Putative heartbeat-evoked potentials in rats and its spatial distribution in the temporal cortex

Area of Science:

• Neuroscience
• Interoception research
• Brain information processing

Background:

• Interoception, the brain's processing of internal body signals, is crucial for cognition and emotion.
• Heartbeat-evoked potentials (HEPs) are neural signals linked to interoception, but their mechanisms remain unclear.
• Investigating HEPs in animal models is essential for understanding their neural basis.

Purpose of the Study:

• To identify and characterize candidate heartbeat-evoked potentials (HEPs) in rats using invasive recording techniques.
• To investigate the neural substrates of HEPs in the rat brain.
• To compare potential rat HEPs with human HEPs to explore neural homology.

Main Methods:

• Utilized microelectrode arrays for simultaneous electrophysiological recordings in rat insular cortex (IC) and auditory cortex (AC).
• Analyzed neural activity synchronized with the cardiac cycle to detect heartbeat-evoked potentials.
• Quantified the amplitude of detected neural fluctuations in relation to heartbeats.

Main Results:

• Identified a neural fluctuation phase-locked to the heartbeat cycle in rats.
• Observed significantly larger amplitude of this putative HEP in the insular cortex compared to the auditory cortex.
• The findings suggest a predominant role of the IC in processing heartbeat-related neural signals, mirroring human studies.

Conclusions:

• A candidate heartbeat-evoked potential was identified in the rat insular cortex.
• The results support the hypothesis that the insular cortex is a key brain region for processing interoceptive signals, including those related to heartbeats, in both rats and humans.
• Further research is warranted to confirm the homology between rat and human HEPs and elucidate their functional significance.