Hotzman- Limbic system Flashcards
Which structures directly or indirectly communicate with the hypothalamus or midbrain periaqueductal gray?
limbic structures
What are the major structures of the limbic cortical areas:
Major limbic cortical areas:
- Parahippocampal gyrus
- Cingulate gyrus
- Prefrontal cortex*
- Temporal pole*
*Sources vary as to whether these are considered limbic structures
Along with the major limbic cortical areas:Major limbic cortical areas: - Parahippocampal gyrus - Cingulate gyrus - Prefrontal cortex* - Temporal pole*
What other structures are included?
- Hippocampal formation
- Amygdala
- Septal area (nuclei)
- Hypothalamus*
What are the 4 basic categories of limbic function (HOME)?
H- Homeostatic functions, including autonomic and neuroendocrine control
O- Olfaction
M- Memory
E- Emotions and drive
What are the functions of these limbic system associated structures?
The olfactory cortex delivers major inputs to which limbic system component?
hippocampal formation
What 3 places to afferent fibers come from to end up in the prefrontal cortex?
All cerebral cortical regions
- All brainstem monoaminergic systems -
Other limbic system structures
What 3 main areas do efferent fibers end up from the prefrontal cortex?
Temporal neocortex(superficial) and deep temporal lobe structures (hippocampus) -
Hypothalamus
- Mediodorsal thalamic nucleus
Afferent fibers to anterior cingulate gyrus come from which 3 places:
- Anterior thalamic nucleus
- Dopaminergic fibers from ventral tegmental area
- Diagonal band of Broca
Efferent fibers from anterior cingulate gyrus come from which 2 places?
Mediodorsal thalamic nucleus
- Subiculum
What are the 2 major thalamic nuclei that play a role in the limbic system (relay links)?
anterior thalamic nuclei
mediodorsal thalamic nuclei
What are the 3 main funcitons of the prefrontal cortex?
Cognitive processes
- Autonomic processes
- Emotional processes, including control over aggression and rage
Damage to the prefrontal cortex can cause?
flat affect; loss of control of cognitive, autonomic, and emotional processes; memory and intellectual deficits
What are the 3 main functions of the cingulate gyrus?
- Processing of visual and somatic sensations
- Cognitive
- Regulation of visceral (autonomic) processes by exerting a general suppressive effect
Damage to the cingulate gyrus may cause?
damage may cause flat affect,
lack of empathy,
autonomic dysfunction,
poor decision making
What are the 3 main components of the parahimppocampal gyrus?
Entorhinal cortex (anterior)
- Parahippocampal cortex (posterior)
- Perirhinal cortex (lateral)
The major afferent source to the hippocampal region from the parahippocampal gyrus is :
the Entorhinal cortex
What part of brain is Involved in the formation of declarative memories and in spatial processing?
Parahippocampal Gyrus
Damage to what structure correlates with a loss in the ability to form new memories and also leads to inability to recognize scenes although objects in the scene can still be recognized (damage to spatial processing)?
parahippocampal gyrus
What 3 structures make up the hippocampal formation?
hippocampus
dentate gyrus
subiculum (subicular cortex)
CA1 (Sommer’s sector)- pyramidal cells of the hippocampus are highly susceptible to , especially during periods of lobe epilepsy
anoxia; temporal
What is the ridge of small granular cells forming the outer border of CA4 of the hippocampus - Thought to play a major role in episodic memory formation?
Dentate gyrus
What is being described ?
Transitional region between entorhinal cortex and hippocampus
- Major output of hippocampus; not a simple relay but functions as a unique computational unit
Subiculum (subicular cortex)
Entorhinal region is major afferent source projecting to the?
hippocampus
Afferent fibers to entorhinal include which 2 structures of brain?
Association cortex (frontal, parieto-occipital, and temporal)
- Cingulate gyrus
Other afferents to the hippocampal formation other than the entorhinal complex of the parahippocampal gyrus are what 3 major afferents:
Monoamine projections from brainstem reticular formation
- Ventral tegmental area (dopamine) - Raphe nuclei (serotonin) - Locus coeruleus (norepinephrine) -
Contralateral hippocampus
- Cholinergic neurons from septal nuclei and diagonal band
Major pathway from the hippocampal formation?
fornix
What are the 3 components of the fornix system and where do they go?
precommissural fornix- septal area
postcommissural fornix- diencephalon (thalamus and hypothalamus)
comissural component-terminates in contralateral hippocampus
What are the 2 other efferent pathways from hippocampal formation other than the fornix?
Neurons in subiculum also project to entorhinal cortex, cingulate cortex, and areas of prefrontal cortex
- Entorhinal cortex projects to amygdala and adjoining regions of temporal neocortex
What does the anterior commissure connect?
temporal lobes
The significance of what projections are that they enable the hippocampal formation to communicate with widespread regions of neocortex and Serve to provide affective (emotional) properties to various modalities of sensory signals (like emotions associated with smell)?
subiculum and entorhinal cortex of the hippocampal formation
What brain formation functions to:
Certain forms of learning and memory
Differentially modulates aggressive behavior
Modulates endocrine functions
hippocampal formation
What 4 certain forms of learning and memory are the function of the hippocampal formation?
Spatial learning (spatial memory)
- Short-term memory
- Consolidation of memory (transferring short-term to long-term)
- Receives, processes, and categorizes sensory information during learning
How does the hippocampal formation modulate aggressive behavior?
Activation of hf closest to amygdala facilitates predatory attack behavior
- Activation of hf closest to septal pole suppresses this form of aggression
How and what part of the hippocampal formation modulates endocrine functions?
Ventral subiculum regulates the hypothalamic-pituitary-adrenal axis
What part of the thalamus is a reciprocal connection with the mammilary body of the hypothalamus and the cingulate gyrus?
anterior nucleus with thalamus
The septal area (ventral septum, diagonal band)
Amygdala/pyriform cortex
and
prefrontal cortex and anterior cingulate gyrus
are all inputs to which thalamic nuclei?
mediodorsal thalamic nucleus
Which specific hippocampal region is highly susceptible to anoxia, particularly during periods of temporal lobe epilepsy?
CA1 (Sommer’s sector)- pyramidal cells are highly susceptible to anoxia, especially during periods of temporal lobe epilepsy
What region of the brain provides the major input to the hippocampus?
entorhinal region
Identify the 3 specific components of the fornix system and the brain regions to which they connect the hippocampus.