Lecture 11 - Limbic system Flashcards
(34 cards)
The hippocampal formation consists of
Dentate gyrus
Entorhinal cortex
Subiculum
Hippocampus proper
The hippocampus consists of
Hippocampus proper + Dentate gyrus
Broca’s Limbic LOBE is purely an ___ term and is composed of _____ , and does not contain any ___structures
- anatomical
- Fornicate gyrus (cingulate + parahippocampal)
- subcortical
describe Maclean’s Limbic SYSTEM
- the TRIUNE BRAIN THEORY
- consists of 3 distinct brain layers:
1. Primitive brain (archipallium) - survival, action brain
2. Intermediate brain (paleopallium, limbic brain) - emotional brain
3. Rational brain (neopallium) - the logical/thinking brain
what are the functions of the Limbic System?
- learning & memory
- control of emotion & instinctive behaviour
What are widely accepted concepts of the Limbic system? (x3)
- analyses sensory stimuli for emotional significance
- stores emotionally significant memory
- impacts cognitive responses required for normal social behaviour/survival
What are the major cortices involved in the LIMBIC SYSTEM? (x5)
- hippocampal formation (D.E.S.H)
- Parahippocampal gyrus
- Cingulate Gyrus
- Oribto-frontal cortex
- subcallosal area
What are the nuclei involved in the LIMBIC SYSTEM? (x3)
- Amygdala
- hypothalamus
- anterior nucleus of Thalamus
What are the fibre tracts involved in the LIMBIC SYSTEM? (x4)
- fornix
- fornical commissure
- cingulum
- uncinate fascicle
The cingulum connects ____
the uncinate fascicle connects ____
- cingulate and parahippocampal gyri
- temporal and frontal lobes (orbitofrontal cortex)
memory is defined as (x3)
- acquisition
- storage
- retrieval
of information
Short-term memory is also know as? it is important for ___
- working, transient, online memory
- performing daily acitivities
Describe the mechanisms of Short-term memory
- > sensory stimulus = < 1s
- > forget stimulus
- > attention + sensory stimulus = few seconds
- > peformance in daily activity
- > forget stimulus
Short-term memory is mediated by
the PFC
short-term memory is encoded into long-term memory by
the hippocampus
Long-term memory can be divided into (x2)
- Explicit memory
- declarative
- conscious processing
- Implicit memory
- non-declarative
- unconscious processing
Explicit memory is divided into __and stored in __
- semantic (Basic knowledge)
- episodic (personal events)
- most higher association cortices
Implicit memory is divided into ___ and stored in (respectively)
- memories of skills and habits (stored in Basal ganglia, cerebellum, motor cortex)
- emotional memories (stored in amygdala)
Which cortical structure is the “door/gate” to the Limbic Loop?
the entorhinal cortex
Describe the features and functions of the Entorhinal cortex (x5)
- rostral most part of parahippocampal gyrus
- door to limbic loop
- contains grid cells for spatial navigation
- first site to be affected in Alzheimer’s disease
- important for learning, memory and spatial nav.
Describe the functions and features of the hippocampus (x4)
- contains TIME NEURONS (for order of events)
- contains PLACE NEURONS (spatial navigation)
- deals with EXPLICIT memory
- converts short-term into long-term memory (specifically “where” & “when” of events)
What is retrograde and anterograde amnesia?
retrograde - unable to retrieve information from long-term memory
anterograde - unable to encode/store new information to long-term memory
What type of amnesia will result from a lesion of the hippocampus?
profound anterograde amnesia where one is unable to store new information into long-term memory and is unable to spatially navigate, but skilled memory and short-term memory are still intact.
The hippocampus Proper is also know as ___. It is divided into ____.
- cornu ammonis
- CA1
- CA2
- CA3
- CA4
