Limbic 1

心？情緒？ 神經生物學基礎？

NH3 Fragrance: Fried chicken Perfume

Olfactory nerve

Motor pathways Emotional responses

? Optic nerve

Cochlear nerve

Limbic 2

Functions of Limbic system

Memory Emotions-related

responses

Limbic 3

Limbic system Amygdaloid body (amygdala) Hippocampal formation Hippocampus Parahippocampal gyrus Dentate gyrus

Septal area / Basal forebrain

Hypothalamus (Limbic) cortex: Cingulate

gyrus, Orbital (Orbiotfrontal) cortex, Prefrontal cortex, Insula

Anterior thalamus

Limbic 4

Amygdaloid Body (Amygdala, AMG) Position: between anterior end of temporal horn of

the lateral ventricle and the ventral surface of lentiform nucleus

Limbic 5

Olfactory nerve

Limbic

Temporal lobe

Olfactory nerve

6 Olfactory pathway

Olfactory nerve

Temporal lobe

Olfactory nerve Olfactory nerve

Temporal lobe

Olfactory nerve

Limbic 7

Olfactory pathway and AMG

Amygdala (AMG)

Limbic 8

AMYGDALA: division / nuclei Dorsal (corticomedial nuclei) Ventrolateral (central nuclei / basolateral nuclei)

Limbic 9

Dorsal (Corticomedial, Cortical) nuclei of AMG blending with uncus with afferents from olfactory bulb

(lateral olfactory area)

Olfactory bulb and cortex

Hypothalamus

AMG (Corticomedial)

Limbic 10

Ventrolateral (central and basolateral nuclei) of AMG

Both nuclei are a part of limbic system. Central nuclei: with corticomedial nu Basolateral nuclei: reciprocal connections with limbic cortex (prefrontal, temporal lobes and

cingulate gyrus); thalamus and brainstem: medio-dorsal (dorsomedial)

nuclei of thalamus, catecholamine nu, raphe nu, parabrachial nu of reticular formation;

septal area and anterior hypothalamus (stria terminalis)

Limbic 11

Interconnections of AMG

Cortex temporal, insular,

prefrontal, occipital

VentroLat-AMG

Thalamus (Medio-dorsal) Hypothalamus Brainstem

Sensory: somatic, visceral, auditory etc

AMG-Co Co-AMG

CM-AMG

Limbic 12

Major pathways for amygdala

Stria terminalis To and from brainstem

for regulations of autonomic responses etc.

Ventral amygdalofugal pathways via Diagonal band of Broca

Medial forebrain bundle

Afferent to AMG

Efferent to AMG

Limbic 13

Stria terminalis: septal area --- AMG

Fornix

Limbic 14

Stria terminalis

Th

Limbic 15 Stria terminalis

Limbic 16

Ventral amygdalofugal pathway (1)

Limbic 17

Ventral amygdalofugal pathway (2)

Emotionally driven activities also with some afferents

Amygdala Hippocampus Limbic cortex

Ventral striatum Ventral pallidum

Thalamus Dorsomedial nu.

Hypothalamus Brainstem

Limbic 18

Diagonal band of Broca in anterior perforated substance (orbital cortex,

behind olfactory tract, with passage of vessels) connections between amygdala and septal area

Limbic 19

Medial forebrain bundle

a collective term for fibers passing the ventral (basal) surface of the brain contains heterogeneous fiber tracts for

different destinations important tracts for ascending and descending

interconnections between septal area, hypothalamus and brainstem

Limbic 20

Median forebrain bundle

Limbic 21

Medial forebrain bundle

Limbic 22

AMG and autonomic nervous system AMG

Septal area / Anterior hypothalamus

Interpeduncular nu. of midbrain

Hypothalamospinal fibers

Habenular nu. of dorsal thalamus

Stria terminalis

Stria medullaris (thalami)

Fasciculus retroflexus

Dorsal longitudinal fasciculus

Limbic 23 Stria medullaris (thalami)

Limbic 24 Stria Medullaris Thalami

Limbic 25

Limbic 26

Functions of Amygdala

Related to emotional feelings Fear Anger

Methods of study Electrical stimulation Functional magnetic resonance imaging (fMRI) Destructive lesions in temporal lobes Kluver-Bucy Syndrome: docility, loss of ability

to learn, and abnormal sexual activity

Limbic 27

Olfactory system and Amygdala

Limbic 28

Fear perception and response

Visual perception Amygdala Neocortex: fear sensations / recognition Autonomic system: (unconscious) responses Conditional reflex, Memory

Limbic 29

Limbic 30

Summary: amygdala Organization corticomedial (olfactory) ventrolateral (limbic)

Connections cortex (limbic: prefrontal, temporal, cingulate) thalamus (medio-dorsal)/brainstem

(catechoaminergic) other limbic structures: septal area, hypothalmus

Pathways Stria terminalis Medial forebrain bundle Ventral amygdalofugal pathway

Limbic 31

Hippocampus Medial (mesial) surface of temporal lobe Anterior-posterior extension

Limbic 32

Hippocampus

Medial surface of temporal lobe

Beneath lateral ventricle

Limbic 33

Hippocampus

Limbic 34

Structure of hippocampus

Dentate gyrus Hippocampus

(proper), cornu ammonis

Parahippocampus gyrus Subiculum

Dentate gyrus

Hippocampus

uncus

Subiculum

Limbic 35

Hippocampus: Alveus

Myelinated axons (leaving & entering hippocampus) on ventricular surfaces of hippocampus; Forming the fimbria of hippocampus continuous with crus of fornix

Hippocampus

Limbic 37

Organization of Hippocampus: 3 layers

Molecular layer Pyramidal cell layer Polymorphic layer parahippocampal

gyrus: neocortex, with 6 layers

Limbic 38

Organization of Hippocampus: CA 1-3 CA (Cornus ammonis); CA1: Sommer’s sector

Limbic 39

Molecular layer of Hippocampus

with axons and dendrites continuous with molecular layers of dentate gyrus and

neocortex

Limbic 40

Pyramidal cell layer of Hippocampus

Large neurons: pyramidal cells

Principal cells of hippocampus;

With dendrites into Molecular layer;

Axons through alveus & fimbria to fornix

Limbic 41

Schaffer collateral

Schaffer collaterals: branches of axons of pyramidal cells;

passing polymorphic and pyramidal cell layers to synapse with dendrites of other pyramidal neurons

Limbic 42

Pyramidal cell layer of hippocampus

pyramidal neurons of CA1: sensitive to oxygen deprivation Temporal sclerosis Alzheimer disease

continuous with layer 5 (internal pyramidal) of neocortex

Limbic 43

Polymorphic cell layer of hippocampus

Beneath alveus, With axons,

dendrites and interneurons;

Equivalent to layer 6 of neocortex

Limbic 44

Organization of Dentate gyrus: 3 layers

Molecular layer Granule cell layer:

principal cells Polymorphic layer: Polymorphic

layer of dentate gyrus: contineous with that of CA3

Limbic 45

Efferent fibers of Dentate gyrus

Mossy fibers Traveling in hilus &

polymorphic layer; giving branches to synapse with pyramidal cells of CA2 and CA3

Roles for memory: long-term potentiation

Limbic 46

Hippocampus: Intrinsic connections

Limbic 47

Long-Term Potentiation (LTP)

present in Schaffer collaterals and mossy fibers of hippocampus

increase in synaptic efficiency following high-frequency activity of a pre-synaptic terminals

as molecular and cellular mechanism nderlying long-term memory

Limbic 48

Afferents to Hippocampus

Limbic 49

Entorhinal afferents

The largest afferents of hippocampal formation Perforant path Alvear path

• Entorhinal area: a part of lateral olfactory area and a gate for other cortical areas; receiving association fibers of temporal lobe and other neocortex

Limbic 50

Alvear path through subcortical

white matter and alveus to end in hippocampus

• Fornix and fimbria afferents: from contralateral hippocampus, from septal areas, basal forebrain cholinergic neurons (substantia inominata)

Limbic 51

Perforant path

axons from entorhinal area through subiculum & base of hippocampus to end in dentate gyrus

Limbic 52

Hippocampal efferents

Limbic 53

Fornix: the largest hippocampal efferents Origin: hippocampus &

parahippocampal gyrus Fimbria Crus: posterior limit of

hippocampus Body: in contact of

splenium (dorsal hippocampal commissure)

Column: above the 3rd ventricle; in front of interventricular foramen

Limbic 54

Column of Fornix pre-commisural protion of

fornix: above anterior commissure; giving fibers to septal area, anterior hypothalamus, substantia inominata

post-commissural portion of fornix: fibers to lateral dorsal thalamic nuclei, hypothalamus (mamillary body via mammilothalamic fasciculus to ant. nu of Th, ventromedial nucleus)

Limbic 55

Fornix

Limbic 56

Fornix

Limbic 57

Limbic 58

Mammillothalamic fasciculus (MTf)

Origin: mamillary body Terminals: anterior

nuclei of thalamus Anterior and lateral

dorsal thalamic nucleus having reciprocal communications with cingulate gyrus, which also has reciprocal communication with parahippocampus gyrus Mam. Body

Th.

Cingulum

Parahippo.

MTf

Limbic 59

Mamillo-thalamic fasciculus

Limbic 60

Mamillo-thalamic (Mamillothalamic) fasciculus / tract

Damaged in Korsakoff syndrome (alcoholic dementia) Amenesia Confabulation Apathy Lack of insight

http://www.youtube.com/watch?v=wDcyBXJAZNM http://www.youtube.com/watch?v=UbSlLtsJfUY

Limbic 61

Hippocampal function & dysfunction: memory and memory disorders

Types of memory Explicit (Declarative) memory: knowledge mainly verbal, language, mathematic contents etc

Implicit memory: learned skills, procedures, emotions associated structures: cerebellum, basal ganglia etc

Limbic 62

Declarative Memory

Steps of memory Immediate recall; Recent memory Memory consolidation; Long-term memory Information retrieving Factors: enhancing, interfering, emotional etc

Role of hippocampus in memory Retention of short-term memory and its Transfer to

long-term declarative memory

Limbic 63

Hippocampus and Memory: Cellular mechanism

Long-term potentiation (LTP) a postulated mechanism for

storage of recent memory requiring for permanent

memory new protein synthesis new synapse formation

Limbic 64

Role of hippocampus in learning “learning and memory”: impaired in mice with defective

functions of neurotransmitters in hippocampus

Limbic 65

Clinical Note of Hippocampus: Alzheimer disease Pathophysiology: cholinergic

hypothesis loss of cholinergic neurons

in basal forebrain projecting to limbic system (particularly hippocampus)

degeneration in entorhinal cortex, and hippocampus

Essential role of hippocampus: bilateral hippocampal lesions lead to memory loss, particularly recent memory

Limbic 66

The story of H.M.

Intractable seizure Temporal lobectomy,

partial Consequences Seizure: under control Blunt emotions Loss of memory

Limbic 67

H.M.

Limbic 68

What happens to H.M.? (How to improve memory for exam? 臨陣磨槍!)

RAM Disk

Hippocampus Cortex

Memory consolidation / Information retrieval

(macro)

Limbic 69

Case history 住台北的一位退休公務員 3/13：上午與太太搭高鐵南下高雄，中午參加一位老朋友的喪禮，晚上到台南，夜宿嫁到台南的女兒家。

3/14：清晨醒來，問：為什麼在這裡？對於昨天 (3/13)參加喪禮的事，一概否認，不記得有到高雄參加喪禮的事。一整天，一直 “ㄏㄨㄟ” 個不停。

3/15：早上離開台南，中午回到台北，一切恢復正常，但對於 3/12 晚間開始到 3/14 之間的事，完全沒有記憶。

What is your diagnosis ? 中邪？

Limbic 70

Transient Global Amnesia (TGA) a transient loss of memory, mainly recent events

with Normal intellectual functions Intact (1) immediate recall and (2) remote memory

Duration: usually resolve within 24 h Etiology and mechanisms: unknown, with transient

lesions (mainly vascular insufficiency) in the hippocampus

Limbic 71

Transient global amnesia

Limbic 72

Cortex

Entorhinal cortex

Subiculum CA3 Dentate gyrus

Perforant pathway

Hippocampus and Cerebral cortex

CA1 Mossy fibers

Schaffer collaterals

Limbic 73

睡醒後就失憶: 她，天天重新做人 (2010.06.12 自由時報) 〔編譯羅彥傑／綜合報導〕英國一名四十七歲的已

婚婦女，因兩次車禍導致腦部受損，喪失自從一九九四年以來的短期記憶，此後每天醒來都是同一天，也讓丈夫每天都得說服她相信兩人是夫妻，頗類似好萊塢愛情喜劇「50 First Dates (我的失憶女友)」劇情。

英國《每日郵報》十一日報導說，住在英格蘭林肯郡斯波耳丁市的米歇兒．菲波茲每天一覺醒來，枕邊人都得說服她，兩人是夫妻。當她表現懷疑時，菲波茲先生就去拿相簿，給她看兩人在一九九七年（十三年前）的結婚照。

米 歇兒在一九八五年與一九九○年先後發生機車與汽車車禍，造成腦部受損。她的記憶最遠可追溯到一九九四年，但此後任何一天發生的事情，隔天就全忘光。這種情 況令人聯想到二○○四年電影「我的失憶女友」，劇中男主角亞當山德勒嘗試追求女主角茱兒芭莉摩，但後者在車禍後就喪失每天日常生活的記憶。

Limbic 74

睡醒後就失憶: 她，天天重新做人 (2010.06.12 自由時報)

米歇兒得使用數以百計的便利貼及手機日曆的記事提醒功能，幫助自己記得每天的行程與要做的事。她做過的事或見過的人，都必須記錄下來，以便日後參考用。當她偶爾離家出外遊玩時，還必須攜帶輸入住家地址的衛星導航系統。

劍橋大學神經科學家耐斯特說，米歇兒罹患的是罕見的順向失憶症（或前行性失憶症）。不過，這對她也有一些好處，譬如沒有電視節目重播的困擾，每一則笑話也都很好笑，因為每次都是第一次聽到。她目前擔任慈善團體志工，每週有三天照顧殘障人士。

Limbic 75

Review: Hippocampus Organization Hippocampus Dentate gyrus

Synaptic pathways Schaffer collaterals Mossy fibers

Major afferents and efferents Alvear path Perforant path Fornix