I.I. Anatomical Location + discussion ofAnatomical Location + discussion of
II.II. Structure and function of theStructure and function of the
hippocampal formation.hippocampal formation.
III.III. The Amygdaloid nucleus complex andThe Amygdaloid nucleus complex and
the function of its 3 components.the function of its 3 components.
IV.IV. Links between the limbic system andLinks between the limbic system and
effector (behaviour) systems.effector (behaviour) systems.
V.V. Links between neurotransmitter-Links between neurotransmitter-
specific projection systems and thespecific projection systems and the
limbic system.limbic system.
VI.VI. Regional Anatomy of these structures.Regional Anatomy of these structures.
I.I. Anatomical Location and Overview.Anatomical Location and Overview.
A.A. Limbic association cortex –Limbic association cortex –
surrounding diencephalonsurrounding diencephalon
-medial + inferior (orbital) surface-medial + inferior (orbital) surface
cingulate gyrus, parahippocampalcingulate gyrus, parahippocampal
gyrus, orbital gyrus, temporal pole.gyrus, orbital gyrus, temporal pole.
(Expression of Feelings)(Expression of Feelings)
FEAR(Fight or Flight))FEAR(Fight or Flight))
Anatomically refers to areasAnatomically refers to areas
surroundingsurrounding the diencephalon (limbus =the diencephalon (limbus =
border) and bordering the cerebralborder) and bordering the cerebral
In 1878 Broca introduced the nameIn 1878 Broca introduced the name
LIMBIC SYSTEMLIMBIC SYSTEM
The “C”-shaped hippocampal formationThe “C”-shaped hippocampal formation
and includes the amygdala, cingulateand includes the amygdala, cingulate
and parahippocampal cortices.and parahippocampal cortices.
The key to learning, memory, andThe key to learning, memory, and
behavior (including emotional behavior)behavior (including emotional behavior)
– of paramount importance in– of paramount importance in
Hypothalamus, AN thalamus, habenularHypothalamus, AN thalamus, habenular
N, interpeduncular N, midbrain tegmentalN, interpeduncular N, midbrain tegmental
N, strai medullaris thalami, fasciculusN, strai medullaris thalami, fasciculus
retroflexus & median forebrain bundleretroflexus & median forebrain bundle
Limbic System: Cortical Areas
Figs. 16-2 and 3
diencephalon, medial +
inferior (orbital) surface
[cinglulate gyrus, parahipp
gyrus, orbital gyrus,
These cortices are near other
association cortices and project
B. the Hippocampal Formation and Amygdala.
The “C” shape, along with the major output paths
for the hippocampus: the fornix.
Limbic SystemLimbic System
The limbic system isThe limbic system is
comprised ofcomprised of
– Hippocampus: involved inHippocampus: involved in
learning and memorylearning and memory
– Amygdala: involved inAmygdala: involved in
– Mammillary BodiesMammillary Bodies
TheThe fornixfornix is a fiber bundleis a fiber bundle
that interconnects thethat interconnects the
hippocampus with thehippocampus with the
mammillary bodiesmammillary bodies
Superiorly it is related to the anterior partSuperiorly it is related to the anterior part
of lentiform nucleus.of lentiform nucleus.
Inferiorly it is related to uncus.Inferiorly it is related to uncus.
Medially it extends to the inferior surfaceMedially it extends to the inferior surface
of the cortex of the temporal lobe.of the cortex of the temporal lobe.
The dorsomedial part of amygdaloid bodyThe dorsomedial part of amygdaloid body
is connected with the primary olfactoryis connected with the primary olfactory
area while venteromedial part isarea while venteromedial part is
component of limbic system.component of limbic system.
Feeling of fear & apprehension leading toFeeling of fear & apprehension leading to
The cortex of the septal region is presentThe cortex of the septal region is present
infront of lamina terminalis beneath theinfront of lamina terminalis beneath the
genu & rostrum of corpus callosum.genu & rostrum of corpus callosum.
The paraolfactory area or the subcallosalThe paraolfactory area or the subcallosal
gyrus lies underneath the rostrum ofgyrus lies underneath the rostrum of
corpus callosum.corpus callosum.
Posterior to parolfactory area & justPosterior to parolfactory area & just
anterior to lamina terminalis isanterior to lamina terminalis is
paraterminal gyrusparaterminal gyrus
Feelings & EmotionsFeelings & Emotions
(Emotion is expression of feelings(Emotion is expression of feelings
andand Antiemotions is Depression)Antiemotions is Depression)
Nature controls Man by two things Pain and PleasureNature controls Man by two things Pain and Pleasure
(Patient =Suffering)(Patient =Suffering)
Pain is PunishmentPain is Punishment
Pleasure is RewardPleasure is Reward
FEAR (DANGER):Horror,HauntedFEAR (DANGER):Horror,Haunted
Amygdaloid damage- ends Fear (Fearless)Amygdaloid damage- ends Fear (Fearless)
Food & SexFood & Sex
Nature`s Priorities (Biological needs)areNature`s Priorities (Biological needs)are
Preservation of life(Food)Preservation of life(Food)
Procreation of life(Sex)Procreation of life(Sex)
Human hasHuman has
self conciousness(I)self conciousness(I)
Damage to Amygdaloid leads to abnormal foodDamage to Amygdaloid leads to abnormal food
habits & Sex (Hypersexualty)habits & Sex (Hypersexualty)
MemoryMemory(Storage of information(Storage of information))
Alzheimers DiseaseAlzheimers Disease
HIPPOCAMPAL DAMAGE CAUSESHIPPOCAMPAL DAMAGE CAUSES
LOSS OF RECENT MEMORYLOSS OF RECENT MEMORY
Diffuse network of nerve fibers & neuronsDiffuse network of nerve fibers & neurons
In tegmental core throughout brainstem.In tegmental core throughout brainstem.
Fills space not occupied by cranial nerveFills space not occupied by cranial nerve
nuclei/ other nuclei/ tracts.nuclei/ other nuclei/ tracts.
Concerned with arousal or alertness byConcerned with arousal or alertness by
Maintains muscle tone & posture duringMaintains muscle tone & posture during
sitting and standing by reticulospinal tractsitting and standing by reticulospinal tract
Seratonergic fibers induce slow sleep &Seratonergic fibers induce slow sleep &
dimnish pain sensationdimnish pain sensation
Nadr. fibers produce paradoxical sleepNadr. fibers produce paradoxical sleep
Dopaminergic fibers preventsDopaminergic fibers prevents
parkinsonian tremor & rigidityparkinsonian tremor & rigidity
TS through brainstem & spinal cordTS through brainstem & spinal cord
showing the reticular formationshowing the reticular formation
Various nuclear regions inVarious nuclear regions in
reticular formation between wellreticular formation between well
defined cranial nerve nucleidefined cranial nerve nuclei
ASCENDING RETICULARASCENDING RETICULAR
ACTIVATING SYSTEMACTIVATING SYSTEM
Ascending fibers of reticular formation toAscending fibers of reticular formation to
cerebral cortex and limbic systemcerebral cortex and limbic system
Convey diffuse input from all sensoryConvey diffuse input from all sensory
Concerned with degree of conciousnessConcerned with degree of conciousness
from sleep to arousalfrom sleep to arousal