How do interoceptive rhythms in the brain coordinate with emotional and cognitive processing across time scales?

The heartbeat as a timing signal for emotion

One of the clearest examples of a body rhythm influencing emotion is the heartbeat. In an experiment that primed people by directing attention to their own heartbeat and then showed them facial expressions, healthy participants recognized negative emotions more readily after the interoceptive prime than after a control condition that directed attention outward [5]. The effect was not just behavioral: electrical brain activity time-locked to the heartbeat, called the heart-evoked potential, was modulated during the recognition of negative faces in healthy controls [5]. This suggests that a cardiac rhythm can act as a preparatory signal that biases how emotional cues are processed moments later.

The same study found that this priming effect was not universal. Patients with behavioral variant frontotemporal dementia and Parkinson's disease showed disrupted negative-emotion recognition after interoceptive priming, while patients with Alzheimer's disease showed broader emotional disruptions but preserved interoceptive mechanisms [5]. The authors linked the integration of interoception and emotion to the volume of the insula and anterior cingulate cortex and to connectivity in the salience network after interoceptive priming, versus the executive network after exteroceptive priming [5]. In other words, the heartbeat's influence on emotion appears to depend on specific brain hubs, and damage to those hubs can break the link.

Interoception is more than one signal

Interoception is not a single channel. A review of the field describes it as having several dimensions: the nature of the bodily signals arriving at the brain, how accurately a person can sense them, how the brain processes them neurally, and how a person interprets them at a higher level [4]. Emotional experience is thought to combine these interoceptive inputs with appraisal guided by external context [4]. This matters for the question of timing because different dimensions may operate on different clocks—raw afferent signals arrive continuously, while accuracy and interpretation unfold over longer periods.

The review also notes that conditions with altered emotional profiles, including anxiety, depression, schizophrenia, posttraumatic stress disorder, emotionally unstable personality disorder, and autism, show distinct changes in interoception [4]. That pattern is consistent with the idea that interoceptive signals contribute to emotional processing, though it does not by itself show how those signals are coordinated in time. The review evaluates interoceptive dimensions through empirical research but does not address coordination across time scales [4].

Aging reshapes the brain's interoceptive network

The coordination between body rhythms and emotion is not fixed across a lifetime. In a study of 62 adults aged 18 to 73 who performed a heartbeat detection task during functional brain imaging, increasing age was linked to decreased activation in interoceptive regions, including the right insular-opercular area and the supplementary motor area [3]. Age also changed task-based functional connectivity, with a decrease in connectivity between the supplementary motor area and the insular network and an increase in connectivity between prefrontal and lateral occipital regions [3].

A path analysis suggested that the effect of age on interoceptive accuracy was mediated by activation in the insular cortex and supplementary motor area and by connectivity between them [3]. A second analysis suggested that the effect of age on alexithymia—difficulty identifying and describing emotions—was mediated by interoceptive decline, even when depressive attitudes were controlled for [3]. This is correlational and mediation-based evidence, not proof of causation, but it points to a shared neural ground between interoceptive decline and emotional processing in older adults [3].

Rhythms as reference scales for experienced time

A broader theoretical proposal places body and brain rhythms at the center of how we experience time itself. The argument is that physical time is measured with artificial clocks, but experienced time is linked to a hierarchy of brain-body rhythms that provide a range of reference scales spanning the full range of experienced time [1]. On this view, changes in body and brain circuits tied to these rhythms may be the source of our subjective feeling of time [1].

This proposal is explicitly about time and episodic memory, not about emotion or cognition in general, and it is presented as an alternative view rather than an established mechanism [1]. It is nonetheless relevant to the question of coordination across time scales: if the brain uses a hierarchy of rhythms as reference scales, then interoceptive rhythms could in principle serve as one layer of that hierarchy. The evidence for this remains theoretical and does not yet demonstrate how such scales would coordinate with emotional or cognitive processing [1].

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