Summary Functional neurological disorders reflect deficiencies in brain networks that lead to distressing motor, sensory, and/or cognitive symptoms that demonstrate positive clinical signs on examination that are incongruent with other known conditions. A central theme in historical and contemporary formulations of functional neurological disorder has been the mechanistic and etiological role of emotions . However, the debate has mostly omitted fundamental questions about the nature of emotions in the first place. In this perspective article, we first describe a set of relevant working principles of the brain (e.g., allostasis, predictive processing, interoception, and affect ), followed by a focused review of the theory of emotion constructed to present a new understanding of what They are the emotions. From this theoretical framework, we formulate how the construction of altered or aberrant emotion categories may be an integral component of the pathophysiology of functional neurological disorder and related functional somatic symptoms. In doing so, we address several topics for the field of functional neurological disorders, including: (i) how energy regulation and the emotional category construction process relate to symptom generation, including review of alexithymia , the ’ ’panic attack without panic’ , dissociation, insecure attachment and the influential role of life experiences; (ii) reinterpret findings from selected neurobiological investigations in functional neurological disorder cohorts through the lens of constructed emotion theory to illustrate their potential mechanistic relevance; and (iii) discuss therapeutic implications. |
The constructivist brain and instances of emotion
Constructed emotion theory offers a constructionist approach to understanding what emotions are by leveraging the brain’s primary role in energy regulation and predictive processing. In the brain, incoming sensory information from the body and the world is compared to features that have already been classified and can be used to give meaning to the current input. Without direct access to what is causing the advent of sensory information, meaning is derived from past events that appear similar to the current state of the body and world. Based on past experiences that share characteristics of equivalence with the present, our brain uses the concepts (i.e., abstract mental representations) that were relevant at that moment, with all possible futures and associated action plans to treat and understand sensory signals. current entrants. In doing so, an individual is using an embodied concept as a prediction.
If a prediction (i.e., the embodied concept) matches the incoming sensory information and prediction error is minimized, similar features from the past are brought together to give meaning to the present, constructing a situated or ad hoc category . When we use an experience of emotion as a reference for present constructed categories, we are constructing a conceptual category for the emotion. If the same set of incoming sensory information were matched with a "non-emotional" concept (e.g., "exhaustion" instead of "sadness") under different circumstances or by another person, a conceptual category for the emotion would not be constructed but a somatic
Conceptual categories are compressed summaries that classify physical (sensory) signals, give them meaning (emotional or somatic), and make the experience an instance of that assigned category.
The primary purpose of the brain’s constructed category, whether for an instance of newly constructed categories help classify, understand, and emote or otherwise, is to allostasis deal with incoming sensory data, and then help inform future situations. Categories provide meaning to incoming sensory information because they represent a grouping of features that have similarities or share a goal. Predictive signals come to include visceromotor and motor action plans, affective properties, and more, as they move along the cortical cytoarchitectonic gradient that prepares the body for expected sensory consequences. Thus, when an ad hoc category is constructed , the individual is prepared to face the present. In this way, the dynamics of predictive processing suggest that action preparation gives rise to experience, and not the other way around . Therefore, ad hoc conceptual categories of emotion are compressed summaries that classify physical signals, give them emotional meaning, and make the experience an instance of that category of emotion.
We postulate that NPT symptoms in some people reflect chronic difficulties in managing allostatic energy through inefficient use of emotional concepts. This does not imply that affected individuals suffer from objective energy deficit , but rather that inherent and ongoing allostatic processes are marked by suboptimal emotional construction. As less granular and efficient concepts like “fatigue” and “discomfort” replace more fine-tuned (i.e., predictive ) emotional concepts, this chronic inefficiency is perpetuated. Despite the clinical heterogeneity of FND, fatigue is the most common shared symptom, reported by 93% of 1048 people surveyed in 16 countries. Fatigue is highly prevalent and a main predictor of quality of life with motor TNF, more so than hypervigilance and severity of motor symptoms6, 162.
Building inefficient emotions can also lead to hyperarousal . Hyperarousal is common in NFTs; This is exemplified by the observation of “non-panic panic attacks” in people with functional seizures , as well as increased sympathetic tone and abnormal startle responses in populations with NPD. People with NPD also have high rates of comorbid post-traumatic stress disorder (PTSD), where hyperarousal is a core symptom. High arousal, particularly when combined with negative valence , is known to trigger increased muscle tension that may be related to chronic pain ; Similar associations are also well accepted for gastrointestinal upset . Additionally, it has been proposed that mood disorders , including major depression , are also related to allostatic mismanagement . Therefore, the high comorbidity among NPDs with selected psychiatric conditions and functional somatic disorders suggests shared inefficiencies in allostatic energy management.
Key results
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An ongoing debate in neurology and psychiatry is the extent to which emotions have a mechanistic or etiological role in functional neurological disorder (FND). Surprisingly, the discussion has largely ignored the question of what emotions are in the first place.
The classical view is that specific emotions, such as fear , can be reliably identified by certain physiological characteristics and/or behavioral patterns. However, between studies, and even between subjects within the same study, there is substantial variability in how emotions match facial movements, vocalizations, patterns of autonomic nervous system physiology, brain activity profiles, and recordings of a single neuron.
In Brain , two professors affiliated with the Athinoula A. Martinos Center for Biomedical Imaging at Massachusetts General Hospital: David L. Perez, MD, MMSc, also director of the Functional Neurological Disorders Unit and Research Program in the Departments of Neurology and Psychiatry, and Lisa Feldman Barrett, PhD, also affiliated with the Department of Psychiatry’s Division of Psychiatric Neuroimaging, and colleagues present a new science of emotion and its implications for the pathophysiology of NFT. The co-first authors of this article were Drs. Johannes Jungilligens and Sara Paredes-Echeverri, two talented postdoctoral researchers from the TNF Research Group.
Allostasis and the predictive brain
The central nervous system predicts the body’s energy needs and tries to meet them through a process known as allostasis . The brain models the body in the world and also interprets physiological signals provided by interoception , the moment-to-moment modeling of the body’s internal state.
The brain compares incoming sensory information from the body and the world with features that have already been classified, giving meaning to the current input. In essence, the brain derives meaning from past events (and concepts) that seem similar to the current experience.
Abstract mental representations and visceromotor and motor action plans used to deal with sensory signals in the past are applied to current sensory information. Thus, the individual uses an "embodied concept" as a prediction .
If the prediction is shown to match the incoming sensory information and the prediction error is minimized, an ad hoc mental "category" is constructed . The newly constructed categories help the brain classify, understand, and manage incoming sensory data.
The theory of constructed emotion
An emotion experience can be a reference for a constructed category. Conceptual categories of emotion categorize physical signals, give them emotional meaning, and make the experience an instance of that emotion category.
Life experiences inform the development and refinement of the repertoire of emotional concepts. Individuals who lack a stable and supportive environment during development may not learn to distinguish signals important from those not important for allostasis . Therefore, the task of creating and reconditioning emotion categories could be performed less efficiently and differently between instances. In this way, the efficiency of the brain’s predictive process may be disrupted and the construction of an emotional category may not be well adapted to the immediate environment.
Reconceptualizing TNFs using constructed emotion theory.
The authors propose that functional somatic and neurological symptoms may be caused by disruptions of predictive processing that is part of the construction of emotional categories. They present six interrelated proposals, which are not intended to apply to all people with NPD:
There is chronic mismanagement of allostatic energy in TNFs related to suboptimal emotional construction. For example, the concept of “chronic fatigue” may gradually supplant a more efficient emotion category construct. Hyperarousal and hypervigilance , two other common symptoms of NPT, are also related to poor energy management .
NFTs can occur in the context of constructing aberrant emotions : some people may have absolute deficiencies in constructing an emotion category for a particular instance. For example, for individuals with high arousal states associated with physical symptoms, such as paroxysmal motor phenomena, perceptual inferences can make sense of them by constructing an emotion category such as "fear" or "being shocked" . Others, in the same instance, may fail to construct an instance of an emotion category, instead predicting (and combining with) a non-emotion concept, such as “shaking and shaking.”
Learning from prediction errors is impaired in NPD: some people with NPD show impairments in sensory processing, impairments in interoceptive accuracy, biased attention, and impairments in motor learning.
Three common symptoms of NFTs can be understood as manifestations of the construction of aberrant emotions:
- Alexithymia (defined in part as difficulties identifying/describing feelings).
- “Non-panic panic attack” (individuals endorse the autonomic symptoms of panic attacks but not the emotion of panic itself).
- Dissociation
Constructed emotion theory helps contextualize the debate about emotion in NPD: individual differences in the construction of emotions help explain why a clinician might assess someone with NPD as “anxious.” For example, while the individual denies the presence of that emotion. A key implication of the theory of constructed emotion is that humans cannot know another person’s subjective emotional experience .
Adverse life experiences can negatively affect an individual’s repertoire of conceptual emotion categories and their refinement: not all people with NPD report early life adversity or history of trauma, but multiple cohort studies have identified associations between the magnitude of adverse experiences and the severity of functional disorders and neurological symptoms. The authors speculate that the construct of aberrant emotions and related factors that contribute to ineffective allostatic modeling (e.g., insecure attachment) may mediate this correlation.
Therapeutic implications
An important therapeutic strategy for patients with NPD may be to guide them to reattribute physical symptoms to newly developed or more refined emotional categories that aid more efficient performance of allostasis. This suggestion contrasts with psychodynamic theories that an emotion concept has been formed but is repressed or "converted" .
Therapies focused on teaching patients to sense, regulate, and meet the body’s needs (i.e., perform "allostatic maintenance" ) merit investigation in TNFs. Bottom-up (e.g., sensorimotor psychotherapy) and top-down (e.g., cognitive behavioral therapy) approaches may have complementary benefits.
