The limbic system is comprised of four different structures of the brain, all which form a complex network for controlling emotions and memory (Rajmohan & Mohandas, 2007).
Note: There is still some debate on whether some other smaller brain structures are part of the limbic system. For simplicity sake, we are going to focus on the four main structures.
Thalamus
The thalamus acts as a sensory relay centre. It takes external stimuli and projects signals to both the amygdala and higher cortical regions for further processing.
Hypothalamus
The hypothalumus plays a role in activating the sympatheic nervous system (which is in charge of involunatry responses to stimuli- the flight or fight response).
Hippocampus
The hippocampus integrates emotional experience with cognition. It is the main brain structure in terms of processing long-term memory and emotional response.
Amygdala
The amygdala is often known as the "emotion" area of the brain. It plays a role in processing emotional information and sending the information to cortical structures.
All these structures work together in order to process stimuli which envokes emotions and aides in memory formation.