Nicotine, the Insular Cortex and Empathy

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A couple of very interesting papers have come to my attention recently. The first one was published very recently in Clinical Endocrinology where they found that those who quit smoking had a 6-fold increase risk for autoimmune thyroid problems. There seems to be a complex interaction between smoking and the immune system in that the authors of the paper were speculating that “transition from current to ex-smoker may lead to limitation in activity, to chronic health conditions, to physical and psychological symptoms and to a higher hospital admissions“. Smoking is associated with a low prevalence of thyroid auto-antibodies, and autoimmune thyroid problems is a huge problem in the world today.

The second paper is very fascinating, considering that anti-smoking activists tend to be intolerant and judgmental Authoritarian Follower types. I’m going to quote some excerpts here:

Does insular stroke disrupt the self-medication effects of nicotine?

Schrand JR., Med Hypotheses. 2010 Sep;75(3):302-4.

Abstract

This paper explores the relationship between insular stroke and the disruption of tobacco use. A functional analysis of the role of the insula in maintaining homeostasis suggests that the insula monitors hypoxia and applies dyspnea to motivate the individual to regulate breathing. From its’ early usage, nicotine has been used to treat respiratory disorders. It increases respiratory drive, promoting better breathing. Insular stroke likely interferes with this self-regulation. A new self-medication model is proposed for tobacco use. The effect on public policy is discussed.

Background: the problem

Naqvi et al. [1] found that those who have had an insula lesion have an increased risk for disruption of smoking activity (odds ratio = 22.0) compared to lesions in other areas. […]

Stress and respiration

Stress occurs when a threat to physiological equilibrium is perceived. It influences constructive behavior change in response to an unbalanced dynamic environment. Mild, short-term stress has a salutatory effect. However, chronic stress has a weakening effect on the neuro-immune systems response to life’s traumatic events and challenges respiration [5]. Recent studies document the particularly devastating effects of severe stress from Adverse Childhood Experiences (ACE’s) [6]. The system is out of balance during the early development years. Childhood stress is related to asthma [7,8] and depression in adulthood [9]. Those with asthma are at increased risk for depression [10]. Those with stress related respiratory disorders are in need of treatment. The insula responds to this need and encourages medication seeking to achieve homeostasis.

Nicotine as self-medication

Functionally, the purpose of tobacco use is to deliver nicotine, a CNS and respiratory stimulant [11]. The Native American population has used tobacco for 2000 years. Tribal shamans used this medicinal herb to treat respiratory disorders [12,13]. In the late 1800’s, physicians used tobacco products to treat asthma [14]. ACE’s have a graded effect on tobacco initiation and use [15], especially in the current population [16]. Those with ACE’s are more likely to be depressed in adulthood [17]. Adolescents with prior or current asthma are 1.5 times as likely to smoke [18]. It has been proposed that nicotine is being used as self-treatment for sleep apnea [19]. It should not be surprising that many are unknowingly using this medicinal herb to treat stress related respiratory disorders. Yes, tobacco use has purpose. However, nicotine improves breathing only temporarily as long as nicotine is in the system.

What is described as ‘‘craving” for nicotine may be no more than chronic mild dyspnea or air hunger. It encourages re-administration as necessary to insure a continuous level of nicotine. Anything that improves breathing is likely to be compulsive to maintain homeostasis.Yes, ask a person to hold their breath for about a minute and see if the insula does not motivate them to fix that serious problem. If they follow that with corrective action such as deep breathing or medication, this action will become compulsive. The potent motivational aspect of the neuro-respiratory system continues to work. Homeostasis is maintained. […]

Insular stroke

A stroke in the right insular cortex reduces the sensitivity to the perception of dyspnea [3]. These stroke patients would not be aware of their hypoxic state, and not motivated to continue treatment with nicotine. The apparently functional stroke patient will get lots of positive feedback from health care workers. But, the human system is still in serious trouble. Having no interest in those choices that improve life is a sign of depression, common in stroke patients.[…]

External homeostasis

While research efforts have focused on internal control systems, the damaging effects of insular stroke are not specific to interoceptive homeostasis. Depending on the extent of damage to the insula, it may also effect the response to the external senses of vision, hearing and smell, etc. It may increase or decrease sensitivity to senses that are involved in the perceived of external homeostasis.

As noted in Naqvi’s narrative [1], patient N enjoyed smoking for many years. But, after the stroke, he not only lost his desire to smoke, but was now ‘‘disgusted by the smell”, a condition similar to hyperosmia. The entire frame of reference for perception of what is pleasurable or painful has been shifted. The insula along with the amygdala has been found to be responsible for prejudice against groups that are considered outside the norm [20]. Because of this pathological condition, sights, sounds and smells of individuals that were once normal may now be perceived as something to be avoided or controlled, . . ..a threat. […]

It is interesting the comment about impaired smell, considering that psychopaths have poor sense of smell. I’m not implying that there is a  connection between insular stroke and psychopathy, but rather a possible role of the insula in empathetic processes.

The other interesting thing about the insular cortex is that it is densely populated with what is called the Von Economo cells or spindle cells which are related to our psyches:

[Von Economo neurons and insular cortex – the bridge between soma and psyche].

Neuropsychiatr. 2010;24(1):64-6.

New research suggests a pivotal role of the anterior insular cortex for the integration of somatic sensation and for intuitive decisions in complex social situations. Functional magnetic resonance imaging (fMRI) has demonstrated a close coupling between the anterior insular cortex and the anterior cingulate gyrus, the only areas with von Economo-neurons. These large spindle cells are exclusively found in species with complex social lifes (apes, cetaceans). Observations in humans showed decreased numbers of von Economo neurons in patients with frontotemporal dementia, or agenesis of the corpus callosum, conditions with impaired theory of mind and interpersonal behaviour. It almost appears as if spindle cells would reach out from the realm of subconscious gut-feelings into the premises of conscious prefrontal planning.

Most likely related to this, the insular cortex is also associated with processes related with empathy:

Area of the Brain That Processes Empathy Identified

Mount Sinai Medical Center (2012, October 24). Area of the brain that processes empathy identified. ScienceDaily.

An international team led by researchers at Mount Sinai School of Medicine in New York has for the first time shown that one area of the brain, called the anterior insular cortex, is the activity center of human empathy, whereas other areas of the brain are not. The study is published in the September 2012 issue of the journal Brain.

Empathy, the ability to perceive and share another person’s emotional state, has been described by philosophers and psychologists for centuries. In the past decade, however, scientists have used powerful functional MRI imaging to identify several regions in the brain that are associated with empathy for pain. This most recent study, however, firmly establishes that the anterior insular cortex is where the feeling of empathy originates.

“Now that we know the specific brain mechanisms associated with empathy, we can translate these findings into disease categories and learn why these empathic responses are deficient in neuropsychiatric illnesses, such as autism,” said Patrick R. Hof, MD, Regenstreif Professor and Vice-Chair, Department of Neuroscience at Mount Sinai, a co-author of the study. “This will help direct neuropathologic investigations aiming to define the specific abnormalities in identifiable neuronal circuits in these conditions, bringing us one step closer to developing better models and eventually preventive or protective strategies.”

Xiaosi Gu, PhD, who conducted the research in the Department of Psychiatry at Mount Sinai, worked with researchers from the United States and China, to evaluate Chinese patients, at Beijing Tiantan Hospital, who were shown color photographs of people in pain. Three patients had lesions caused by removing brain tumors in the anterior insular cortex; nine patients had lesions in other parts of the brain and 14 patients (the controls) had neurologically intact brains. The research team found that patients with damage restricted to the anterior insular cortex had deficits in explicit and implicit empathetic pain processing.

“In other words, patients with anterior insular lesions had a hard time evaluating the emotional state of people in pain and feeling empathy for them, compared to the controls and the patients with anterior cingulate cortex lesions.” said Dr. Jin Fan, corresponding author of this study and an assistant professor at the Department of Psychiatry at Mount Sinai.

According to Dr. Gu, this study provides the first evidence suggesting that the empathy deficits in patients with brain damage to the anterior insular cortex are surprisingly similar to the empathy deficits found in several psychiatric diseases, including autism spectrum disorders, borderline personality disorder, schizophrenia, and conduct disorders, suggesting potentially common neural deficits in those psychiatric populations.

“Our findings provide strong evidence that empathy is mediated in a specific area of the brain,” said Dr. Gu, who now works at University College London. “The findings have implications for a wide range of neuropsychiatric illnesses, such as autism and some forms of dementia, which are characterized by prominent deficits in higher-level social functioning.” […]

While doing some research about the Éiriú Eolas breathing program based on the stimulation of the vagus nerve, I stumbled upon nicotine’s pro-neuroplasticity role quoted here. In commenting about it with other practitioners of the breathing program, I was surprised to realize how many of them smoked to relieve stress and to breathe better. I count myself luckily among them.

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