How are memories stored and retrieved in the human brain?

Memories are stored and retrieved in the human brain through a complex series of biological processes, collectively known as memory consolidation. Memory consolidation is the process of transforming information into a stable, lasting representation over time, allowing memories to be accessed later on. It is a dynamic process that involves multiple stages and cognitive functions in both short-term and long-term memory storage systems.

The first stage of memory consolidation is called encoding or registration. During this phase, sensory impressions or experiences are converted into neuronal representations in the form of electrical signals which then travel throughout the brain’s neural networks. This sets off a series of intricate biochemical events resulting in synaptic modifications that create distinct patterns within existing neural pathways associated with specific thoughts and experiences. Consequently, new memories become “wired” into our brains by forming tight junctions between neurons that make up distinct neural pathways for each experienced event. In other words, neurons come together to essentially "talk" to one another about our past experiences – thus leading us to recall such details when we encounter similar situations down the line (i.e., associative learning).

Once these newly formed memories are consolidated into long-term storage centers within the brain (such as areas like hippocampus), they can be recalled at any point via a retrieval mechanism involving neuromodulators secreted from structures like amygdala (a part of limbic system). Such chemicals help activate regions primarily responsible for retrieving stored memories depending on contextual cues such as sight, sound or smell by binding with their respective receptors located among neurons involved in encoding those particular memories during initial acquisition stages; thus triggering them back out again! Ultimately though it's all dependent on how well we encoded those bits originally – something referred to as "retrieval strength". A great deal more research needs to be conducted before we could confidently explain exactly what occurs during this realtime search & retrieval procedure but scientists believe this model offers some insight nonetheless when trying make sense out of how our minds store information over periods beyond immediate moments!