The insula, or insular cortex, is a folded area of cerebral cortex concealed within the lateral sulcus on each side of the human brain. It helps the nervous system integrate information about the body’s internal condition with sensory events, learned significance, attention, action, and subjective experience. Its best-supported functions involve interoception, pain and temperature processing, taste, autonomic regulation, and participation in large-scale networks that evaluate which events deserve processing. The insula also contributes to emotion, uncertainty, craving, social cognition, and aspects of cognitive control, although none of these abilities belongs exclusively to this structure. Uddin and colleagues’ anatomical review and a 2024 systems-level review provide complementary summaries.
A useful way to understand its role is to ask three connected questions: What is happening inside the body? What does that change mean in the present situation? Which adjustments in attention, physiology, and behavior are appropriate? Different insular subdivisions and their partners contribute to different portions of this process. The answers depend on thalamic, brainstem, somatosensory, frontal, cingulate, limbic, and other pathways. A visible change in insular activity is consequently evidence of participation in processing, rather than a unique readout of any particular feeling.
Where is the insula located?
Each hemisphere contains an insula embedded below the frontal, parietal, and temporal opercula. In an ordinary side view of the brain it remains hidden because these surrounding cortical folds cover it. The circular sulcus marks much of its boundary, while the central insular sulcus separates anterior from posterior portions. Several short anterior gyri and longer posterior gyri provide anatomical landmarks, although individual folding patterns vary. The insula lies near major branches of the middle cerebral artery, a practical concern in stroke and neurosurgery. These features are described in the clinical neuroanatomy overview and the human insula review.
“Insula” and “insular cortex” generally refer to the same cortical territory. It is sometimes called the Island of Reil, reflecting historical neuroanatomical description. Its cortex varies microscopically: relatively granular posterior areas, transitional dysgranular regions, and more agranular anterior areas differ in cellular layering and connectivity. Such cytoarchitectonic patterns help researchers identify organization, but microscopic boundaries do not correspond to single psychological faculties.
What does the insula do? The central functions
Sensing and interpreting changes inside the body
Interoception encompasses neural sensing, interpretation, and integration of signals concerning internal bodily conditions, including cardiovascular, respiratory, gastrointestinal, thermal, and other physiological states. It includes unconscious regulation as well as conscious sensations. Insular territories receive and combine parts of this information, allowing bodily signals to influence awareness, learning, behavioral priorities, and physiological regulation. The interoception consensus roadmap defines the field more broadly than the popular idea of simply “feeling your heartbeat.”
Bodily information is distributed across pathways. Receptors in organs and tissues transmit signals through peripheral nerves and spinal and brainstem circuits; information reaches multiple thalamic and cortical targets. The vagus nerve is an important route for visceral communication, but it is one component of this system rather than a direct one-step line to an emotional center. A heartbeat can be registered physiologically without entering conscious awareness, and a person may experience urgency or nausea even when the underlying body-state signal is being interpreted in a context-dependent way.
Detecting relevance and coordinating attention
Salience is the behavioral or physiological relevance of information in a particular context. A sudden sound, unexpected error, internal discomfort, social signal, or important goal cue can become salient for different reasons. The anterior insula often participates with the dorsal anterior cingulate cortex in a distributed network called the salience network. Reviews link this system to identifying significant changes and coordinating processing across other networks. Uddin’s review and Menon and Uddin’s network model are foundational sources.
One influential model proposes that the anterior insula helps shift resources among internally oriented processing, goal-directed executive operations, and externally directed attention. The model explains why the same region can be active during tasks involving sensations, errors, demands, or emotional cues. Network switching is a model supported by several kinds of functional-connectivity data; its precise direction, mechanism, and causal scope remain research questions. A salience-network signal cannot, by itself, identify whether someone is afraid, interested, in pain, or motivated.
Contributing to feeling states and emotion
A feeling state emerges through interacting sensory, interoceptive, predictive, affective, attentional, and cognitive processes. Insular involvement is consistent with the contribution of bodily information and its significance to subjective experience. The anterior insula often appears in studies of emotional awareness, while posterior and middle portions are more often associated with particular bodily signals and sensory dimensions. Craig’s influential theoretical account placed the anterior insula at the center of a proposed pathway for human subjective feeling; later anatomy and network research refined that picture.
Experiments do not establish that every emotion requires a single insular locus. Fear, joy, sadness, disgust, shame, pain-related distress, and empathy recruit overlapping, distributed systems in ways shaped by task design, learning, attention, and individual differences. An insular response may reflect visceral sensation, novelty, bodily arousal, task difficulty, or the need for behavioral adjustment. Treating one activation cluster as an emotional label illustrates the reverse-inference error identified by Poldrack.
Pain, temperature, and bodily discomfort
Posterior insular and neighboring opercular regions participate in human thermosensory and nociceptive processing. Brain stimulation, clinical lesions, intracranial recordings, and imaging converge in showing that the operculo-insular system is important for aspects of temperature and pain-related sensation. However, pain is a multidimensional experience produced by distributed neural processes, including sensory discrimination, affective valuation, memory, expectations, and behavioral regulation. See the review of posterior insular-opercular nociceptive pathways.
The appearance of insula activity on a pain scan does not certify how much pain an individual is experiencing, and absent or reduced activity does not prove a person is pain-free. Experimental nociceptive stimulation, experienced pain, chronic pain, and clinical suffering are different targets of measurement. The anatomy also matters: interpretations that merge the posterior insula, parietal operculum, and anterior insula into one undifferentiated “pain center” obscure their distinct contributions.
Taste, appetite-related processing, and learned bodily consequences
The insula and adjacent frontal opercular cortex form important parts of gustatory processing. Research investigates how taste quality, intensity, pleasantness, visceral consequences, and learned preferences are represented across these areas. The precise organization of taste-responsive populations, especially claims of a simple “taste map,” is disputed and varies across methods and species. A review of taste coding in insular cortex documents the competing findings.
The role extends beyond detecting tastes. In animal models, insular circuits contribute to linking food-related cues with later internal outcomes, including aversion learning. A 2026 review of sensory and bodily-state association examines these mechanisms primarily in rodents, with connections to human research. Results from targeted rodent circuit manipulations offer useful causal evidence in those animals; equivalent human causal conclusions require human evidence.
Autonomic regulation and motivation
The insula is embedded in networks that connect awareness of physiological changes with patterns of autonomic activity. Experimental tasks can recruit it alongside changes in cardiovascular response, respiration, discomfort, and alertness. Autonomic regulation depends on reciprocal brainstem, hypothalamic, thalamic, cortical, and peripheral mechanisms. The insula participates within that architecture rather than independently “controlling the heart” or selecting every bodily reaction.
Craving offers another example of bodily significance becoming behaviorally relevant. A well-known lesion study reported that some smokers with insular damage experienced unusually abrupt disruption of cigarette addiction. The result supports a contribution to urges and learned interoceptive incentives but does not show that removing or suppressing insula activity is a safe or effective addiction treatment. The original evidence is reported in Naqvi and colleagues’ lesion study.
Why anterior, middle, and posterior insula matter
The insula is heterogeneous in anatomy, connectivity, and experimental response patterns. A widely used heuristic distinguishes posterior regions more closely linked to sensory and body-state processing, middle regions participating in integration, dorsal anterior territories associated with attention and cognitive demands, and ventral anterior territories more often associated with affective and social aspects of tasks. These are tendencies in distributed data, not sealed compartments. Functional meta-analysis and connectivity reviews demonstrate overlap as well as specialization: Kurth and colleagues’ meta-analysis; Uddin and colleagues’ anatomical review.
Posterior insula receives information relevant to somatic, visceral, pain, temperature, and sensorimotor processes. The operculum and nearby cortical territories interact with it closely. Middle insular areas are often treated as integrative zones, yet no universally agreed middle-insula computation has been identified. Dorsal anterior insula frequently appears during performance monitoring, demanding tasks, uncertain choices, and salience processing, while ventral anterior areas more often appear in affective and social tasks. Distinguishing these territories helps prevent a whole-insula activation from becoming a sweeping claim about feeling or decision-making.
The left and right insulae have partly asymmetric anatomical relationships and sometimes show different task effects. Some accounts emphasize right anterior insula involvement in attention and salience, but a universal left-versus-right division of body feeling and emotional thinking is unsupported. Differences depend on task, population, analysis, and lesion location. For broader evidence on hemisphere specialization, see the English Hub’s Left Brain vs. Right Brain: Hemispheres, Specialization, and Myths.
How bodily signals become meaningful
Interoception involves several distinguishable levels. The body generates physiological changes; neural receptors encode features of those changes; signals travel through peripheral and central pathways; interacting brain networks interpret signals in relation to expectations and goals; some consequences become consciously experienced. Regulation can also proceed without awareness. An internal sensation is therefore an outcome of multiple transformations rather than a transparent copy of an organ’s condition. The Khalsa and colleagues consensus paper stresses the importance of separating interoceptive processes and levels of measurement.
Consider a racing heartbeat before a public presentation. Cardiovascular changes may be influenced by movement, posture, autonomic state, and contextual stress. A person might experience the changes as anticipation, apprehension, excitement, or hardly notice them. The insula contributes to bodily representation within a broader system containing contextual memory, learned appraisal, action plans, and ongoing perception. Neither the pulse nor the insula alone determines which feeling is reported.
Interoceptive accuracy, interoceptive attention, sensitivity to particular signals, self-reported body awareness, confidence, and metacognitive insight are distinct measurements. Good performance at detecting cardiac signals need not imply equivalent skill in judging respiratory or gastrointestinal sensations. Researchers should define exactly which dimension and bodily system they measured, rather than use “good interoception” as a blanket personal trait.
The salience network and its connections
The salience network commonly includes the anterior insular cortex and dorsal anterior cingulate cortex, along with context-dependent participation from frontal and subcortical regions. Different studies use different atlases, acquisition methods, and network definitions, so its exact borders vary. The network is investigated through correlated fluctuations during rest and coordinated task responses. Findings indicate recurring organization, while labels are provisional models of functional cooperation rather than physical cables connecting isolated modules. Salience network review.
Anatomical and functional relationships connect insular territories to thalamus, anterior cingulate, somatosensory cortex, frontal and temporal regions, amygdala, striatum, and brainstem regulatory circuits. The amygdala contributes to learning about biologically and behaviorally significant events, among other functions; the insula participates in representing and evaluating bodily and situational significance. Their interactions vary by experiment and context. See the published Amygdala: Threat, Salience, Learning, and Emotion for that neighboring EN-30 anatomical territory.
The hippocampus supplies important contextual and memory-related functions that can influence how the same bodily sensation is interpreted in different situations. The insula’s role in present physiological significance can consequently depend on remembered context. The English Hub’s Hippocampus: Memory, Context, and Spatial Processing addresses the related anatomy. To understand how anatomically separate nodes contribute jointly to behavior, see Neural Circuits: How Brain Networks Generate Behavior.
Descriptions of the insula as a “switch” or “hub” should be read as network hypotheses. Functional connectivity quantifies statistical relationships among recorded signals; it does not, on its own, establish information flow, direction, or conscious control. Causal intervention and converging lesion evidence may strengthen a network account, yet stimulation and lesions often affect fibers and connected territories beyond the named region.
How scientists investigate the insula
Structural MRI and anatomical segmentation
High-resolution magnetic resonance imaging reveals tissue anatomy, sulci, cortical thickness, and gross lesions. Researchers can identify the insula, reconstruct surfaces, and compare anatomical features across groups. Such measures do not directly record neuron firing or subjective feeling. Group differences in volume or thickness also do not establish a diagnostic abnormality in a particular person.
Functional MRI
Blood-oxygen-level-dependent fMRI measures local changes in a hemodynamic signal associated with neural activity and vascular physiology. It does not directly measure an emotion, thought, or neurotransmitter concentration. Experiments use contrasts between conditions and statistical modeling; spatial resolution, preprocessing, task differences, vascular factors, and statistical thresholds influence results. Insular fMRI activation supports a conclusion that a region participates in an experimental condition, conditional on design and analysis. It rarely establishes the precise mental operation present. The general methodological issue is explained in Poldrack’s analysis of reverse inference.
Resting-state and task-based connectivity
Functional connectivity studies quantify relationships between measured signals across areas; diffusion MRI estimates orientations of water diffusion to infer likely white-matter pathways. Neither technique sees a complete neural conversation. Causal connectivity models depend on assumptions, sampling, and model selection. Network diagrams help summarize hypotheses, but an arrow drawn between the insula and cingulate cortex is not automatically a verified causal command.
EEG, MEG, and intracranial recordings
EEG measures scalp voltage fluctuations arising mainly from synchronized electrical activity in neural populations. MEG records the associated magnetic fields. Both provide fine temporal information, but identifying signals from a deep, folded structure such as the insula is challenging. Source reconstruction introduces assumptions, and a scalp pattern cannot routinely be attributed to the insula alone. Intracranial recordings from implanted electrodes offer more local access in selected clinical patients, with restricted sampling and clinical-selection limitations.
Lesions and direct electrical stimulation
Focal strokes and surgical lesions offer important evidence about functions affected when a region or its connections are damaged. They are often more informative for causal inference than activation alone, while vascular territories, neighboring injury, reorganization, and preexisting clinical differences complicate interpretation. Direct stimulation may transiently elicit sensations or alter processing, but it can recruit passing fibers and network partners. A 2023 intracranial stimulation study of 17 neurosurgical patients reported heterogeneous subjective responses across insular sites, supporting subdivision-level investigation rather than a single universal insular experience. See the primary stimulation study.
Animal circuits and translational limits
Rodent and nonhuman-primate studies can trace pathways, manipulate targeted populations, and test learning mechanisms with a degree of experimental control unavailable in healthy humans. Their insular homologues, neuronal organization, ecological behaviors, and experimental contexts are not identical to human experience. These studies provide hypotheses and, within the tested species and task, causal evidence. Human emotion or awareness claims require independent human validation. The 2026 sensory–bodily-state review explicitly concentrates on animal models.
What evidence is strongest?
Anatomical evidence firmly establishes the insula’s location, subdivisions, and extensive cortical and subcortical connections. Converging lesion, neuroimaging, and stimulation findings support roles in interoception-related processes, pain and temperature, sensory integration, and taste. Meta-analytic functional differentiation supports regional heterogeneity, while large-scale imaging reveals repeatable network affiliations. These are relatively established findings, although their exact mechanistic decomposition remains incomplete. Kurth et al.; Uddin et al..
The salience-network framework has substantial supportive data as a functional model, but proposed switching and direction-of-control mechanisms remain partly dependent on task and analytic assumptions. Strong claims about the insula being the essential generator of conscious selfhood, empathy, disgust, or all emotion go beyond what current evidence isolates. The anterior-insula awareness proposal is influential and scientifically productive, with competing interpretations continuing to be investigated. Craig; Uddin.
Links between atypical insular anatomy or activation and psychiatric symptoms are primarily group-level research associations, often heterogeneous across diagnoses and studies. Their causal interpretation, specificity, reproducibility, and individual predictive value must be evaluated separately. The 2024 cellular and systems review highlights the complexity of translating insula findings into explanations of psychiatric conditions.
What happens if the insula is damaged?
Effects depend on which insular territory and connections are affected, the side and size of the lesion, and associated damage. A systematic review of 25 reports involving 49 patients with strokes confined to the insula described motor and somatosensory problems, dysarthria, aphasia, and vestibular-like symptoms, as well as less frequent swallowing, taste, autonomic, awareness, and other disturbances. Small clinical samples and selective case reporting limit generalization. Systematic review of insular strokes.
Insula injury can occur with broader middle cerebral artery strokes and may coexist with urgent neurological symptoms. Sudden difficulty speaking, facial droop, weakness, severe imbalance, or other abrupt neurological changes warrant emergency assessment; a reader cannot localize a stroke to the insula from symptoms alone. Later functional outcomes also reflect connected regions and brain-wide reorganization.
Lesion observations illuminate necessity under particular circumstances, but a change in a psychological process after damage does not imply that the region previously performed that entire process in isolation. Network disruption, altered bodily feedback, and compensatory changes may contribute to clinical presentation.
Insula, anxiety, depression, addiction, and other conditions
Research has implicated insular circuitry in anxiety-related bodily vigilance, panic-like sensations, substance craving, depression-associated processing, psychosis-related salience hypotheses, and several other conditions. These are broad scientific associations, and they do not imply one lesion pattern or one activation result shared by all affected individuals. Different diagnoses, symptoms, medications, physiological states, and measurement strategies can generate different results. The interoception and mental health roadmap calls for careful measurement and clinically useful validation.
For anxiety, insular findings are often discussed in relation to anticipated bodily threat and the interpretation of uncertain sensations. Yet a person feeling highly aware of heartbeat or respiration cannot infer an abnormal insula from the sensation. For addiction, experimental findings concern urges and salience, while treatment effectiveness requires separate clinical trials. For psychotic disorders, group studies of structure and network organization do not establish a specific diagnostic insula biomarker. The 2024 review provides an example of how cellular and systems evidence can be assembled without implying diagnostic certainty.
Clinical diagnoses are made through established clinical assessment, not through a single insular fMRI response, resting-state connectivity score, thickness estimate, or consumer “brain scan.” There is no validated general-purpose “insula function test” that identifies an individual’s personality, emotional health, or psychiatric condition from one imaging measurement.
Is the insula responsible for empathy, disgust, and consciousness?
These familiar claims grew partly from studies in which insular activity covaried with particular emotions, social evaluations, and subjective awareness. But activation across many tasks reduces its selectivity. An observer seeing insular activation cannot distinguish disgust from pain, task demands, or an interoceptive response without independent experimental constraints. This is the precise problem of reverse inference described in Poldrack’s methodological article.
Empathy involves representing another person’s condition, affective resonance, attention, learned norms, context, and regulatory abilities; these functions depend on interacting networks. Similarly, experiences of disgust may engage insular and other systems with distinct sensory and social components. Claims that the insula is the single seat of empathy, morality, self-awareness, or consciousness cannot be established from coactivation. The influential anterior-insula awareness theory remains a theory of contribution within a larger architecture, rather than a universally established exclusive location for awareness.
Does interoceptive training change the insula?
Breathing exercises, attention to internal sensations, meditation, body-oriented therapies, and biofeedback can alter attention, arousal, subjective reports, and measured brain signals under certain conditions. Any specific therapeutic claim requires evidence from appropriately controlled trials that examine meaningful outcomes, not merely changes in fMRI activation. A change in insula connectivity following an intervention is a research observation; it does not automatically demonstrate improved emotional regulation, clinical recovery, or lasting neuroplasticity.
Popular instructions to “activate the insula” or “reset the salience network” overstate the precision of currently available self-help tools. The value of a practice should be judged by what it reliably improves, for whom, for how long, and with what risks. Individuals with panic symptoms, trauma-related symptoms, or distressing bodily hypervigilance may react differently to intensive internal attention. In those settings, intervention choices belong within individualized clinical assessment rather than an anatomical slogan.
Common misconceptions about the insula
“The insula is the brain’s emotion center.” Emotional processes depend on interacting systems, and insular subdivisions are involved in sensory, regulatory, attentional, and affective tasks. The word “center” conceals the network organization established by anatomical and functional studies.
“The anterior insula contains the entire conscious self.” This extrapolates from a theoretical proposal and wide activation patterns to an exclusive causal claim that current experiments cannot establish. Human subjective awareness has multiple interacting physiological and neural contributors.
“More insula activity means more anxiety, empathy, or bodily intelligence.” The meaning and direction of an activation contrast depend on task conditions, baseline, individual physiology, and analytic choices. A higher signal is not intrinsically healthier, more conscious, or more pathological.
“Heartbeat counting gives a simple score of how well your insula works.” Several studies challenge the task’s construct validity and comparability with other cardiac tasks. A meta-analysis of heartbeat tasks found only a small association between counting and discrimination accuracy, and a large methodological study highlighted biases and interpretive complications.
“If scientists see a sensation in fMRI, they have found its neural cause.” Neuroimaging generally reveals associations under specific conditions. Stronger causal claims require appropriately designed experiments, perturbation evidence, lesion studies, or convergent models. Even these identify contributions at particular scales, not a complete explanation of experience.
Frequently asked questions
Is the insula part of the limbic system?
The insula has sometimes been classified with limbic or paralimbic structures, but contemporary research more usefully describes its subdivisions and network connections. Its activities extend across sensory, autonomic, affective, social, and executive domains. “Limbic” is therefore an anatomical or historical shorthand rather than a sufficient explanation of insular function.
Does the insula control fear?
It can participate in bodily arousal, salience, anticipation, and interpretation of threat-related sensations. Fear learning and expression involve interacting cortical and subcortical systems, including the amygdala and several other regions. Insular activation alone does not prove that a person feels fear.
Is the insula the same as the salience network?
No. The insula is an anatomical cortical region, and the salience network is an inferred pattern of cooperating regions and activity. Anterior insular subdivisions form important nodes in many accounts of that network, alongside dorsal anterior cingulate and other areas.
What is the difference between the insula and the anterior cingulate cortex?
Both can contribute to salience-network activity, but they have different anatomical locations, cellular organization, and connection patterns. Insular territories are strongly implicated in integrating body-state and sensory significance; cingulate territories participate in monitoring, effort, value, control, and action-related processes. Neither structure has one invariant psychological role across tasks.
Can damage to the insula eliminate emotions?
Clinical effects vary widely. Damage may alter sensory, autonomic, language, balance, craving, or awareness-related functions, but the distributed organization of emotional processing makes a universal loss of emotion an unsupported prediction. Specific deficits depend on lesion characteristics and wider network effects.
Can an MRI scan tell whether my insula is functioning normally?
Structural MRI may detect lesions or major anatomical abnormalities, and research fMRI can examine group-level patterns or task responses. Routine imaging does not yield a single clinically validated score of insular emotional or interoceptive health. Interpretation belongs to the relevant clinical question and established diagnostic pathway.
Why is the insula active during so many different tasks?
Its subdivisions sit at the intersection of sensory, physiological, affective, and attentional systems. Tasks differ in demands but often involve bodily significance, novelty, effort, or context-sensitive prioritization. Activation is therefore meaningful only with respect to the experimental comparison and converging evidence.
Does the right insula do something entirely different from the left?
Laterality effects exist in some studies, but they do not support a universal personality or emotion split. Both hemispheres contain heterogeneous insular subdivisions, and right-versus-left results vary with task and method.
Conclusion
The insula contributes to how bodily conditions enter perception, become significant in context, and interact with attention, feeling, motivation, and behavior. Its posterior and anterior subdivisions participate differently within distributed circuits, and the salience-network account explains part of this organization. The strongest interpretation combines neuroanatomy, careful definitions of interoception, experimentally constrained imaging, causal evidence where available, and explicit attention to limitations. The insula provides a major window into brain–body integration, while complex feelings and behavior remain properties of interacting systems.
Related Articles
How the Brain Produces Behavior: Neurons, Circuits, and Networks
Amygdala: Threat, Salience, Learning, and Emotion
Salience Network: Insula, Attention, and Brain-State Switching
References
Linking sensory experience to bodily states in the insular cortex (2026). Review.