Limbic System Flashcards
limbic functions
homeostasis, olfaction, memory, emotion (HOME)
Papez’s structures (OG)
cingulate, hippocampus, fornix, mammillary bodies, anterior thalamus (cingle out the hippos for mammillary ants)
expanded papez
added prefrontal cortex, association cortex, amygdala, hypothalamus
common limbic physiologic/neurologic properties
herpes, seizures, cholinergic inervation and opiate receptors
septal nuclei + nucleus basalis of meynert
cholinergic input for brain (memory)
mesocorticolimbic dopamine system
positive reinforcing brain mechanisms (drugs and pleasure)
tract: fornix
connects hippocampus to mammillary and septal nuclei (major efferent)
tract: mammillothalamic tract
connects mammillary bodies to anterior thalamus
tract: perforant path
connects entorhinal cortex to dentate (hippocampus afferent)
cingulate cortex (rostral, caudal)
rostral: emotions and motor; caudal: visual spatial and memory
orbital frontal lobe
personality, behavioral control, self-awareness
temporal lobe (hippo, parahippo, entorhinal cortex)
memory
inner core/subcortical components of limbic
anterior thalamic nucleus, mammillary body, hypothalamic nuclei, septal nuclei
hypothalamus fxn
pleasure center, autonomic, endocrine integration
amygdala
preservation of self behaviors (social, aggression), attribtues affective significance to visual stimuli, lesion = tameness. PTSD. response to faces. integration of emotions, fear and memory.
septum/septal region
preservation of species behaviors (sexual, emotionality). tumor of septal region –> rage attack
tract: stria terminalis
connects amygdala with septum, hypothalamus, bed nuclei, nucleus accumbens
tract: ventral amygdalofugal pathway
connects amygdala with hypothalamus, brainstem, septum
medial forebrain bundle
connects hypothalamic nuclei and amygdala and brainstem nuclei
Kluver-Bucy
bilateral large temporal lobe lesions (amygdala, hippo, uncus) –> psychic blindness, visual agnosia, oral tendencies, hypermetamorphosis, tameness/placidity, hypersexuality
etiology of kluver-bucy
herpetic viral encephalitis, anoxia, Pick’s disease, subarachnoid hemorrhage, alzheimer’s
Geschwind syndrome
sensory limbic HYPERconnection, increased concern with philosophical/cosmic/religious issues, hyposexuality, hypergraphia, interpersonal stickiness
interictal personality
hyperconnection
kluver-bucy syndrome
disconnection
most pleasurable regions
lateral hypothalamus, medial forebrain bundle (catecholamines, dopaminergic systems) and nucleus accumbens
addictive drug system
mesolimbic dopamine system
pain and punishment
lesions to ventromedial nucleus of hypothal produces pain
hippocampus
acquisition of facts and events (declarative memory). lesion –> amnestic states.
declarative memory (medial temporal lobe)
episodic (events) & semantic (facts)
hippocampal formation
hippocampus, dentate gyrus, subiculum. (neocortex too).
Wernicke Korsakoff’s
chronic alcoholism, thiamine deficiency. acute = encephalopathy, chronic = anterograde & retrograde amnesia. lesions in mammillary bodies and thalamus
lesion of cingulate (anterior?)
contralateral motor neglect, abolish conditioned emotional responses. blunting. can treat OCD. sociopathy? akinetic mutism (anterior).
tourette’s
anterior cingulate abnormalities. reduced TS stx seen after disconnection of AC from thalamus
anterior cingulate function
integration of thought, motivation and emotion with movement
orbital frontal lob syndrome
disinhibited, tactless, bawdy, boastful, grandiose (phineas gage)
frontal or dorsolateral syndrome
apathetic, slow, automaton-like, vacant
medial frontal syndrome
akinetic mutism, inert, speechless but intact sleep/wake cycle
