Have you ever wondered what allows you to monitor your internal states? How do you know what you are feeling? This fascinating ability is called interoception. Welcome to another deep dive into the fascinating realms of neuroscience and psychology here at Neuroverse. In episode 76. "Interoception", Carolina and Clara unraveled the intricate world of this critical yet often overlooked aspect of human perception.
Interoception is our capacity to perceive internal body states, encompassing the processes of sensing, interpreting, integrating, and regulating signals from within our bodies. Often referred to as our "sixth sense", interoception significantly shapes our sense of self and influences our emotions and decision-making processes.
Artwork by April Zanne Johnson
from https://www.saatchiart.com/print/Painting-Interoception-Doors-Migration-Series/320682/3250721/view
Probing Internal States
While the majority of neuroscience research has focused on how we perceive the external world (visual, auditory, olfactory, touch cues), less is known about how we process internal signals such as biochemical signals (peptides from food), mechanical signals (proprioception), and sensing our heart rate. These internal signals are crucial in how we experience our emotions and ultimately guide our decisions.
The episode highlights the challenges of probing and measuring such subjective internal signals which can greatly vary within and across individuals. Self-report methods are often used in interoception studies, where participants describe their internal experiences. While useful, these methods have significant limitations. Self-reports are subjective and can be influenced by a person's current mood, memory biases, and language abilities. Additionally, people may not always be aware of their internal states or accurately describe them, leading to inconsistencies in the data. For example, a common method to estimate interoceptive accuracy is known as the heartbeat detection task, where study participants are asked to count their own heart rates in a given amount of time. Performance in such a task can be influenced by factors like anxiety, attention, and physiological differences in the strength of the heartbeat or body composition. The complexity of studying interoception is further compounded by the bidirectional signaling between the brain and internal organs, making it challenging to pinpoint the origin of these signals.
To overcome these challenges, advancements in neuroimaging and wearable technology are providing more objective and comprehensive insights. Neuroimaging techniques, like functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), allow scientists to observe brain activity in real-time. These methods help identify which brain regions process interoceptive signals and how these regions communicate. For instance, fMRI studies have highlighted a major role of the anterior insular cortex in interoception, revealing its connection to our sense of self and emotional processing.
Wearable technology, such as smartwatches and fitness trackers, can monitor physiological signals like heart rate, skin conductance, and temperature continuously. This real-time data collection enables researchers to study interoception in natural settings outside the lab. For example, tracking heart rate variability can provide insights into how stress and anxiety affect interoceptive accuracy. These wearables can also give feedback to users, helping them become more aware of their internal states and potentially improving their interoceptive abilities through biofeedback training.
By correlating real-time physiological data from wearables with brain activity observed through neuroimaging, researchers can better understand the dynamic relationship between the brain and body. This integrated approach helps pinpoint how internal signals are processed and how they influence our emotions and behaviors.
Why Does Interoception Matter?
Deficits in interoception are linked to a condition known as alexithymia, the impaired ability to be aware of and describe one's own emotions. Studies show that individuals with alexithymia often have difficulty detecting their own heart rates and exhibit reduced neural responses in brain regions associated with emotional processing, suggestive of poorer interoceptive ability. This association between deficits in emotional processing and interoception highlights the importance of interoception in emotional awareness and regulation.
Further, it supports Antonio Damasio's Somatic Marker Hypothesis, which highlights the role of bodily states in shaping emotions and decision-making. This theory challenges the notion that human reasoning is solely based on cognition, emphasizing the influence of bodily signals. According to Damasio, emotions play a key role in making fast, rational decisions under uncertain situations, and changes in the body (somatic markers) underlie these emotions.
The episode delves into various ways in which interoceptive processes intricately linked to cognitive processes like self-related thoughts and memory. Another important cognitive process that is associated with interoception is theory of mind, the ability to understand and predict others' thoughts and feelings, which sits at the core of what it is to be a social human. The concept of mentalizing, or thinking about the mental states of oneself and others, is also discussed in the episode. This ability is closely linked to interoception, as understanding one's own internal states can help predict and empathize with others' emotions.
Of course these concepts of mentalizing and empathy had to be related back to what is happening in the brain, in true Neuroverse fashion, and so another fascinating topic that was covered was mirror neurons. These neurons fire both when an individual performs an action and when they observe someone else performing the same action. This mirroring process helps in understanding the intentions behind actions and plays a significant role in empathy and social cognition.
In Conclusion
Interoception, our internal sixth sense, plays a pivotal role in shaping our perception of self and the world. By understanding its mechanisms and implications, we can better appreciate the profound connection between our bodies and minds. Whether through scientific research or mindfulness practices, enhancing our interoceptive awareness holds promise for improving our overall well-being.
Listen to the episode here to find out more!
This article was written by Shivali Verma and edited by Clara Lenherr
Shivali Verma is a Master’s student in Brain and Mind Sciences at UCL. She is most interested in researching neurodegeneration, and is passionate about bridging the gap between scientific complexity and everyday understanding.
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