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Verbal working memory task. (A) The measurement of interest was high-gamma activity during 'high-load' working memory trials containing four stimuli. Participants listened to stimulus letters, followed by a 2-s silent period, after which participants heard a target letter and overtly answered 'Yes' or 'No' regarding whether the target letter was included in the set for a given trial. (B) According to previous literature 2,4 , working memory maintenance is theorized to be exerted during a 2-s silent period, whereas working memory scanning subsequently takes place following target onset. Since this working memory task minimally requires semantic or syntactic processing, common and differential high-gamma augmentations during this and the aforementioned task (Fig. 1A) are expected to reveal the profiles of task-related activation that may be attributable to verbal working memory operations. The response time was defined as the period between target offset and response onset.
Source publication
Abstract Auditory naming is suggested to require verbal working memory (WM) operations in addition to speech sound perception during the sentence listening period and semantic/syntactic processing during the subsequent judgement period. We attempted to dissect cortical activations attributable to verbal WM from those otherwise involved in answering...
Contexts in source publication
Context 1
... 1) [1][2][3] . Verbal working memory function is suggested to consist of two distinct processes, referred to as (i) working memory maintenance characterized by brief storage of mental rep- resentations of speech sounds and (ii) working memory scanning characterized by subsequent retrieval of what was just heard and for appropriate responses ( Fig. 2) [2][3][4] . Here, we attempted to segregate cortical activation attrib- utable to verbal working memory function from those otherwise involved in semantic and syntactic processing for auditory naming, using measurement of event-related high-gamma modulations on electrocorticography (ECoG) 5,6 . While undergoing extraoperative ECoG ...
Context 2
... evaluation, patients with focal epilepsy were assigned (i) an auditory naming task (i.e.: overt naming in response to a spoken question 7 ; Fig. 1) and (ii) an auditory working memory task 8 . This working memory task was designed to effectively localize electrode sites involved in either maintenance or scanning of auditory letter stimuli (Fig. 2). Augmentation of high-gamma activity (70-110 Hz) on ECoG was treated as a summary measure of cortical activation 5,7,9 ...
Context 3
... that high-gamma augmentation was prominent at iPreCG during the working memory maintenance period, whereas high-gamma augmentation during the working memory scanning period was observed in broad areas including the prefrontal regions 8 . Taking into account that our working memory task does not require semantic or syntactic processing (Fig. 2), we hypothesized that the iPreCG high-gamma aug- mentation during the sentence listening period of the naming task would be attributed to working memory main- tenance function. In the present study, we specifically tested our prediction that the magnitude of high-gamma augmentation at a given iPreCG site during naming task sentence ...
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... period of the naming task would be attributed to working memory main- tenance function. In the present study, we specifically tested our prediction that the magnitude of high-gamma augmentation at a given iPreCG site during naming task sentence listening (Fig. 1A) would positively correlate to that during working memory task maintenance period ( Fig. 2A). We designed the statistical analysis to determine the independent effect of age on high-gamma measures, since patients with a wide range of age were included in the present ...
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... clarify the cortical dynamics of naming task judgement process non-attributable to working memory scan- ning, we determined the spatiotemporal patterns of common and differential high-gamma augmentations during the naming task judgement (i.e.: period after stimulus offset; Fig. 1A) and working memory task scanning periods ( Fig. 2A) in the same patient cohort. We specifically predicted that left frontal association neocortices would show greater extent of high-gamma augmentation during the naming task judgement period compared to during the working memory task scanning period. The task is also known as an auditory description naming task 7,72 . In each trial, a ...
Context 6
... The inclusion criteria consisted of patients who underwent the auditory naming (Fig. 1A) and verbal working memory ( Fig. 2A) tasks during extraoperative subdural ECoG recording at Children's Hospital of Michigan or Harper University Hospital. The exclusion criteria consisted of: (i) presence of massive brain malformations, (ii) severe cognitive dysfunction defined by verbal IQ or verbal comprehension index <70, (iii) inability to complete the tasks, (iv) ...
Context 7
... working memory task. This task, as described in our previous study 8 (Fig. 2), represents a letter-based, auditory version on the Sternberg working memory task 4 . Participants were instructed to remember a verbally provided set of two or four letters for 2 s and to overtly decide whether a subsequent target letter had been included. The measurement of interest in the present study was high-gamma activity during ...
Context 8
... of the main- tenance period); (2) [HG WM scanning ]: high-gamma amplitude during the working memory task scanning period, defined as the mean across the 400-ms period between 200 and 600 ms after target offset, which was assumed to be minimally involved in primary auditory or articulation processes taking into account the mean response time 23,24 (Fig. 2B) To determine the association between neural activations during naming task judgement and working memory task scanning periods. Likewise, we determined whether the variance in the mag- nitude of left-hemispheric high-gamma modulation during the naming task judgement period accounted for high-gamma modulations during working memory ...
Similar publications
We review the theory and algorithms of electrophysiological brain connectivity analysis. This tutorial is aimed at providing an introduction to brain functional connectivity from electrophysiological signals, including electroencephalography (EEG), magnetoencephalography (MEG), electrocorticography (ECoG), stereoelectroencephalography (SEEG). Vario...
Citations
... For instance, findings in anatomical magnetic resonance imaging (MRI) have demonstrated the existence of a large frontal cortex in all great ape species-humans included (Semendeferi et al. 2002)-emphasizing the particular interest of investigating anatomical structures and related functions of the frontal regions. Moreover, the functions of the frontal lobe, often associated to problem solving, emotion processing and especially evaluative judgment, communication and language or even motor and sexual behaviors (Davidson 1992;Barbas 2000;Binder et al. 2004; Barbas et al. 2011;LeDoux 2012;Frühholz and Grandjean 2013;Kambara et al. 2018), as well as their related brain structures are shared by most primate species. This includes two critical brain structures that are the focus of this article: the orbitofrontal cortex (OFC) and the inferior frontal gyrus (IFG). ...
Introduction
The ability to process verbal language seems unique to humans and relies not only on semantics but on other forms of communication such as affective vocalizations, that we share with other primate species—particularly great apes (Hominidae).
Methods
To better understand these processes at the behavioral and brain level, we asked human participants to categorize vocalizations of four primate species including human, great apes (chimpanzee and bonobo), and monkey (rhesus macaque) during MRI acquisition.
Results
Classification was above chance level for all species but bonobo vocalizations. Imaging analyses were computed using a participant-specific, trial-by-trial fitted probability categorization value in a model-based style of data analysis. Model-based analyses revealed the implication of the bilateral orbitofrontal cortex and inferior frontal gyrus pars triangularis (IFGtri) respectively correlating and anti-correlating with the fitted probability of accurate species classification. Further conjunction analyses revealed enhanced activity in a sub-area of the left IFGtri specifically for the accurate classification of chimpanzee calls compared to human voices.
Discussion
Our data—that are controlled for acoustic variability between species—therefore reveal distinct frontal mechanisms that shed light on how the human brain evolved to process vocal signals.
... It is an important and novel finding of this study that the Dr. Neuronowski ® training method has significant clinical benefits for the amelioration of speech production functions-in particular, for naming and verbal fluency. Both naming and verbal fluency require the engagement of working memory and, furthermore, verbal fluency is additionally based on processing speed and auditory attention [64][65][66] . The experimental training might have enhanced these functions, which in turn resulted in improvement of speech production. ...
People with aphasia (PWA) often present deficits in non-linguistic cognitive functions, such as executive functions, working memory, and temporal information processing (TIP), which intensify the associated speech difficulties and hinder the rehabilitation process. Therefore, training targeting non-linguistic cognitive function deficiencies may be useful in the treatment of aphasia. The present study compared the effects of the novel Dr. Neuronowski ® training method (experimental training), which particularly emphasizes TIP, with the linguistic training commonly applied in clinical practice (control training). Thirty four PWA underwent linguistic and non-linguistic assessments before and after the training as well as a follow-up assessment. Patients were randomly assigned to either experimental (n = 18) or control groups (n = 16). The experimental training improved both non-linguistic functions (TIP and verbal short-term and working memory) and linguistic functions: phoneme discrimination, sentence comprehension, grammar comprehension, verbal fluency, and naming. In contrast, the control training improved only grammar comprehension and naming. The follow-up assessment confirmed the stability of the effects of both trainings over time. Thus, in PWA, Dr. Neuronowski ® training appears to have broader benefits for linguistic and non-linguistic functions than does linguistic training. This provides evidence that Dr. Neuronowski ® may be considered a novel tool with potential clinical applications.
... The working memory capacity of school aged children is less developed in comparison to that of adults (Kambara et al., 2018). The literature shows that WM is still developing in school-aged children, and significantly improves during these years (Camos and Barrouillet, 2011;Magimairaj and Montgomery, 2012;Camos and Barrouillet, 2014). ...
Introduction
Children experience unique challenges when listening to speech in noisy environments. The present study used pupillometry, an established method for quantifying listening and cognitive effort, to detect temporal changes in pupil dilation during a speech-recognition-in-noise task among school-aged children and young adults.
Methods
Thirty school-aged children and 31 young adults listened to sentences amidst four-talker babble noise in two signal-to-noise ratios (SNR) conditions: high accuracy condition (+10 dB and + 6 dB, for children and adults, respectively) and low accuracy condition (+5 dB and + 2 dB, for children and adults, respectively). They were asked to repeat the sentences while pupil size was measured continuously during the task.
Results
During the auditory processing phase, both groups displayed pupil dilation; however, adults exhibited greater dilation than children, particularly in the low accuracy condition. In the second phase (retention), only children demonstrated increased pupil dilation, whereas adults consistently exhibited a decrease in pupil size. Additionally, the children’s group showed increased pupil dilation during the response phase.
Discussion
Although adults and school-aged children produce similar behavioural scores, group differences in dilation patterns point that their underlying auditory processing differs. A second peak of pupil dilation among the children suggests that their cognitive effort during speech recognition in noise lasts longer than in adults, continuing past the first auditory processing peak dilation. These findings support effortful listening among children and highlight the need to identify and alleviate listening difficulties in school-aged children, to provide proper intervention strategies.
... The left perisylvian areas have been closely linked to backward digit repetition [101][102][103]. The inferior precentral gyrus has been shown to be important for short term retention of auditory stimuli before further processing and motor transformation [104,105]. Structural and functional aberrations in the perisylvian cortical regions like the precentral gyrus, the inferior frontal gyrus, and the superior temporal gyrus are widely implicated in the auditory processing dysfunction that may underlie auditory hallucinations in schizophrenia [106][107][108]. Overall, our findings are in line with the existing literature on neural correlates of phonological working memory; however, these preliminary results with modest effect sizes need replication in larger samples. ...
Objective:
Schizophrenia is associated with impairment in multiple cognitive domains. There is a paucity of research on the effect of prolonged illness duration (≥ 15 years) on cognitive performance along multiple domains. In this pilot study, we used the Global Neuropsychological Assessment (GNA), a brief cognitive battery, to explore the patterns of cognitive impairment in recent-onset (≤ 2 years) compared to chronic schizophrenia (≥ 15 years), and correlate cognitive performance with brain morphometry in patients and healthy adults.
Methods:
We assessed cognitive performance in patients with recent-onset (n = 17, illness duration ≤ 2 years) and chronic schizophrenia (n = 14, duration ≥ 15 years), and healthy adults (n = 16) using the GNA and examined correlations between cognitive scores and gray matter volumes computed from T1-weighted magnetic resonance imaging images.
Results:
We observed cognitive deficits affecting multiple domains in the schizophrenia samples. Selectively greater impairment of perceptual comparison speed was found in adults with chronic schizophrenia (p = 0.009, η2partial = 0.25). In the full sample (n = 47), perceptual comparison speed correlated significantly with gray matter volumes in the anterior and medial temporal lobes (TFCE, FWE p < 0.01).
Conclusion:
Along with generalized deficit across multiple cognitive domains, selectively greater impairment of perceptual comparison speed appears to characterize chronic schizophrenia. This pattern might indicate an accelerated or premature cognitive aging. Anterior-medial temporal gray matter volumes especially of the left hemisphere might underlie the impairment noted in this domain in schizophrenia.
... 46 Our previous ECoG studies of auditory naming-related neural dynamics reported that older age was associated with a greater degree of inferior-precentral high-gamma augmentation during stimulus listening as well as a greater degree of left rostral middle-frontal high-gamma augmentation immediately following stimulus offset. 12,47 In the present study, younger patients had a longer response time compared to older ones. The effect of variance in response time across age is expected to be more prominent in the time windows long after stimulus onset as well as long before response onset. ...
... Complementing the findings above, neurophysiological studies have reported SMS involvement behind various aspects of language comprehension and intelligibility (Caplan et al., 2000;Kambara et al., 2018;Keitel et al., 2018;Park et al., 2015;Rogalsky et al., 2008). These studies however diverge in their functional interpretation of this effect. ...
... These studies however diverge in their functional interpretation of this effect. Some suggest that SMS facilitates comprehension through covert rehearsal of information in the articulatory loop of working memory (Caplan et al., 2000;Kambara et al., 2018;Rogalsky et al., 2008). On the other hand, electromagnetic studies of cortical activity during speech recognition have revealed that SMS This document is copyrighted by the American Psychological Association or one of its allied publishers. ...
The capacity for language has evolved remarkably quickly in recent human history. Its advent likely coincided with a range of cognitive innovations not found elsewhere at this level of complexity in the rest of the animal kingdom. This late yet near-simultaneous florescence of higher language and cognition is difficult to account for in terms of strictly modular neurocognitive systems, each with its own dedicated function and evolutionary trajectory. Nor does it legitimize the neurocognitive study of language in isolation from other systems of human thought and action. In the wake of emergentist approaches to key human cognitive abilities, the present article considers language as the differentiated product of multiple neural networks dedicated to qualitatively distinct cognitive functions—including (at least) the cortical systems of general semantic cognition and control and the sensorimotor systems supporting language production. A model is proposed to account for how these systems congregate to produce language, featuring a dual-stream architecture of the semantic interface into item-based and item-independent semantic knowledge on the one hand, and a notion of the sensorimotor interface as a key component for the temporal tracking and verbal rehearsal of task-relevant information on the other. Avenues are also offered for enriching this architecture in future versions of the model. Finally, it is proposed that language is an “optimal” combination of these neurocognitive systems, enabling fast and cost-effective transfer of information at the systems level. This last point underpins evidence for the privileged status of language as a tool for adaptive thought and behavior, as well as some important features of brain evolution, development, and functional organization.
... However, longterm memory consolidation is not only based on mesial temporal lobe function but also on an extensively and bilaterally distributed process (60). Long-term memory storage depends on a functioning precedent of short-term memory storage, e.g. the short-term maintenance of verbal memory occurs in left neocortical networks (left pre-central, supra-marginal, and inferior frontal gyri) (61). An impaired short-term memory process is a possible cause for impairment of long-term memory consolidation. ...
Rationale
High frequency oscillations (HFO; ripples = 80–200, fast ripples 200–500 Hz) are promising epileptic biomarkers in patients with epilepsy. However, especially in temporal epilepsies differentiation of epileptic and physiological HFO activity still remains a challenge. Physiological sleep-spindle-ripple formations are known to play a role in slow-wave-sleep memory consolidation. This study aimed to find out if higher rates of mesial-temporal spindle-ripples correlate with good memory performance in epilepsy patients and if surgical removal of spindle-ripple-generating brain tissue correlates with a decline in memory performance. In contrast, we hypothesized that higher rates of overall ripples or ripples associated with interictal epileptic spikes correlate with poor memory performance.
Methods
Patients with epilepsy implanted with electrodes in mesial-temporal structures, neuropsychological memory testing and subsequent epilepsy surgery were included. Ripples and epileptic spikes were automatically detected in intracranial EEG and sleep-spindles in scalp EEG. The coupling of ripples to spindles was automatically analyzed. Mesial-temporal spindle-ripple rates in the speech-dominant-hemisphere (left in all patients) were correlated with verbal memory test results, whereas ripple rates in the non-speech-dominant hemisphere were correlated with non-verbal memory test performance, using Spearman correlation).
Results
Intracranial EEG and memory test results from 25 patients could be included. All ripple rates were significantly higher in seizure onset zone channels (p < 0.001). Patients with pre-surgical verbal memory impairment had significantly higher overall ripple rates in left mesial-temporal channels than patients with intact verbal memory (Mann–Whitney-U-Test: p = 0.039). Spearman correlations showed highly significant negative correlations of the pre-surgical verbal memory performance with left mesial-temporal spike associated ripples (rs = −0.458; p = 0.007) and overall ripples (rs = −0.475; p = 0.006). All three ripple types in right-sided mesial-temporal channels did not correlate with pre-surgical nonverbal memory. No correlation for the difference between post- and pre-surgical memory and pre-surgical spindle-ripple rates was seen in patients with left-sided temporal or mesial-temporal surgery.
Discussion
This study fails to establish a clear link between memory performance and spindle ripples. This highly suggests that spindle-ripples are only a small portion of physiological ripples contributing to memory performance. More importantly, this study indicates that spindle-ripples do not necessarily compromise the predictive value of ripples in patients with temporal epilepsy. The majority of ripples were clearly linked to areas with poor memory function.
... Using subdural electrodes to study free of epileptiform activity EEG segments in patients with epilepsy it was observed that during a simple auditory-motor task the auditoryverbal stimuli elicited augmented gamma-oscillations in the posterior portion of the superior temporal gyrus, whereas hand-motor responses elicited gamma-augmentation in the pre and postcentral gyri (Nagasawa et al., 2010). A left-lateralized region in the posterior Sylvian fissure at the parietal-temporal boundary showed particularly robust MEG (magnetoencephalography) (Levelt et al., 1998) and electrocorticography (Kambara et al., 2018) gamma-band responses to both sensory and motor phases of visual picture naming and auditory naming tasks. These tasks are related to the working memory (WM). ...
... The auditory-motor integration circuit is represented by a small set of areas in the superior temporal and temporoparietal cortex, temporal, and frontal areas (Hickok et al., 2003). During naming task judgement, left middle-frontal activation appeared to be well-attributable to WM scanning function, whereas left orbitofrontal activation may be attributable less to WM scanning but more largely to syntactic/semantic processing (Kambara et al., 2018). It was observed that during picture naming test, a region in the left posterior temporal lobe showed prominent activation (i.e., peak activity of dipole sources in the individual magnetic response) starting about 200 msec after picture onset and peaking at about 350 msec, with congruent consistent activation in the right parietal cortex, peaking at about 230 msec after picture onset, thus preceding and partly overlapping with the left temporal response (Levelt et al., 1998). ...
Background: Repetitive transcranial magnetic stimulation (RTMS) has been suggested as a possible therapeutic alternative for patients with schizophrenia (SCZ) and treatment-resistant auditory verbal hallucinations (AVH). The aim of the studies presented here was to investigate how RTMS affects clinical symptoms, electroencephalographic responses, and brain functional networks. We suspected improvement of symptoms accompanied by changes in EEG activity, event-related potentials, and sensory gating.
Subjects and methods: Ten patients with schizophrenia (mean age 32.4, SD = 6.85, 7m, 3f) and six healthy controls (mean age 30.3, SD = 7.5, 4m, 2f) participated in this study. Nine patients were on antipsychotic medication. The patients were randomly selected into two groups, the treatment group (TG) and the control group (CG). The active low-frequency 1Hz RTMS was delivered in ten daily sessions of 900 pulses at two different EEG locations: T3-P3 (TG) and Cz (CG). Clinical symptoms were investigated with psychometric scales like Quality of Life (QoL), Depression Anxiety Stress Scales (DASS), and Psychotic Symptom Rating Scale with Auditory Hallucinations Subscale (PSYRATS AHS). The neurophysiological tests employed were cortical and cutaneous silent period, mid-latency auditory evoked potentials (P50, N100, P200) using a paired click paradigm, P300 obtained with an auditory oddball paradigm, and the cognitively driven auditory-motor task (AMT). Time, frequency domains, and functional network organization of different neurophysiological markers were analyzed. P300 oscillatory activity was analyzed with EEG source connectivity (e.g., participation coefficient) and for the auditory-motor task-induced oscillations, we used network integration parameters of graph theory (i.e., characteristic path length - CPL and small worldness - SW). The patient's results obtained after the treatment (T2) were compared with data obtained at baseline condition (T1) and with data from the third group of healthy controls (HC).
Results: There were no significant changes between TG and CG on QoL, DASS, and PSYRATS AHS scores or neurophysiological data after the RTMS treatment. We also calculated pre-post RTMS changes for all patients. N100 showed the most marked changes after RTMS in left temporoparietal region, from -0.57 μV (SD 0.97) to -2.39 μV (SD 1.59), (p = 0.006, η2 = 0.346) and in medial posterior region (p = 0.038, η2 = 0.218) suggesting a modulation of this marker over both stimulation sites. After RTMS, N100-P300 voltage increased for six patients, two in TG and four in CG, but also decreased in patients from TG who showed the best clinical outcome. The EEG power spectral density (PSD) during the auditory oddball paradigm increased in T2, mainly for the alpha band and beta band globally, for six subjects, two in TG and four in CG. The connectivity results for the frequent stimuli of the auditory oddball paradigm showed increased network segregation during T2 for the beta band, in seven patients, four in CG, and three in TG. The study revealed that patients with schizophrenia exhibit higher gamma PSD in a period between two auditory commands of AMT, compared to HC, which was modified by RTMS without being significant. The change was visible, locally, over the left temporoparietal region, when the task was done with the non-dominant hand, showing that during this condition, gamma synchronization is a marker of “neural effort” and workload during the working memory-related time and not during the auditory or motor cortical activation. Graph theory analyzed for low-gamma EEG activity elicited in between the auditory stimuli, an epoch of the auditory-motor task we called “non-cortical activation” and which is related to the working memory, showed a decreased SW index after RTMS when the task was performed with the non-dominant hand. This SW effect observed in the patients was similar to that of the HC group. Kendall's tau-b correlation showed a strong, negative correlation between the SW index of low-gamma phase oscillations and PSYRATS AHS scores in T1, which was statistically significant (τb = −0.788, p = 0.032). After RTMS (T2) the correlation was strongly positive (τb = 0.733, p = 0.039).
Discussion: The sample size of this study was small to achieve TG-CG statistical significance (e.g., PSYRATS AHS pre-calculated N was 16). Individual data showed controversial results, sometimes with the improvement of AVH severity and neurophysiological data in patients treated at the Cz EEG location. N100 from the paired click paradigm showed the most marked changes at the left temporoparietal region. P300 was performed with a passive auditory oddball paradigm by “automatic” discrimination between two tones without asking the subject to move the finger or count the target stimuli. The findings we obtained with P300 amplitude, which in most cases decreased after RTMS, might be in direct relation to a habituation effect, which is seen in healthy subjects (Polich, 1989).
Conclusion: Based on the patient ́s clinical evaluations and all the neurophysiological measurements presented in the studies of this thesis we cannot affirm that left temporoparietal (T3-P3) RTMS is more effective than vertex (Cz) RTMS in patients with schizophrenia and auditory verbal hallucinations. Some interesting neurophysiological observations were made, particularly changes of N100 amplitude at the left temporoparietal region and low gamma activity during the period in between auditory commands of a cognitively driven task. N100 amplitude measured from a paired click paradigm and low gamma activity measured in-between auditory stimuli of AMT performed with the non-dominant hand might be of interest to assess the neuromodulatory aftereffects of RTMS in patients with SCZ and AVH. The small-world network of low gamma activity showed a significant main effect of the condition (AMT and resting state) for HC and SCZ-T2 suggesting that RTMS might have influenced the network by restoring the SW index. Further, studies with a multimodal neurophysiological approach are necessary to assess RTMS effectiveness for patients with SCZ and AVH.
... Studies which report data for more than one area may be listed multiple times. Note that in humans, ECoG measurements of LFPs biased are toward temporal and frontal sites as a result of clinical considerations (Tallon-Baudry et al., 2001;Howard et al., 2003;Axmacher et al., 2008Axmacher et al., , 2010van Vugt et al., 2010;Khursheed et al., 2011;Maris et al., 2011;van der Meij et al., 2012;Noy et al., 2015;Kambara et al., 2017Kambara et al., , 2018Myroshnychenko et al., 2017;Ni et al., 2017;Johnson et al., 2018a,b;Zhang et al., 2018;Alagapan et al., 2019b;Gehrig et al., 2019;Boran et al., 2020 Synchronized activity between brain areas provides a potential means to modulate communication during WM and other tasks (Varela et al., 2001;Fries, 2005Fries, , 2015Sakurai and Takahashi, 2008;Canolty et al., 2010;Fell and Axmacher, 2011;Luczak et al., 2013;Canavier, 2015;Yuste, 2015;Avena-Koenigsberger et al., 2018;Singer, 2018;Hahn et al., 2019). ...
Neural signatures of working memory (WM) have been reported in numerous brain areas, suggesting a distributed neural substrate for memory maintenance. In the current manuscript we provide an updated review of the literature focusing on intracranial neurophysiological recordings during WM in primates. Such signatures of WM include changes in firing rate or local oscillatory power within an area, along with measures of coordinated activity between areas based on synchronization between oscillations. In comparing the ability of various neural signatures in any brain area to predict behavioral performance, we observe that synchrony between areas is more frequently and robustly correlated with WM performance than any of the within-area neural signatures. We further review the evidence for alteration of inter-areal synchrony in brain disorders, consistent with an important role for such synchrony during behavior. Additionally, results of causal studies indicate that manipulating synchrony across areas is especially effective at influencing WM task performance. Each of these lines of research supports the critical role of inter-areal synchrony in WM. Finally, we propose a framework for interactions between prefrontal and sensory areas during WM, incorporating a range of experimental findings and offering an explanation for the observed link between intra-areal measures and WM performance.
... By analyzing the changes in different rhythms, some studies have found that the alcohol has significant effects on EEG. [18] has been investigated the effects on EEG signals of heavily drinking students, and the results show that the EEG has more synchronization in the theta (4)(5)(6)(7)(8) and gamma (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45) Hz) bands during eyes closed, both with and without a mental-rehearsal task. It has also shown the differences in functional connectivity compared with the light-drinking controls. ...
... Although the frontal and parietal cortex which support high level of cognitive processes are involved in WM [39], [40], there are differences of WM functions between frontal and parietal. The frontal involves in many verbal expression processes, including verbal WM [41], and the parietal mediates the brain functions such as spatial WM [42]. The classification accuracies of the frontal are significantly higher than the parietal in WM tasks. ...
More and more people are exposed to drinking and in addicted. In recent years, Electroencephalography (EEG) technology has been used to diagnose the effects of alcohol on brain structure and functions. Since the brain contains a variety of different functions, it is difficult to explore the effects of alcohol on a certain cognitive function by single tasks to induce EEG signals. Additionally, alcohol has an effect on the performance of the working memory (WM) which is particularly susceptible to external stimulus and recovering in the short-term. This study investigates the differences of the EEG signals on the WM-load before and after alcohol intake by using the working memory tasks. Ten participants take part in the N-back experiments with taking alcohol. After preprocessing the EEG signals, seven different features are selected to classify the different WM-load levels, and these features are also used to distinguish the states whether in drinking or not. At last, the support vector machine (SVM) is applied for the classification and the accuracies for some subjects can achieve 100% in the time domain. This work not only provides a new way to explore the effects of alcohol on the specific functions of the brain but also indicates that mild alcohol consumption could alter the perception of the brain on working memory load and reduce the WM-load level.
