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.
Some Abilities are Spared 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.
Immediate vs. Delayed Recall in Hippocampal Patients From Rempel-Clower et al. (1996)
Some Abilities are Spared 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.
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 cha chase 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. The area of the cortex controlling the limb increased with task mastery even without awareness. 1 2 3 4 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 frontal cortex, thalamus, basal ganglia, and hypothalamus. Projects to the posterior neocortex.
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.
Hemispheric Asymmetries 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.
Hippocampal vs. Perirhinal Lesions
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.
Denby et al. (2009). AJNR. 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
mm-cubed mm-cubed mm-cubed Diencephalic Amnesia Associated with damage to the mammillary bodies and the dorsomedial and anterior thalamic nuclei. Volume Volume Volume 120 100 80 60 40 20 0 Ctl Alc Kor 2000 1500 1000 500 0 Ctl Alc Kor 400 300 200 100 0 Ctl Alc Kor Harding et al. (2000). Brain.
Anterior Nuclei of the Thalamus Harding et al. (2000). Brain, 123, p. 146
Summary: Neurobiology of Memory