limbic system Flashcards
Gray matter in medial and basal parts of the hemisphere that forms a border around the brainstem
Limbic Lobe
the limbic is aka
synthetic Lobe
the limbic system controls _____
emotion, behavior and drive
Memory
what are the connecting pathways
alveus
fimbria
fornix
mammilothalamic tract
stira terminalis
what makes up the hippocampal formation
hippocampus
dentate gyrus
parahippocampal gyrus
seahorse in coronal section
hippocampus
Convex ventricular surface covered with ependyma, beneath which lies a thin layer of white matter
alveus
Curved elevation of gray matter extending throughout the entire length of the floor of the inferior horn of the lateral ventricle
Hippocampus
expanded anterior end of hippocampus
Pes hippocampus
consists of nerve fibers that have originated from the hippocampus
Alveus
alveus will converge medially to form _____
fimbria
Fimbria is continuous with the ______
crus of the fornix
Hippocampus terminates where
posteriorly beneath the splenium of the corpus callosum
Narrow, notched band of gray matter between the fimbria of the hippocampus & parahippocampus
Dentate gyrus
the dentate is cont anteriorly c _____
uncus
the dentate is cont posteriorly c _____
indusium griseum
thin; vestigial layer of gray matter covering the superior surface of the corpus callosum
Indusium griseum
Embedded in superior surface of indusium griseum
medial & lateral longitudinal striae
remnants of white matter of vestigial indusium griseum
Striae
Between the hippocampal fissure and collateral sulcus
Parahippocampal Gyrus
Situated partly anterior and partly superior to the tip of the inferior horn of the lateral ventricle
Amygdaloid Nucleus (Amygdala)
emerges from posterior aspect of amygdaloid nuc
Stria terminalis
Anteriorly, the body of the fornix is connected to the corpus callosum by the
septum pellucidum
Fimbria now leaves the posterior end of the hippocampus as
crus of fornix
2 crura connected by transverse fibers
commissure of the fornix
Crura converge to form the
body of the fornix
Body of the fornix splits anteriorly into
2 anterior columns of the fornix
Each column disappears into the lateral wall of the 3rd ventricle to reach
mammillary bodies
connects the mammillary body with anterior nuclear group of thalamus
Mammillothalamic tract
Mammillothalamic tract is responsible for
Memory
emerges from posterior aspect of amygdaloid nucleus and runs a bundle of fibers posteriorly in the roof of the inferior horn of the lateral ventricle on the medial side of the tail of the caudate nucleus
Stria terminalis
stria terminalis is responsible for
Control of autonomic, neuroendocrine and behavioral responses
3 layers of hippocampus
Molecular layer - superficial; nerve fibers and scattered small neurons
Pyramidal layer - large pyramid-shaped cells
Polymorphic layer - inner
3 layers of dentate gyrus
Molecular layer
Granular layer - densely arranged rounded or oval neurons with axons terminating on dendrites of pyramidal cells of hippocampus
Polymorphic layer
Declarative (Explicit) Memory
conscious recall of facts and experiences
Nondeclarative (Implicit) memory
Nonconscious learning of skills, habits and other acquired behaviors
2 types of declarative memory
Semantic
Episodic
Semantic (Nonunique, generic)
memory of culturally and educationally acquired encylopedic knowledge such as meaning of words, arithmetical facts, geography, history
Episodic (Unique)
memory of personally experienced facts and events with special spatial and temporal localization
loc of semantic
Temporal neocortex
loc of episodic
Mesial temporal cortex (hippocampus, entorhinal cortex, perirhinal cortex and parahippocampal gyrus
cortico-cortical connections from anterior neocortices to entorhinal cortex, hippocampus-mamillary bodyanterior and medial thalamic nuclei via fornix and mammillothalamic tract; basal forebrain cholinergic nuclei (nucleus basalis of Meynert)
Short Term Memory
Memory of a limited amount of information held continuously in consciousness for a short period (<60s)
Decays in seconds if not refreshed continuously
loc of short term memory
Left hemisphere dominant
left prefrontal cortex
verbal
right prefrontal cortex
nonverbal
Implicit Memory
Supports the learning and retention of skills
“Knowing how”
Procedural (skill learning)
repeated performance of a motor act enhances and automates future skill for the same act; resistant to forgetting
Priming
short-lived enhancement of perceptually based performance following a recent exposure to visually similar material
Procedural (skill learning) loc
Functions of subcortical circuits particularly the basal ganglia and cerebellum
