Impact of Bodily and Neural Rhythms on Auditory Perception

• Applicant: Esra Al
• Subject Area: Human Cognitive and Systems Neuroscience ; Cardiology, Angiology ; Cognitive, Systems and Behavioural Neurobiology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 504477414

The repeated presentation of the same sensory stimulus can evoke different perceptual outcomes: sometimes we may consciously perceive it and other times not notice it at all. To explain how the same physical stimulus can be perceived differently at different times, most studies have focused exclusively on brain activity. However, recent work has demonstrated that bodily processes—such as the cardiac cycle and respiration—also impact our perception, cognition, and behavior. Indeed, my colleagues and I have found that conscious perception of a stimulus is affected by the phase of the cardiac and respiratory cycle. Moreover, we have shown that the strength of cortical responses to heartbeats influences stimulus perception. Importantly though, the underlying mechanism of cardiorespiratory effects on perception remains unclear. In this proposal, I present a two-year plan to investigate this underlying mechanism more comprehensively. I will investigate how respiratory and cardiac signals interact with neuronal dynamics, and their joint effect on auditory perception. To study neuronal dynamics, I will specifically focus on neuronal oscillations, neuronal excitability levels, as well as connectivity patterns. I will examine these neuronal processes using intracranial electrocorticography (ECoG) in surgical epilepsy patients, along with electroencephalography (EEG) in healthy human participants, while monitoring their respiratory and cardiac activity. The high spatial resolution of ECoG will allow me to observe local effects in interoceptive regions associated with body-brain interactions. Combined with whole-brain EEG, this will provide novel insights into both local and global network dynamics underlying body-brain interactions and their effects on perception. Furthermore, brain-body interactions have been implicated in anxiety disorders, which are the most common mental health disorders in adults. Elevated anxiety levels can result in hyperarousal and can trigger abnormalities in perceptual processes. To address the role of anxiety in brain-body dynamics, I will first investigate whether cardiorespiratory effects on perception are influenced by individual anxiety levels. As a further step, I will test the causal influence of arousal on these cardiorespiratory effects. Long term, insights from this proposed work can help us understand the underlying bodily and neuronal mechanisms of perceptual variability. This can then potentially inform clinical interventions to optimize perceptual abilities.

• DFG Programme: WBP Fellowship
• International Connection: USA
• Host: Saskia Haegens, Ph.D.