Limbic System Flashcards
Cortical structures in the limbic system
-also called the…
also called the "Limbic Lobe" structures -septal area -cingulate gyrus -parahippocampal gyrus -hippicampus related areas -orbitofrontal cortex -prefrontal cortex
where is the septal area
area surrounding end of rostrum of corpus callosum
associated subcortical nuclei of the limbic system
amygdala
hypothalamus
septal nuclei
anterior thalamic group
amygdala location
located deep to the uncus
septal nuclei location
deep to septal cortical region
near the fornix and anterior comissure
nerve fiber pathways in the limbic system
mamillothalamic tract
fornix
stria terminalis
medial forebrain bundle
limbic lobe connections
organizes as a complex loop
- mamillary bodies to anterior thalamic group via mamillothalmic tract
- anterior thalamic group to cingulate gyrus
- cingulate gyrus to parahippocalpal gyrus
- parahippocampal gyrus to hippocampus
- hippocampus to mamillary bodies and septal region via the fornix
amygdala is connected to the limbic circuit via the….
connections to the septal region and hypothalamus via stria terminalis
limbic system afferents
cortex
reticular formation
cortex
-projects to what parts of limbic system
all parts of limbic lobe
amygdala
hypothalamus
RF
-projects to what parts of limbic system
all parts of limbic lobe
amygdala
hypothalamus
efferents
-limbic lobe projects to…
all parts of cortex
hypothalamus and RF
limbic lobe projects to cortex by way of…
thalamic gating
efferents
-what structures does the amygdala project to….
dorsomedial thalamic nucleus
brainstem RF
efferents
-amygdala projects to dorsomedial thalamic nucleus, which projects to _____
dorso medial thalamic nucleus, which in turn projects to prefrontal cortex (medial forebrain bundle)
efferents
-how does the amygdala project to the brainstem RF
both directly an indirectly via the hypothalamus (medial forebrain bundle)
limbic system function
generates behaviors necessary for preservation of the individual and the species (motivation, emotion, learning, and memory)
limbic system has very powerful effect on which systems
hypothalamus
ANS
lesions of the hippocampus and amygdala must be _____ to result in major deficits of normal behavior
bilateral
_____ stimulation of the limbic system may result in abnormal behavior
unilateral
limbic system has been labeled the _____ system
-what do these stand for?
3-F, 1-R system
- fighting
- fleeing
- feeding
- sexual behavior
hippocampus
-functions
attention
memory
spatial orientation
stress
hippocampus: attention
- what type of stimulation produces alertness and searching behavior?
- alertness runs through what other circuitry
unilateral or bilateral stimulation
alertness and awareness are cycled through the RF as the reticular activating system
hippocampus: memory
- bilateral lesion results in…
results in loss of recent memory and inability to form new memories
hippocampus: memory system
- involved in…
formation of declarative (explicit; memory of facts) memories, not procedural (implicit; motor memory) memory
hippocampus: memory
- what is the process of consolidation
transfer of short-term memories into lasting memories
hippocampus: spacial orientation
- hippocampus has a _____, which makes what possible
cognitive mapping system
makes it possible for us to compare present spatial situation with those already experienced
hippocampus: stress
- projections go to…
anterior hypothalamus
hippocampus: stress pathway
- stress causes this pathway to…
- what is the result of this?
release CRF (corticotropin releasing factor) this then acts at the pituitary to release ACTH (adrenocorticotropic hormone)
hippocampus: stress pathway
- ACTH function
acts on the adrenal glands to secrete cortisol and vasopressin
hippocampus: stress pathway
- what type of stress is this
- what type of stress is this not
the stress the body senses when there is an injury, not stress related to fear or neuroscience
stress related to fear releases _____ from _____ and results in _____
releases norepinephrine from adrenal medulla and increases sympathetic output
septal nuclei
-responsible for…
pleasure
rage
septal nuclei: pleasure
-stimulation of septal nuclei and _____ can result in…
surrounding hypothalamus (parts of the anterior division) can result in sexual arousal; pleasure/euphoria from drug activation
septal nuclei: rage
-bilateral lesions of the septal region result in…
hyperexcitability (exaggerated jumping when startled)
rage (unprovoked attacks)
amygdala functions
sensory-affective interactions
emotion
modulator or controller of hypothalamic activities
amygdala: sensory-affective interactions
- explain this role
- lesions produce…
amygdala is important for instinctive reactions to sensory stimuli, including the motivational and emotional significance of sensations
lesions produce inappropriate emotional responses to sensory stimuli
amygdala: emotion
- emotional component of…
- important for…
emotional component of learning
important for developing emotional reactions to new experiences, which, if repeated, become instinctive emotional reactions.
amygdala: emotion nuclei
- implicated in…
learned memory of fear
amygdala: modulator or controller of hypothalamic activities
- stimulation or lesion of the amygdala can produce…
autonomic effects, arousal, sexual activity, motor activity related to eating, aggressive behavior
amygdala: modulator or controller of hypothalamic activities
- functional locations within the amygdala
lateral amygdala
medial amygdala
lateral amygdala
- stimulation produces…
- based on the…
produces
-a gradual build up of aggressive behavior (anger)
-hyperphagia (overeating - lateral hypothalamus)
-pleasure reactions
-tameness
based on the normal social behaviors of an individual
medial amygdala
-stimulation produces…
decreased aggressive behavior
aphagia (medial hypothalamus)
decreased sadness
decreased fear-associated defensive behavior
limbic system interaction with hypo
-generally throught to be displayed as…
autonomic component of aggressive or defensive behaviors
limbic system interaction with hypo
-medial limbic of amygdala to medial hypo are more attuned to what behaviors?
behaviors generated out of defense of self
limbic system interaction with hypo: lateral limbic parts of amygdala
- receive _____ from _____
- connected more with…
- region is associated with _____ behaviors
receive powerful sensory association cortical input
connected more with lateral divisions of the hypo
more associated with predatory or feeding behaviors
anterior septal region
- more attuned to acting in _____
- this region is thought to function in the _____
acting in satisfaction or pleasure
this region is thought to function in the euphoria associated with the onset of addictions: cocaine, methamphetamines
