How The Brain Works: A Constructionist Approach to Mind-Brain Correspondence (Part 4)

article how the brain works

October 17, 2024

The Interoceptive Network

The interoceptive network is a crucial system in the brain that processes internal bodily signals—like heart rate, breathing, and other physiological states—which is central to understanding emotions and consciousness. According to Barrett (2017), interoception is fundamental to how emotions are constructed, as it forms the basis for the brain's predictions and interpretations of bodily states. The interoceptive network includes both the default network and the salience network, playing an essential role in the integration of internal states into broader emotional and cognitive experiences. Below, I will explain where it fits in relation to previously discussed brain architecture:

Network 1. Default Network (DN)

The default mode network is typically active during rest, self-referential thinking, and mind-wandering. It includes areas like the medial prefrontal cortex and the posterior cingulate cortex. Interoceptive processing is also relevant to the DMN, as the integration of bodily sensations with past experiences and self-related reflections is important for the construction of emotions (Barrett, 2017). The DMN helps process autobiographical memories and integrate interoceptive states with concepts and mental simulations, contributing to the construction of emotion and self-awareness (Andrews-Hanna et al., 2014).

In this context, the interoceptive network includes the DMN, supporting the brain's understanding of the body in relation to the self, particularly during moments of reflection or contemplation. This interplay helps to create a cohesive narrative about one's own internal experience.

Network 2. Salience Network (SN)

The salience network is primarily involved in detecting and filtering out the most relevant information—both internal and external—at any given moment. This network includes key structures like the insula and the anterior cingulate cortex (ACC), which are closely tied to interoception. The insula is a major hub for processing interoceptive signals and acts as a gateway, integrating internal body states with emotional, cognitive, and attentional processes (Craig, 2009).

The salience network is responsible for shifting attention to emotionally significant or physiologically relevant information. For instance, if you feel a quickening heartbeat, the salience network will prioritize this internal sensation, perhaps leading to a constructed emotional experience like anxiety or excitement. Therefore, the salience network is an integral component of the interoceptive network, as it plays a crucial role in filtering and prioritizing interoceptive signals (Barrett & Simmons, 2015).

3. Connections to Other Networks

The other intrinsic networks also have indirect interactions with the interoceptive system:

Frontoparietal Control Network (FPCN): The FPCN interacts with the interoceptive network through executive control functions, especially when we try to regulate emotions or consciously attend to internal sensations. The interoceptive information supports decision-making processes and helps to inform how we regulate our emotional responses (Barrett, 2017).
Ventral and Dorsal Attention Networks: These networks are involved in allocating attention to both salient stimuli and top-down tasks. The interoceptive network contributes to this by signaling changes in internal bodily states that may require shifts in attention. For example, an unexpected sensation like pain or a rapid heartbeat could engage these attention networks to focus on that sensation (Menon & Uddin, 2010).

Summary

The interoceptive network is a foundational part of the brain's ability to understand and integrate internal bodily signals. It includes both the salience network and the default mode network, providing the internal body-state information that helps determine which stimuli are most relevant (Barrett & Simmons, 2015).

In essence, the interoceptive network is woven into the broader fabric of brain functioning to help build our understanding of the body, emotions, and the self. This integration allows us to respond appropriately to both internal sensations and external stimuli.

- Ramon D.
Founder, BrainFrst Inc.

References
Barrett, L. F. (2017). How Emotions Are Made: The Secret Life of the Brain. Houghton Mifflin Harcourt.
Barrett, L. F., & Simmons, W. K. (2015). Interoceptive predictions in the brain. Nature Reviews Neuroscience, 16(7), 419-429.
Craig, A. D. (2009). How do you feel—now? The anterior insula and human awareness. Nature Reviews Neuroscience, 10(1), 59-70.
Andrews-Hanna, J. R., Smallwood, J., & Spreng, R. N. (2014). The default network and self-generated thought: Component processes, dynamic control, and clinical relevance. Annals of the New York Academy of Sciences, 1316(1), 29-52.
Menon, V., & Uddin, L. Q. (2010). Saliency, switching, attention and control: a network model of insula function. Brain Structure and Function, 214(5-6), 655-667.