Exam 4 Flashcards
(42 cards)
What is Retrograded amnesia
The inability to remember events prior to impairment.
Caused by damage to the entire hippocampal formation which can extend back 15 years or more.
extensive impairment occurs with broader damage or deterioration (Alzheimer’s, Parkinson’s, Huntington’s disease.
What is Anterograde amnesia
An impairment in forming new memories
Damage in CA1 part in both hippocami cause moderate anterograde amnesia but severe is damage include the rest of the hippocampus
Memory consolidation and physiology of this process
The process in which the brain forms a more or less permanent physical representation of a memory.
Hippocampus and adjacent cortex seem to be activated during consolidation.
How is the temporal cortex involved in memory function and consolidation?
It include the hippocampus which stores new memories temporaily before they are later moved to the prefrontal cortex
How is the prefrontal cortex role involved in memory function and consolidation?
It is responsible for encoding new memories and retrieval of old memories
Neurotransmitters involved in memory function and consolidation
Increasing dopamine levels by injecting the dopamine precursor levodopa improves memory in humans.
Glutamate receptors being blocked, disables the hippocampi resulting in impaired retrival and consolidation.
The physiology of LTP/learning
Long-term potential (LTP) is a persistent strengthening of synapses that result from the stimultaneous activation of presynaptic and postsynapic neurons. Appears to be a characteristic of much of neural tissue in areas likeily involved in learning.
Includes: Hippocampus; visual, auditory and motor cortex.
LTP & the NMDA Receptors
Initially, glutamate activates the AMDA receptors but not the NMDA receptors, which are blocked by magnesium ions. However, if the activation is strong enough to partially depolarize the postsynaptic membrane, the magnesium ions are ejcted. The NMDA receptors can then be activated, allowing sodium and calcium ions to enter.
Where are certain types of memories stored in the cortex?
Long-term memory= hippocampus
Explicit memories= hippocampus
Short-term memory= prefrontal cortex
Spatial Memory= Hippocampus and medial entorhinal cortex.
Procedural Memory (Motor Skills)= Cerebellum.
Emotional Memory= Amygdala.
Visual Memory= Frontal and occipital lobes.
Auditory Memory= Auditory cortex, including the superior temporal lobe
Iconic Memory
- Holds visual information ~500 ms
- Neurons in occipital lobe responsible for holding incoming visual input
Echoic Memory
- Holds auditory information ~3 seconds
- Neurons in temporal lobe responsible for holding incoming auditory input
Haptic Memory
- Holds somatosensory information 150 ms – 10 sec (10,000 ms) depending on
receptor type - Neurons in parietal lobe responsible for holding incoming somatosensory input
Donald Hebb; The 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.
How does sleep/ napping impact consolidation and performance?
Hippocampus tranfers info to the cortex during times of rest.
Human EGG and PET studies show the hippocampus repeatedly activating the cortical areas that participated in the daytime learning, and reactivation was accompanied by significant task improvement the next morning w/o further practice.
Reconsolidation and vulnerability
The process where a previously formed memory, after being retrieved, becomes temporarily vulnerable to modification or even disruption.
Our brain does this because it helps in responding to a changing enviroment by weakening a now irrelevant memory or strengthening an adaptive one.
Dementia and physiology/causes (e.g neurofibrillary tangles, beta amyloid)
Substantial loss of memory and other cognitive abilities.
Most common is Alzheimer’s disease (60-80%), a disorder characterized by progressive brain deterioration and impaired memory and other cogntive abilities.
Clumps of beta amyloid (plaques) cluster among axon terminals and interfere with neural transmission.
The ratio of AB42 to AB40 leads to the accumulation of the protein tau to form neurofibrillary tangles inside neurons; tangles are associated with the death of brain cells.
Brain regions and IQ
Overall, larger brain size and volume is associated with better cognitive functioning and higher intelligence. The specific regions that show the most robust correlation between volume and intelligence are the frontal, temporal and parietal lobes of the brain
What is the PFIT theory?
General intelligence depends on how well parietial and frontal brain networks integrate with each other.
What are the gender differences in IQ and brain physiology?
- No major differences in general IQ, but some subtest differences
- Women tend to show slightly better verbal abilities (gray matter increased in frontal areas)
- Men tend to show slightly better visuospatial abilities and higher variability in quantitative abilities (gray matter increased in frontal and parietal lobes)
- differences could be due to social effects or sexual dimorphism in the brain
How does IQ impact glucose usage?
Brains of people with higher IQ use __less_ glucose
Higher IQ = more efficient brain
Brains of people with lower IQ use __more_ glucose (they have to think harder so use more brain power)
What is the heritability of IQ?
Averages at 50% but increases with age, from 41% in childhood to 55% in adolescence and 66% in adulthood.
What is the importance of myelin for IQ?
increased white matter, equals increased myelin, = faster neural conduction and nerve conduction velocity.
Myelination, speed of info processing, and intelligence all follow a curvilinear time path, increasing from childhood to maturnity and then declining in old age.
What is the Flynn Effect??
A worldwide increase in IQ scores over the last several decades, at a rate of about 3 points per decade, IQ Increase of 5-25 points with every generation
What is the heritability of Schizophrenia?
Familial disorder, increases with genetic closeness. Identical twin are three times at higher risk if one twin has it compared to faternal twins.
