Flashcards in Learning and Memory Deck (46):
What is meant by the term "multiple memory systems"?
-Three different memory systems (explicit, implicit, and emotional)
What is explicit memory?
-Able to bring these memories to mind on demand
What is implicit memory?
-Don't consciously need to think about memory
-E.g., riding a bike
What is emotional memory?
-Conscious and unconscious memory
-Attraction, fear, etc.
What did Lashley have to say about the location of memory in the brain?
-No neural centre for memory
What structures are important for explicit memory?
What structures are important for episodic/autobiographical memory?
-Type of explicit memory
-Uncinate fasciculus (important in autonoetic awareness - aware of something, can change that in the future)
-IPFC (frontal lobe) - encodes episodic memory
-rPRF (frontal lobe) - retrieves episodic information
What structures are important for semantic memory?
-Type of explicit memory
-IPFC (frontal lobe)
What structures are important for implicit memory?
-Neocortex (premotor cortex) *
-Basal ganglia *
What structures are important for emotional memory?
How can memory be divided temporally?
-Sensory, short-term, and long-term memory
-Sensory memory (iconic, echoic, and haptic)
-Short-term memory (based mostly on chunking - mainly acoustic)
-Long-term memory (semantics of information - what it means)
What are the different types of amnesia?
-Infantile (experienced by everyone, LTM not fully developed but individual can still learn)
-Transient global (not permanent, affects whole system)
-Fugue state (forget everything about yourself, usually transient)
-Electrocompulsive therapy/alcohol (usually transient)
-Specific vs. global
What is the difference between retrograde and anterograde amnesia?
-Retrograde: forget information prior to injury
-Anterograde: forget information after the injury
What is Ribot's law?
-Retrograde amnesia is time-dependent
-The severity of the injury determines how far back in time the amnesia extends **
-The majority of retrograde amnesia disappears, leaving only a few seconds or minutes of loss immediately prior to injury
What are the three theories to explain Ribot's law? **
-Consolidation theory: States that the role of the hippocampus is to consolidate new memories, a process that makes them permanent
-Multiple-trace theory: Autobiographic memory is stored in the hippocampus, factual semantic information is stored in adjacent temporal structures, and general semantic memories are stored in other cortical areas (older memories are accessed more and are stored in different areas based on their reactivation, overlap between all three areas). Postulates both multiple kinds of amnesia and changes in memory with the passage of time
-Reconsolidation theory: Proposes that memories rarely consist of a single trace or neural substrate. Memory reenters a labile phase when recalled and is then restored as a new memory
What is priming?
-Recent experiences affect what comes to mine (doesn't have to be conscious)
What is the depth-of-processing effect?
-Improvement in subsequent recall of an object about which a person has given thought to its meaning or shape
What is the study-test modality shift?
-Process by which subjects, when presented with information in one modality (reading) and tested in another modality (aurally), display poorer performance than when they are instructed and tested in the same modality
What is episodic (autobiographical) memory?
-Memory containing autobiographic events that took place in specifiable temporal and spatial contexts
-Singular events that individual can recall and that centre on the individual themselves
What is autonoetic awareness?
-Awareness of one's self, or self-knowledge
-Ability to travel in subjective time
What is semantic memory?
-All knowledge that is not autobiographical
What two main structures make up the hippocampus? What are the main cell types in these two structures?
-Ammon's horn - pyramidal cells ("motor" cells)
-Dentate gyrus - stellate granule cells ("sensory" cells)
What are the main connections into and out of the hippocampus?
-Perforant pathway (connection between the hippocampus and posterior neocortex)
-Fimbria-fornix (connects hippocampus to the thalamus, frontal cortex, basal ganglia, and hypothalamus)
-Forms a loop of synapses
What do lesions to the CA1 regions of the hippocampus cause?
-Limited retrograde amnesia
What does incomplete hippocampal damage cause?
-Retrograde amnesia covering 15-25 years
What does complete hippocampal damage and damage to the surrounding structures cause?
-Retrograde amnesia covering 40-50 years
What does complete removal of the hippocampus cause?
-Complete retrograde and anterograde amnesia for explicit information
What does early damage lead to the inability to remember? What can the person still remember?
-Can't remember familiar surroundings or where objects are located; appointments/events; daily activities
-Can remember factual knowledge; how to read, write, and speak
What does damage to the fimbria-fornix pathway cause?
-Retrograde and anterograde amnesia, but can remember factual information, and how to read, write, and speak
Damage to the frontotemporal connections, as well as the temporal stem, can contribute to what?
What is generally found with hippocampus lesions?
-Anterograde deficits are more severe
-Episodic memories are more affected than semantic memories
-Autobiographic memories are especially affected
-Patients cannot time travel to past or future
What is the functional result of lesions to the rhinal cortex vs. lesions to the hippocampus?
-Rhinal cortex includes entorhinal and perirhinal cortex and projects to hippocampus
-Rhinal damage = object recognition impairment
-Hippocampal damage = context impairment
What are the specializations of the left and right hemisphere in memory?
-Left (word lists, consonant trigrams, nonspatial associations, Hebb recurring-digit test)
-Right (face recognition, spatial position, maze learning, block tapping)
What are the specializations of the frontal lobe in memory?
-IPFC (encodes semantic and episodic information)
-rPRF (retrieves episodic information)
What are the specializations of the parietal and occipital lobes in memory?
-Colour, faces, objects, topography
What is herpes simplex encephalitis? What is its effect on memory?
-MTL damage leads to anterograde amnesia
-Damage to LTL and insula produces severe retrograde amnesia
-Insula is good at remembering well-practiced verbal tasks, but not novel tasks
What is Alzheimer's disease? What is often its effect on memory?
-First causes anterograde amnesia (MTL)
-Retrograde amnesia as damage spreads to temporal and frontal cortices
-Mainly affects explicit memory, but can affect implicit memory too
What is Korsakoff's syndrome? What is often its effect on memory?
-Thiamine (vitamin B1) deficiency
-Damage: medial thalamus, mamillary bodies of hypothalamus (thiamine is important here), general atrophy
-Six major symptoms: anterograde amnesia, retrograde amnesia, confabulation (fabricated or misinterpreted memories), meagre conversation content, lack of insight, apathy
What is Huntington's disease? What is often its effect on memory?
-Loss of cells in the basal ganglia
-Leads to deficits on tests of implicit memory
How are the neocortex (motor cortex) and cerebellum involved in implicit memory?
-Motor cortex: Acquisition of implicit knowledge requires a reorganization of the motor cortex. More practice = larger cortical map (pursuit-rotor test)
-Cerebellum: Takes part in learning discrete, adaptive, behavioural responses - classical conditioning
How does fear conditioning in emotional memory work?
-Noxious stimulus is associated with neutral stimulus
-Fear response is then elicited by neutral stimulus
-Mediated by the amygdala
-Damage to amygdala disrupts emotional memory but not implicit or explicit memory
What are the neural substrates for short-term memory?
-Info relating to objects/movements may be mediated through ventral/dorsal pathways, respectively, to two different regions of the PFC
-Damage to polymodal sensory areas such as the left posterior temporal lobe or posterior parietal lobe may lead to specific short-term memory deficits (e.g., being able to repeat spoken word but not written word after a short delay)
What are three tests that can be done to assess frontal lobe function?
-Compound stimulus (single modality): Presented with images a few seconds apart - same or different?
-Visual word pairs: Recognition (patients with left temporal removal show a mild deficit, in keeping with their difficulty with verbal memory); recency (frontal lobe groups were impaired, although left-side group was significantly worse)
-Complex movement copying (e.g., set of three): Frontal lobe lesions showed errors of sequence, intrusion, omission
What two streams in the brain are important in short-term memory with respect to the frontal lobe?
-Temporal/ventral stream (objects): "Vision for recognition"; dorsolateral prefrontal cortex
-Parietal/dorsal stream (locations): "Vision for action"; mid-dorsolateral frontal cortex
What is the difference between object recognition and object recency?
-Recency: Presented with pairs of words, occasionally two words would come up with a question mark between them and subjects had to indicate which word they read more recently
-Recognition: In some cases, only one word (out of the two words) had been presented before so the subjects just had to recognize the word that had been previously presented