Limbic System: Manaye Flashcards
List the brain structures associated with the limbic system.
- involve motor and nonmotor areas that will integrate your learning, memory, and emotions
- all the animals mate through pheromones
- smell is important to like your food or stay in certain environments
Amygdala Entorhinal cortex Hippocampal formation Cingulate gyrus & cingulum Hypothalamus Thalamus Septum
What is the entorhinal cortex and what structures in the brain is it closely related to?
it is part of the limbic system
- located in the anterior part of the parahippocampal gyrus, on the medial surface of the temporal lobe
- transition zone between hippocampus and temporal neocortex
- multiple inputs to the entorhinal cortex, including fibers from the cingulate gyrus, basolateral amygdala, olfactory cortex, and cortical association areas
-entorhinal cortex funnels highly processed cortical information to the hippocampal formation and serves as its major output pathway
How are all the limbic structures connected?
through long term potentiation (Allard’s lecture)
CA1-4
The hippocampus is composed of two major components, the dentate gyrus and the hippocampus proper – the latter also referred to as Ammon’s horn or cornu Ammonis (CA regions). The Ammon’s horn region is divided into four subregions – area CA4 or the hilus, areas CA3, CA2, and CA1.
What is learning and what are the routes in which it occurs?
- is the acquisition of new experiences (information)
- strengthen of receptors and synapses
-can be achieved through plasticity, associative and Non-Associative learning
How strong must a stimulus be for an individual to learn?
it depends on the individual and ???
What is the function of the limbic system?
It is the system controlling learning, emotion, motivation, and memory in man. It has two parts; cortical and subcortical components.
- drives and rewards, crucial to motivational state
- affects visceral activities central to emotional expression
- influences sensory and associative mechanisms that are critical ingredients of perceptions and perhaps thought
Where is the majority of the limbic system located?
around the rim of the lateral ventricle
What is the role of the Paul McLean (1949) in the limbic system?
expanded on the Papez circuit in the article “Psychosomatic Brain and the Viscera
What is the role of the Papez (1930) in the limbic system?
Linked the structures comprising the “Limbic System” as having a role in emotions.
What is the role of the Broca (1878) in the limbic system?
“Le Grande Lobe Limbique” (Grand Limbic Lobe) – this is a reference strictly to anatomical organization
What is the rhinencephalon?
part of the brain associated with the olfaction
What is the hippocampal formation?
- it is closely associated with the adjacent dentate gyrus and forms an S-shaped structure
- consists of the dentate gyrus, hippocampus proper, and the subiculum
- each of these components have 3 layers of neurons
- embryologically the hippocampal formation is an extension of the medial edge of the temporal lobe
Where is the dentate gyrus located?
occupies the interval between the hippocampus and parahippocampal gyrus
What is the subiculum?
the part of the parahippocampal gyrus that is in direct continuity with the hippocampus
Describe the anatomy of the hippocampal formation.
- part of the limbic system
- located in the temporal lobes
- composed of dentate gyrus, CA1-3, and subiculum
- perforant pathway
What is the perforant pathway and what is its function?
- provides a connectional route from the entorhinal cortex to all fields of the hippocampal formation, including the dentate gyrus, all CA fields (including CA1), and the subiculum
- perforant activates the Ca3 neurons in the hippocampus which is important for encoding memory
What is the histology of the limbic system? What are the layers of the hippocampus?
- cortical structure of parahippocampal gyrus is six layers
- as the cortex is traced into the hippocampus there’s a gradual transition from a six to three layered arrangement
the hippocampus has:
- outer molecular layer
- middle pyramidal layer
- inferior and inner polymorphic layer (CA1, CA2, CA3, and CA4 (cornu Ammonis)
Describe the distribution of hippocampal neurons.
- cluster of neurons entering the dentate gyrus known as CA1-CA4 are pyramidal cells
- neurogenesis only occurs in the dentate gyrus within the limbic system
- most of the neurons in the dentate gyrus are granular cells
What is long term potentiation?
- increased excitability during altered chemical state on repeated stimulation of synapses
- is due to augmentation of postsynaptic potentials overtime
What is the fundamental postulate of the molecular mechanisms of memory storage?
anatomical connections between neurons
-these mechanisms are set by genetics and the strength and effectiveness of synapses
Is memory predetermined?
NO but it can be altered by experiences
What are the neural mechanisms of learning?
?????
What is learned (where in the brain; organization level?
???
What is perceptual learning?
functions to identify objects and situations
What is stimulus-response learning?
involves making a response when a particular stimulus is present as
- classical conditioning
- operant conditioning
What is motor learning?
involves forming new circuits in the motor system
What is relational learning?
involves identifying connections between stimuli
What are associated with associative and non-associative learning?
associative:
- classical conditioning
- operant conditioning
non-associative
- habituation, sensitization
- perceptual in nature
- recognition of objects and situations
Which type of learning involves acquisition of new motor behaviors, associations between new stimuli and existing behaviors, and new associations between familiar stimuli and existing responses?
associative learning
What is habituation in non-associative learning?
- repeated exposure to a stimulus results in REDUCED responding to that stimulus
- generally neutral, non-noxious stimuli