Further than just muscle memory, every cell in our bodies actually has "memories". That's why heart transplant patients can experience personality changes from the donor:
Excuse my ignorance in asking, but is this trustworthy? I'm a layperson regarding biology and I was always assumed that organs outside of the brain don't contribute to memory. At the end of the article is the statement "Data not available / No data was used for the research described in the article." Is it possible to see the data?
We know there are lots of biological mechanisms that retain state at the cellular level to put it in CS-ish terms. A fraction of these mechanisms could plausibly be transmitted outside the cell (e.g., miRNA).
These mechanisms may or may not encode memories as we typically understand them, i.e., the ability to remember an event or fact, but could very plausibly shift personality, preferences, etc.
Not to mention that most neurotransmitters are produced / collected from the gut. Many seem to be produced / used as signalling molecules by gut microbiota.
>> can experience personality changes from the donor
> organs outside of the brain don't contribute to memory
Interesting question. To start, personality typically refers to the totality of a person's behaviors, not the memories they may be able to bring forth. Behavior, esp automatic, is informed by cognitive states informed by the body.
Affect is the general sense of feeling that you experience throughout each day. It is not emotion but a much simpler feeling with two features. The first is how pleasant or unpleasant you feel, which scientists call valence. . . . The second feature of affect is how calm or agitated you feel, which is called arousal. [0]
Simple pleasant and unpleasant feelings come from an ongoing process inside you called interoception. Interoception is your brain’s representation of all sensations from your internal organs and tissues, the hormones in your blood, and your immune system.
...[M]oment-to-moment interoception infuses us with affect, which we then use as evidence about the world. People like to say that seeing is believing, but affective realism demonstrates that believing is seeing.
0. Barrett, Lisa Feldman. How Emotions Are Made: The Secret Life of the Brain (p. 72). HarperCollins. Kindle Edition.
I remember seeing a docmentary about this. There was a man who received a transplant arm from someone who died and started to exhibit the donor's manners and ended up planning an elaborate scheme to get revenge on the donor's twin brother.
https://www.sciencedirect.com/science/article/abs/pii/S03069...