Summary
Amygdala and hippocampus circuits that process emotion and form memories.
In depth
Amygdala processes fear and emotional memory; hippocampus forms new memories and spatial maps; cingulate cortex and hypothalamus connect emotion with bodily response.
The amygdala assigns emotional significance. The hippocampus consolidates memory. The limbic system interacts with the cortex to modulate behaviour.
Remember: the limbic concept is somewhat outdated but still useful.
Components include the amygdala, hippocampus, cingulate gyrus, septal nuclei, parts of the hypothalamus, thalamus and orbitofrontal cortex. LeDoux's work showed a fast subcortical route to the amygdala (the low road) for rapid fear responses, and a slower cortical route for appraisal. Damage to the amygdala (Urbach-Wiethe disease) impairs fear recognition. The hippocampus (a seahorse shape) forms episodic memory and spatial maps, and is affected early in Alzheimer disease. London taxi drivers show enlarged posterior hippocampus.
The concept of a unitary limbic system is debated, as emotion involves widespread networks. PTSD, anxiety and depression involve altered amygdala, hippocampal and prefrontal function. Stress hormones can shrink hippocampal dendrites.
Example: the smell-memory link arises because the olfactory bulb projects directly to the amygdala and hippocampus.
Frequently asked questions
What is Limbic System?
Amygdala and hippocampus circuits that process emotion and form memories.
Which area of biology covers Limbic System, and how advanced is it?
Limbic System is one of the 54 topics in Neuroscience. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Hippocampus and Memory Consolidation, Taste and Smell, Brain Regions.
Can you give an example of Limbic System?
PTSD involves a hyperactive amygdala and reduced prefrontal control.
What should I learn before Limbic System?
Work through the Beginner topics in Neuroscience first, such as Nervous System, Neuron, Central and Peripheral Nervous Systems, then return to Limbic System. Intermediate topics assume the Beginner vocabulary.
What topics are related to Limbic System?
The closest topics to Limbic System are Hippocampus and Memory Consolidation, Taste and Smell, Brain Regions, Neurogenesis. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Limbic System?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Limbic System. To practise the whole of Neuroscience, use the Neuroscience quiz.
How is Limbic System different from Hippocampus and Memory Consolidation?
Limbic System: Amygdala and hippocampus circuits that process emotion and form memories. Hippocampus and Memory Consolidation: The hippocampus encodes new episodic memories and gradually transfers them to the cortex during sleep. Read both side by side and note what each one explains.
How should I study Limbic System step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Hippocampus and Memory Consolidation and explain the difference aloud. Finally, take the Neuroscience quiz and come back to this page for any question you miss.