Nat Commun's working memory representation of the visual cortex regulates the distraction effect

Written ︱ Zhou Zhou responsible editor ︱ Wang Sizhen’s advanced cognition relies on working memory (WM), which is the ability to maintain and perform operations on the internal representations of information when the information in the environment is not available
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Early research focused on the main role of the prefrontal cortex in supporting the characterization of WM [1, 2]
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However, it has recently been discovered that multivariate activity patterns in the early visual cortex can encode WM content [3, 4]
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Therefore, this specific binary relationship between the WM process coordination area (located in the fronto-parietal network) and the memory information storage area (located in the sensory cortex) promotes the development of the WM sensory recruitment model (The sensory recruitment model of WM) [ 5,6, 7]
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The model believes that the feedback signal from the frontal parietal cortex recruits the perceptual coding mechanism used in the sensory cortex to achieve precise memory storage
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 However, the view that the visual cortex plays a key role in working memory is still being questioned, and the main aspects of the sensory recruitment model remain unclear
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For example, it is not clear how the neural circuits of the early visual cortex encode the afferent perception while maintaining the WM representation [8]
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To answer this question, several recent studies have evaluated how WM representations are maintained in the presence of scattered feelings that are not related to behavior
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However, these studies have not reached a unified conclusion
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 Previous research has not been able to link the behavioral evidence of distraction with the distortions in the coded WM representations, because either distraction (or distraction) has no effect on behavior, or it only affects the group level or needs to be divided.
WM manifestations behind the heart are deviated [9]
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If WM features are not strong enough for distraction, these WM features may play a limited role
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At present, there is a lack of key evidence linking the behavioral performance of individual WM with the neural representation of the information in WM
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 Recently, the research group of Professor Clayton E.
Curtis of New York University in the United States published a research paper entitled "Working memory representations in visual cortex mediate distraction effects" in the journal Nature Communication, and found that distraction (distraction) leads to small memory errors.
Deviation can be predicted by the neural decoding deviation of the early visual cortex, but not by other areas; in the early visual cortex, the neural representation of working memory information and behavioral performance are intertwined, which strengthens its importance in visual memory
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The study pointed out the key role of sensory areas in the maintenance of WM and supported a key prediction of the sensory recruitment model
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The author used a memory-guided saccade task (Figure 1 A, B) for the testees to accurately quantify the accuracy, deviation, and reaction time of WM.
This task can measure WM representations and joint distractions before, during, and after distraction Characterization
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First, the author examined whether distractions affect the quality of WM (Figure 1 C, D)
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Compared with trials without distractions, memory-guided saccades showed less precision in trials presented with distractions (Figure 1D) and slower saccade activation (Figure 1E)
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The author observed that a short-lived behavior-related interference factor can affect the performance of WM
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In other words, distraction caused by distractions can affect WM performance
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  Figure 1 Note that distraction stimulation can impair working memory performance (Source: Hallenbeck et al.
, Nat Commun, 2021) The author then used functional magnetic resonance (fMRI) to analyze the BOLD response of the visual region of interest (ROI)
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In the test without distractions, two modes of ROIs of the field of view map were obtained (Figure 2A)
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The first mode: During the delay, the amplitude of continuous activity increases from the early visual cortex (V1-V3, V3AB) to the parietal cortex (IPS0/1, IPS2/3) and then to the dorsal ROI of the frontal cortex (sPCS) This is consistent with previous reports [10]
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The second mode: the spatial selectivity of continuous activity differs between ROIs, which is reflected in the difference between the receptive field (RFin) that is consistent with the WM target area and the opposite receptive field (RFout) of the WM target area
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The phase response caused by distractions is particularly strong in the parietal and frontal cortex (Figure 2B)
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Finally, in order to better visualize the visual evoked response associated with distractions, the author averaged the BOLD response (Figure 2C)
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These results indicate that spatially specific BOLD activation persists during WM and responds to distractions 
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Figure 2 BOLD response (hV4 in lateral ventral area, LO1 in lateral retina area) sorted by the position of voxel receptive field (RF) in different brain regions during WM delay (Source: Hallenbeck et al.
, Nat Commun, 2021) To verify the above In conclusion, the author established a visual and quantitative analysis model of spatial WM representation-polar angle inverted encoding model (IEM), and reconstructed the planar heat map of the spatial representation at each time point of each experiment (Figure 3 A, B), and visualize the relative representations of WM targets (Figure 3 C, D) and distractors (Figure 3 E, F), respectively
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Figure 3 IEM-based WM reconstruction and distractor representation (Source: Hallenbeck et al.
, Nat Commun, 2021) The IEM model results show that in the absence of distractors, all visual, parietal and frontal ROIs The WM target position is stably encoded (Figure 4A), and the fidelity value of all ROIs increases significantly when the WM target is presented, and continues throughout the entire WM target encoding process (Figure 4D); in the case of distracting objects, WM characterization There has been a significant decrease in the intensity of (Figure 4B), and the fidelity of interference positions in all ROIs increases with time (Figure 4E)
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In addition, the results also show that the distractor positions of the overall response of all ROIs are more representative than the WM target positions (Figure 4C)
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Therefore, the model can effectively simulate (encode) WM targets and distractions, and it also proves that distractions (distractions) affect WM representation
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Figure 4 The effect of distraction (distraction) on the dynamics of WM representation (Source: Hallenbeck et al.
, Nat Commun, 2021) Figure 5 WM representation is temporarily disturbed by a participating distraction (Source: Hallenbeck et al.
, Nat Commun, 2021) Further, the author studied how WM representations are affected by distractions and how to recover from distractions on a time dynamic scale
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The computer simulation calculated the reconstruction and related fidelity values ​​corresponding to each period before, during and after the distraction (Figure 5A)
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The statistical results show that in the distraction phase, the WM target representations of the ROIs of the tested brain regions are significantly damaged (Figure 5 A, B); in the post-distraction phase, the fidelity of the WM targets of the visual cortex and parietal cortex ROI The degree is lower than that of the control group (no distractors), which indicates that the distractors reduce the quality of WM target representation, and the WM representation does not fully recover after distraction; in the pre-distraction phase, the lateral abdominal area and lateral retinal area The fidelity of the WM targets of ROI, and parietal cortex ROI is lower than that of the control group, suggesting that when participants know that distractions will appear in the trial, they may adopt a different strategy to encode WM representations.
This is not the case in the experiment of mind and matter
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In order to verify the above-mentioned possibilities, the author further improved the model and test procedures to quantitatively analyze the multiple possibilities in the presence of distractions (Figure 6A)
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It is confirmed that the fidelity of WM target is very stable, and the change of training or test time point has almost no effect on the ability to reconstruct WM representation (Figure 6B).
The presence of distractors will lead to WM target information in the visual cortex and the posterior parietal cortex.
The obvious loss (Figure 6C-E)
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These results fully show that distraction (distraction) does not change the original form of WM representation
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Figure 6 The loss of WM fidelity when distracted cannot be explained by different encoding formats (Source: Hallenbeck et al.
, Nat Commun, 2021) Finally, the author explored to what extent the change in WM representation is related to the distraction The induced changes in neurological signs are related
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First, the test results show that the WM characterization error is significantly biased towards the direction of distraction, that is, the memory error will be attracted by nearby distractions (Figure 7A)
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Secondly, the representation deviation of the WM targets in the visual cortex V1-V3 significantly predicted memory errors, but this correlation was not found in other brain regions ROI (Figure 7B-D)
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These results indicate that the WM representations encoded by the neuronal group activity of the visual cortex are not only easily disturbed by distractions (distractions), but also that the distractions distort the neural representations, leading to systemic memory errors
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Figure 7 In the visual cortex, memory errors are associated with WM representation bias induced by distractions (Source: Hallenbeck et al.
, Nat Commun, 2021).
Conclusion and discussion of the article, inspiration and prospects.
The study tested how distraction interferes with work The representation of memory to resolve the early controversy between the visual cortex and the frontal parietal cortex
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The results obtained by the author provide evidence support for the WM sensory recruitment model.
The high precision of WM in the visual cortex may depend on the interaction between the control mechanism of the fronto-parietal cortex and the precise coding mechanism in the early visual cortex, rather than special use.
Independent system for perception and memory
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Original link: https://doi.
org/10.
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Curtis, CE & D'Esposito,