LIMBIC SYSTEM Flashcards
What is the limbic system?
3
- phylogenetically ancient CORTICAL AN SUBCORTICAL STRUCTURES
- NEURAL CIRCUITS FOR INSTINCTIVE AND EMOTIONAL ASPECTS OF BEAVIOUR AND MEMORY.
- RICH INTERCONNECTIONS with the HYPOTHALAMUS; THE CONTROLLER OF THE AUTONOMIC SYSTEM
What is the ROLE OF THE LIMCI SYSTEM? 4
Instinctual and Motivating 4 F’s
- FORNICATING
- FEEDING
- FIGHTING
4 FLIGHT/FLEEING
List the limbic System Structures: 8
- Hypothalamus
- Thalamus
- Hippocampus
- Fornix
- Amygdala
- Mammillary Bodies
- Limbic lobe
- SEPTAL NUCELI: a small group of nuclei in the MEDIAL WALL of FRONTAL LOBE having RECIPROCAL CONNECTIONS with
- OLFACTORY BULB, HIPPOCAMPUS, AMYGDALA
HIPPOCAMPUS LOCATION AND SIZE
5cm long
- Curved sheet of the cortex
- FOLDED into MEDIAL surface of the TEMPORAL LOBE
- OCCUPYING FLOOR of the INFERIOR HORN OF THE LATERAL VENTRICLE
What are the major PARTS OF THE HIPPOCAMPUS?
3
3 major parts
- SUBICULUM
- HIPPOCAMPUS
- DENTATE GYRUS: involved in NEUROGENESIS for FORMATION of NEW MEMORIES.
- ammon horn
Purpose of the Denate Gyrus in the Hippocampus
DENTATE GYRUS: is involved in the NEUROGENESIS for the FORMATION of NEW MEMORIES.
What are the SEPTAL NUCLEI?
SEPTAL NUCELI: a small group of nuclei in the MEDIAL WALL of FRONTAL LOBE having RECIPROCAL CONNECTIONS with
- OLFACTORY BULB, HIPPOCAMPUS, AMYGDALA
UNDERSTANDING ALZHEIMER’S DISEASE: 4
- SUBICULUM + ENTORHINAL CORTEX = 1st sites affected
- it impairs memories
- BRAIN CELLS AND THE BRAIN CONNECTIONS DEGENERATE - 1 in 50 Australians have Dementia
- 10% of people over 65
- 30% of people over 85
3, LEADING CAUSE OF DEATH IN WOMEN in AUS
- greater than HEART DISEASE and CANCER
- It is a BRAIN DISORDER - memory, thinking skills, ability to perform basic taks
Understanding the Connection between HYPOTHALAMUS AND MAMMILLARY GLANDS
4
- LOCATED ANTERIOR INFERIOR TO THALAMUS
- REGULATES BASIC DRIVES AS THE MAIN “AFFECTOR” of the LIMBIC SYSTEM
- CENTRAL REGULATOR of AUTONOMIC and ENDOCRINE functions
- MAMMILARY BODIES ARE CONNECTED TO THE HYPOTHALAMUS BY PROJECTING FIBRES to THALAMUS, BRAINSTEM AND HIPPOCAMPUS.
What is the FORNIX? What does it do?
4
FORNIX = FIBRES arising from CELL BODIES in the SUBICULUM and HIPPOCAMPUS proper Gather into A FASICLE
- C -shaped Fasicle of fibres that links HIPPOCAMPUS with the MAMMILLARY BODIES of the HYPOTHALAMUS
- PRINCIPLE EFFERENT PATHWAYS FROM HIPPOCAMPUS
—3. PROJECTS TO SEPTAL NUCLEI (SMALL GROUP OF NUCLEI in MEDIAL WALL of FRONTAL LOBE)
What is the Amygdala?
STRUCTURE?
NUCLEI?
PROCESSING?
Structure:
- Almond-shaped nuclei
- lies deep to Uncus
- Anterior to HIPPOCAMPUS
- abutting the TAIL of the CAUDATE NUCLEUS
3 MAJOR NUCLEI
- 1. BASOLATERAL (bottom left)
- 2. Central Nucleus (CeA) (top)
- 3. Corticomedial nucleus (right)
PROCESSING: FEARFUL AND THREATENING STIMULI
Where does the Amygdala Recieve information?
Where does it send information to? via?
RECEIVES: AFFERENT information (visual, auditory, somatosensory, gustatory, olfactory). FROM THE BRAINSTEM
THEN SENDS INFORMATION TO - Via the STRIA TERMINALS
**HYPOTHALAMUS (and BRAINSTEM)
Amygdala Connections: from, to amygdala nuclei, sends to, for
1.THALAMUS + BRAINSTEM (visceral nuclei, PAG, Reticular Information) + HIPPOCAMPUS + NOCIORECPTIVE INFORMATION
- OLFACTORY INFORMATION + MEMORY SYSTEM + THALAMUS + HYPOTHALAMUS
- SENSORY INFORMATION (visual, auditory, somatosensory) + PREFRONTAL CORTEX + HIPPOCAMPUS + THALAMUS
- THALAMUS + BRAINSTEM (visceral nuclei, PAG, Reticular Information) + HIPPOCAMPUS + NOCIORECPTIVE INFORMATION
To Central amygdala nuclei
SENDS OUT: HYPOTHALAMUS AND RETICULAR FORMATION
- OLFACTORY INFORMATION + MEMORY SYSTEM + THALAMUS + HYPOTHALAMUS
To CORTICOMEDIAL NUCLEI
SENDS OUT: to HYPOTHALAMUS, RETICULAR INFORMATION + OLFACTORY SYSTEM
FOR: EMOTIONAL AFFECTIVE RESPONSE to SMELL and FOOD
- SENSORY INFORMATION (visual, auditory, somatosensory) + PREFRONTAL CORTEX + HIPPOCAMPUS + THALAMUS
TO: BASOLATERAL NUCLEI
SENDS out: TO ASSOCIATION CORTICES AND LIMBIC CORTEX
FOR: Attaching emotional significance to Stimuli
Explain simply the Papez Circuit
8
- Cingulate Cortex
- Via Cingulum
- To HIPPOCAMPUS
- Via FORNIX
- To MAMMILLARY BODIES
- Via MAMMILLO-THALAMIC TRACT
- To THALAMUS ANTERIOR NUCLEI
- then back to CINGULATE CORTEX
What is the Papez Circuit?
The Papez circuit is a fundamental component of the limbic system.
It is a closed neural circuitry that starts and ends in the hippocampus.
- hypothalamus regulates the autonomic nervous system activity during the expressions of emotion
- Recent studies show that Papez circuit has a more significant role in memory functions than in emotions
