1. Limbic system Semmelweis University
Department of Anatomy, Histology and Embryology
2nd year
Kocsis Katalin

2. General view of the limbic brain
mammalian brain organized on the base of two major basic theories
1) Modularity theory
-specialised functions localized to different brain areas
2) Neuronal network theory
complex functions, features
- learning, memory, intelligence personality
- functional integration
- processing of information is in neuronal networks, scattered brain areas

3. Functions of the limbic system
Complex human functions:
-personality, behaviour, learning, memory, emotions
Basic functions
-reproduction, stress, autonomic functions

4. Pierre Paul Broca (1878) – French neuroanatomist „Limbic lobe” – ring shaped cortical area on the medial surface of hemispheres: - parolfactory area (subcallosal area) - uncus - subcallosal gyrus (paraterminal gyrus) - parahippcampal gyrus - hippocampus - cingulate gyrus („limbic gyrus”) Smell is the main function of the limbic lobe
Pierre Paul Broca

5. -emotional feeling and expression
Papez presumed at first (1937): limbic lobe - functions related to the behaviour and emotions , emotions and motivated activity - localized in distinct brain structures
Papez proposed: -cingulate gyrus and hippocampus are connected with hypothalamus, anterior thalamic nuclei (limbic thalamus) through neuronal pathways:
Papez- circuit
-emotional feeling and expression
-interconnections constitute a harmonious mechanism
-cingulate gyrus is a receptive region for experiencing of emotion
Subcortical structures are connected to the limbic lobe:
Diencephalon
mamillary bodies
thalamic nuclei
medial and lateral habenular ncll.
James Papez
( )
American anatomist

6. Components of limbic system
Cortical areas
gyrus cinguli
gyrus subcallosus
prefrontal cortical areas – anterior part of frontal lobe (rostral to motor areas)
piriform cortex –parahippocampal g. anterior part, including uncus, lat. olf. stria
entorhinal cortex – parahippocampalis g.
hippocampus
dentate gyrus
subiculum - pre/parasubiculum
parahippocampal gyrus
Subcortical limbic areas
Diencephalon habenula
mamillary body(hypothalamus)
anterior thalamic nuclei (limbic thalamus)
Telencephalon olfactory bulb
anterior olfactory nucleus
nucleus of the lateral olfactory tract
septum
nucleus tractus diagonalis
nucleus accumbens (ventral striatum)
amygdala
nucleus stria terminalis
Mesencephalon interpeduncular n., raphe dorsalis and medianus n.
ventral tegmental nucleus, centr. gray matter

8. Nomenclature Parolfactory area (subcallosal area)
-a small area of cortex on the medial surface of the frontal lobe,
immediately in front of and below the subcallosal (=paraterminal) gyrus
Gyrus subcallosus = gyrus paraterminalis
Septal nuclei
-in the septum pellucidum: only a few scattered neurons
- nuclei of „true septum” (septum verum) are ventral to the septum pellucidum
- extend into the subcallosal gyrus
Piriform cortex (olfactory cortex)= rhinecephalon = olfactory brain=nose brain
- olfactory bulb, tract, lat. olfactory stria, ant. perf. substance, ant. part parahippocampal gyrus,
uncus, amygdala (dorsomed)
-paleopallium, oldest part of hemisphere – projections to enthorinal cortex
Entorhinal cortex
-behind the ant. part of parahippocampal gyrus (piriform cortex)
-projections to hippocampal formation (archicortex)
Rhinal sulcus (16)
-minor sulcus in the parahippocampal gyrus on the ventral-medial margin of the anterior temporal lobe
-the rhinal sulcus continuous with the collateral sulcus along the lateral margin of parahippocampal gyrus
Isthmus of cingulate gyrus (9)
-connects the neocortical cingulate gyrus
to parahippocampal gyrus
paleocortex
archicortex
transitional
BrainInfo (2007),
Neuroscience Division, National Primate Research Center,
University of Washington,

9. Gyrus parahippocampalis
Gyrus uncinatus
Uncus
Limbus Giacomini
Gyrus intralimbicus
Gyrus parahippocampalis B

10. limbic system scheme: afferentation
nucl. ant. thalami
limbic system scheme: afferentation

11. Papez circle

12. limbic system scheme: Papez circle
nucl. ant. thalami
limbic system scheme: Papez circle

13. limbic system scheme: efferentation
nucl. ant. thalami
limbic system scheme: efferentation

14. Prefrontal cortex - human
Complex functions:
-working memory, attention,
cognition, emotion
-executive control
-regulates behavioral inhibition
-jugdment, foresight
Prefrontal cortex - human
Dorsomedial prefrontal cortex
-extensive connections with sensorimotor and association neocortex (contemporary and past sensory experiences)
Orbitofrontal cortex
-strong connections with amygdaloid complex
-project heavily to subcortical limbic structures:
hypothalamus and septum
influences on behavioral and autonomic functions
Reciprocal relationship between dorsal and ventral prefrontal cortex
cognitive - emotional interactions

15. Amygdaloid complex Basolateral nuclei (younger)
Extraordinarily complex
Involved in many aspects of behavior but: there is no single high level function
Swanson and Petrowich:
„neither a structural nor a functional unit”
Amygdaloid complex
-implicated in emotional processing
-critically involved in mediating the stress on hippocampal memory processes – amygdalo-hippocampal interactions
Basolateral nuclei (younger)
-extensive reciprocal relations: sensory assotiation cortex (parietal, temporal), frontal lobe and
ventral striatum (putamen, and caudate n. ventral parts)
n. accumbens, Meynert’s n. basalis, dorsal thalamus
-projections from olfactory bulb, entorhinal cortex, cingulate gyrus, subcallosal area
Corticomedial nuclei (older)
-descending pathways to n. dorsalis n.vagi, brainstem cardiovascular centers,
locus coeruleus, n. raphe dorsalisventral tegmental nucleus
-peptidergic neurons(enkephalin, CRH, somatostatin, cholecystokinin)
-HYPOTHALAMUS – tractus amygdalo-hypothalamicus ventralis + stria terminalis - reciprocal
Many authors have attempted to divide this complex into clear functional units, largely without succes
corticomediális, basolaterális subnuclei

16. Nucleus accumbens (limbikus striatum)
N. accumbens functional aspects:
-responsible for motivated, goal-directed behaviors
-(compulsive drug seeking in cocaine addicts)
-interface between limbic and motor system
Normally descending projections from prefrontal cortex to n. accumbens, as well as other limbic regions, exert inhibitory control over reward-seeking behaviors

17. Hippocampal formation: hippocampus, gyrus dentatus, subiculum

18. Hippocampus afferents
somatic, visual, auditory, olfactory and motor information
from:
regio entorhinalis, olfactory cortex, neocortex
other hippocampus (comm. fornicis/hippocampi)
gyrus cinguli
thalamus (anterior and lateral dorsal nuclei)
septal region
corpus amygdaloideum
hypothalamus

19. Hippocampus efferents
Fornix
Hypothalamusba (Corpus mamillare)
Septum region
Papez-circuit
Thalamus (nucl. ant. thalami)
Gyrus cinguli
Gyrus parahippocampalis (regio entorhinalis, subiculum)

20. Hippocampal formation: hippocampus, gyrus dentatus, subiculum
G. dentatus
Ammon-horn
Subiculum
Fimbria
Alveus
Sulcus hippocampi
G. parahippo-
campalis

21. Hippocampal formation: hippocampus, gyrus dentatus, subiculum

22. Hippocampus connections I.
Papez-circuit
Cingulum
Nucl. anterior
thalami
Fasc. mamillothalamicus
(Vicq-d’Azyr-köteg
Fornix

23. Hippocampus connections II.
Commissura hippocampi (fornicis)
G. cinguli
Cingulum
Fornix
Frontallappen MD
Nucl. ant. thalami
Nuclei habenulae
Stria med. thalami
Fasc. mamillothalamicus
Septumregion
C. mamillare
Hypothalamus
Hippocampus
Stria terminalis+
Broca-Diagonalband
G. parahippocampalis
Temporallappen
Area entorhinalis
Amygdala

24. Hippocampal formation function
memory
short term
long term
memory processing functions (learning)
from short term to long term
rational memory - hippocampus, Papez-circle
emtional or autonomic - amygdala
motor memory - sensory and motor cortex areas through the thalamus
anger, motivation, consciousness, agression

26. References