3.13.14 29 Limbic system Flashcards
Describe the olfactory pathway
Olfactory receptors in epithelium cells –>
Olfactory nerve bundles –> Cribriform plate –>
Olfactory bulb (Mitral cells) –> Olfactory tract –>
1. Lateral (–> anterior perforated substance, piriform cortex, amygdala)
and 2. Medial (–> contralateral bulb via anterior commissure) olfactory stria
What is the term describing leakage of CSF through the nasal passages? What causes this?
Rhinorrhea
Fractures to the floor of the anterior cranial fossa (cribriform plate, ethmoid bone)
What is the term for the loss or impairment of smell?
Anosmia
Intracranial pressure results in the compression of the temporal lobe, leading to epileptic discharges producing a “burning rubber” smell; this is referred to as…
Uncinate fits; irritation of the olfactory areas (piriform cortex and entorhinal areas; amygdala)
Describe the Papez circuit
Entorhinal cortex (Parahippocampal gyrus) –> Dentate gyrus –>
Hippocampus –> fornix (fimbriae, crus, body, column) –>
Mammillary body –> mammillothalamic tract –>
Anterior nucleus of thalamus –>
Cingulate gyrus –>
Entorhinal cortex (Parahippocampal gyrus)
Which specific structure of the limbic system is related to learning and memory?
Hippocampus
What precedes the mammillary bodies in the Papez circuit?
The fornix (fimbriae –> crus –> body –> columns)
What specific structure of the limbic system is related to pleasure?
Septal region/nucleus
To what other structures is the septal nucleus connected?
Amygdala (via stria terminalis)
Habenular nucleus (via stria medullaris)
Olfactory lobe, hippocampus, hypothalamus
What specific structure of the limbic system is related to emotional expression?
The amygdala
What behavioral function does the hippocampus serve?
Learning and memory (short term –> long term)
What behavioral function does the septal region serve?
Pleasure center
What behavioral function does the habenular nucleus serve?
Reproduction
What behavioral function does the amygdala serve?
Emotional response (sensory integration center) Endocrine activity Sexual behavior Food/water intake Modulation of hypothalamic activity
To what structures is the cingulate gyrus connected?
Reciprocal connections to the thalamus (anterior nucleus) Entorhinal cortex (parahippocampal gyrus)
What major visceral functions does the limbic system affect through the brainstem?
Cardiovascular and respiratory rate
Gastric and evacuative function
What would a bilateral lesion of the hippocampi affect?
Impairment of recent events (verbatim… idk, try to conceptualize)
The limbic system an anatomic substrate for the convergence of what three functions?
Cognitive activities (cortical), emotional experience (amygdala), and expression (output)
What is the cause of Korsakoff’s syndrome? What does it affect? What are the symptoms?
Thiamine deficiency (chronic alcoholism) Mammillary bodies, hippocampus, dorsomedial thalamic nucleus (memory) Inability to form new memories (pt fabricates stories to compensate)
What is another name for Korsakoff’s syndrome?
Amnestic confabulatory syndrome
What is the name for the disease that results from a thiamine deficiency?
Korsakoff’s syndrome or Amnestic confabulatory syndrome
What is the name for the syndrome that results from bilateral lesions to the temporal lobe?
Kluver-Bucy syndrome
What important areas are affected by Kluver-Bucy?
The temporal lobes, specifically the amygdala, hippocampus, and parahippocampal gyrus
What are symptoms of Kluver-Bucy syndrome?
Absence of emotional response (fear, rage, aggression)
Overly attentive to sensory stimuli (orally examines objects)
Hypersexuality
Psychic blindness (inability to recognize objects)
A patient with a history of chronic alcoholism fabricates stories due to a loss of ability to form new memories. What is this called? What is the problem?
Korsakoff’s Syndrome
Thiamine deficiency
Lesions to mammillary bodies, hippocampus, and dorsomedial thalamic nuclei
A patient shows lack of emotional response, and tends to be fairly touchy-feely and places objects in his mouth; his libido is through the roof… guy can’t stop talking and thinking about sex; he also has issues visually identifying objects. What is this called? What is the problem?
Kluver-Bucy syndrome
Bilateral damage to the temporal lobes (amygdala, hippocampus, parahippocampal gyrus)
5 F’s are associated with what? What are they?
Limbic system! Feeding Feeling Fleeing Fighting F... sex... ;D
