance imaging (fMRI) to examine the neurological basis for understanding wh-questions in wh-in-situ languages such as Korean, where wh-elements maintain their original positions instead of moving explicitly within the sentence. Our hypothesis centered on the role of the salience and attention network in comprehending wh-questions in wh-in-situ languages, such as the discernment of wh-elements, the demarcation between interrogative types, and the allocation of cognitive resources towards essential constituents vis-à-vis subordinate elements in order to capture the speaker's communicative intent. We explored subject and object wh-questions and scrambled wh-questions, contrasting them with yes/no questions in Korean. Increased activation was observed in the left anterior insula and bilateral frontal operculum, irrespective of the wh-position or scrambling of wh-element. These results suggest the interaction between the salience and attentional system and the syntactic linguistic system, particularly the left anterior insula and bilateral frontal operculum, in comprehending wh-questions in wh-in-situ languages.


Subject(s)
Comprehension , Language , Magnetic Resonance Imaging , Humans , Female , Male , Comprehension/physiology , Adult , Young Adult , Brain Mapping , Frontal Lobe/physiology , Frontal Lobe/diagnostic imaging , Republic of Korea , Insular Cortex/physiology , Insular Cortex/diagnostic imaging
4.
Cell Rep ; 43(4): 114027, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38568813

ABSTRACT

The insular cortex is involved in diverse processes, including bodily homeostasis, emotions, and cognition. However, we lack a comprehensive understanding of how it processes information at the level of neuronal populations. We leveraged recent advances in unsupervised machine learning to study insular cortex population activity patterns (i.e., neuronal manifold) in mice performing goal-directed behaviors. We find that the insular cortex activity manifold is remarkably consistent across different animals and under different motivational states. Activity dynamics within the neuronal manifold are highly stereotyped during rewarded trials, enabling robust prediction of single-trial outcomes across different mice and across various natural and artificial motivational states. Comparing goal-directed behavior with self-paced free consumption, we find that the stereotyped activity patterns reflect task-dependent goal-directed reward anticipation, and not licking, taste, or positive valence. These findings reveal a core computation in insular cortex that could explain its involvement in pathologies involving aberrant motivations.


Subject(s)
Goals , Insular Cortex , Animals , Mice , Insular Cortex/physiology , Male , Motivation/physiology , Reward , Mice, Inbred C57BL , Neurons/physiology , Behavior, Animal/physiology , Cerebral Cortex/physiology
5.
J Affect Disord ; 356: 604-615, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38631423

ABSTRACT

BACKGROUND: Romantic relationship dissolutions (RRDs) are associated with posttraumatic stress symptoms (PTSS). Functional magnetic resonance imaging in RRD studies indicate overlapping neural activation similar to posttraumatic stress disorder. These studies combine real and hypothetical rejection, and lack contextual information and control and/or comparison groups exposed to non-RRD or DSM-5 defined traumatic events. AIM: We investigated blood oxygen level dependent (BOLD) activation in the hippocampus, amygdala, and insula of participants with RRDs compared with other traumatic or non-trauma stressors. METHODS: Emerging adults (mean age = 21.54 years; female = 74.7 %) who experienced an RRD (n = 36), DSM-5 defined trauma (physical and/or sexual assault: n = 15), or a non-RRD or DSM-5 stressor (n = 28) completed PTSS, depression, childhood trauma, lifetime trauma exposure, and attachment measures. We used a general and customised version of the International Affective Picture System to investigate responses to index-trauma-related stimuli. We used mixed linear models to assess between-group differences, and ANOVAs and Spearman's correlations to analyse factors associated with BOLD activation. RESULTS: BOLD activity increased between index-trauma stimuli as compared to neutral stimuli in the hippocampus and amygdala, with no significant difference between the DSM-5 Trauma and RRD groups. Childhood adversity, sexual orientation, and attachment style were associated with BOLD activation changes. Breakup characteristics (e.g., initiator status) were associated with increased BOLD activation in the hippocampus and amygdala, in the RRD group. CONCLUSION: RRDs should be considered as potentially traumatic events. Breakup characteristics are risk factors for experiencing RRDs as traumatic. LIMITATION: Future studies should consider more diverse representation across sex, ethnicity, and sexual orientation.


Subject(s)
Amygdala , Hippocampus , Magnetic Resonance Imaging , Stress Disorders, Post-Traumatic , Humans , Female , Male , Hippocampus/diagnostic imaging , Hippocampus/physiopathology , Amygdala/diagnostic imaging , Amygdala/physiopathology , Young Adult , Stress Disorders, Post-Traumatic/physiopathology , Stress Disorders, Post-Traumatic/diagnostic imaging , Case-Control Studies , Adult , Insular Cortex/diagnostic imaging , Insular Cortex/physiopathology , Insular Cortex/physiology , Interpersonal Relations , Students/psychology , Students/statistics & numerical data , Adolescent , Object Attachment , Cerebral Cortex/diagnostic imaging , Cerebral Cortex/physiopathology
6.
Curr Biol ; 34(9): 1880-1892.e5, 2024 05 06.
Article in English | MEDLINE | ID: mdl-38631343

ABSTRACT

Learning to discriminate overlapping gustatory stimuli that predict distinct outcomes-a feat known as discrimination learning-can mean the difference between ingesting a poison or a nutritive meal. Despite the obvious importance of this process, very little is known about the neural basis of taste discrimination learning. In other sensory modalities, this form of learning can be mediated by either the sharpening of sensory representations or the enhanced ability of "decision-making" circuits to interpret sensory information. Given the dual role of the gustatory insular cortex (GC) in encoding both sensory and decision-related variables, this region represents an ideal site for investigating how neural activity changes as animals learn a novel taste discrimination. Here, we present results from experiments relying on two-photon calcium imaging of GC neural activity in mice performing a taste-guided mixture discrimination task. The task allows for the recording of neural activity before and after learning induced by training mice to discriminate increasingly similar pairs of taste mixtures. Single-neuron and population analyses show a time-varying pattern of activity, with early sensory responses emerging after taste delivery and binary, choice-encoding responses emerging later in the delay before a decision is made. Our results demonstrate that, while both sensory and decision-related information is encoded by GC in the context of a taste mixture discrimination task, learning and improved performance are associated with a specific enhancement of decision-related responses.


Subject(s)
Discrimination Learning , Insular Cortex , Taste Perception , Taste , Animals , Mice , Taste/physiology , Male , Insular Cortex/physiology , Discrimination Learning/physiology , Taste Perception/physiology , Decision Making/physiology , Mice, Inbred C57BL , Female , Neurons/physiology
7.
Curr Biol ; 34(9): 1918-1929.e5, 2024 05 06.
Article in English | MEDLINE | ID: mdl-38636514

ABSTRACT

The insular cortex, or insula, is a large brain region involved in the detection of thirst and the regulation of water intake. However, our understanding of the topographical, circuit, and molecular mechanisms for controlling water intake within the insula remains parcellated. We found that type-1 cannabinoid (CB1) receptors in the insular cortex cells participate in the regulation of water intake and deconstructed the circuit mechanisms of this control. Topographically, we revealed that the activity of excitatory neurons in both the anterior insula (aIC) and posterior insula (pIC) increases in response to water intake, yet only the specific removal of CB1 receptors in the pIC decreases water intake. Interestingly, we found that CB1 receptors are highly expressed in insula projections to the basolateral amygdala (BLA), while undetectable in the neighboring central part of the amygdala. Thus, we recorded the neurons of the aIC or pIC targeting the BLA (aIC-BLA and pIC-BLA) and found that they decreased their activity upon water drinking. Additionally, chemogenetic activation of pIC-BLA projection neurons decreased water intake. Finally, we uncovered CB1-dependent short-term synaptic plasticity (depolarization-induced suppression of excitation [DSE]) selectively in pIC-BLA, compared with aIC-BLA synapses. Altogether, our results support a model where CB1 receptor signaling promotes water intake by inhibiting the pIC-BLA pathway, thereby contributing to the fine top-down control of thirst responses.


Subject(s)
Drinking , Insular Cortex , Receptor, Cannabinoid, CB1 , Animals , Receptor, Cannabinoid, CB1/metabolism , Male , Mice , Drinking/physiology , Insular Cortex/physiology , Cannabinoids/metabolism , Cannabinoids/pharmacology , Neurons/physiology , Neurons/metabolism , Mice, Inbred C57BL , Neuronal Plasticity/physiology , Basolateral Nuclear Complex/physiology , Basolateral Nuclear Complex/metabolism
8.
Asian J Psychiatr ; 95: 103991, 2024 May.
Article in English | MEDLINE | ID: mdl-38484483

ABSTRACT

BACKGROUND: Interoception, the neural sensing of visceral signals, and interoceptive awareness (IA), the conscious perception of interoception, are crucial for life survival functions and mental health. Resilience, the capacity to overcome adversity, has been associated with reduced interoceptive disturbances. Here, we sought evidence for our Insula Modular Active Control (IMAC) model that suggest that the insula, a brain region specialized in the processing of interoceptive information, realizes IA and contributes to resilience and mental health via cortico-subcortical connections. METHODS: 64 healthy participants (32 females; ages 18-34 years) answered questionnaires that assess IA and resilience. Mental health was evaluated with the Beck Depression Inventory II that assesses depressive mood. Participants also underwent a 15 minute resting-state functional resonance imaging session. Pearson correlations and mediation analyses were used to investigate the relationship between IA and resilience and their contributions to depressive mood. We then performed insula seed-based functional connectivity analyzes to identify insula networks involved in IA, resilience and depressive mood. RESULTS: We first demonstrated that resilience mediates the relationship between IA and depressive mood. Second, shared and distinct intra-insula, insula-cortical and insula-subcortical networks were associated with IA, resilience and also predicted the degree of experienced depressive mood. Third, while resilience was associated with stronger insula-precuneus, insula-cerebellum and insula-prefrontal networks, IA was linked with stronger intra-insula, insula-striatum and insula-motor networks. CONCLUSIONS: Our findings help understand the roles of insula-cortico-subcortical networks in IA and resilience. These results also highlight the potential use of insula networks as biomarkers for depression prediction.


Subject(s)
Depression , Insular Cortex , Interoception , Magnetic Resonance Imaging , Resilience, Psychological , Stress, Psychological , Humans , Female , Adult , Male , Young Adult , Interoception/physiology , Adolescent , Insular Cortex/physiology , Insular Cortex/diagnostic imaging , Insular Cortex/physiopathology , Depression/physiopathology , Stress, Psychological/physiopathology , Nerve Net/diagnostic imaging , Nerve Net/physiology , Nerve Net/physiopathology , Awareness/physiology , Connectome/methods , Cerebral Cortex/diagnostic imaging , Cerebral Cortex/physiology , Cerebral Cortex/physiopathology
9.
J Neurosci ; 43(34): 6046-6060, 2023 08 23.
Article in English | MEDLINE | ID: mdl-37507228

ABSTRACT

A clear understanding of the neural circuit underlying emotion regulation (ER) is important for both basic and translational research. However, a lack of evidence based on combined neuroimaging and neuromodulation techniques calls into question (1) whether the change of prefrontal-subcortical activity intrinsically and causally contributes to the ER effect; and (2) whether the prefrontal control system directly modulates the subcortical affective system. Accordingly, we combined fMRI recordings with transcranial magnetic stimulation (TMS) to map the causal connections between the PFC and subcortical affective structures (amygdala and insula). A total of 117 human adult participants (57 males and 60 females) were included in the study. The results revealed that TMS-induced ventrolateral PFC (VLPFC) facilitation led to enhanced activity in the VLPFC and ventromedial PFC (VMPFC) as well as attenuated activity in the amygdala and insula during reappraisal but not during nonreappraisal (i.e., baseline). Moreover, the activated VLPFC intensified the prefrontal-subcortical couplings via the VMPFC during reappraisal only. This study provides combined TMS-fMRI evidence that downregulating negative emotion involves the prefrontal control system suppressing the subcortical affective system, with the VMPFC serving as a crucial hub within the VLPFC-subcortical network, suggesting an indirect pathway model of the ER circuit. Our findings outline potential protocols for improving ER ability by intensifying the VLPFC-VMPFC coupling in patients with mood and anxiety disorders.SIGNIFICANCE STATEMENT Using fMRI to examine the TMS effect, we uncovered that the opposite neural changes in prefrontal (enhanced) and subcortical (attenuated) regions are not a byproduct of emotion regulation (ER); instead, this prefrontal-subcortical activity per se causally contributes to the ER effect. Furthermore, using TMS to amplify the neural changes within the ER circuit, the "bridge" role of the VMPFC is highlighted under the reappraisal versus nonreappraisal contrast. This "perturb-and-measure" approach overcomes the correlational nature of fMRI data, helping us to identify brain regions that causally support reappraisal (the VLPFC and VMPFC) and those that are modulated by reappraisal (the amygdala and insula). The uncovered ER circuit is important for understanding the neural systems underlying reappraisal and valuable for translational research.


Subject(s)
Cognition , Emotional Regulation , Magnetic Resonance Imaging , Neural Pathways , Prefrontal Cortex , Transcranial Magnetic Stimulation , Female , Humans , Male , Brain Mapping , Cognition/physiology , Emotional Regulation/physiology , Prefrontal Cortex/cytology , Prefrontal Cortex/diagnostic imaging , Prefrontal Cortex/physiology , Anxiety/physiopathology , Mood Disorders/physiopathology , Social Inclusion , Social Isolation , Photic Stimulation , Amygdala/physiology , Insular Cortex/physiology , Asian , Young Adult
10.
Nature ; 615(7951): 292-299, 2023 03.
Article in English | MEDLINE | ID: mdl-36859543

ABSTRACT

Emotional states influence bodily physiology, as exemplified in the top-down process by which anxiety causes faster beating of the heart1-3. However, whether an increased heart rate might itself induce anxiety or fear responses is unclear3-8. Physiological theories of emotion, proposed over a century ago, have considered that in general, there could be an important and even dominant flow of information from the body to the brain9. Here, to formally test this idea, we developed a noninvasive optogenetic pacemaker for precise, cell-type-specific control of cardiac rhythms of up to 900 beats per minute in freely moving mice, enabled by a wearable micro-LED harness and the systemic viral delivery of a potent pump-like channelrhodopsin. We found that optically evoked tachycardia potently enhanced anxiety-like behaviour, but crucially only in risky contexts, indicating that both central (brain) and peripheral (body) processes may be involved in the development of emotional states. To identify potential mechanisms, we used whole-brain activity screening and electrophysiology to find brain regions that were activated by imposed cardiac rhythms. We identified the posterior insular cortex as a potential mediator of bottom-up cardiac interoceptive processing, and found that optogenetic inhibition of this brain region attenuated the anxiety-like behaviour that was induced by optical cardiac pacing. Together, these findings reveal that cells of both the body and the brain must be considered together to understand the origins of emotional or affective states. More broadly, our results define a generalizable approach for noninvasive, temporally precise functional investigations of joint organism-wide interactions among targeted cells during behaviour.


Subject(s)
Behavior, Animal , Brain , Emotions , Heart , Animals , Mice , Anxiety/physiopathology , Brain/physiology , Brain Mapping , Emotions/physiology , Heart/physiology , Behavior, Animal/physiology , Electrophysiology , Optogenetics , Insular Cortex/physiology , Heart Rate , Channelrhodopsins , Tachycardia/physiopathology , Pacemaker, Artificial
11.
Nature ; 614(7949): 725-731, 2023 02.
Article in English | MEDLINE | ID: mdl-36755097

ABSTRACT

Temperature is a fundamental sensory modality separate from touch, with dedicated receptor channels and primary afferent neurons for cool and warm1-3. Unlike for other modalities, however, the cortical encoding of temperature remains unknown, with very few cortical neurons reported that respond to non-painful temperature, and the presence of a 'thermal cortex' is debated4-8. Here, using widefield and two-photon calcium imaging in the mouse forepaw system, we identify cortical neurons that respond to cooling and/or warming with distinct spatial and temporal response properties. We observed a representation of cool, but not warm, in the primary somatosensory cortex, but cool and warm in the posterior insular cortex (pIC). The representation of thermal information in pIC is robust and somatotopically arranged, and reversible manipulations show a profound impact on thermal perception. Despite being positioned along the same one-dimensional sensory axis, the encoding of cool and that of warm are distinct, both in highly and broadly tuned neurons. Together, our results show that pIC contains the primary cortical representation of skin temperature and may help explain how the thermal system generates sensations of cool and warm.


Subject(s)
Insular Cortex , Neurons , Skin Temperature , Somatosensory Cortex , Animals , Mice , Cold Temperature , Neurons/physiology , Somatosensory Cortex/cytology , Somatosensory Cortex/physiology , Touch Perception/physiology , Hot Temperature , Skin Temperature/physiology , Spatio-Temporal Analysis , Insular Cortex/cytology , Insular Cortex/physiology
12.
Proc Natl Acad Sci U S A ; 119(22): e2203680119, 2022 05 31.
Article in English | MEDLINE | ID: mdl-35622887

ABSTRACT

Noradrenergic activation of the basolateral amygdala (BLA) by emotional arousal enhances different forms of recognition memory via functional interactions with the insular cortex (IC). Human neuroimaging studies have revealed that the anterior IC (aIC), as part of the salience network, is dynamically regulated during arousing situations. Emotional stimulation first rapidly increases aIC activity but suppresses it in a delayed fashion. Here, we investigated in male Sprague-Dawley rats whether the BLA influence on recognition memory is associated with an increase or suppression of aIC activity during the postlearning consolidation period. We first employed anterograde and retrograde viral tracing and found that the BLA sends dense monosynaptic projections to the aIC. Memory-enhancing norepinephrine administration into the BLA following an object training experience suppressed aIC activity 1 h later, as determined by a reduced expression of the phosphorylated form of the transcription factor cAMP response element-binding (pCREB) protein and neuronal activity marker c-Fos. In contrast, the number of perisomatic γ-aminobutyric acid (GABA)ergic inhibitory synapses per pCREB-positive neuron was significantly increased, suggesting a dynamic up-regulation of GABAergic tone. In support of this possibility, pharmacological inhibition of aIC activity with a GABAergic agonist during consolidation enhanced object recognition memory. Norepinephrine administration into the BLA did not affect neuronal activity within the posterior IC, which receives sparse innervation from the BLA. The evidence that noradrenergic activation of the BLA enhances the consolidation of object recognition memory via a mechanism involving a suppression of aIC activity provides insight into the broader brain network dynamics underlying emotional regulation of memory.


Subject(s)
Basolateral Nuclear Complex , Emotions , Insular Cortex , Neural Inhibition , Recognition, Psychology , Visual Perception , Animals , Arousal , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/physiology , Cyclic AMP Response Element-Binding Protein/metabolism , Emotions/drug effects , Emotions/physiology , GABA Agonists/pharmacology , Insular Cortex/drug effects , Insular Cortex/physiology , Male , Neural Inhibition/drug effects , Neural Inhibition/physiology , Norepinephrine/administration & dosage , Norepinephrine/pharmacology , Rats , Rats, Sprague-Dawley , Recognition, Psychology/drug effects , Recognition, Psychology/physiology , Visual Perception/physiology
13.
Nat Commun ; 13(1): 717, 2022 02 07.
Article in English | MEDLINE | ID: mdl-35132070

ABSTRACT

In humans, risk attitude is highly context-dependent, varying with wealth levels or for different potential outcomes, such as gains or losses. These behavioral effects have been modelled using prospect theory, with the key assumption that humans represent the value of each available option asymmetrically as a gain or loss relative to a reference point. It remains unknown how these computations are implemented at the neuronal level. Here we show that macaques, like humans, change their risk attitude across wealth levels and gain/loss contexts using a token gambling task. Neurons in the anterior insular cortex (AIC) encode the 'reference point' (i.e., the current wealth level of the monkey) and reflect 'loss aversion' (i.e., option value signals are more sensitive to change in the loss than in the gain context) as postulated by prospect theory. In addition, changes in the activity of a subgroup of AIC neurons correlate with the inter-trial fluctuations in choice and risk attitude. Taken together, we show that the primate AIC in risky decision-making may be involved in monitoring contextual information used to guide the animal's willingness to accept risk.


Subject(s)
Decision Making/physiology , Gambling/psychology , Insular Cortex/physiology , Models, Psychological , Animals , Brain Mapping , Choice Behavior/physiology , Macaca , Male , Motivation , Neurons/physiology , ROC Curve , Reward , Risk-Taking
14.
Neuroimage ; 249: 118887, 2022 04 01.
Article in English | MEDLINE | ID: mdl-34999203

ABSTRACT

An essential core function of one's cognitive flexibility is the use of acquired knowledge and skills to adapt to ongoing environmental changes. Animal models have highlighted the influence serotonin has on neuroplasticity. These effects have been predominantly demonstrated during emotional relearning which is theorized as a possible model for depression. However, translation of these mechanisms is in its infancy. To this end, we assessed changes in effective connectivity at rest and during associative learning as a proxy of neuroplastic changes in healthy volunteers. 76 participants underwent 6 weeks of emotional or non-emotional (re)learning (face-matching or Chinese character-German noun matching). During relearning participants either self-administered 10 mg/day of the selective serotonin reuptake inhibitor (SSRI) escitalopram or placebo in a double-blind design. Associative learning tasks, resting-state and structural images were recorded before and after both learning phases (day 1, 21 and 42). Escitalopram intake modulated relearning changes in a network encompassing the right insula, anterior cingulate cortex and right angular gyrus. Here, the process of relearning during SSRI intake showed a greater decrease in effective connectivity from the right insula to both the anterior cingulate cortex and right angular gyrus, with increases in the opposite direction when compared to placebo. In contrast, intrinsic connections and those at resting-state were only marginally affected by escitalopram. Further investigation of gray matter volume changes in these functionally active regions revealed no significant SSRI-induced structural changes. These findings indicate that the right insula plays a central role in the process of relearning and SSRIs further potentiate this effect. In sum, we demonstrated that SSRIs amplify learning-induced effective connections rather than affecting the intrinsic task connectivity or that of resting-state.


Subject(s)
Association Learning , Connectome , Insular Cortex , Nerve Net , Neuronal Plasticity , Selective Serotonin Reuptake Inhibitors/pharmacology , Adult , Association Learning/drug effects , Association Learning/physiology , Citalopram/pharmacology , Female , Gyrus Cinguli/diagnostic imaging , Gyrus Cinguli/drug effects , Gyrus Cinguli/physiology , Humans , Insular Cortex/diagnostic imaging , Insular Cortex/drug effects , Insular Cortex/physiology , Magnetic Resonance Imaging , Male , Nerve Net/diagnostic imaging , Nerve Net/drug effects , Nerve Net/physiology , Neuronal Plasticity/drug effects , Neuronal Plasticity/physiology , Parietal Lobe/diagnostic imaging , Parietal Lobe/drug effects , Parietal Lobe/physiology , Rest , Selective Serotonin Reuptake Inhibitors/administration & dosage , Young Adult
15.
Hum Brain Mapp ; 43(2): 733-749, 2022 02 01.
Article in English | MEDLINE | ID: mdl-34811847

ABSTRACT

There is growing recognition that the composition of the gut microbiota influences behaviour, including responses to threat. The cognitive-interoceptive appraisal of threat-related stimuli relies on dynamic neural computations between the anterior insular (AIC) and the dorsal anterior cingulate (dACC) cortices. If, to what extent, and how microbial consortia influence the activity of this cortical threat processing circuitry is unclear. We addressed this question by combining a threat processing task, neuroimaging, 16S rRNA profiling and computational modelling in healthy participants. Results showed interactions between high-level ecological indices with threat-related AIC-dACC neural dynamics. At finer taxonomic resolutions, the abundance of Ruminococcus was differentially linked to connectivity between, and activity within the AIC and dACC during threat updating. Functional inference analysis provides a strong rationale to motivate future investigations of microbiota-derived metabolites in the observed relationship with threat-related brain processes.


Subject(s)
Connectome , Fear/physiology , Gastrointestinal Microbiome/physiology , Gyrus Cinguli/physiology , Insular Cortex/physiology , Nerve Net/physiology , Adult , Conditioning, Classical/physiology , Female , Gyrus Cinguli/diagnostic imaging , Humans , Insular Cortex/diagnostic imaging , Magnetic Resonance Imaging , Male , Models, Theoretical , Nerve Net/diagnostic imaging , RNA, Ribosomal, 16S , Young Adult
16.
Cell ; 184(26): 6344-6360.e18, 2021 12 22.
Article in English | MEDLINE | ID: mdl-34890577

ABSTRACT

The anterior insular cortex (aIC) plays a critical role in cognitive and motivational control of behavior, but the underlying neural mechanism remains elusive. Here, we show that aIC neurons expressing Fezf2 (aICFezf2), which are the pyramidal tract neurons, signal motivational vigor and invigorate need-seeking behavior through projections to the brainstem nucleus tractus solitarii (NTS). aICFezf2 neurons and their postsynaptic NTS neurons acquire anticipatory activity through learning, which encodes the perceived value and the vigor of actions to pursue homeostatic needs. Correspondingly, aIC → NTS circuit activity controls vigor, effort, and striatal dopamine release but only if the action is learned and the outcome is needed. Notably, aICFezf2 neurons do not represent taste or valence. Moreover, aIC → NTS activity neither drives reinforcement nor influences total consumption. These results pinpoint specific functions of aIC → NTS circuit for selectively controlling motivational vigor and suggest that motivation is subserved, in part, by aIC's top-down regulation of dopamine signaling.


Subject(s)
Brain Stem/physiology , Insular Cortex/physiology , Motivation , Neural Pathways/physiology , Animals , Behavior, Animal , Dopamine/metabolism , Female , Learning , Male , Mice, Inbred C57BL , Neurons/physiology , Nucleus Accumbens/metabolism , Time Factors
17.
Science ; 374(6570): 1010-1015, 2021 Nov 19.
Article in English | MEDLINE | ID: mdl-34793231

ABSTRACT

How does the brain maintain fear within an adaptive range? We found that the insular cortex acts as a state-dependent regulator of fear that is necessary to establish an equilibrium between the extinction and maintenance of fear memories in mice. Whereas insular cortex responsiveness to fear-evoking cues increased with their certainty to predict harm, this activity was attenuated through negative bodily feedback that arose from heart rate decelerations during freezing. Perturbation of body-brain communication by vagus nerve stimulation disrupted the balance between fear extinction and maintenance similar to insular cortex inhibition. Our data reveal that the insular cortex integrates predictive sensory and interoceptive signals to provide graded and bidirectional teaching signals that gate fear extinction and illustrate how bodily feedback signals are used to maintain fear within a functional equilibrium.


Subject(s)
Fear , Feedback, Physiological , Insular Cortex/physiology , Animals , Conditioning, Classical , Cues , Extinction, Psychological , Heart Rate , Interoception , Male , Mental Recall , Mice , Mice, Inbred C57BL , Vagus Nerve/physiology
18.
Cell ; 184(24): 5902-5915.e17, 2021 11 24.
Article in English | MEDLINE | ID: mdl-34752731

ABSTRACT

Increasing evidence indicates that the brain regulates peripheral immunity, yet whether and how the brain represents the state of the immune system remains unclear. Here, we show that the brain's insular cortex (InsCtx) stores immune-related information. Using activity-dependent cell labeling in mice (FosTRAP), we captured neuronal ensembles in the InsCtx that were active under two different inflammatory conditions (dextran sulfate sodium [DSS]-induced colitis and zymosan-induced peritonitis). Chemogenetic reactivation of these neuronal ensembles was sufficient to broadly retrieve the inflammatory state under which these neurons were captured. Thus, we show that the brain can store and retrieve specific immune responses, extending the classical concept of immunological memory to neuronal representations of inflammatory information.


Subject(s)
Immunity , Insular Cortex/physiology , Neurons/physiology , Animals , Colitis/chemically induced , Colitis/complications , Colitis/immunology , Colon/pathology , Dextran Sulfate , Female , Inflammation/pathology , Male , Mice , Mice, Inbred C57BL , Peritoneum/pathology , Peritonitis/complications , Peritonitis/immunology , Peritonitis/pathology , Synapses/metabolism , Zymosan
19.
Proc Natl Acad Sci U S A ; 118(44)2021 11 02.
Article in English | MEDLINE | ID: mdl-34716272

ABSTRACT

Actions with identical goals can be executed in different ways (gentle, rude, vigorous, etc.), which D. N. Stern called vitality forms [D. N. Stern, Forms of Vitality Exploring Dynamic Experience in Psychology, Arts, Psychotherapy, and Development (2010)]. Vitality forms express the agent's attitudes toward others. In a series of fMRI studies, we found that the dorso-central insula (DCI) is the region that is selectively active during both vitality form observation and execution. In one previous experiment, however, the middle cingulate gyrus also exhibited activation. In the present study, in order to assess the role of the cingulate cortex in vitality form processing, we adopted a classical vitality form paradigm, but making the control condition devoid of vitality forms using jerky movements. Participants performed two different tasks: Observation of actions performed gently or rudely and execution of the same actions. The results showed that in addition to the insula, the middle cingulate cortex (MCC) was strongly activated during both action observation and execution. Using a voxel-based analysis, voxels showing a similar trend of the blood-oxygen-level-dependent (BOLD) signal in both action observation and execution were found in the DCI and in the MCC. Finally, using a multifiber tractography analysis, we showed that the active sites in MCC and DCI are reciprocally connected.


Subject(s)
Behavior/physiology , Gyrus Cinguli/physiology , Insular Cortex/physiology , Adult , Attitude , Brain/physiology , Brain Mapping/methods , Cerebral Cortex/physiology , Female , Humans , Magnetic Resonance Imaging/methods , Male
20.
Neuroimage ; 244: 118581, 2021 12 01.
Article in English | MEDLINE | ID: mdl-34543763

ABSTRACT

During real-world locomotion, in order to be able to move along a path or avoid an obstacle, continuous changes in self-motion direction (i.e. heading) are needed. Control of heading changes during locomotion requires the integration of multiple signals (i.e., visual, somatomotor, vestibular). Recent fMRI studies have shown that both somatomotor areas (human PEc [hPEc], human PE [hPE], primary somatosensory cortex [S-I]) and egomotion visual regions (cingulate sulcus visual area [CSv], posterior cingulate area [pCi], posterior insular cortex [PIC]) respond to either leg movements and egomotion-compatible visual stimulations, suggesting a role in the analysis of both visual attributes of egomotion and somatomotor signals with the aim of guiding locomotion. However, whether these regions are able to integrate egomotion-related visual signals with somatomotor inputs coming from leg movements during heading changes remains an open question. Here we used a combined approach of individual functional localizers and task-evoked activity by fMRI. In thirty subjects we first localized three egomotion areas (CSv, pCi, PIC) and three somatomotor regions (S-I, hPE, hPEc). Then, we tested their responses in a multisensory integration experiment combining visual and somatomotor signals relevant to locomotion in congruent or incongruent trials. We used an fMR-adaptation paradigm to explore the sensitivity to the repeated presentation of these bimodal stimuli in the six regions of interest. Results revealed that hPE, S-I and CSv showed an adaptation effect regardless of congruency, while PIC, pCi and hPEc showed sensitivity to congruency. PIC exhibited a preference for congruent trials compared to incongruent trials. Areas pCi and hPEc exhibited an adaptation effect only for congruent and incongruent trials, respectively. PIC, pCi and hPEc sensitivity to the congruency relationship between visual (locomotion-compatible) cues and (leg-related) somatomotor inputs suggests that these regions are involved in multisensory integration processes, likely in order to guide/adjust leg movements during heading changes.


Subject(s)
Insular Cortex/physiology , Locomotion/physiology , Motor Cortex/physiology , Adult , Evoked Potentials , Female , Humans , Leg/physiology , Magnetic Resonance Imaging , Male , Young Adult
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