lecture 5: memory 2

Question 1

how did working memory come about?

Answer 1

The modal model made a distinction between STM and LTM (said ltm needed stm to come about) but was rejected in part because it could not handle
data from patients such as KF showing impaired STM and intact LTM (stm and ltm are distinct)

The working memory approach used dual task
methodology to fractionate WM into central executive, phonological loop, and visuo-spatial sketchpad, and solved a key problem that plagued the modal model.

*Neuropsychological and neuroimaging studies
have provided some insights into neural underpinnings of each WM component.

*Baddeley’s updated working memory model adds an
‘episodic buffer’ and posits specific connections between components of WM and LTM.

Question 2

working memory approach

Answer 2

used dual task
methodology to fractionate WM into central executive,
phonological loop, and visuo-spatial sketchpad, and
solved a key problem that plagued the modal model

Neuropsychological and neuroimaging studies have provided some insights into neural underpinnings
of each WM component.

*Baddeley’s updated working memory model adds an
‘episodic buffer’ and posits specific connections between components of WM and LTM

Question 3

Encoding

Answer 3

How we perceive/interpret our experiences; has a large influence on retention

Question 4

semantic encoding

Answer 4

Retention benefits from semantic encoding: when we meaningfully associate new information to what we already know.

Question 5

Neuroimaging of Encoding and Retrieval

Answer 5

*Prior to the widespread use of neuroimaging during the 1990s, there was little progress in understanding the brain basis of encoding vs. retrieval processes

*Neuroimaging techniques allowed a simple but important advance: the ability to measure separately brain activity during encoding and retrieval

*Early studies used levels of processing methodologies to study encoding, and simple cued recall or recognition paradigms to study retrieval

Question 6

Blocked design fMRI encoding study

Answer 6

Make semantic judgments (abstract/concrete) during one block

Make nonsemantic judgments (upper case/lower case) during separate block

Compared average activity during the two blocks

Assess memory performance after scanning

Question 7

Henry Molaison

Answer 7

IQ (=118)remained above average;
perception, attention, language comprehension/production, reading ability all intact

STM normal; severely impaired LTM

Generally characteristic of amnesic syndrome:
impaired LTM, normal or near-normal IQ and other cognitive abilities.

Question 8

viral encephalitis

Answer 8

an inflammation of the brain caused by a virus

Question 9

clive wearing

Answer 9

On 27 March 1985, Wearing, then an acknowledged expert in early music at the height of his career with BBC Radio 3, contracted herpesviral encephalitis, a herpes simplex virus that attacked his central nervous system. Since then, he has been unable to store new memories.

Question 10

Anterograde amnesia

Answer 10

impaired memory for experiences that occur after incident/lesion that caused amnesia

Question 11

Retrograde amnesia

Answer 11

impaired memory for experiences that
occurred prior to incident/lesion that caused amnesia

Damage to hippocampus and nearby structures in the MTL can cause both AA and RA, thereby linking these structures to
explicit/declarative memory

Question 12

Confabulation

Answer 12

Confabulation is a type of memory error in which gaps in a person’s memory are unconsciously filled with fabricated, misinterpreted, or distorted information. When someone confabulates, they are confusing things they have imagined with real memories.

Question 13

Evidence from patient HM

Answer 13

-Removed all of entorhinal cortex and perirhinal cortex (plus amygdala)

Removed 2/3rds of hippocampal formation; posterior hippocampus and parts of
parahippocampal cortex spared – contrary to Scoville’s original report.

Question 14

case rb

Answer 14

Selective damage to the hippocampus (CA1 region)
after cardiac arrest and consequent anoxia

Question 15

Episodic memory:

Answer 15

Episodic memory refers to the capacity for recollecting an autobiographical memory of events that occurred in a particular spatial and temporal context

Question 16

Semantic memory:

Answer 16

Semantic memory is conscious long-term memory for meaning, understanding, and conceptual facts about the world. Semantic memory is one of the two main varieties of explicit, conscious, long-term memory, which is memory that can be retrieved into conscious awareness after a long delay (from several seconds to years).

Question 17

mtl

Answer 17

medio temporal lobe (where hippocampus is)

Question 18

Anterograde Memory Deficits in Patients with MTL Damage

Answer 18

Episodic memory:
Impaired on both recall and recognition tests for words, objects, faces, spatial information, as well as ongoing events in everyday life.

Impairments tend to be more severe with more MTL damage, e.g., H.M./Clive Wearing much more impaired than patient R.B.

Semantic knowledge acquired before amnesia generally OK.

Question 19

Can patients with MTL damage acquire new semantic memories?

Answer 19

H.M. acquired some new vocabulary and knowledge of public figures who became famous after his operation; but very limited.

Question 20

Patient KC

Answer 20

Suffered head trauma as a result of motorcycle accident in 1980; severe memory impairment

K.C. suffered from severe anterograde amnesia, in both verbal and non-verbal domains. This was accompanied by a selective retrograde amnesia for personal events experienced prior to the time of his injury (episodic memory), with relative preservation of memory for personal and world facts (semantic memory)

KC has no episodic memories of any events from before or after
his head injury. He has intact semantic knowledge for information
acquired before his head injury. Can he acquire any new semantic
Yes – can learn some new vocabulary and definitions – but like
H.M., his ability to learn new semantic knowledge is limited.

Question 21

coronal

Answer 21

shows innermost brain

Question 22

saggital

Answer 22

side view

Question 23

fmri

Answer 23

Axial (a.k.a. transverse) plane refers to a horizontally-oriented plane which, when passes through the body in its anatomical position, divides it into upper and lower parts.

Question 24

3 planes used to view brain scans

Answer 24

The different planes that Radiologists use are axial (divides the body into top and bottom halves), coronal (perpendicular), and sagittal (midline of the body). Radiologists call images that are axial or coronal view differently as they reverse left and right.

Question 25

Semantic Dementia

Answer 25

severe loss of access to various kinds of semantic knowledge

Left temporal pole is
frequently implicated in semantic dementia.

Semantic dementia patients can show intact episodic memory, at
least for non-verbal material.

Question 26

Recollection and Familiarity

Answer 26

Episodic retrieval is often discussed in unidimensional
terms: higher or lower probability of recall or recognition
on a memory test

Question 27

Recollection

Answer 27

remembering specific details and context or source

Question 28

Familiarity

Answer 28

knowing or feeling that item/object/person
is “old”, without remembering specific details, context, or source

Question 29

remember/know paradigm

Answer 29

The remember/know procedure. The remember/know (RK) procedure (Tulving, 1985) is the most widely used method to investigate dual process theories of recognition memory. Participants are asked to decide whether a previously studied item is ‘remembered’ from the study episode or whether they just ‘know’ that it is old

Question 30

rapid consolidation

Answer 30

contributes to the initial storage of declarative memories (episodic and to some extent semantic). That is, new memories seem to be stored in a hippocampal-dependent way

Question 31

slower consolidation

Answer 31

interacts with neocortex over the course of days/months/years, leads to stable memory trace in the neocortex that no longer depends on the hippocampus. That is, older memories may become hippocampal-independent.

Question 32

“Ribot’s law” (1882)

Answer 32

In cases of amnesia produced
by brain damage, recent memories are more affected than remote memories.

Law applied not just to anterograde vs. retrograde amnesia, but also to
recent vs. remote memories within
the retrograde component of amnesia

Question 33

Standard consolidation theory (SCT; Squire)

Answer 33

Memories initially depend on the hippocampus, and are gradually transferred from to cortex. Time-limited role for hippocampus in all declarative memory (both episodic and semantic).

Question 34

Multiple-trace theory (MTT; Nadel & Moscovitch)

Answer 34

Each time an event is remembered, new memory is created. The older the event, the greater number of traces (more likely to be semantic) and more resilient to damage. Time-limited role of hippocampus in retrieval of semantic memories, but permanent role in retrieval of contextually-detailed episodic memories.

Question 35

H.M. and Retrograde Amnesia

Answer 35

*Unable to retrieve any episodic memories
from the 11 yrs before his surgery
*Could retrieve memories from childhood well
*Appears to support Ribot’s law/SCT
*But is the temporal gradient because of his seizures?
*Later studies of HM revealed poor
autobiographical memory even for childhood
- is that due to age-related brain changes?
(Squire, Neuron, 2009)

Question 36

Not all Amnesic Patients Show a Temporal Gradient in RA

Answer 36

Patient KC: No episodic memories from any period of time in his life, though he does have access to “semantic” autobiographical
knowledge (knows some facts about his life, such as where he went to high school).

Question 37

temporal gradient

Answer 37

Evidence consistently shows poor episodic memory for events that occurred in weeks/months and even years
before onset of amnesia.

But a temporal gradient requires evidence for preserved
remote memories along with poor memory for more recent episodes.

Question 38

Varying Load in the n-back Task

Answer 38

The N-back task requires participants to decide whether each stimulus in a sequence matches the one that appeared n items ago. Although N-back has become a standard “executive” working memory (WM) measure in cognitive neuroscience, it has been subjected to few behavioral tests of construct validity.

Question 39

clive wearing

Answer 39

Clive Wearing taught us about hippocampal dependent formation of long term memory. Clive Wearing is a prominent British musician. In 1985, he contracted herpes simplex encephalitis, a disease that caused swelling of brain tissue resulting in damage to his hippocampus

Wearing experiences complete retrograde amnesia, which means that he has lost all memories of his past. In addition, he also experiences anterograde amnesia, meaning that he is unable to form and store new memories

Question 40

Several fMRI studies have reported evidence, at encoding and retrieval,
linking the hippocampus with recollection. what/s wrong with claiming that?

Answer 40

It has been argued that recollection may just be a “stronger” form of memory than familiarity. Maybe the hippocampus is related to strong
memories vs. weak memories, not to recollection vs. familiarity per se

*Evidence from amnesic patients with hippocampal damage is mixed: some show deficits in both recollection and familiarity, but a few cases of restricted hippocampal damage show deficits restricted to recollection

Summary: Evidence from both neuroimaging and amnesic patients clearly shows
that hippocampus plays a role in recollection. Less clear whether it also plays a
role in familiarity.

Question 41

• Working memory is composed of 3 components:

Answer 41

1) Central Executive (general all-purpose processor that
can hold onto a few items) is assisted by 2 domain-specific
subsystems, the 2) visuospatial sketchpad and the
3) phonological loop

Question 42

phonological loop

Answer 42

can hold ~3 items of speech-based
info, and is not critical for transferring information to LTM
(central executive can do that)

Damage to phonological loop should affect short-term
verbal memory but not long-term memory à Patient K.F.

Question 43

• How to find neural substrates of the central executive?

Answer 43

– n-back task

N-back tasks are continuous-recognition measures that present stimulus sequences, such as letters or pictures; for each item in the sequence, people judge whether it matches the one presented n items ago.