THE LIMBIC SYSTEM

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THE LIMBIC SYSTEM

• Institute of Anatomy, 2nd and 1st Medical
  Faculty
• R. Druga

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LIMBIC SYSTEM

• Limbic cortex g. cinguli g.
  parahippocampalis hippocampal formation (gyrus
  dentatus, hippocampus, subiculum)
• Subcortical structures amygdala, septum verum,
  habenula, hypothalamus

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Funkce limbického systému

• Emocní reakce a jejich kontrola (Papez 1937)
• Viscerální mozek (MacLean 1949)
• Pametové mechanizmy, Emoce

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Intraventricular aspect of the hippocampus (hippo
campus from above)
1- hippocampal body 2 head and digitationes
hippocampi 3 hippocampal tail 4 fimbria
(fornix) 5 fornix 6 subiculum 10 collateral
eminence
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Andersen s circuit
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Papez circuit
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Papez circuit Papezuv okruh

• Hippocampal formation fornix hypothalamus (
  mamillary ncc.) tr. mamillothalamicus -
  thalamus (ant. ncc.) gyrus cinguli gyrus
  parahippocampalis (entorhinal area, 28)
  hippocampal formation

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Spoje hippokampální formaceConnections of the
hippocampal formation

• Afferent cortical
• Associative neocortex
• Parahippocampal and cingular gyrus, entorhinal
  cortex (area 28)
• Olfactory cortex
• Afferent subcortical
• Amygdala
• Thalamus (MD, ncc. mediani)
• Hypothalamus
• Septum verum

• Efferent cortical
• Subiculum area 28, parahippocampal gyrus
  associative cortical areas
• Efferent subcortical
• Fornix
• Hypothalamus (mamillary nuclei)
• Thalamus (ant. ncc.)
• Septum verum
• Ventral striatum
• amygdala

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Neocortex hippokampální formace

• Primární sensorická oblast (SI, AI, VI)
• Asociacní korová oblast (SII, A II, VII)
• Gyrus cinguli , g. parahippocampalis (area 28,
  35, 36)
• Hippocampus

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Funkce hippokampální formace

• Korové asociacní oblasti - hippokampální formace
  limbické struktury (septum, hypothalamus,
  amygdala)
• Ucení a pamet
• Schopnost se ucit a pamatovat si slova, císla,
  fakta, místa, tváre
• Poškození ztráta pameti (amnesia, anterográdní,
  CA 1)
• Hippokampální formace proces ucení a vytvárení
  pametových stop
• Nemá význam pro uchovávání dlouhodobé pameti
  (neocortex, thalamus ?)
• Hippokampální place cells - mení aktivitu v
  souvislosti se zmenami v okolí
• Intrahippokampální navigacní mapy

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Functions of the hippocampal formation

• Cortical association areas Hippocampal
  formation other limbic structures (septum,
  hypothalamus, amygdala
• Learning and memory
• The ability to learn and remember words, faces,
  places, events
• Damage Loss of memory (amnesia, anterograde,
  CA 1)
• Hippocampal formation is important for the
  process of learning or forming of the memory
  traces
• Hippocampus is not important for the long-term
  storage of informations (long-term memory)
  neocortex, thalamus ?
• Hippocampal place cells the firing of
  single hippocampal cells changes with position
  of animal in relation to its surroundings
  (different corners of the cage)
• Intrahippocampal navigation maps

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SEPTUM VERUM
AMYGDALA, NUCLEUS BASALIS
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SEPTUM PELLUCIDUM
SEPTUM VERUM(septal nuclei Ch 1, Ch 2)
NC. BASALIS Ch 4 group of cholinergic neurons
projecting to the neocortex and to the amygdala
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SEPTUM VERUM

• Reciproké spoje s hippocampem, hypothalamem, s
  gyrus cinguli
• Efferentní spoje do thalamu a amygdaly
• Cholinergní neurony (Ch1, Ch2) projikující do
  hippocampu
• Stimulace vyvolává agresivní chování
• Lese - redukce agresivity

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Amygdala, amygdalar complex - spoje
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Amygdala (amygdalar nuclei) - connections

• Corticomedial nuclei - receive afferents from
  olfactory bulb, olfactory cortex, hypothalamus,
  septum
• Basolateral nuclei - receive afferents from the
  thalamus and parts of the cerebral cortex
  (prefrontal, temporal)
• Efferent connections hypothalamus (stria
  terminalis, VM), thalamus (MD), hippocampal
  formation (28, subiculum), septal nuclei, ventral
  striatum, prefrontal and temporal cortex, brain
  stem nuclei (SGC, RF, parasympathetic cranial
  nerve nuclei.

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Amygdala functions I.

• Stimulation
• Corticomedial group salivation, licking,
  chewing, emptying of the rectum and the bladder
• Basolateral group increased attention, stopping
  of motor activity, arousal, fear ( autonomic
  reactions), rage
• In humans feeling of anxiety, fear,
  hallucinations
• Amygdala is frequently focus of epileptic
  seizures !!

• Destruction
• Reduction of aggressivity and defensive reactions
• Reduction or loss of emotional reactions

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Amygdala functions II.

• Amygdala is involved in learning (remembering)
  whether something is good or bad .
• Amygdala differenciates a dangerous and
  nondangerous signals.

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VELKÉ MEDIÁTOROVÉ SYSTÉMYMAJOR
NEUROTRANSMITTER SYSTEMS
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Cholinergic system
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Cholinergic system

• Cholinergní group target structure
• Ch 1, Ch 2
  hippokampus
• Septum verum
• Ch 3
  bulbus olfactorius
• Area diagonalis
• Ch 4
  neocortex, amygdala
• Nucleus basalis
• Ch 5, Ch 6 thalamus
  
• RF
• Ach augments the excitability of cortical
  neurons, improves circulation, supports memory
  mechanism

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Dopaminergic pathways
Noradrenergic pathways Serotoninergic pathways
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Dopaminergic system

• Substantia nigra, pars compacta - A 9
• Area tegmentalis ventralis (VTA), - A 10
• Striatum
• Globus pallidus
• Neocortex
• Decrease - Parkinsonismus

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Noradrenergic system

• Locus coeruleus - A 7
• Spinal cord
• Brain stem cranial nerves sensitive nuclei (nc.
  V.)
• Cerebellum Purkyne cells
• Hypothalamus
• Thalamus (nc. VPL, nc. VPM, corpora geniculata
• Neocortex, Hippocampal formation
• Part of the ascending activation system of the RF
• Regulation of transmision of sensory signbals
  (pain, posterior horns of the spiunal cord)
• Regulation of circulation
• Essential to feel emergized
• Without NA you feel exhausted, tired, without
  energy

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Serotoninergní systém

• Rapheální jádra RF
• Vzestupný a sestupný systém
• Všechny korové formace, Limbický systém,
  Striatum, thalamus, hypothalamus, mozkový kmen,
  mícha
• Aktivita vzestupného systému zmeny nálady
• Aktivita sestupného systému analgesie
• Snížení synthésy - deprese, podráždenost,
  poruchy spánku, insomnie
• Nadmerne zvýšená hladina (serotoninový syndrom
  tres, zvýšení TK, zrychlení akce srdecní,
  zmatenost, bezvedomí)
• Slunecní osvit zvyšuje produkci ( v zime
  deprese,podráždení, úzkostné stavy)

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SEROTONINERGIC SYSTEM

• Reticular formation (rapheal nuclei)
• Ascending and descending systems
• All cortical formations, Limbic system, Basal
  ganglia, Thalamus, Hypothalamus , Brain stem,
  Spinal cord
• Activity in descending system analgesia
• Decrease of synthesis- depression, irritability,
  sleep disorders, insomnia
• Increase of synthesis tremor, increase of blood
  pressure anf heart rate, confusion,
  unconsciousness
• Sun lighting increases production (winter
  depression, irritability, anxiety)

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Glutamatergic system

• Excitatory neurotransmitter
• Majority of ascending and descending pathways
• All descending cortical pathways
  (corticostriatal, corticothalamic, corticospinal)
• Descending brain stem pathways
• Efferent cerebellar pathways (dentato thalamic)
• Commissural pathways (corpus callosum)
• Associative cortical pathways

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GABAergic system

• GABA - Inhibitory neurotransmitter
• Local interneurons ( neocortex, hippocampus,
  thalamic nuclei, cerebellar cortex)
• Striatal efferent projections
• Globus pallidus efferent projections
• Purkyne cells projections

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Nitric oxide

• Gaseous neurotransmitter
• Produced by NOSynthasis
• Neuronal, endothelial, inducible
• 200 µm 2 millions of synaptic contacts
• Local interneurons
• NO increases releasing of neurotransmitters
• Vasodilatation !!! (endothelial NOS)
• Damage of neurons (neurodegenerative diseases)

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Cévní zásobení mozkuVasculature of the CNS
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Vertebrobasilar system
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Vertebrobasilary carotic systems
Circle of Willis
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The Circle of Willis

• Communication between vertebral and a. carotis
  interna systems
• Anterior and posterior communicating arteries
  allow blood to flow between both systems (PCA) or
  between right and left vessels (ACA)

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CT AG, 3-D
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Longitudinal system Segmental (radicular) system
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Liquor cerebrospinalis Produced by the choroid
plexus Ventricles and subarachnoid space 140
mlPhysical support of the brain (floats within
the fluid)Channel for chemical communication
within the CNS (neurons- fluid- walls of
ventricles neurons)
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Dural sheaths
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CEREBRAL VENTRICLES
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MRI T2
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Ventriculus lateralis pars centralis
3rd ventricle
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Ventriculus lateralis cornu temporale
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Dekuji za pozornost
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