Neurovisceral Integration Model: the Brain-Heart Connection
150 years ago, Claude Bernard showed the connection between the brain and the heart. This scientist proposed that the prefrontal cortex had a regulative function over the subcortical circuits related to motivated responses. Years later, Thayer and Lane (2000) called this connection the neurovisceral integration model.
The model showed a network of neural structures related to physiological, cognitive, and emotional regulation. The name of that network is the central autonomic network (CAN). The network forms an internal regulation system. Through it, the brain can control motor, neuroendocrine, and behavioral responses, all of which are necessary for adaptive behavior.
That central autonomic network influences the heart through the sympathetic and parasympathetic nervous systems. The interaction is actually the source of heart rate variability (HRV).
“When the heart is affected it reacts on the brain; and the state of the brain again reacts through the pneumo-gastric [vagus] nerve on the heart; so that under any excitement there will be much mutual action and reaction between these, the two most important organs of the body.”
The neurovisceral integration model and heart rate variability
Your HRV is a result of the interactions between your autonomous nervous system (ANS) and the intrinsic mechanism of heart functioning. The activity of the SNA finds itself in the balance between the sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS).
The activation of the SNS produces an increase in your heart rate through low-frequency impulses. It’s also responsible for changes in your heart rate from physical or mental stress. On the other hand, the SNP reduces heart rate by high-frequency electrical impulses.
In this way, the intrinsic cardiac mechanisms and the activity connected with the sympathetic and parasympathetic nerves act in the sinoatrial node.
In order to understand this in practical terms, let’s look at it this way. The VHR is just the variation of frequency of the heartbeat during a set interval of time. The most common way to measure it is through an electrocardiogram (EKG).
Recently, research on this model proposed that there’s a relationship between the VHR measured by the PSNS and cardiac indexes of attention and emotion.
This is how researches established the connection between the brain and the heart. Several different studies have shown a reduced VHR in some illnesses characterized by insufficient emotional regulation.
Thus, the neurovisceral integration model proposes an association between the regulation of certain systems with vagus functioning and the VHR. That’s why certain risk factors for cardiovascular disease or heart attack are related to reduced functioning of the vagus nerve.
Biological risk factors
Lifestyle-related risk factors
- Physical inactivity
- Being overweight
Risk factors that can’t be modified
- History of cardiovascular disease
Other risk factors
- Psychosocial factors
According to the neurovisceral integration model, the VHR is also related to emotional regulation. Emotions reflect the capability that people have of adapting to vital changes in their environment.
Scientists recently discovered a difference between individuals with higher VHRs while resting compared to those with lower levels. When those with lower VHRs are at rest, they produce appropriate emotional responses.
In addition to this, the increase in VHR associated with emotional regulation accompanies changes in the blood flow to the brain. This happens in areas identified as important for emotional regulation and inhibitive processes.
Lastly, researchers have tried to determine the relationship between VHR and cognitive regulation. Many of the things you do every day involve cognitive processes. Some of them are:
- Remembering how to work.
- Mental flexibility.
- Sustained attention.
In addition, research has determined that the higher one’s VHR, the better one’s executive functioning and efficiency on all levels. This information is truly valuable for the comprehension of your psyche, and especially of your body overall.