What is the term used for the hypothetical physical changes in the brain that correspond to memory traces?

The term "engram" refers to the physical representation or trace of memory stored within the brain. It is often conceptualized as the hypothetical changes in the structure or chemistry of the brain that correspond to specific memories or learned information. When we learn something new, various neural processes occur, leading to changes in synaptic strength and neural connectivity, and these changes are what form the engram for that memory.

Engrams suggest that memories are not mere abstract concepts but are instead grounded in identifiable changes in brain tissue. Researchers have sought to map out these changes, linking them to behaviors and experiences, thereby illustrating how memories are encoded and stored neurologically.

Other options do not capture this same concept. Neurotransmitters are chemicals that transmit signals across synapses between neurons. Neural pathways refer to the connections between neurons that facilitate signal transmission and communication in the brain but do not specifically denote the physical trace of a memory. Memory schema, on the other hand, represents a cognitive framework that helps organize and interpret information but is not associated with physical changes in the brain itself. Thus, "engram" is the most accurate term for the physical manifestations of memory in the brain.