Chapter 18 Flashcards
anterograde amnesia
Unable to form most new memories
Short-term memory stores information for
a brief period of time, which can be extended by rehearsal, but fades if not stored more permanently
Long-term memory is
a more permanent storage of information
Explicit memory includes
facts and events that we recall spontaneously and consciously
Episodic memories
autobiographical; semantic memories are for facts
Implicit memories are
motor skills that can be performed automatically without full awareness of how we do the task
Emotional memories
the affective properties of the stimulus
Amnesia
loss of existing memories or the inability to form new memories
With amnesia there is an
event or incident that causes the memory loss
retrograde amnesia
Loss of memory from before the event
Retrograde amnesia is
time-dependent, with more recent events more likely to be lost
Traumatic brain injury often results in
time-dependent retrograde amnesia, with longer periods of amnesia being associated with more severe injuries
Some events can be retained as
islands of memory within the period of retrograde amnesia
Prospective memory
remembering things you intend to do, such as run an errand or call a friend
Destination memory
memory for past interactions, such as who you told a story to
Childhood or infantile amnesia
the inability to remember events from the first 4 years of life and difficulty recalling things that happened in about the first decade of life
Childhood or infantile amnesia is due to
developmental changes in cognitive abilities and memory systems that occur in the first decade of life
alternative hypothesis to Childhood or infantile amnesia
the rapid proliferation of new hippocampal neurons early in life might disrupt stored memories
A fugue state
when an individual loses memory of their personal history
A fugue state may be due to
damage to memory systems of the medial temporal lobe
Amnesias can exist for
specific categories of items, such as human faces, fruits and vegetables, or animals and birds
Autonoetic awareness of time is the awareness that
there is a continuum from our past to our present to our future and allows us to do mental time travel to our past and our future
Autonoetic awareness depends on the
hippocampus and frontal lobes, as damage to these areas can cause the loss of this self-knowledge
It is possible to remember facts and general knowledge without being able to
remember personal, autobiographical details, suggesting these processes depend on different brain regions
Semantic memory Involves regions of the
temporal and frontal lobes that are distinct from the areas involved in episodic memory
fMRI studies identified a network of left-hemisphere regions that are active during
semantic memory tasks and largely overlap with the default network
Network of temporal-lobe structures and parts of the ventral-stream pathway support
explicit memory
Multiple thalamic nuclei support
explicit memory because they serve to relay information from the prefrontal cortex to the temporal lobe
Hippocampus includes two
gyri
Ammon’s horn contains
pyramidal cells divided into four output layers known as CA1 through CA4
Dentate gyrus contains
stellate granule cells
stellate granule cells
sensory cells that undergo neurogenesis to produce new cells throughout life
The cells of the hippocampus are sensitive to
oxygen deprivation, with CA1 cells being most sensitive, followed by the other CA cells, then the stellate cells of the dentate gyrus
Patients with damage to the CA1 region have
a few years of retrograde amnesia, whereas those with greater damage have longer periods of amnesia
Hippocampus stores memories when they are formed, but older memories are stored in the
adjacent cortex
Early damage to the hippocampus results in
profound problems with episodic memory, but fairly normal semantic memory
Damage to the hippocampal connections resembles amnesia associated with damage to the
hippocampus itself
Rhinal cortex of the temporal lobe includes the
perirhinal and entorhinal cortex and is part of the pathway for information flowing into the hippocampus from the neocortex
Rhinal cortex is often damaged in patients with
medial-temporal-lobe lesions, making it difficult to determine what deficits are due to hippocampal damage and which are due to rhinal cortex damage
Lesions to the hippocampus resulted in
no problems with object recognition, but the use of context was impaired
Lesions to the rhinal cortex impaired
object recognition
Damage to the right temporal cortex impairs
face recognition, spatial position, and maze learning
Damage to the left temporal lobe impairs
memory for word lists, lists of consonants, and nonspatial associations
Bilateral lesions of the parietal and occipital lobes can result in specific forms of
amnesia, including color amnesia, prosopagnosia, object anomia, and topographic amnesia
Damage to the left prefrontal cortex is predicted to interfere with
encoding semantic and episodic memories
Damage to the right prefrontal cortex is predicted to interfere with
retrieving episodic memory
Using language and motor skills relies on
implicit memory
Priming is an experimental test of
implicit memory in which a stimulus is presented initially to make it more likely for the subject to respond later to the same or a similar stimulus
Patients with amnesia do about as well as control subjects saying the word that was on the studied list or identifying a previously seen picture, even though the patients
do not remember the training
The proposed implicit memory circuit suggests that
multiple regions of the cortex and the substantia nigra project to the basal ganglia, which projects to the premotor cortex
Brain-imaging studies during the pursuit rotor implicit memory task find increased activity in the
basal ganglia, motor cortex, and cerebellum
Patients with Huntington disease have degeneration of the
basal ganglia
Huntington disease patients are impaired on classic tests of
implicit memory, such as mirror drawing
Patients with Parkinson disease, which is characterized by
impairments of the basal ganglia, also show deficits of implicit memory
Successful treatment of Parkinson disease with l-dopa also improves
implicit memory
Cerebellum projects to the
motor regions of the cortex via the thalamus
Cerebellum is involved in
classical conditioning tasks, such as eyeblink conditioning
Cerebellar lesions in rabbits prevent the rabbits from
learning the cue that a puff of air is coming, so they should blink their eye
Neurotransmitters ascending from the brainstem are associated with memory (4)
Cholinergic
Serotonergic
Noradrenergic
Dopaminergic
Impairments in the cholinergic system are associated with
Alzheimer disease
Amnesia can result from damage to the ascending cholinergic and
serotonergic cells simultaneously
Emotional Memory Involves both
bottom-up and top-down processing
Emotional Memory
Memory for the affective properties of a stimulus
Fear conditioning uses a
noxious stimulus paired with a neutral stimulus to evoke an emotional response
Amygdala is involved in
fear conditioning
The amygdala plays an important role in
emotional memory
The amygdala is made of many
nuclei, including the basolateral complex, the cortical nucleus, and the central nucleus
Regions of the amygdala influence the
autonomic nervous system and the hypothalamus
Damage to the amygdala impairs
emotional memory, but not implicit or explicit memory
Short-Term Memory
Forms a record of recent events and the order in which they occurred
Short-Term Memory Holds information for a
short time while we use the information
Short-term memory for object information uses the
ventral stream and for motor information uses the dorsal stream, both of which project to the frontal lobe
Patients with damage to the medial temporal lobe retain
normal short-term memory
Patients with damage to the posterior temporal lobe or temporo–parieto–occipital junction have
short-term memory impairments
Frontal-lobe damage is often associated with
with short-term memory impairments
Patients with frontal-lobe damage are significantly impaired on the
recency test
Left-frontal-lobe damage is most significant for what type of material
verbal material
right-frontal-lobe damage is most significant for what type of material
nonverbal material
Neuropsychological Testing
Common tests present two stimuli, one after the other Patient needs to report whether both stimuli were they same or which one they had seen most recently
Interference Tasks
Subjects are shown five lists of words and told to recall as many words as possible, The first four lists all contain words from the same category, such as sports or foods
The fifth list is from a different category
In proactive interference, the earlier lists interfered with the ability to
recall information on the later, similar lists
Patients with frontal-lobe damage show
proactive interference but do not show release from interference
Savant syndrome
Some individuals can remember large amounts of information for long periods of time
Superior autobiographical memory
Individuals with highly superior autobiographical memory show almost complete recall for personal events in their lives, down to the weather on the day an event happened
Superior autobiographical memory - These people have increased
gray matter in temporal and parietal lobes and larger fiber projections to the frontal lobe
Finding the neural basis of memory is challenging because
memory changes over time
For a study of short-term visual memory, fMRI showed activity in the
attentional, salience, visual, and default networks
Therefore, most of the neocortex was involved in a single
short-term memory task
System consolidation theory
Hippocampus consolidates new memories, which are then stored elsewhere in the cortex
Multiple-trace theory
different aspects of the memory (autobiographical components, factual semantic components, etc.) are stored in different parts of the cortex simultaneously
Reconsolidation theory
as memories are recalled, they are changed or edited before being reconsolidated in their new form
Trace transformation theory
: memories are initially encoded in the posterior hippocampus, but move to the anterior hippocampus, then to the medial prefrontal cortex, losing detail with each transformation
Associative inference enables us to
combine what we already know with novel information to interpret the current situation
Memories may be reconstructed to focus on the
“gist,” or essence, of the memory, enabling us to remember and adapt to similar situations in the future
