Into the Insula

Interoception and the Feeling Self

By Kai MacDonald

HANDLES: Carry Them Home.

One of the primary brain areas involved in the awareness of the feeling self is the insula, an area which contains a neural representation of the “state of the feeling body.”
Circuits and states of mind involving the insula may be convergence points between acts of deliberate interoception, dyadic emotional resonance, and important state shifts in experiential psychotherapy.

Imagine, if you will, our brief journey’s guide: an aged and scarlet-hooded Dante, his stooped back mirroring the arc at the top of the curved staff on which he leans.

Imagine further that this same curve intimates a question: that mark whose hooked top grabs your mind with one end and points it somewhere with the other.

Suddenly, tearing off his hood, we see that our guide today is not Dante, but the eminent neuroscientist A.D. Craig, whose recent review: “How do you feel—Now? The anterior insula and human awareness” [1] will be our guidebook.

Today, thankfully, our guide is leading us not into the sinner-strewn hell of the Inferno, but into a hidden part of the brain called the insula. With his title-worthy question (which, one will note, is also an apt entrée point of experiential therapy), Craig deftly shepherds us into a startling, synesthetic world of feeling-focused functional neuroscience, crafting a felt-sense centered theory of awareness that has startling resonance with a host of experiential psychotherapies including AEDP. Given these resonances, and the importance of the insula in many aspects of emotional awareness and human brain function, I herein highlight a few key aspects of Craig’s theory and touch on their implications for psychotherapy. For psychotherapists who work with emotion directly, the convergence of many components of Craig’s model with the “present, feeling focus” of experiential therapy in general–and AEDP in particular–is nothing but remarkable.

In his densely-referenced review, Craig—whose scientific research addresses both pain and perception–expands on his illuminative earlier review of interoception, the “sense of the physical state of the body” [2]. The insula, according to Craig, contains a sensorimotor, somatotopic map of “the feeling state of the body,” summed into a “global emotional moment” and time-stamped by special chronometric (time keeping) neurons that create distinctions between past and present selves and keep our stock of internal states fresh and ordinal.

The following is a selected (and selective!) list of the diverse experiential states correlated with insula activation: maternal and romantic love; other emotions (anger, fear, sadness, happiness, disgust, hate); social exclusion; unfairness; empathy (and lack of it); thirst; air hunger; sensual touch; heartbeat awareness; the feeling of agency or awareness of body control during hand movements (i.e., “body ownership”); itch; sexual arousal; heat and cool sensations; distention of the rectum, bladder and esophagus; the firsthand, empathic and imagined experience of gustatory emotion; awareness of errors; learning about pain; the felt sense that accompanies belief, disbelief and uncertainty; and risk prediction (see [1] for specific references). What all of these diverse states have in common (read them again and check) is all of them activate and/or utilize a body-based “sensory map” of corporeal feelings: in Damasio’s terms, they have “somatic markers” [3], or what Gendlin called a “felt sense”[4]. Perhaps unsurprisingly, the insula is an area that people can be trained to activate [5] and which seems to respond more actively [6] and even grows [7] as the result of present-focused meditation training. A fruitful area of speculation as regards psychotherapy is how the insula might be affected by dyadic metatherapeutic processing, a unique form of attention and one of the mainstays of AEDP practice [8].

The insula, though tucked inside the visible surface of the brain, is a part of the cortex. And though many simple models of the brain locate feelings in the subcortex and thinking in the cortex, modern discussions of the awareness and experience of emotions are more nuanced, and highlight the importance of global cortical “re-representations” of subcortically-generated emotional information, especially in regards to mindful awareness [9, 10]. In this regard, it is notable that though the insula is a cortical area, it is intimately connected with critical regions in the subcortex and midbrain (i.e., the amygdala). As an organizational principle in the brain, each step toward conscious awareness appears to require another neurobiological level of integration and re-representation [11]. Said differently, the kind of experiential awareness that facilitates verbal communication—the conscious awareness of how I feel–requires cortical re-representation; the insula may be part of the circuit that is the apogee of this re-presented information.

What is the impact of the insula in day-to-day life ? Neuroscience points to three interrelated processes: decision-making, fortune-telling and action selection.

On the topic of decision-making: though often thought of as a cognitive process, activation of the insula and corresponding non-cognitive, non-propositional “feelings states” plays a prominent role in modern theories of human decision-making, including decisions related to economics [12], anxiety [13], drug use [14, 15] and morality ([13, 16], and see [17] for review). As such, the insula appears to be an important component in a dynamic coalition of brain regions that codes “how we feel in the present,” and uses these valenced, often nonconscious feeling states to guide action.

From a temporal standpoint, the arrow of decision-making points into the future. In this regard, the insula appears to play the role of a somatic soothsayer, projecting states of the feeling self into the imagined future to help us anticipate what is coming, and how it will feel if the imagined event happens. In support of this model, neuroimaging experiments reveal that the insula is activated in anticipation of negative outcomes, providing a felt sense of motivation that informs our decisions to approach or avoid [18-20]. The brain, in its crucial role as a predicting machine [21], creates our felt sense about a forthcoming decision or situation based partly on a feed-forward projection of the memory of our feeling self in the past [13, 18]. Predictably, since it is a critical region in generating this felt sense, the insula’s sensitivity to stimuli has been proposed to underlie a predisposition to future-fearing conditions like anxiety disorders [22, 23], and the tendency to avoid loss [23]; its genetically-determined relationship with the amygdala may influence a person’s susceptibility to trauma [24]. In a therapy setting, thinking of patients differing in the function and sensitivity of this brain region, as well as its connections to other areas like the amygdala, gives a neurobiological basis to conceptualize different people’s sensitivity to, fearfulness of, and capacity to attend to and tolerate states of in-the-moment feeling.

On the role of the insula in action: feelings impact decision-making, and decision-making often leads to action. On this point, it is notable that the insula has an intimate relationship with a second critical, prefrontal cortical convergence area called the anterior cingulate [1]. The anterior cingulate plays a role in internal conflict (between context and impulse, or thinking and feeling, for example), impacting volition and motivation. Interestingly, alterations in anterior cingulate function may contribute to impulsivity [25], helplessness, and loss of control [26] and—on the flip side–courage in the face of fear [20], and the loss of phobic avoidance [27]. Like the insula, the anterior cingulate has significant interconnections with autonomic and emotional regions including the amygdala, hypothalamus, orbitofrontal cortex, and brainstem regions associated with behavioral programs and bodily regulation [1]. Functionally, when the system is working, the anterior cingulate may utilize information about “the overall felt sense” of a situation from the insula along with contextual and inhibitory signals from other frontal and prefrontal areas to determine what the person does or does not do in the real world [20].

After summarizing the importance and neurobiology of the same present, feeling self we privilege in experiential psychotherapy, Craig discusses the role of the insula in the evolution of the human brain; here he divines the dyadic. Consistent with the last decade of research into social-cognitive-affective neuroscience, and drawing on evolutionary studies of the factors that biased the growth and development of the cerebral cortex [28], Craig states that the evolutionary advantage of the insula’s development is that: “it would improve emotional communication between conspecifics— crucial for hominoid primates.” If we replacing the more ethological terms “conspecifics” with “feeling others” and “hominoid primates” with “humans,” we see the relational component of the insula resonating in the diverse spheres of evolutionary biology, functional neuroscience, and finally landing (here we are) in dyadic, feeling-focused therapy. If this final connection is not a wonder-full example of consilience between state-of-the-art neuroscience and AEDP’s dyadic, affect-focused methodology, I can’t imagine what is.

Here, Virgils all, we part, the question “How do you feel—now?” firmly anchored in our insula, a part of the coalition of brain regions that instantiate present-moment states of embodied feelings. In an upcoming issue of Transformance, we will resume our journey and discuss both the temporal aspects of the feeling self, and how mindful, dyadic attention to felt states actually acts as a neurobiological “railroad switch” shifting between the distinct brain networks which underlie state shifts [29].