Memory
Psychology 3910
Guest Lecture by Steve Smith
Note: Due to copyright restrictions, I had to remove the images from
the Weschler Memory Scales from the slides I posted online.
Wechsler Memory Scales - III
• Consists of 11 subtests, 6 primary and 5 optional.
• Primary
– Logical Memory (e.g.,
the “Anna Thompson
passage”; 2 tests)
– Verbal Paired
Associates (2)
– Faces (2)
– Family Pictures (2)
– Letter-Number
Sequences
– Spatial Span
• Optional
– Basic Awareness
Assessment
– Word Lists (2)
– Visual Reproduction
– Digit Span
– Mental Control
(reordering days,
months, etc.)
Rey Complex Figures Task: Assesses Spatial Memory
Specificity of Tasks
• The subtests of the WMS-III
and similar tools are not
random.
– Based on deficits shown by
patients with brain damage.
• Memory deficits can involve
different time frames as well
as different types of memory.
Outline
• Patient H.M. and the Medial Temporal Lobes
• Patient J.K. and Implicit Memory
• Patient K.C. and Two Kinds of Explicit Memory
• The Hippocampus and Memory
• Multiple Memory Systems
Part I: Patient H.M. and the
Medial Temporal Lobes • Suffered a laceration of the left supraorbital region
at age 9.
• Developed several epilepsy in his teens.
– Foci appeared to be in medial temporal lobes.
– High doses of anticonvulsants did not provide adequate
seizure control.
William Beecher Scoville
performed a bilateral anterior
temporal lobectomy on August
23, 1953.
The Extent of H.M.’s Lesion
Outcome of the Surgery
• Seizures were severely reduced.
• His overall IQ score rose from
104 to 118 (average = 100).
• Memory problems emerged.
– Dense anterograde amnesia.
“Every day is alone in itself, whatever
enjoyment I’ve had, and whatever
sorrow I’ve had… It’s like waking from a
dream; I just don’t remember.”
• Short-term memory was relatively intact
– Forward digit span = 7
– Backward digit span = 5
– Impairments emerged when stimuli exceeded STM.
– Impairments also emerged after delays.
Some Abilities are Spared
From Rempel-Clower et al. (1996)
Immediate vs. Delayed Recall in
Hippocampal Patients
• Preserved linguistic, social, motor, and basic
problem-solving skills.
• Autobiographical memory for his presurgical life
was partially preserved.
– Superior memory for remote vs. recent (presurgical)
events.
Some Abilities are Spared
H.M. and other amnesic patients, like controls, benefit from the
prior exposure. H.M. retained improvement 4 months later.
Session 1) asked H.M. to draw target patterns
Session 2) Just shown dots and asked to connect them
Findings = priming , H.M. drew more target patterns. Once again, he
had no recollection that he had ever done anything like this before.
Procedural/Motor
Memory
• Mirror-Drawing
Performance improved
dramatically.
H.M. claimed that he
had never done the
task before.
H.M. Demonstrates Memory for
Stimulus - Response Learning
Showed retention
2 years later!!!
Later Life…
• H.M. could
encode some
novel stimuli if
allowed time to
study it.
• Limited spatial
abilities
(including his
neighborhood).
• Died December 2, 2008.
Impact of H.M.
• H.M. demonstrated that damage to the hippocampus
and nearby cortex leads to anterograde amnesia.
Explicit Memory Circuit
Impact of H.M.
• His selective impairments proved that memory is
not a unitary construct.
– Different brain systems are involved in different forms
of memory.
Part II: Patient J.K. and Implicit Memory
Golin Recognition Task
Priming
• Previous experience with a stimulus influences
later responses to that stimulus.
– Influenced by perceptual factors (e.g., font, CAPS,
modality, etc.).
– Not influenced by depth of processing.
chase chase cha_ _
• Perceptual priming utilizes a posterior cortical network
involving extrastriate areas.
Patient J.K.
• Developed Parkinson’s disease
in his mid-70’s.
• Had age-normal explicit
memory.
• He was able to encode new
information about current
events.
• Impairments in performing
previously learned motoric tasks
(e.g., turning on lights).
Procedural Memory System
• Responsible for memory of rules, habits.
• An automatic, unconscious, implicit memory system.
• Affected in Huntington’s disease.
• Spared by hippocampal/diencephalic damage.
Procedural Memory System • Learning sequences of responses activates motoric
areas.
• Repeated exposure to a sequence leads to
decreased RTs.
1 2 3 4
The area of the cortex controlling the limb increased with
task mastery…even without awareness.
Remember that in the lecture, we had sample trials with 12 different responses
(e.g., 1, 4, 3, 4, 2, 1, 4, 3, 2, 1, 4, 3).
Classical Conditioning
• Animal studies indicate that the cerebellum is necessary for some forms of conditioning to occur (e.g., eyeblink conditioning). – Cerebellar lesions abolish the CR.
– But, timing is everything in the brain…
Delay vs. Trace Conditioning
• Delay Conditioning
– The CS is still present when the US starts.
– Both stimuli end at the same time.
– No memory trace is necessary.
Delay vs. Trace Conditioning
• Trace Conditioning
– There is a brief interval between the end of
the CS and the beginning of the US.
– A memory trace is required.
Delay vs. Trace Conditioning
• Delay Conditioning
– Requires activation in the
interpositus nucleus of the
cerebellum as well as in
the cerebellar cortex.
– Not impaired by hippocampal damage.
• Trace Conditioning
– Impaired by hippocampal damage.
– Does this mean it’s a form of declarative memory?
Part III: Patient K.C. and Two
Kinds of Explicit Memory
• Traumatic head injury
following a motorcycle
accident.
• Damage to the medial
temporal lobes, frontal,
parietal, and occipital
cortex (especially in the
LH).
Tulving et al. (1991). JEP.
Patient K.C.
• Preserved semantic knowledge
about real-world events.
• Preserved linguistic and analytic
skills, and STM.
• Preserved semantic knowledge
about his own life (e.g., knew which
high school he attended).
• But, he had no episodic memory
about his life.
https://www.youtube.com/watch?v=tXHk0a3RvLc
Elements of Episodic Memory
• A sense of subjective time.
• Autonoetic awareness, or the ability to be aware
of subjective time.
• A “self” that can travel in subjective time.
The Case of Clive Wearing
• https://www.youtube.com/watch?v=ipD_G
7U2FcM
Patient M.L.
• Has complete loss of autobiographical memory
for events both before and after brain injury.
• Has damage to right ventral frontal cortex.
• This region is
connected to the
medial temporal lobe
via the uncinate
fasciculus.
Implications of Patient K.C. and M. L.
• The neural substrates of episodic and semantic
memory are different.
• Episodic memory utilizes a circuit involving the
hippocampus and (left) PFC.
Part IV:
The Hippocampus and Memory
• Input from neocortex projects to the granule cells
of the dentate gyrus.
Hippocampal Anatomy
• These cells then project to pyramidal cells in
Ammon’s horn (via the mossy fibre pathway and
the Schaeffer collateral pathway).
Hippocampal circuitry
Projects to the
posterior neocortex.
Projects to the frontal
cortex, thalamus, basal
ganglia, and hypothalamus.
Hippocampal Circuit Diagram
Hippocampal Circuit Damage
• Extent of damage may influence length of
retrograde amnesia.
– Lesions isolate to CA1 (patients R.B. and D.G.) were
associated with 1-2 years of amnesia.
– Lesions to the hippocampus and surrounding
structures were associated with 15-25 years of
amnesia.
• Complete loss of the hippocampus results in
complete retrograde and anterograde amnesia.
– Some implicit memory remains (patient V.C.).
Theories of Hippocampal Function
• Site of memory storage.
• Consolidation of memories.
– Problem: some retrograde amnesia extends for
decades…were the memories stored in the
hippocampus that long?
• Address book for storage locations.
• Tagging memories with respect to context (time
and location of occurrence).
Part V: Multiple Memory Systems
• Damage to the left and right temporal lobes
leads to different patterns of deficits.
– Right temporal lobe damage leads to impairments on
face-recognition, spatial-position, and maze-learning
tasks (e.g., stylus maze).
Hemispheric Asymmetries
• Damage to the left and right temporal lobes
leads to different patterns of deficits.
– Left temporal lobe damage leads to impairments on
most language-based memory tests, as well as on the
Hebb recurring-digits test.
• No effect
in left
temporal
lobe
patients.
• HERA
– Hemispheric encoding and
retrieval asymmetry
• Frontal lobe contributes to
encoding and retrieval.
– Left PFC = encoding of both
episodic and semantic
memory.
– Right PFC = episodic
memory retrieval.
Hemispheric Asymmetries
Hippocampal vs. Perirhinal Lesions
Hippocampal vs. Perirhinal Lesions
• Animals with
hippocampal lesions
are normal on object
discrimination but
impaired on context
discrimination
• Animals with rhinal
cortex lesions show
the opposite pattern.
Hippocampal vs. Perirhinal Lesions
Diencephalic Amnesia
• Korsakoff’s syndrome – B1 (Thiamine) deficiency associated
with alcoholism.
• Neuropsychological symptoms – Anterograde amnesia
– Temporally graded retrograde amnesia
– Confabulation
– Meagre content in conversation
– Poor insight
– Apathy
Denby et al. (2009). AJNR.
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Harding et al. (2000). Brain.
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Diencephalic Amnesia
• Associated with damage to the mammillary bodies
and the dorsomedial and anterior thalamic nuclei.
Anterior Nuclei of the Thalamus
Harding et al.
(2000). Brain,
123, p. 146
Summary: Neurobiology of Memory