Chapter 13: Memory & Learning Flashcards
Define learning and memory
Learning = the process of acquiring new information Memory = 1) the ability to store and receive new information 2) the specific info stored in the brain
What is retrograde amnesia?
Difficulty in retrieving memories formed before the onset of amnesia.
Declarative memory
Things you know that you can tell others (i.e., where I was born)
Non-declarative memory
things you know that you can show by doing (i.e., how to ride a bike)
What was patient N.A.’s declarative memory loss caused by?
Damage to the dorsomedial thalamus (limbic system structure connected to the hippocampus) and the mammillary bodies which caused him to be unable to encode new declarative memories. (Korsakoff’s syndrome)
What was patient K.C.’s deficit in forming or retrieving new episodic memories caused by?
Patient K.C. was unable to retrieve or form episodic memories, but his general knowledge remained good. This was caused by extensive damage to left and right frontoparietal cortex and a severe shrinkage of hippocampus on both sides.
Define skill learning and which areas of the brain it is associated with
Skill learning is the process of learning to perform a challenging task simply by repeating it over and over. Sensorimotor skills, perceptual skills and cognitive skills are all impaired when there is damage to the basal ganglia, a group of forebrain nuclei.
What is instrumental conditioning?
Instrumental conditioning (operant) is a form of associative learning in which the likelihood that an act (instrumental response) will be performed depends on the consequences (reinforcing stimuli) that follow it.
Explain cognitive maps and the research behind it.
Rats solving a maze do not simply learn via a series of turns, but use a cognitive map: a mental representation of the relative spatial organization of objects and information
- hippocampus appears crucial for spatial learning
- rat hippocampus contains many neurons that selectively code spatial location, called place cells.
Describe the process of encoding, consolidation and retrieval of memory
1) encoding: first process in memory system, in which the information entering sensory channels is passed into short-term memory.
2) consolidation: short-term memory goes into long-term memory.
3) retrieval: use of stored long-term memory for use in working memory
Describe the enriched/unenriched condition rat experiment and the neurobiological results.
- Impoverished condition (IC): animals housed individually, isolated.
- Standard condition (SC): animals housed in small groups
- Enriched condition (EC): animals housed in large social groups in special cages containing various toys and other features.
- EC animals have a heavier, thicker cortex, especially in somatosensory and visual areas
- EC animals have more dendritic branches on cortical neurons
- EC animals show enhanced recovery from brain damage
Habituation
A form of nonassociative learning in which an organism becomes less responsive to repeated stimuli.
- slug and retracted gill experiment. Long-term habituation is due to a retraction of some synaptic terminals.
Hebbian synapse
a synapse that is strengthened when it successfully drives the postsynaptic cell
Long-term potentiation
Experimentally induced pre-synaptic activity (a tetanus) causes post-synaptic neurons to produce larger EPSPs, which causes them to become stronger and more effective.
LTP is a stable and enduring increase in the effectiveness of synapses following repeated strong stimulation.
Most studied form is that LTP occurs at synapses that use glutamate
- glutamate is critically dependent on the NMDA receptor.
- drugs that block NMDA receptors prevent new LTP in this region, but does not affect synaptic changes that have already occured.
- NMDA receptors work in conjunction with AMPA receptors
Describe the process of a popular LTP pathway
- during normal activity, the release of glutamate only acts on AMPA receptors. NMDA receptors can’t respond to glutamate because MG2+ ions block the NMDA’s receptors CA2+ ion channel; thus few CA2+ ions can enter the neuron.
- this changes if large quantities of glutamate are released. This depolarizes the postsynaptic membrane enough so that the MG2+ plug is pulled.
- causes intracellular enzymes that affect AMPA receptors
1) causes existing AMPA receptors to move toward the synapse
2) increases AMPA conductance of NA+ and K+ ions,
3) thereby increases the production of AMPA receptors. A retrograde transmitter diffuses back into the presynaptic neuron to induce it to release more glutamate.
