Encoding strategy accounts for individual differences in change detection measures of VSTM

Linke, Annika C.; Vicente-Grabovetsky, Alejandro; Mitchell, D. N.; Cusack, Rhodri

doi:10.1016/j.neuropsychologia.2010.11.034

Cited by 69 publications

(99 citation statements)

References 50 publications

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“…The importance of encoding mechanisms in determining ASTM capacity is also suggested by the relationship between individual differences in behavioral performance and the specificity with which frequencies were encoded. These results accord with a recent behavioral study that found performance to be determined by attentional selection during the encoding phase (31) and a meta-analysis of neuroimaging data from five different visual short-term memory studies (17) showing that performance correlates with activity in several parietal and frontal regions during the encoding but not the maintenance phase.…”

Section: Discussionsupporting

confidence: 91%

See 1 more Smart Citation

Stimulus-specific suppression preserves information in auditory short-term memory

Linke

Vicente-Grabovetsky

Cusack

2011

Proc. Natl. Acad. Sci. U.S.A.

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Philosophers and scientists have puzzled for millennia over how perceptual information is stored in short-term memory. Some have suggested that early sensory representations are involved, but their precise role has remained unclear. The current study asks whether auditory cortex shows sustained frequency-specific activation while sounds are maintained in short-term memory using high-resolution functional MRI (fMRI). Investigating short-term memory representations within regions of human auditory cortex with fMRI has been difficult because of their small size and high anatomical variability between subjects. However, we overcame these constraints by using multivoxel pattern analysis. It clearly revealed frequency-specific activity during the encoding phase of a change detection task, and the degree of this frequency-specific activation was positively related to performance in the task. Although the sounds had to be maintained in memory, activity in auditory cortex was significantly suppressed. Strikingly, patterns of activity in this maintenance period correlated negatively with the patterns evoked by the same frequencies during encoding. Furthermore, individuals who used a rehearsal strategy to remember the sounds showed reduced frequency-specific suppression during the maintenance period. Although negative activations are often disregarded in fMRI research, our findings imply that decreases in blood oxygenation level-dependent response carry important stimulus-specific information and can be related to cognitive processes. We hypothesize that, during auditory change detection, frequency-specific suppression protects short-term memory representations from being overwritten by inhibiting the encoding of interfering sounds.individual differences | memory capacity | multivoxel pattern analysis S ounds are ephemeral, and to interpret, integrate, or compare them, it will often be necessary to generate a stable representation in some form of short-term memory. Auditory perception and short-term memory are, thus, closely linked processes, and recent findings suggest that early sensory regions are recruited by both (reviews in refs. 1 and 2). Evidence in the auditory modality mainly stems from electrophysiology (3), suggesting that the function of auditory cortex goes beyond coding for simple features of complex sounds (4). In humans, the role of early sensory regions in short-term memory has not been directly addressed, because investigating auditory cortex is limited by the spatial and temporal resolution of functional MRI (fMRI) and the large interindividual differences in auditory cortex anatomy (5). Thus, existing fMRI studies of auditory short-term memory (ASTM) do not typically show significant or meaningful involvement of early auditory regions during the short-term maintenance of nonverbal sounds (6).We focused on identifying whether human auditory cortex would show continuous stimulus-specific responses while participants had to remember sequences of simple tones. We drew on the well-established characteristic...

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Section: Discussionsupporting

confidence: 91%

“…It is possible that how information is encoded into short-term memory determines performance in change detection tasks (17). Therefore, we asked whether the specificity with which auditory information was encoded predicted individual memory capacity.…”

Section: Suppression Of Sensory Regions During the Maintenance Of Audmentioning

confidence: 99%

Stimulus-specific suppression preserves information in auditory short-term memory

Linke

Vicente-Grabovetsky

Cusack

2011

Proc. Natl. Acad. Sci. U.S.A.

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“…Nevertheless, the results here suggest that the ability to elevate visual attention (N2pc) and memory access (SPCN) processes in rPPC may be an important step to explaining individual differences in VSTM performance. Indeed, the tDCS-induced improvement here is most likely attentional rather than VSTM-specific (Desimone and Duncan, 1995;Desimone, 1996;Awh et al, 2000Awh et al, , 2006Awh and Jonides, 2001;Woodman et al, 2007;Cusack et al, 2009;Berryhill et al, 2011;Linke et al, 2011;Gladwin et al, 2012), as the functional roles of PPC have been well established in updating spatial mapping (Morris et al, 2007;Prime et al, 2008), directing attention to salient stimuli (Nobre, 2001;Rushworth and Taylor, 2006;Chao et al, 2011), binding features (Friedman-Hill et al, 1995;Ellison et al, 2007), monitoring temporal patterns (Coull and Nobre, 1998), deploying top-down attentional bias (Kastner and Ungerleider, 2001;Pessoa and Ungerleider, 2004), and VSTM maintenance Marois, 2004, 2005;Vogel and Machizawa, 2004;Tseng et al, 2010) and retrieval (Olson and Berryhill, 2009;Eimer and Kiss, 2010;Berryhill, 2012). Thus, an attentional boost, whether externally via tDCS or internally by other means (Tseng and Bridgeman, 2011) will indeed predict an improvement in VSTM performance, and is very compatible with previous ERP findings on VSTM (Vogel and Machizawa, 2004;McCollough et al, 2007) and change detection (Pourtois et al, 2006).…”

Section: An Attentional Account Of the Effects Of Tdcsmentioning

confidence: 90%

Unleashing Potential: Transcranial Direct Current Stimulation over the Right Posterior Parietal Cortex Improves Change Detection in Low-Performing Individuals

Tseng¹,

Hsu²,

Chang³

et al. 2012

Journal of Neuroscience

245

215

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The limits of human visual short-term memory (VSTM) have been well documented, and recent neuroscientific studies suggest that VSTM performance is associated with activity in the posterior parietal cortex. Here we show that artificially elevating parietal activity via positively charged electric current through the skull can rapidly and effortlessly improve people's VSTM performance. This artificial improvement, however, comes with an interesting twist: it interacts with people's natural VSTM capability such that low performers who tend to remember less information benefitted from the stimulation, whereas high performers did not. This behavioral dichotomy is explained by event-related potentials around the parietal regions: low performers showed increased waveforms in N2pc and contralateral delay activity (CDA), which implies improvement in attention deployment and memory access in the current paradigm, respectively. Interestingly, these components are found during the presentation of the test array instead of the retention interval, from the parietal sites ipsilateral to the target location, thus suggesting that transcranial direct current stimulation (tDCS) was mainly improving one's ability to suppress no-change distractors located on the irrelevant side of the display during the comparison stage. The high performers, however, did not benefit from tDCS as they showed equally large waveforms in N2pc and CDA, or SPCN (sustained parietal contralateral negativity), before and after the stimulation such that electrical stimulation could not help any further, which also accurately accounts for our behavioral observations. Together, these results suggest that there is indeed a fixed upper limit in VSTM, but the low performers can benefit from neurostimulation to reach that maximum via enhanced comparison processes, and such behavioral improvement can be directly quantified and visualized by the magnitude of its associated electrophysiological waveforms.

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“…Adults with better metacognition might therefore be able to adopt better strategies to adapt to changes in VSTM through the lifespan. For example, a strategy that may be helpful, and used especially by participants of higher fluid intelligence, is to attend to only a subset of items when presented with more than can be remembered (Cusack et al, 2009;Linke et al, 2011;Atkinson et al, 2017). Conversely, it may sometimes be beneficial to attend to the configuration of all items in the display, to the extent that these provide context, as described above, that helps to anchor memories of individual items (Bengson and Luck, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…Palva et al, 2010;Mitchell and Cusack, 2011;Honkanen et al, 2015;Siebenhuhner et al, 2016), and fMRI (e.g. Todd and Marois, 2005;McNab and Klingberg, 2008;Linke et al, 2011;Stevens et al, 2012;Ester et al, 2013;Vicente-Grabovetsky et al, 2014;Galeano Weber et al, 2016;Veldsman et al, 2017), with some differences reported across age groups (for a review see Sander et al, 2012).…”

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confidence: 99%

Visual short-term memory through the lifespan: preserved benefits of context and metacognition

Mitchell¹,

Cam‐CAN²,

Cusack³

2017

Preprint

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Visual short-term memory ability falls throughout the lifespan in healthy adults. Using a continuous report task, in a large, population-based sample, we first confirmed that this decline affects the quality and quantity of reported memories as well as knowledge of which item went where. Visual and sensorimotor precision also worsened with advancing age, but this did not account for the reduced memory performance.We then considered two strategies that older individuals might be able to adopt, to offset these memory declines: the use of contextual encoding, and metacognitive monitoring of performance.Context and metacognitive awareness were both associated with significantly better performance, however these effects did not interact with age in our sample. This suggests that older adults retain their capacity to boost memory performance through attention to external context and monitoring of their performance. Strategies that focus on taking advantage of these preserved abilities may therefore help to maintain short-term memory performance with advancing age. The paper reports on analysis of the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) data.3

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Encoding strategy accounts for individual differences in change detection measures of VSTM

Cited by 69 publications

References 50 publications

Stimulus-specific suppression preserves information in auditory short-term memory

Stimulus-specific suppression preserves information in auditory short-term memory

Unleashing Potential: Transcranial Direct Current Stimulation over the Right Posterior Parietal Cortex Improves Change Detection in Low-Performing Individuals

Visual short-term memory through the lifespan: preserved benefits of context and metacognition

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