39 Limbic sytem Flashcards
Cortex beneath the middle cerebral artery is called?
Insula
The medial part of the temporal lobe contains?
- Hippocampus, the convoluted cortex
2. Parahippocampal formation: gyrus below the hippocampus
________is the fiber bundle that arises from the hippocampus, it runs C-shape course on the medial wall of the hemisphere, on the surface of hippocampus.
Fornix
The olfactory pathway is unique in that it does not go to the _____________.
thalamus
How is the olfactory system related to the limbic system?
Olfactory nerve > bulb > tract > primary olfactory area/cortex > amygdala
Components of the limbic lobe?
○ Cingulate gyrus
○ Septal area
○ Parahippocampus gyrus (with amygdala) [rhinal sulcus and collateral sulcus]
○ Hippocampus = hippocampal formation
Rhinal sulcus is anterior/posterior part of the parahippocampus.
Anterior
The collateral sulcus is between _________ and __________ of the parahippocampus.
lingual gyrus and fusiform gyrus
The parahippocampal gyrus bends backward. The bent-back segment is called the _________.
uncus
Anterior part of the parahippocampal gyrus is the _______ area (area ___)
Entorhinal area; area 28
The piriform lobe consists of the ____________ and __________and appears to be pear-shaped.
uncus and entorhinal area
_________ is a nuclear mass located beneath the surface of the uncus .
Amygdala
The primary olfactory area consists of?
- cortex covering amygdala
- cortex in front of amygdala
- cortex in part of the entorhinal area
At the anterior end of the lateral ventricle, the _____________________ continues ventrally as a thickened medial wall. The medial wall contains the ____________.
septum pellucidum; septal nuclei (in the septal wall)
_____________________is on the orbital (ventral) surface of the prefrontal cortex; is topographically and functionally closely related to the medial part of the prefrontal cortex and the amygdala.
Orbitofrontal cortex
The junction of the ventral parts of the caudate nucleus and the putamen (ventral striatum) lying next to the septal area is the ________________________.
nucleus of accumbens
__________________ is near the end of olfactory tract, base of striatum and globus pallidus, amygdala, nucleus of accumbens consisting of cholinergic neurons projecting to the entire neocortex.
Basal forebrain
What will happen in severe atrophy of the basal forebrain cholinergic system?
Parkinson’s disease
Components of the hippocampus?
- subiculum
- dentate gyrus
- CA (conu ammonis)
- fornix
The part of fornix running along the hippocampus is called ________.
fimbria
The limbic lobe surrounds the ____________ and is surrounded by the _______________.
Diencephalon;
neocortex
What functions are regulated by the limbic output to the basal ganglia?
- learned skill
2. instinctive actions (mating, eating, feeding)
Other than the basal ganglia, limbic lobe also projects to?
- hypothalamus for autonomic and visceral functions
2. other cortical areas for memory, emotion and behaviour
Describe the connections between limbic lobe and the hippocampus in memory formation.
Sensory association areas (esp temporal) and cingulate gyrus > entorhinal area > via perforant pathway > dentate gyrus of hippocampus > CA1,2,3 in schaffer collaterals.
> via fornix > neocortex storing long-term memory.
The perforant pathway perforates the ________ on its ways to dentate gyrus.
subiculum
Memory stored in hippocampus is ____________.
new and short-term
Describe the Papez circuit .
entorhinal area > via perforant pathway > hippocampus > via fornix > mammillary body > via mammillothalamic tract > anterior nucleus of thalamus > via internal capsule > cingulate gyrus > via cingulum > entorhinal area
___________ is the fiber tract beneath the cortex of cingulate gyrus.
Cingulum
Conu ammonis
CA1 is affected in what patients?
Alzheimer’s dementia, epilepsy, ischemia
Conu ammonis
CA2 is important in?
Lesion?
Social cognition (remembering familial members); damage will cause autism, schizophrenia
Atrophy of ________________ can be seen in Korsakoff Sydrome.
mammillary body
Symptoms of Korsakoff Syndrome (alcoholims)?
- loss of recent memory
- confusion
- hallucination
- confabulation, fabrication
Hippocampus is connected to the hypothalamus and septal area via __________.
fornix
Amygdala is connected to the hypothalamus and septal area via __________.
stria terminalis
Septal nuclei connect with brain areas like ______________ involving in reward, and its major output is to _____________.
VTA, nucleus accumbens;
hypothalamus > affect autonomic and hormonal activities
Activation of hippocampus glutamatergic projections to lateral septum exerts ____________effects on feeding.
anorexic
Activation of hippocampus ______________ projections to lateral septum exerts anorexic effects on feeding.
glutamatergic
Amygdala is involved in response to stimuli with emotional significance (fear, pain).
Afferents?
sensory association and insular areas
Efferents of amygdala?
- orbitofrontal and medial prefrontal cortices (complex behaviours)
- anterior cingulate gyrus (unpleasantness of painful stimuli)
- striatum (selection of behaviour/movement)
- medial dorsal nucleus of thalamus
- hypothalamus
In the __________ cortex, midline group of thalamic nucleus (reuniens nucleus) may inhibit the expression of fear.
medial prefrontal
Lesion of _____________ may cause exaggeration of fear.
Reuniens nucleus (midline group of thalamic nucleus) in the medial prefrontal cortex
What is Kluver-Bucy syndrome?
Bilateral lesion of anterior temporal lobe including amygdala
Which of the following are symptoms of Kluver-Bucy syndrome?
A. Visual agnosia (cannot recognize familiar places and faces)
B. Altered dietary habits
C. Hyposexuality
D. Hyperorality (oral examination of all objects)
E. Docile behaviour
F. Expression of primitive behaviours
All except C - hypersexuality
Symptoms of medial prefrontal and orbitofrontal amygdala areas lesions ?
A. Anxiety B. Schizophrenia C. Autism D. Bipolar E. Post-traumatic stress disorder F. Phobia G. Depression
All except D
Signs and symptoms of Schizophrenia
§ Hallucinations
§ Delusions
§ Disorganized thinking (speech)
§ Movement disorders (agitation)
§ Reduced feelings of pleasure
□ No emotional expression
□ Depressed mood, irritability
□ Reduced speaking, monotone
□ Lack of motivation
□Withdrawal from friends and family
