scholarly journals Transcranial Magnetic Stimulation of the Right Superior Parietal Lobule Modulates the Retro-Cue Benefit in Visual Short-Term Memory

2021 ◽  
Vol 11 (2) ◽  
pp. 252
Author(s):  
Fabiano Botta ◽  
Juan Lupiáñez ◽  
Valerio Santangelo ◽  
Elisa Martín-Arévalo

Several studies have shown enhanced performance in change detection tasks when spatial cues indicating the probe’s location are presented after the memory array has disappeared (i.e., retro-cues) compared with spatial cues that are presented simultaneously with the test array (i.e., post-cues). This retro-cue benefit led some authors to propose the existence of two different stores of visual short-term memory: a weak but high-capacity store (fragile memory (FM)) linked to the effect of retro-cues and a robust but low-capacity store (working memory (WM)) linked to the effect of post-cues. The former is thought to be an attention-free system, whereas the latter would strictly depend on selective attention. Nonetheless, this dissociation is under debate, and several authors do not consider retro-cues as a proxy to measure the existence of an independent memory system (e.g., FM). We approached this controversial issue by altering the attention-related functions in the right superior parietal lobule (SPL) by transcranial magnetic stimulation (TMS), whose effects were mediated by the integrity of the right superior longitudinal fasciculus (SLF). Specifically, we asked whether TMS on the SPL affected the performance of retro cues vs. post-cues to a similar extent. The results showed that TMS on the SPL, mediated by right SLF-III integrity, produced a modulation of the retro-cue benefit, namely a memory capacity decrease in the post-cues but not in the retro-cues. These findings have strong implications for the debate on the existence of independent stages of visual short-term memory and for the growing literature showing a key role of the SLF for explaining the variability of TMS effects across participants.

2020 ◽  
Author(s):  
Holly Lockhart ◽  
Blaire Dube ◽  
Kevin John MacDonald ◽  
Naseem Al-Aidroos ◽  
Stephen Emrich

Although recent evidence suggests that visual short-term memory (VSTM) is a continuous resource, little is known about how flexibly this resource can be allocated. Previous studies using probabilistic cues to indicate two different levels of probe probability have found that response precision can be predicted according to a continuous allocation of resources that depends on attentional priority. The current study used a continuous report procedure and attentional prioritization via simultaneous probabilistic spatial cues to address whether participants can use up to three levels of attentional priority to allocate VSTM resources. Three experiments were performed with differing priority levels, different cues, and cue presentation time. Although group level analysis demonstrated flexible allocation, there was limited evidence that participants were using three priority levels. An individual differences approach revealed that a minority of participants were using three levels of attentional priority, demonstrating that, while possible, it is not the predominant pattern of behavior.


2015 ◽  
Vol 8 (2) ◽  
pp. 216-223 ◽  
Author(s):  
Antje Kraft ◽  
Mads Dyrholm ◽  
Stefanie Kehrer ◽  
Christian Kaufmann ◽  
Jovita Bruening ◽  
...  

2010 ◽  
Vol 22 (11) ◽  
pp. 2570-2593 ◽  
Author(s):  
Steve Majerus ◽  
Arnaud D'Argembeau ◽  
Trecy Martinez Perez ◽  
Sanaâ Belayachi ◽  
Martial Van der Linden ◽  
...  

Although many neuroimaging studies have considered verbal and visual short-term memory (STM) as relying on neurally segregated short-term buffer systems, the present study explored the existence of shared neural correlates supporting verbal and visual STM. We hypothesized that networks involved in attentional and executive processes, as well as networks involved in serial order processing, underlie STM for both verbal and visual list information, with neural specificity restricted to sensory areas involved in processing the specific items to be retained. Participants were presented sequences of nonwords or unfamiliar faces, and were instructed to maintain and recognize order or item information. For encoding and retrieval phases, null conjunction analysis revealed an identical fronto-parieto-cerebellar network comprising the left intraparietal sulcus, bilateral dorsolateral prefrontal cortex, and the bilateral cerebellum, irrespective of information type and modality. A network centered around the right intraparietal sulcus supported STM for order information, in both verbal and visual modalities. Modality-specific effects were observed in left superior temporal and mid-fusiform areas associated with phonological and orthographic processing during the verbal STM tasks, and in right hippocampal and fusiform face processing areas during the visual STM tasks, wherein these modality effects were most pronounced when storing item information. The present results suggest that STM emerges from the deployment of modality-independent attentional and serial ordering processes toward sensory networks underlying the processing and storage of modality-specific item information.


2006 ◽  
Vol 18 (7) ◽  
pp. 1147-1155 ◽  
Author(s):  
L. Romero ◽  
V. Walsh ◽  
C. Papagno

Neuropsychological reports and activation studies by means of positron emission tomography and functional magnetic resonance imaging have suggested that the neural correlates of phonological short-term memory are located in the left hemisphere, with Brodmann's area (BA) 40 being responsible for short-term storage, and BA 44 for articulatory rehearsal. However, a careful review of the literature on the role of left BA 40 shows that the data are equivocal. We tested these hypotheses by means of repetitive transcranial magnetic stimulation (rTMS). Participants performed four tasks: two phonological judgements, thought to require only articulatory rehearsal without the contribution of short-term storage; a digit span, which involves both, short-term storage and articulatory rehearsal; and a pattern span, this last being the control task. The sites of stimulation were left BA 40, left BA 44 and the electrode location vtx, plus a baseline without TMS. Reaction times increased and accuracy decreased in the case of the phonological judgements and digit span after stimulation of both left sites, suggesting that BA 40, in addition to BA 44, is involved in phonological judgements. Possible explanations are discussed, namely, the possibility that (i) the neural correlates of rehearsal are not limited to BA 44 and (ii) phonological judgements involve processes other than rehearsal. We also consider the effects of using different tasks and responses to resolve some of the discrepancies in the literature.


CNS Spectrums ◽  
2007 ◽  
Vol 12 (7) ◽  
pp. 527-536 ◽  
Author(s):  
Giuseppe Vallar

ABSTRACTBrain-damaged patients with lesion or dysfunction involving the parietal cortex may show a variety of neuropsychological impairments involving spatial cognition. The more frequent and disabling deficit is the syndrome of unilateral spatial neglect that, in a nutshell, consists in a bias of spatial representation and attention ipsilateral to of extrapersonal, personal (ie, the body) space, or both, toward the side of the hemispheric lesion. The deficit is more frequent and severe after damage to the right hemisphere, involving particularly the posterior-inferior parietal cortex at the temporo-parietal junction. Damage to these posterior parietal regions may also impair visuospatial short-term memory, which may be associated with and worsen spatial neglect. The neural network supporting spatial representation, attention and short-term memory is, however, more extensive, including the right premotor cortex. Also disorders of drawing and building objects (traditionally termed constructional apraxia) are a frequent indicator of posterior parietal damage in the left and in the right hemispheres. Other less frequent deficits, which, however, have a relevant localizing value, include optic ataxia (namely, the defective reaching of visual objects, in the absence of elementary visuo-motor impairments), which is typically brought about by damage to the superior parietal lobule. Optic ataxia, together with deficits of visual attention, of estimating distances and depth, and with apraxia of gaze, constitutes the severely disabling Balint-Holmes' syndrome, which is typically associated with bilateral posterior parietal and occipital damage. Finally, lesions of the posterior parietal lobule (angular gyrus) in the left hemisphere may bring about a tetrad of symptoms (left-right disorientation, acalculia, finger agnosia, and agraphia) termed Gerstmann's syndrome, that also exists in a developmental form.


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