Working memory, long-term memory, and medial temporal lobe function

In the paper

“it is noteworthy that the patients performed well at the 10-sec delay (our Fig. 1A).”

What the sources say

• Not checked yetcites Aggleton et al. 1992

In the paper

“Unfortunately, Ranganath and Blumenfeld's (2005) review mistakenly illustrated not the performance of the four patients with MTL damage, but the performance of five different patients from the same study who had mixed etiologies and no evidence of damage to the MTL (our Fig. 1D).”

What the sources say

• Not checked yetcites Ranganath and Blumenfeld 2005

In the paper

“Thus, the patients were, as a group, impaired only after delays of 30 sec or longer”

What the sources say

• Not checked yetcites Aggleton et al. 1992

In the paper

“Similarly, at the intermediate delay (6-8 sec), where patients first exhibited impaired performance, the average delay for the four study items was 11 sec.”

What the sources say

• Not checked yetcites Buffalo et al. 1998

In the paper

“In both tests of relational information, patients performed worse than controls even at a lag of one item, i.e., when no stimuli intervened between study and test.”

What the sources say

• Not checked yetcites Hannula et al. 2006

In the paper

“Accordingly, and as one might expect, the relational (conjunction) condition in Olson et al. (2006b) was more difficult than the item (feature) condition.”

What the sources say

• Not checked yetcites Olson et al. 2006b

In the paper

“Moreover, in one experiment (Experiment 2), patients were impaired in the conjunction condition even when the study-test delay was as short as 1 sec (average delay of 2 sec for all three study items).”

What the sources say

• Not checked yetcites Olson et al. 2006b

In the paper

“At the 1-sec delay, patients performed as well as controls at all array sizes.”

In the paper

“In the first experiment, we used the same procedure as was used previously (Hannula et al. 2006) and obtained the same results.”

What the sources say

• Not checked yetcites Hannula et al. 2006

In the paper

“activity in the left anterior hippocampus and subiculum was greater during retrieval of four novel scenes than during retrieval of two novel scenes (Schon et al. 2009).”

What the sources say

• Not checked yetcites Schon et al. 2009

In the paper

“Axmacher et al. (2007) noted increased activity in the left hippocampus during encoding and maintenance of four trialunique faces, but not during the encoding or maintenance of one or two trial-unique faces”

What the sources say

• Not checked yetcites Axmacher et al. (2007)

In the paper

“Patients with hippocampal damage and one patient with large MTL lesions (G.P.) performed well and similarly to controls when only a small number of object-location associations needed to be remembered, but the patients exhibited an abrupt decline in performance when as many as three or four object locations needed to be remembered.”

What the sources say

• Not checked yetcites Jeneson et al. 2010

In the paper

“both Experiments 1 and 2 was observed after a relatively long delay (average delay of 9 sec across all three study item positions).”

In the paper

“In Experiment 2, the controls unaccountably performed better than they did in Experiment 1 (even though the conjunction condition was identical in the two cases).”

In the paper

“the capacity limit for patients corresponded to the point where controls first made errors.”

In the paper

“the patients were impaired in tasks where distraction minimally affected control performance.”

In the paper

“Across tests involving names, faces, or object-location conjunctions (as in Olson et al. 2006b, discussed above), there was concordance between the performance of MTL patients and the effect on control performance of introducing distraction between study and test.”

What the sources say

• Not checked yetcites Shrager et al. 2008
• Not checked yetcites Olson et al. 2006b

In the paper

“in studies that directly assessed the effect of memory load on MTL activity during short-delay tasks, MTL activity was enhanced for tasks involving greater demands on memory.”

In the paper

“in Experiment 1, at the 1-sec delay, patients performed like controls.”

In the paper

“activity in the hippocampus was associated with maintenance of a single face across a 7-sec delay (Nichols et al. 2006).”

What the sources say

• Not checked yetcites Nichols et al. 2006

In the paper

“for the complex stimuli, activity was greater when participants performed a two-back task than when they performed a one-back task.”

What the sources say

• Not checked yetcites Lee and Rudebeck 2010

In the paper

“activity in the anterior hippocampus was associated with maintenance of complex geometrical shapes early during a 7 -13-sec delay period (Ranganath et al. 2005)”

What the sources say

• Not checked yetcites Ranganath et al. 2005

In the paper

“this effect of memory load was also observed in entorhinal cortex and perirhinal cortex during the delay period of the same task (Schon et al. 2010).”

What the sources say

• Not checked yetcites Schon et al. 2010

In the paper

“In each of these cases, the MTL activity that occurred while maintaining information in memory was correlated with subsequent measures of long-term memory.”

In the paper

“activity in the parahippocampal gyrus was associated with maintenance of novel photographs across a 10-sec delay (Schon et al. 2004)”

What the sources say

• Not checked yetcites Schon et al. 2004

In the paper

“in a fourth study, which required the encoding and maintenance of four face-house pairs, long-term memory success was predicted by hippocampal activity at the time of encoding (Bergmann et al. 2010).”

What the sources say

• Not checked yetcites Bergmann et al. 2010

In the paper

“In tasks where working memory (or subspan memory) alone was sufficient to support performance, patients performed as well as controls regardless of the kind of material to be held in mind.”

In the paper

“performance on memory tests that were interleaved during the encoding phase and that involved short retention intervals was not associated with MTL activity.”

What the sources say

• Not checked yetcites Bergmann et al. 2010

In the paper

“MTL activity associated with the foils presented during a recognition test predicted subsequent performance on a second, surprise recognition test that assessed long-term retention of the foils (Stark and Okado 2003).”

What the sources say

• Not checked yetcites Stark and Okado 2003

In the paper

“enhanced MTL activity with greater memory load was observed when participants tried to remember complex rather than simple stimuli (Lee and Rudebeck 2010).”

What the sources say

• Not checked yetcites Lee and Rudebeck 2010

In the paper

“Activation in left hippocampus during encoding (white bars) and maintenance (black bars) of one, two, or four faces.Activation increased as memory load increased.”

What the sources say

• Not checked yetcites Axmacher et al. 2007

In the paper

“Earlier reviews of short-term retention of visual information in memory-impaired patients (Ranganath and Blumenfeld 2005;Graham et al. 2010) highlighted findings from five studies where retention of novel, complex, and difficult-to-verbalize visual material was impaired after delays of 6 -10 sec”

What the sources say

• Not checked yetcites Ranganath and Blumenfeld 2005
• Not checked yetcites Graham et al. 2010

In the paper

“Three of these studies involved patients with presumed or confirmed bilateral MTL damage (Aggleton et al. 1992;Buffalo et al. 1998;Holdstock et al. 2000).”

What the sources say

• Not checked yetcites Aggleton et al. 1992
• Not checked yetcites Buffalo et al. 1998
• Not checked yetcites Holdstock et al. 2000

In the paper

“if the material to be learned exceeds working memory capacity, if the material is difficult to rehearse, or if attention is diverted, performance depends on long-term memory even when the retention interval is brief.”

In the paper

“patients with damage to MTL structures (the hippocampus and the adjacent entorhinal, perirhinal, and parahippocampal cortices) demonstrated intact immediate memory for strings of digits, words, tones, and nonsense visual patterns and shapes”

What the sources say

• Not checked yetcites Drachman and Arbit 1966
• Not checked yetcites Wickelgren 1968
• Not checked yetcites Baddeley and Warrington 1970

In the paper

“Similarly, because a short retention interval reduces the probability that attention will be diverted, working memory is sometimes sufficient to support performance in tasks involving short delays so long as the amount of information to be maintained is not too great.”

In the paper

“Early studies of memory-impaired patients with medial temporal lobe (MTL) damage found immediate memory and working memory (sometimes referred to as short-term memory) to be intact, despite markedly impaired performance on tasks of longterm memory”

What the sources say

• Not checked yetcites Drachman and Arbit 1966
• Not checked yetcites Baddeley and Warrington 1970
• Not checked yetcites Milner 1972

In the paper

“The point is that long-term memory sometimes benefits performance even when memory is tested immediately after or within seconds of learning (see also Baddeley et al. 2010Baddeley et al. , 2011;;Brady et al. 2011).”

What the sources say

• Not checked yetcites Baddeley et al. 2010
• Not checked yetcites Baddeley et al. 2011
• Not checked yetcites Brady et al. 2011

In the paper

“Intact performance at the shortest delays indicates that immediate memory was intact.”

In the paper

“if the material to be learned exceeds working memory capacity, if the material is difficult to rehearse, or if attention is diverted, performance depends on long-term memory even when the retention interval is brief.”

In the paper

“Given the limits of immediate memory capacity (typically only three to four simple visual objects can be maintained even for a delay as short as 1 sec) (Luck and Vogel 1997;Cowan 2001)”

What the sources say

• Not checked yetcites Luck and Vogel 1997
• Not checked yetcites Cowan 2001

In the paper

“as well as an intact ability to maintain a limited amount of information in memory by rehearsal, even for several minutes”

What the sources say

• Not checked yetcites Milner 1972

In the paper

“if the material to be learned exceeds working memory capacity, if the material is difficult to rehearse, or if attention is diverted, performance depends on long-term memory even when the retention interval is brief.”

In the paper

“In several recent studies, patients with bilateral MTL damage were found to be impaired at remembering visual information across delays as short as a few seconds.”

In the paper

“Still, a limited amount of information may be held in mind indefinitely if attention is continuously directed toward the memorandum.”

In the paper

“The key factors that determine whether working memory is sufficient to support performance, or whether performance must also depend on long-term memory, are the amount of information that can be held in mind and how amenable this information is to active rehearsal.”

In the paper

“In the first study (Aggleton et al. 1992), information about the localization and extent of the lesions (caused by viral encephalitis) was not available.”

What the sources say

• Not checked yetcites Aggleton et al. 1992

In the paper

“The majority of these impairments were observed in delayed matchto-sample tasks or change-detection tasks where the delays were 4 sec or longer”

What the sources say

• Not checked yetcites Aggleton et al. 1992
• Not checked yetcites Buffalo et al. 1998
• Not checked yetcites Holdstock et al. 2000

In the paper

“suggest that MTL lesions impair performance only when immediate memory and working memory are insufficient to support performance.”

In the paper

“The other two studies are less informative about MTL function.”

In the paper

“At the same time, the same information can be lost from working memory even after a short interval if attention is diverted (Drachman and Arbit 1966;Milner 1972).”

What the sources say

• Not checked yetcites Drachman and Arbit 1966
• Not checked yetcites Milner 1972

In the paper

“Because the probability that attention will be diverted increases with the amount of time that has passed since learning, long-term memory is often needed to support performance on tasks involving long delays.”

In the paper

“MTL damage has also been found to impair retention after short delays of more familiar, concrete visual stimuli.”

In the paper

“The patients in the former study were also impaired on a change-detection task that required retention of three colored squares across delays of 4 or 8 sec (Olson et al. 2006a).”

What the sources say

• Not checked yetcites Olson et al. 2006a

In the paper

“Similarly, Eng et al. (2005) obtained a capacity estimate of 1.1-1.5 faces (with memory display durations of 500-3000 msec) using a sample of Harvard undergraduates.”

What the sources say

• Not checked yetcites Eng et al. 2005

In the paper

“It seems reasonable to suppose that long-term memory benefited control performance when the largest demands were made on memory (longer delays and larger array sizes).”

In the paper

“Note that patients were intact when task requirements were less demanding and likely within the limits of working memory capacity.”

In the paper

“Memory capacity is smaller for older adults than for undergraduate students (Jost et al. 2011).”

What the sources say

• Not checked yetcites Jost et al. 2011

In the paper

“However, the same faces reappeared several times during testing (16 study faces repeated six times each across 96 trials).”

What the sources say

• Not checked yetcites Ezzyat and Olson 2008

In the paper

“the relational memory question (which required maintenance of information about the items in each scene) involved a higher memory load than the item memory question (which required maintenance only of enough information to recognize the scene as familiar).”

What the sources say

• Not checked yetcites Hannula et al. (2006)

In the paper

“Apart from the difficulty of knowing the capacity estimates of the highly similar faces used in this study, a difficulty also arises because the task did not involve trial-unique stimuli.”

What the sources say

• Not checked yetcites Ezzyat and Olson 2008

In the paper

“It is, therefore, notable that in two of the studies involving faces, the inter-item similarity was high (Olson et al. 2006a;Ezzyat and Olson 2008).”

What the sources say

• Not checked yetcites Olson et al. 2006a
• Not checked yetcites Ezzyat and Olson 2008

In the paper

“These considerations make it difficult to rule out the possibility that, for the older participants in these studies, visual working memory capacity was exceeded even when the material involved three colored squares or one face.”

In the paper

“even at a lag of one item, participants still needed to try to hold in mind a number of previous scenes (up to nine), because the decision to identify each item as old or new sometimes depended on as many as nine previous items”

What the sources say

• Not checked yetcites Hannula et al. (2006)

In the paper

“even though the inter-stimulus interval was only 3 sec, the delay between the initial presentation of a study scene and the assessment of memory for object location was as long as 14 sec.”

In the paper

“In two studies, MTL damage impaired retention of information about the relations between items or features, even at quite short delays (Hannula et al. 2006;Olson et al. 2006b).”

What the sources say

• Not checked yetcites Hannula et al. 2006
• Not checked yetcites Olson et al. 2006b

In the paper

“This arrangement allowed for the possibility that healthy controls could gain an advantage over patients through learning.”

In the paper

“As discussed in the section on visual discrimination (below), there is precedence for such learning effects in controls (but not patients) in a similar task where perceptual judgments involved items that were repeated many times (Kim et al. 2011).”

What the sources say

• Not checked yetcites Kim et al. 2011

In the paper

“The findings from humans, together with the findings from nonhuman primates and rats, provide no positive evidence for impaired working memory after MTL damage.”

In the paper

“For example, in the Nichols et al. (2006) study, patients exhibited intact changedetection performance for colored squares at a 1-sec delay.”

What the sources say

• Not checked yetcites Nichols et al. 2006

In the paper

“In two studies where memory for a single face was probed using a changedetection task, patients with MTL damage exhibited impaired performance after delays of 4 sec (Olson et al. 2006a) and 7 sec (Nichols et al. 2006).”

What the sources say

• Not checked yetcites Olson et al. 2006a
• Not checked yetcites Nichols et al. 2006

In the paper

“However, these estimates of immediate memory capacity were all obtained from young adults.”

In the paper

“Indeed, the findings are fully consistent with the traditional view that memory was impaired after delays of 6-30 sec because it is difficult to maintain difficult-to-verbalize material in working memory.”

In the paper

“patient H.M. repeated back six digits without error (his premorbid digit span) but then could not succeed at seven digits even after 25 repetitions of the same digits”

What the sources say

• Not checked yetcites Drachman and Arbit 1966

In the paper

“suggests that retention of features plus conjunctions involves a greater memory load than remembering only the features themselves.”

What the sources say

• Not checked yetcites Stefurak and Boynton 1986

In the paper

“In some studies in monkeys and also in humans (e.g., Barense et al. 2005;Graham et al. 2006), discrimination learning involved the same stimulus materials over multiple trials.”

What the sources say

• Not checked yetcites Barense et al. 2005
• Not checked yetcites Graham et al. 2006

In the paper

“We suggest that controls made errors when the material to be remembered exceeded immediate memory capacity and thereby limited what could be maintained in working memory.”

In the paper

“lesions of the perirhinal cortex might sometimes impair performance on tasks like these, not because of demands on perception but because of demands on memory.”

In the paper

“even for tests at a lag of 1, participants had to try to hold in mind many previous scenes because they did not know whether the memory question would concern the most recently presented scene or a scene presented up to nine items earlier.”

What the sources say

• Not checked yetcites Olson et al. (2006b)

In the paper

“In this case, participants were required to hold in mind only one scene at a time.”

In the paper

“These findings, which included data from a task like that used by Olson et al. (2006b), suggest that impaired performance was attributable to impaired long-term memory.”

What the sources say

• Not checked yetcites Olson et al. (2006b)

In the paper

“MTL activity is not typically observed in imaging studies that assess activity during working memory tasks”

What the sources say

• Not checked yetcites Courtney et al. 1996
• Not checked yetcites Courtney et al. 1997
• Not checked yetcites Cohen et al. 1997

In the paper

“in studies directly comparing memory for features and memory for conjunctions, performance is typically poorer when individuals must distinguish combinations of features from recombinations of features than when they must identify single features”

What the sources say

• Not checked yetcites Mitchell et al. 2000
• Not checked yetcites Olson et al. 2006b, Experiment 1
• Not checked yetcites Wheeler and Treisman 2002

In the paper

“the impairment that was observed in Test trials appeared either immediately after the corresponding scene had been presented (lag 1), five trials later (lag 5), or nine trials later (lag 9).”

What the sources say

• Not checked yetcites Olson et al. (2006b)

In the paper

“In some cases, controls have an opportunity to learn about the stimulus material as the task progresses, thereby gaining an advantage over memory-impaired patients.”

In the paper

“Across tasks involving a range of different procedures and visual materials (novel visual objects, faces, colors, and information about relations between items), MTL damage has been found to impair performance even at short delays and sometimes when relatively little material needs to be remembered.”

In the paper

“the serial presentation of study items meant that, on twothirds of the trials, one or two sample images intervened between study and test.”

What the sources say

• Not checked yetcites Olson et al. (2006b)

In the paper

“In patient studies where MTL damage impaired performance after short retention delays, the task requirements often made substantial demands on long-term memory and exceeded what could be managed within working memory.”

In the paper

“healthy individuals can sometimes remember single features (e.g., the colors and shapes of objects) without remembering the relations between them (e.g., which color was bound to which shape) (Stefurak and Boynton 1986)”

What the sources say

• Not checked yetcites Stefurak and Boynton 1986

In the paper

“some recent studies involving complex visual stimuli, such as faces and photographs of scenes, have reported MTL activity in association with short-delay recognition memory tasks”

What the sources say

• Not checked yetcites Mitchell et al. 2000
• Not checked yetcites Ranganath and D'Esposito 2001
• Not checked yetcites Stern et al. 2001

In the paper

“The abrupt discontinuity in performance that we observed in the object-location task suggests a similar interpretation, that is, an impairment was evident only when immediate memory capacity was exceeded.”

In the paper

“In other cases, the amount of test material presented likely exceeds what can be held within immediate memory.In this circumstance, controls gain an advantage by drawing on their intact capacity for long-term memory”

What the sources say

• Not checked yetcites Baddeley et al. 2010
• Not checked yetcites Baddeley et al. 2011
• Not checked yetcites Brady et al. 2011

In the paper

“This pattern of performance is strikingly similar to the pattern of performance exhibited by patient H.M. on the digit task (Drachman and Arbit 1966).”

What the sources say

• Not checked yetcites Drachman and Arbit 1966

In the paper

“We suggest an alternative perspective, namely, that most, if not all, of these studies in fact make a significant demand on long-term (or supraspan) memory.”

In the paper

“the majority of imaging studies where MTL activity was observed during a short-delay task also made large demands on memory.”

In the paper

“even though stimuli were presented simultaneously, information nonetheless must be retained in memory as attention shifts back and forth between the stimuli.”

In the paper

“the patients failed in those same tasks because they could not successfully draw on long-term memory.”

In the paper

“patients with MTL damage exhibited a sharp discontinuity in performance as the string length increased.”

What the sources say

• Not checked yetcites Drachman and Arbit 1966

In the paper

“and also that the activity observed at the time of encoding correlates positively with long-term retention of the material that was presented.”

What the sources say

• Not checked yetcites Ranganath et al. 2005
• Not checked yetcites Lee and Rudebeck 2010

In the paper

“Many of the tasks that have been used make a significant demand on long-term (or supraspan) memory.”

In the paper

“Instead, this activity is more likely to reflect processes related to the formation of longterm memory.”

In the paper

“This result raises the possibility that MTL activity observed during learning is related, not to working memory or other online processes, but to the formation of long-term memory.”

In the paper

“when material must be retrieved following the redirection of attention, performance must depend on a stable memory store (”

• Also stated in: § MTL activity during and after learning as a predictor of long-term memory · plain

  “long-term memory”

• Also stated in: § MTL activity during and after learning as a predictor of long-term memory · plain

  “) that permits the organization and retrieval of large amounts of information.”

In the paper

“In studies of the capacity limit for visual working memory, activity in the intraparietal sulcus and regions of occipital cortex increased up to an array size of three or four visual objects and leveled off at the point where capacity was reached (Todd andMarois 2004, 2005;Vogel and Machizawa 2004;Xu and Chun 2006).”

What the sources say

• Not checked yetcites Todd andMarois 2004, 2005
• Not checked yetcites Vogel and Machizawa 2004
• Not checked yetcites Xu and Chun 2006

In the paper

“and working memory for faces was associated with sustained activity in posterior fusiform gyrus (Ranganath et al. 2004).”

What the sources say

• Not checked yetcites Ranganath et al. 2004

In the paper

“The finding of a correlation between activity during encoding and subsequent long-term memory does not, of course, exclude the possibility that the fMRI signal in such cases contains additional information related to working memory itself (Ranganath et al. 2005;Lee and Rudebeck 2010).”

What the sources say

• Not checked yetcites Ranganath et al. 2005
• Not checked yetcites Lee and Rudebeck 2010

In the paper

“For example, short-term retention (working memory) of visual stimuli was associated with sustained activity in inferotemporal cortex (Fuster and Jervey 1982).”

What the sources say

• Not checked yetcites Fuster and Jervey 1982

In the paper

“There is, in fact, an abundant literature demonstrating that MTL activity at the time of learning can predict subsequent longterm memory performance (see Paller and Wagner 2002).”

What the sources say

• Not checked yetcites Paller and Wagner 2002

In the paper

“Yet, questions about the possible role of the MTL in immediate memory and working memory do not turn on any particular retention interval.”

In the paper

“In addition, working memory for motion direction was associated with sustained activity in area MT (Bisley and Pasternak 2000;Bisley et al. 2004)”

What the sources say

• Not checked yetcites Bisley and Pasternak 2000
• Not checked yetcites Bisley et al. 2004

In the paper

“encoding into long-term memory is a relatively automatic and continuous process”

What the sources say

• Not checked yetcites Ryan and Cohen 2004
• Not checked yetcites Zarahn et al. 2005
• Not checked yetcites Olsen et al. 2009

In the paper

“These observations provide only weak support for interpreting MTL activity during short-delay tasks as a reflection of the operation of working memory.”

In the paper

“Cells in prefrontal cortex are maximally active during the delay portion of the delayed-response task (Fuster and Alexander 1971).”

What the sources say

• Not checked yetcites Fuster and Alexander 1971

In the paper

“Nonetheless, it is striking that the extent of MTL activity observed at the time of encoding is influenced by the demands on memory imposed by the task”

What the sources say

• Not checked yetcites Ranganath et al. 2005
• Not checked yetcites Lee and Rudebeck 2010