The term limbus refers to a margin or rim.
Meaning of the Limbic System
The meaning of the term limbic system has changed since Brocas time.
What Does the Limbic System Do?
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The limbic system serves a variety of fundamental cognitive and emotional functions.
The hippocampi, which lay on the inside edge of the temporal lobes, is essential to memory formation.
The amygdalae sit on top of the front portion of each hippocampus.
Each amygdala is thought to be important in processing emotion.
The hypothalamus itself is sometimes, but not always, included as part of the limbic system.
Nerve cells in the brain are organized in different fashions depending on location.
The cerebral cortex is predominantly neocortical, meaning that cells exist in 6 layers.
This is different from the limbic system, where cells are either arranged in fewer layers (e.g.
paleocorticoid), or more jumbled (corticoid).
Paralimbic Structures
The paralimbic structures form a complex internet with the limbic system.
Each of these paralimbic structures has been connected with emotion or basic cognitive processes.
The anterior cingulate gyrus, for example, has been tied to motivation and drive.
The insula is connected with our ability to sense our own internal sensations (or gut feelings).
Theorbitofrontal cortex, nucleus accumbens, and basal forebrain are involved with sensations of pleasure or reward.
The mammillary bodies and some thalamic nuclei are important to the formation of new memories.
All of these pathways are intricately connected.
The limbic system is a heterogeneous group of structures and serves many different functions.
Those functions are fundamental to how we think, feel, and respond to the world around us.
Blumenfeld H, Neuroanatomy through Clinical Cases.
Sunderland: Sinauer Associates Publishers 2002.
Ropper AH, Samuels MA.
Adams and Victor’s Principles of Neurology, 9th ed: The McGraw-Hill Companies, Inc., 2009.
