Limbic System Flashcards
What is declarative memory?
Declarative memory is the ability to remember facts and events that have specific temporal and spatial context (“I was interviewed at the doctor’s office yesterday”) as well as semantic knowledge (general knowledge about the word including new word meanings).
What is procedural memory?
Procedural memory is the ability to learn new skills
What type of memory is impaired in lesions of the hippocampus?
Declarative memory is impaired in hippocampal lesions. HM had bilateral hippocampal surgery to relieve epilepsy but resulted in profound anterograde amnesia.
What type of memory is impaired in lesions of the cerebellum/basal ganglia?
Procedural memory
What is the definition of short term memory?
Short term memory is considered memory that lasts for fractions of a second to seconds. Most sensory systems involve this type of memory, and its processes take place in the sensory cortex.
What is the definition of working memory and where in the brain does it generally occur?
Working memory is memory that lasts for seconds to minutes. It occurs in the frontal cortex. Actions like preparing a recipe involve working memory.
What is the definition of long term memory and where in the brain does it generally occur?
Long term memory lasts for days to years and is stored in the cortex. Memory starts in the hippocampus and moves to the cortex.
What evidence is there that the neocortex is the site for long term memory storage?
Lesion and fMRI studies indicate the neocortex is the site for long term memory storage. Lesions in the inferotemporal cortex cause the loss of the ability to recognize faces.
What is associative memory?
Associative memory is the process of learning to associate several different cues with a particular fact or object. An example would be playing charades, where early rounds require many different cues to elicit a particular things (say, the movie “Lord of the Rings”). Subsequent rounds, however, only require a few cues because they have been associated with that thing.
How does LTP account for associative memory?
LTP occurs through coincidence detectors, frequently NMDA channels, which require simultaneous depolarization and glutamate binding. The simultaneous display of two stimuli activate these channels and lead to the increased expression of AMPS channels at that synapse, causing associations. Long term consolidation of this effect is caused by Ca2+ phosphorylating CamKinase2, which can then phosphorylate itself even in the absence of Ca2+, resulting in increased AMPA expression.
Under what circumstances do hippocampal synapses undergo LTP?
Only CA1 and CA3 neurons in the hippocampus may undergo LTP, and then only when they are being stimulated by large titanic bursts. CA3 neurons are important for associative memory formation.
What is the molecular mechanism of LTP?
The post-synaptic neuron is depolarized by EPSPs generated at a given synapse. Simultaneously, NMDA receptors at a different synapse on the same neuron are activated by Glutamate. The depolarization repels the Mg2+ plug from the NMDA channels, and the Glu opens the channels, allowing influx of Ca2+. Ca2+ then phosphorylates CAM Kinase 2 which then triggers the expression of AMPS channels on the surface of the neuron.
How are synapse formation and adult neurogenesis involved in learning and memory?
Synapses are not static. Adult dendrites and axons do not undergo rearrangement, but synapse formation and retraction are active in adults. Adult neurogenesis occurs in the olfactory bulbs (assisting in olfactory learning) and possibly in the cerebellum and hippocampus as well.
What structures are affected in the early stages of alzheimer’s disease?
In it’s early stages, the disease affects synaptic transmission in limbic and association cortices. There is a loss of the ability to encode new declarative memories in an individual with otherwise normal intelligence, motor, and sensory functions.
What actions and brain structures are involved in the expression of emotion?
Autonomic visceral actions are controlled by the hypothalamus and somatic-motor actions are coordinated by the midbrain reticular formation in the brainstem.
