Heartbeat shapes how your brain processes information

Also consider tDCS trans-cranial direct current simulation and learning rate?

- tDCS and learning rate: https://www.google.com/search?q=tDCS+and+learning+rate

Visual cortex responded differently to same stimulus depending on whether it was during or in between heart contractions. How do we know it’s not an artifact of the hemodynamic dependent signal in fMRI (BOLD)?