Exam 4 Flashcards
(51 cards)
Define Retrograde amnesia, the common causes/affiliated brain regions.
Definition: loss of memories for events that occured before an injury
Common Causes: caused by damage to the entire hippocampal formation possibly from 15 or more years prior, extensive impairment occurs with broader damage or deterioration from another disease (Alzeihmer’s, Parkinson’s, Huntington’s)
Define Anterograde amnesia and the common causes/affiliated brain regions.
Definition: loss of ability to form new memories
Cause:
- Moderate Damage: damage to Cortical Area A 1 in both hippocami
- Severe Damage: damage to the entire hippocampus region
Who is patient H.M.?
A man who suffered from extreme epilepsy. His doctors removed the medial temporal lobes on both hippocampi, most of the amygdalae, and entorhinal cortex.
- Major symptoms: complete inability to form new memories, but was extremely intelligent and could remember in great detail
- Contribution: provided insight into the brain’s memory processes, and highlighted the important of the amygdalae and hippcampi
State the proposed memory consolidation process and name the brain regions involved.
The process of consolidating a short-term memory into a long-term memory.
Brain Regions: hippocampus and adjacent cortex are involved in consolidation
How is the temporal cortex involvded in memory function and consolidation?
The temporal cortex contains the hippocampus, this works to temporarily store new memories before they later move to the prefrontal cortex
How is the prefrontal cortex involved in memory function and consolidation?
- encodes new memories
- retrieval of old memories
State the neurotransmitters and their roles involved in memory function and consolidation.
Dopamine: aids memory in humans, injecting dopamine precursor (levodopa) improves memory in humans
Glutamate: aids retrieval and consolidation processes, when glutamate receptors are blocked the hippocampi is disabled resulting in impaired retrieval and consolidation
Where are emotional memories stored in the cortex?
amygdala
Define long-term Potential (LTP) and its connection to learning.
LTP is a peristent strengthening of synapses which result from the simultaenous activation of presynaptic and postsynaptic neurons. This appears to be a characteristic of a lot of neural tissue, especially in areas involved with learning
What areas of the brain are involved in LTP?
- Hippocampus
- Visual, auditory, and motor cortex
Where are explicit memories stored in the cortex?
hippocampus
What is the relationship between LTP and NMDA receptors?
Initially glutamate activates the AMDA receptors but not the NMDA receptors (they are blocked by magnesium ions).
- When the activation is strong enough: the postsynaptic membrane is partially depolarized resulting in the magnesium ions to eject. The NMDA receptors can then be activated allowing sodium and calcium ions to enter
- the calcium influx results in LTP
Where are spatial memories stored in the cortex?
Hippocampus and medial entorhinal cortex
Where are long-term memories store in the cortex?
hippocampus
Where are short-term memories stored in the cortex?
Prefrontal cortex
Where are procedural memories (motor skills) stored in the cortex?
Cerebellum
Where are visual memories stored in the cortex?
frontal and occipita lobes
Where are auditory memories stored in the cortex?
auditory cortex, including the superior temporal lobe
Define the iconic memory.
Holds visual information
- around 500 milliseconds
Neurons in occipital lobe is responsible for holding the incoming visual input of the iconic memory
Define echoic memory.
Holds auditory information
- around 3 seconds
Neurons in the temporal lobe are responsible for holding incoming auditory input of the echoic memory
What is the Donald Hebb rule?
The principle stating that if an axon of a presynaptic neuron is active while the postsynaptic neuron is firing, the synapse between them will be strengthened
Define the processes of reconsolidation and vulnerabiity.
The process in which a previously formed memory, after beign retrieved, becomes temporarily vulnerable to change/disruption.
- Purpose: helps in responding to a changing environment by weakening a now irrelevant memory (memoring a new way to drive home) or strengthening an adaptive one (how to buy groceries)
Define haptic memory.
Holds somatosensory information
- around 150 ms to 10 s depending on the receptor type
- neurons in the parietal lobe are responsible for holding incoming somatosensory input from the haptic memory
How does sleep/napping impact consolidation and performance?
The hippocampus transfers information to the cortex during times of rest.
- Human EEG and PET scans show the hippocampus repeatedly activating the cortical areas participating in daytime learning, when reteasted there was significant task improvement the next morning w/o further practice
