Limbic system Flashcards
Where is the limbic system located?
Made up of cortical and subcortical structures in the medial and inferior regions of the cerebral hemispheres
What functions are related to the limbic system?
Emotion
Motivation
Olfaction
Emotional association with memory
What cortical structures make up the limbic lobe?
Parahippocampal gyrus
Cingulate gyrus
Subcallosal gyrus
What connects the cortical areas of the limbic lobe?
Cingulum
What are the subcortical structures of the limbic system?
Hippocampus
Amygdala
Hypothalamus
Septal nuclei
Anterior nucleus of thalamus
Nucleus accumbens
What types of behaviors are coordinated by the hypothalamus?
Drive-related behaviors
What can occur with hypothalamus impairment?
Aggressive behavior
Feeling over-stressed
Hypo- or hyperthermia
Fatigue
Weight gain or loss
Hypo- or hyperactive sex drive
What is the primary function of the hippocampus?
Memory centers - formation of episodic memories
What are secondary functions of the hippocampus?
Role in spatial navigation
Associated with learning and emotions
What are the two areas where neurogenesis occurs?
Hippocampus
Olfactory cortex
What are the functions of the amygdala?
Emotional responses
Attaches emotional content to memories
Linked to fear response
What can occur with damage to the amygdala?
Increased aggression
Irritability
Loss of emotional control
Difficulty recognizing emotions, fear in particular
What is connected by the fornix?
Connects hippocampus to mammillary body
What is connected by the medial forebrain bundle?
Connects hypothalamus to olfactory cortex, septum, midbrain, reticular formation, medulla, and neocortex
What are the parts of the Papez circuit?
Cingulate gyrus to hippocampus to fornix to mammillary body to mammillothalamic tract to anterior nucleus of thalamus to cingulate gyrus
What is the role of the Papez circuit?
Formation of emotion and consolidation of episodic memory
What is connected by the longitudinal stria?
Hippocampus with septal area
What is connected by the stria terminalis?
Amygdala with ventromedial nucleus of hypothalamus and nucleus tractus solitarius
What function is associated with the stria terminalis?
Emotional control of food intake
What function is associated with the longitudinal stria?
Pleasure and memory
What function is associated with the fornix?
Emotion and memory
What function is associated with the medial forebrain bundle?
Behavior and motivation
What is connected by the diagonal band of Broca?
Amygdala to septal area
What function is associated with the diagonal band of Broca?
Pleasure and emotion
What function is associated with direct amygdalo-hypothalamic fibers?
Emotion and autonomic functions
What is the function of the mammillary body?
Formation of memory
What is the function of the septal area?
Important pleasure area of brain
What is the function of nucleus accumbens?
Involved in reward, pleasure, and addiction
Pleasure center
What are the sections of the limbic cortex?
Orbitofrontal cortex
Olfactory gyrus
Cingulate gyrus
What is the function of the orbitofrontal cortex?
Required for decision making
What is the function of the cingulate gyrus?
Maternal behavior and emotion
What can cause anterograde amnesia?
Bilateral damage to the medial temporal lobes including the hippocampus
Where does the neuronal degeneration of Alzheimer’s disease begin?
Hippocampus
What causes Kluver-Bucy syndrome?
Bilateral lesions of amygdala and hippocampus
What are the features of Kluver-Bucy syndrome?
Tameness
Loss of fear
Decreased aggression
Oral tendency
Change in dietary habits
Visual defects
Excessive sex drive
Placidity
Psychic blindness
Hypermetamorphosis
Anterograde amnesia
What is hypermetamorphosis?
Excessive attentiveness to visual stimuli with a tendency to touch every stimulus
What is Korsakoff syndrome?
Memory disorder is caused from a vit B1 deficiency
Associated with alcoholism
What are the features of Korsakoff syndrome?
Anterograde and retrograde amnesia
confabulation
What are the 3 mental components of emotion?
Cognition
Affect
Conation
What is conation?
The urge to act
What are the fear inducing areas?
Posterior hypothalamus
Amygdala
What are the two physical modalities of emotion?
Exteriorization
Interiorization
What are the inducing areas for rage?
Periventricular area and the fibers connecting it with hypothalamus
What are the inhibiting areas for rage?
Neocortex, septum, hippocampus, and cingulate gyrus
What is sham rage?
Only a physical component, mental components are absent
Shows rage for any type of stimulus
What causes sham rage?
Diencephalic and forebrain lesions
What are the inducing areas for placidity and tameness?
Ventromedial nucleus of hypothalamus
Nucleus accumbens
Septal area
Amygdala
What is a primary motivated behavior?
Related directly to maintaining homeostasis
What is a secondary motivated behavior?
Indirectly helps to achieve homeostasis
Influenced by habit, learning, intellect, and emotional factors
What are the reward areas of the brain?
Prefrontal cortex
Ventromedial hypothalamus
Medial forebrain bundle
Nucleus accumbens and ventral tegmentum area and their interconnections
Dorsal brain stem area
What are the avoidance areas of the brain?
Lateral portion of posterior hypothalamus
Dorsal mid-brain gray area (periventricular area)
Entorhinal cortex
What can cause an increase in sexual activity?
Lesion of piriform cortex and amygdala
What is neuronal/synaptic plasticity?
Structural and functional changes at a synaptic level
The basis for learning and memory
What are the types of synaptic plasticity?
Post-tetanic potentiation
Habituation
Sensitization
Long-term potentiation
Long-term depression
What is post-tetanic potentiation?
Application of same stimulus repeatedly increases the post-synaptic response
What is habituation?
Repeated stimulus decreases post-synaptic response
What is sensitization?
Habituated stimulus paired with a noxious stimulus repeatedly causes augmented postsynaptic response
What is long-term pontentiation?
Repeated stimulation of presynaptic neuron enhances synaptic transmission
What is long-term depression?
Repeated stimulation of presynaptic neuron decreases synaptic strength
What is non-associative learning?
Learn about a single stimulus
Inborn reflex
What is the definition of memory?
Acquisition, storage, and retrieval of information
What are the two forms of short-term memory?
Instantaneous memory
Working memory
What are the two types of long-term memory?
Declarative/conscious memory
Non-declarative/unconscious /procedural memory
What type of memory is affected by electrical shock?
Short-term
What type of memory is affected by a temporal lobe lesion?
Short-term
What are the two forms of explicit memory?
Episodic
Semantic
What are other names for explicit memory?
Declarative memory
Conscious memory
Recognition memory
Awareness memory
Episodic and semantic memory
Where is explicit memory encoded?
Hippocampus
What are other names for implicit memory?
Non-declarative memory
Unconscious memory
Reflexive memory
Habit memory
Procedural memory
Where is implicit memory encoded?
Cerebellum and striatum
What is confabulation?
Describing of events that never occurred to fill a memory gap
