The Limbic System Flashcards
Limbic structures to familiarize yourself with and be ready to identify:
Bolded in Notes:
Cyngulate gyrus, Parahippocampal gyrus, Hippocampal Formation, Amygdala, Olfactory Cortex, Hypothalamus, and Basal Ganglia
Others: Medial orbitofrontal cortex, Temporal Pole, Anterior Insula, Thalamus, Basal Forbrain and Septal Nuclei, and Brainstem
What are the main functions of the Limbic system?
Homeostasis - Hypothalamus
Olfaction – Olfactory Cortex
Memory – Hippocampal and Parahippocampal gyri
Emotions - Amygdala
Major pathways: Fornix (means arch)
Consists of output axons from the hippocampus to
•Mamilary bodies
•Lateral septal nucleus
•Anterior thalamus
Also consists of input axons to the hippocampus from
•Medial septal nuclei (which may modulate memory function)
Major pathways-Fornix (special case): Circuit of Papez
The Circuit of Papez plays a role in the convergence of cognitive activities, emotional experience, and expression
What is the route of the Circuit of Papez?
Parrahippocampal gyrus –> hippocampus –> fornix –> mammillary bodies (part of hypothalamus) –> thalamus –> cyngulate gyrus –> parahippocampal gyrus.
Major pathway-Stria terminalis & ventral amygdalofugal pathway
Axons forming reciprocal connections between the amygdala to the hypothalamus
These circuits connect emotional and homeostatic centers
Major pathway-Medial forebrain bundle
Diffuse group of axons that carry information between amygdala, brainstem nuclei, and hypothalamus
Damage to components of the limbic system causes profound dysfunctions including:
Memory loss (retrograde and enterograde amnesias – (HM)
Olfactory dysfunction (loss and/or hallucinations)
Emotional disturbances (anxiety, rage, fearlessness, etc.)
Autonomic and homeostatic dysfunctions
Personality changes
Changes in sexual and grooming behaviors
Seizures
Be sure to review and be ready to identify the anatomical structures of the limbic system
Slides 2, 3, 7, 8, and 10 include illustrations of limbic system structures/pathways
