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Frontal Lobe AnatomyFrontal Lobe Anatomy Inhibition and voluntary Inhibition and voluntary

controlcontrol A model task: working A model task: working

memory memory

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This Lecture

Long Term Memory Long Term Memory role of hippocampus in consolidationrole of hippocampus in consolidation role of frontal regions in encoding and role of frontal regions in encoding and

retrievalretrieval right frontal regions and representation of right frontal regions and representation of

self...self...

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FINAL EXAM:FINAL EXAM: 182 Dennison 182 Dennison Wednesday, 4/19 Wednesday, 4/19 4:00 pm - 6:00 pm.4:00 pm - 6:00 pm.

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Long Term Memory and its Dysfunction

Memory: the ability to retain & recollect the Memory: the ability to retain & recollect the contents of our experiencecontents of our experience

typically multimodaltypically multimodal rich in associationsrich in associations

The ability to acquire new skills & demonstrate The ability to acquire new skills & demonstrate improved performance as a result of improved performance as a result of experience.experience.

Human AmnesiaHuman Amnesia

Anterograde: Anterograde: Inability to acquire NEW memories.Inability to acquire NEW memories. RetrogradeRetrograde: Inability to recollect OLD memories.: Inability to recollect OLD memories.

Human AmnesiaHuman Amnesia

Scoville & Milner (1957) H.M. Scoville & Milner (1957) H.M. bilateral removal of bilateral removal of hippocampus (medial hippocampus (medial temporal lobes).temporal lobes).

Wada testing to avoid Wada testing to avoid bilateral bilateral hippocampectomies.hippocampectomies.

Unilateral removals: Unilateral removals: material-specific deficit: material-specific deficit: (Right- nonverbal; Left: (Right- nonverbal; Left: verbal)verbal)

Case H.M.-- PROFOUND ANTEROGRADE AMNESIA

High Average intelligenceHigh Average intelligence STM: normal- digit span 7 forward; 5 backwardSTM: normal- digit span 7 forward; 5 backward Can converse normally, perform mental mathCan converse normally, perform mental math No post-operative personality changes No post-operative personality changes Unable to acquire new memories...Unable to acquire new memories...

all modalitiesall modalities all material (verbal, nonverbal)all material (verbal, nonverbal) names, people, places, events, route findingnames, people, places, events, route finding all are affected.all are affected.

Early animal models of HM were unsuccessful

WHY?WHY? (Hint: remember what happened with (Hint: remember what happened with blindsight)blindsight)

Testing the wrong type of memoryTesting the wrong type of memory

What Amnesics can learn:What Amnesics can learn: Milner (1962) mirror drawingMilner (1962) mirror drawing Warrington & Weiskrantz (1968) perceptual learning Warrington & Weiskrantz (1968) perceptual learning

(degraded cues, priming)(degraded cues, priming) Weiskrantz & Warrington (1979) classical conditioningWeiskrantz & Warrington (1979) classical conditioning

Types of Long Term MemoryTypes of Long Term Memory

Declarative/Explicit

consciously accessible consciously accessible Episodic: personal/public episodesEpisodic: personal/public episodes Semantic: facts, events, routesSemantic: facts, events, routes Tested with recall / recognition:Tested with recall / recognition:

"Have you seen this before?"; "Can you "Have you seen this before?"; "Can you remember...?"; "Is this one of the items remember...?"; "Is this one of the items you studied...?”you studied...?”

Nondeclarative/Procedural/ImplicitNondeclarative/Procedural/Implicit

Does not require conscious recollectionDoes not require conscious recollection

Examples:Examples: conditioningconditioning skills (motor skills, mirror reading)skills (motor skills, mirror reading) priming (e.g. stem completion)priming (e.g. stem completion)

Skill AcquisitionSkill Acquisition

Mirror drawing improvesMirror drawing improves Amnesics = ControlsAmnesics = Controls

An example of the dichotomy...

Phase 1Phase 1

Read & rate words Read & rate words (living/non):(living/non):

Lead Lead

BearBear

FearFear

Work...Work...

Phase 2Phase 2

EXPLICIT TEST:EXPLICIT TEST:

""Complete stem with a word you Complete stem with a word you just read"just read"

lea_ lea_ bea_ bea_

OR IMPLICIT TEST:OR IMPLICIT TEST: "Complete "Complete

stem with first word that stem with first word that comes to mind"comes to mind"

lea_ ---> lead or leaflea_ ---> lead or leaf bea_ ---> beat or bearbea_ ---> beat or bear

Priming is spared in AmnesiaPriming is spared in Amnesia

Amnesics cannot recall Amnesics cannot recall study items.study items.

But stored But stored representation is representation is accessed automatically.accessed automatically.

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CuedRecall

Fill-in

ControlsAmnesics

The Hippocampal circuit & Explicit Memory

Hippocampus - part of a circuit Hippocampus - part of a circuit withwith input to & from parietal, input to & from parietal, temporal, frontal lobes & limbic temporal, frontal lobes & limbic system (amygdala).system (amygdala).

HippocampusHippocampus

The Hippocampal circuit & Explicit Memory

Hippocampus - part of a circuit Hippocampus - part of a circuit withwith input to & from parietal, input to & from parietal, temporal, frontal lobes & limbic temporal, frontal lobes & limbic system (amygdala).system (amygdala).

CA1 , CA2 , CA3 layers of HPC CA1 , CA2 , CA3 layers of HPC form a circuit allowing access to form a circuit allowing access to cortexcortex CA1 layer - sensitive to anoxia & CA1 layer - sensitive to anoxia &

epileptic activity (CASE R.B.)epileptic activity (CASE R.B.)

Damage to HPC or its Damage to HPC or its inputs/outputs --> LTM inputs/outputs --> LTM impairmentimpairment

Role of Hippocampus in Explicit Memory

NOT the location of LTMNOT the location of LTM NOT necessary for retrieval of LTMNOT necessary for retrieval of LTM NOT the location of STMNOT the location of STM HPC: immediate experience --> LT memories HPC: immediate experience --> LT memories CONSOLIDATIONCONSOLIDATION Explicit memory - stores single events w/ context.Explicit memory - stores single events w/ context. Learning is fast (one-trial learning-- but forgetting endures).Learning is fast (one-trial learning-- but forgetting endures). Representations are Representations are

accessible by various cognitive systemsaccessible by various cognitive systems modality-generalmodality-general give rise to sense of familiarity.give rise to sense of familiarity.

Implicit memory...

Reactivation of the processing structures engaged Reactivation of the processing structures engaged during learning.during learning.

Learning is incremental, gradual, slowLearning is incremental, gradual, slow Representations are specific to a task and or the Representations are specific to a task and or the

learning modality.learning modality. Involves multiple systems (cortex, basal ganglia)Involves multiple systems (cortex, basal ganglia)

More on the encoding and retrieval of explicit LTM...More on the encoding and retrieval of explicit LTM...

Frontal Contributions to LTM

Recency JudgmentsRecency Judgmentsknowledge of temporal knowledge of temporal

contextcontext give a list of itemsgive a list of items probe w/ two items probe w/ two items

asking: asking:

““Which one of Which one of these items these items came most came most recently?”recently?”

Frontal Contributions Source MemoryFrontal Contributions Source Memory ability to identify ability to identify

(remember) the context in (remember) the context in which a memory was which a memory was acquiredacquired

task: judge which of two task: judge which of two characters uttered a characters uttered a particular fact.particular fact.

Mt. Everest Keeps growing

Marco Polowas Venetian

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True/False Psyd/Hypno

ControlsFrontal

HERA:HERA: Hemispheric Encoding/Retrieval Asymmetry (Tulving et al., 1994)

HERA:HERA: Hemispheric Encoding/Retrieval Asymmetry (Tulving et al., 1994)

PET studies w/normal subjects showPET studies w/normal subjects show Left HemLeft Hem. is critical to . is critical to encodingencoding

into LTM into LTM Lateral Prefrontal areasLateral Prefrontal areas all materials: verbal & nonverbalall materials: verbal & nonverbal Why? associating meaning with Why? associating meaning with

eventsevents Right HemRight Hem. is critical to . is critical to retrievalretrieval

from LTMfrom LTM Lateral Prefrontal areasLateral Prefrontal areas all materials: verbal & all materials: verbal &

nonverbalnonverbal Why? memory requires reflection Why? memory requires reflection

about self / personal experienceabout self / personal experience

Right Frontal Lobe & SelfRight Frontal Lobe & Self

Craik et al., 1999 - PET study with 4 conditionsCraik et al., 1999 - PET study with 4 conditions

How well does the word stubborn describe...How well does the word stubborn describe... You?You? Lee Bollinger?Lee Bollinger? How socially desireable?How socially desireable? How many syllables?How many syllables?

RESULT: RESULT: Only self-referential instruction activated Right Only self-referential instruction activated Right prefrontal cortex prefrontal cortex ( same areas activated by memory retrieval)( same areas activated by memory retrieval)

Conclusion:Conclusion: Right frontal regions are important for Right frontal regions are important for representation of self.representation of self.

Memory Summary

WM vs. LTM LTM: IMPLICIT vs. EXPLICITWM vs. LTM LTM: IMPLICIT vs. EXPLICIT Explicit (personal episodes, semantics/factsExplicit (personal episodes, semantics/facts))

Amnesia -- anterograde or retrogradeAmnesia -- anterograde or retrograde Establishing new explicit memories requires Establishing new explicit memories requires

encoding, consolidation, retreivalencoding, consolidation, retreival

hippocampus -- consolidation (HM & RB)hippocampus -- consolidation (HM & RB) HERA:HERA:

Left frontal- encoding (context info)Left frontal- encoding (context info) Right frontal- retrieval (self)Right frontal- retrieval (self)