Exploring spatiotemporal neural dynamics of the human visual cortex

The human visual cortex is organized in a hierarchical manner. Although previous evidence supporting this hypothesis has been accumulated, specific details regarding the spatiotemporal information flow remain open. Here we present detailed spatiotemporal correlation profiles of neural activity with low‐level and high‐level features derived from an eight‐layer neural network pretrained for object recognition. These correlation profiles indicate an early‐to‐late shift from low‐level features to high‐level features and from low‐level regions to higher‐level regions along the visual hierarchy, consistent with feedforward information flow. Additionally, we computed three sets of features from the low‐ and high‐level features provided by the neural network: object‐category‐relevant low‐level features (the common components between low‐level and high‐level features), low‐level features roughly orthogonal to high‐level features (the residual Layer 1 features), and unique high‐level features that were roughly orthogonal to low‐level features (the residual Layer 7 features). Contrasting the correlation effects of the common components and the residual Layer 1 features, we observed that the early visual cortex (EVC) exhibited a similar amount of correlation with the two feature sets early in time, but in a later time window, the EVC exhibited a higher and longer correlation effect with the common components (i.e., the low‐level object‐category‐relevant features) than with the low‐level residual features—an effect unlikely to arise from purely feedforward information flow. Overall, our results indicate that non‐feedforward processes, for example, top‐down influences from mental representations of categories, may facilitate differentiation between these two types of low‐level features within the EVC.     

Video Game Structural Characteristics: A New Psychological Taxonomy

Excessive video game playing behaviour may be influenced by a variety of factors including the structural characteristics of video games. Structural characteristics refer to those features inherent within the video game itself that may facilitate initiation, development and maintenance of video game playing over time. Numerous structural characteristics that influence gambling frequency and expenditure have been identified in the gambling literature, and some researchers have drawn comparisons between the rewarding elements in video gaming and those in slot machine gambling. However, there have been few rigorous attempts to classify and organise the psycho-structural elements of video games in a similar way to gambling. In order to aid current psychological understanding of problem video game playing and guide further research questions in this area, a new taxonomy of video game features is proposed, which includes: (a) social features, (b) manipulation and control features, (c) narrative and identity features, (d) reward and punishment features, and (e) presentation features. Each category is supported with relevant theory and research, where available, and the implications of these features for excessive video game playing are discussed.     

基于信息约简的脑电信号特征提取*★

背景：脑机接口系统中，对大脑想象的反应速度是衡量脑机接口系统质量的一个重要标准，因此关于脑电信号的分析，对脑电信号特征进行筛选就显得尤为重要，尽可能少的特征来标示相应的动作是提高速度的一个重要途径。 目的：利用约简方法对脑电信号特征进行特征筛选，降低脑电特征数目。 方法：首先利用不同的脑电特征分析方法，提取特征，并进行分类；其次把连续的脑电信号离散化，利用脑电信号组建脑电信号信息表，最后利用约简理论，对脑电信号进行特征约简，并利用约简特征进行分类，验证分类准确率。 结果与结论：利用信息约简的方法及特征标示，把连续的脑电信号特征离散化，利用离散化的脑电信号特征构建信息表，并进行特征筛选，在保证分类准确率的情况下降低了特征的数量。不足之处在于，该方法对分类特征进行标记只能在两类之间进行，对多类型分类特征进行标记和分类特征进行约简将是下一步工作的重点。     

Relationship network quality: adolescent adjustment and perceptions of relationships with parents and friends

Early, mid-, and late adolescents (N = 406) from an ethnically diverse community completed questionnaires describing positive and negative features of relationships with their mothers, fathers, and same-sex best friends. School grades, self-reported adjustment problems, and self-worth differed as a function of both the number of relationships that adolescents described as high on positive features and the number of relationships that adolescents described as high on negative features. Adolescents with relationships that were uniformly good quality (i.e., high on positive features and low on negative features) were better adjusted than adolescents with relationships that were uniformly poor quality (i.e., low on positive features and high on negative features). The results failed to support the proposition that a single high quality relationship buffers against suboptimal levels of support in other relationships.     

Clustering of Gaze During Dynamic Scene Viewing is Predicted by Motion

Where does one attend when viewing dynamic scenes? Research into the factors influencing gaze location during static scene viewing have reported that low-level visual features contribute very little to gaze location especially when opposed by high-level factors such as viewing task. However, the inclusion of transient features such as motion in dynamic scenes may result in a greater influence of visual features on gaze allocation and coordination of gaze across viewers. In the present study, we investigated the contribution of low- to mid-level visual features to gaze location during free-viewing of a large dataset of videos ranging in content and length. Signal detection analysis on visual features and Gaussian Mixture Models for clustering gaze was used to identify the contribution of visual features to gaze location. The results show that mid-level visual features including corners and orientations can distinguish between actual gaze locations and a randomly sampled baseline. However, temporal features such as flicker, motion, and their respective contrasts were the most predictive of gaze location. Additionally, moments in which all viewers’ gaze tightly clustered in the same location could be predicted by motion. Motion and mid-level visual features may influence gaze allocation in dynamic scenes, but it is currently unclear whether this influence is involuntary or due to correlations with higher order factors such as scene semantics.     

Atypical depression: current status and relevance to melancholia

OBJECTIVE: The Diagnostic and Statistical Manual, Fourth Edition (DSM-IV, 1994) included atypical features as an illness specifier for major depression and dysthymia. We asked whether subsequent literature supported its validity and addressed the relationship between depression with atypical features and melancholia. METHOD: Literature review focusing on studies addressing the validity of atypical depression, supplemented by the authors' previously unpublished data. RESULTS: Most studies support the discriminant validity of depression with atypical features relative to melancholia and depression having neither melancholic nor atypical features. However, studies addressing illness course suggest that criteria for depression with atypical features define a heterogeneous patient population. CONCLUSION: DSM-IV criteria for depression with atypical features define a valid, but heterogeneous disorder. Criteria including age of onset and chronicity may define a more homogeneous group that is distinct from both melancholia and other depressed patients.     

DSM melancholic features are unreliable predictors of ECT response: a CORE publication

OBJECTIVE: To determine the relationship between baseline melancholic features with outcomes in patients with major depressive disorder referred for electroconvulsive therapy (ECT). METHOD: In a multihospital (Consortium for Research in ECT) collaborative ECT study, SCID-1 interviews were obtained at study entry. Ratings of the 24-item Hamilton Rating Scale for Depression were obtained thrice weekly during the course of ECT, once during a subsequent treatment-free week, and periodically during 6-month continuation treatment with either bitemporal ECT or nortriptyline plus lithium (continuation pharmacotherapy). RESULTS: The evaluable sample was severely ill with a mean 24-item Hamilton Rating Scale for Depression score of 35.2 (+/-6.9). Of 489 patients, 63.6% (311) met DSM-IV criteria for melancholic features. During acute ECT, 62.1% of those with melancholic features remitted, as compared with 78.7% for those without melancholic features (P = 0.002). During medication continuation treatment (continuation pharmacotherapy), relapse rates were higher for those with melancholic features than for those without these features. Conversely, with continuation ECT, the rate of relapse was lower for those with, compared with those without, melancholic features. CONCLUSIONS: Ascertaining melancholic features by SCID-1 criteria does not identify depressed patients more likely to respond to ECT as had been anticipated from the literature. Melancholic features were associated with poorer treatment outcomes in acute ECT. Those with melancholic features were less likely to relapse with continuation ECT, but those with melancholic features were more likely to relapse with continuation pharmacotherapy. The limitations of the DSM-IV criteria for melancholia are discussed.     

Alexithymic features in relation to the dexamethasone suppression test in a Finnish population sample

Hypothesizing that a positive DST result could reflect an aberrant stress reaction in subjects with alexithymic features, the authors investigated the relationship between alexithymic features and DST results in 266 subjects from a Finnish adult population sample. Alexithymic features were assessed with the Beth Israel Questionnaire. The authors found a statistically significant association between observed alexithymic features and a positive DST result. This association could be seen after adjustment separately for age, social rank, marital status, and the occurrence of depression.     

An OSAHS evaluation method based on multi-features acoustic analysis of snoring sounds

Snoring is the most direct symptom of obstructive sleep apnea hypopnea syndrome (OSAHS) and implies a lot of information about OSAHS symptoms. This paper aimed to identify OSAHS patients by analyzing acoustic features derived from overnight snoring sounds. Mel-frequency cepstral coefficients, 800 Hz power ratio, spectral entropy and other 10 acoustic features were extracted from snores, and Top-6 features were selected from the extracted 10 acoustic features by a feature selection algorithm based on random forest, then 5 kinds of machine learning models were applied to validate the effectiveness of Top-6 features on identifying OSAHS patients. The results showed that when the classification performance and computing efficiency were taken into account, the combination of logistic regression model and Top-6 features performed best and could successfully distinguish OSAHS patients from simple snorers. The proposed method provides a higher accuracy for evaluating OSAHS with lower computational complexity. The method has great potential prospect for the development of a portable sleep snore monitoring device.     

Impaired olfaction and other prodromal features in the Parkinson At-Risk Syndrome Study

To test the association between impaired olfaction and other prodromal features of PD in the Parkinson At-Risk Syndrome Study. The onset of olfactory dysfunction in PD typically precedes motor features, suggesting that olfactory testing could be used as a screening test. A combined strategy that uses other prodromal nonmotor features, along with olfactory testing, may be more efficient than hyposmia alone for detecting the risk of PD. Individuals with no neurological diagnosis completed a mail survey, including the 40-item University of Pennsylvania Smell Identification Test, and questions on prodromal features of PD. The frequency of reported nonmotor features was compared across individuals with and without hyposmia. A total of 4,999 subjects completed and returned the survey and smell test. Of these, 669 were at or below the 15th percentile based on age and gender, indicating hyposmia. Hyposmics were significantly more likely to endorse nonmotor features, including anxiety and depression, constipation, and rapid eye movement sleep behavior disorder symptoms, and to report changes in motor function. Twenty-six percent of subjects with combinations of four or more nonmotor features were hyposmic, compared to 12% for those reporting three or fewer nonmotor features (P < 0.0001). Hyposmia is associated with other nonmotor features of PD in undiagnosed individuals. Further assessment of hyposmic subjects using more specific markers for degeneration, such as dopamine transporter imaging, will evaluate whether combining hyposmia and other nonmotor features is useful in assessing the risk of future neurodegeneration.     

Severe behaviour problems associated with rapid cycling bipolar disorder in two adults with profound mental retardation

ABSTRACT. The authors report the clinical histories of two adults with profound mental retardation, features of rapid cycling bipolar disorder, and periodic maladaptive behaviour. In each case, primary features of mania and depression were identified, operationaliy defined and measured with an ongoing data system, which was used to track SIB and aggression. In the first case, data analysis across days showed that 1-week episodes of depressive features alternated with 2-week episodes of manic features and that SIB was only associated with the depressive features. In the second case, episodes of manic and depressive features alternated every few days, and aggression was only associated with the manic features. These cases suggest that severe behaviour problems can be a state-dependent phenomenon of bipolar disorder. The behaviour monitoring system provided an objective methodology for aiding in the diagnosis of bipolar disorder with profoundly handicapped adults.     

The significance of psychotic affective disorders.

A study of 253 patients with primary and secondary affective disorders disclosed that psychotic features were more frequent among bipolar patients. Except for more frequent psychiatric hospitalization among unipolar patients with psychotic features, no demographic, family history, or parental home variable was found to distinguish between those with and without psychotic features. Chance variation probably accounted for the few symptoms whose frequencies were different depending on the presence or absence of psychotic features. The results failed to support the validity of a classification of affective disorders based on the presence or absence of psychotic features.     

Partial validation of the atypical features subtype of major depressive disorder.

BACKGROUND: Symptoms of the atypical features subtype of major depressive disorder include mood reactivity, hypersomnia, hyperphagia, leaden paralysis, and rejection sensitivity. This subtype was introduced into the mood disorders section of the DSM-IV following a series of antidepressant trials showing that such patients responded preferentially to monoamine oxidase inhibitors. Studies aimed at validating the atypical features subtype have yielded inconsistent results. Our study sought to reevaluate the validity of atypical depression by examining the demographic and clinical features of a large cohort of depressed patients who met DSM-IV criteria for atypical features. METHODS: We evaluated 579 psychiatric outpatients with a current diagnosis of major depressive disorder for the presence of atypical features. Detailed demographic and clinical information was obtained for each patient through semistructured interviews. Using the available literature, we made a series of a priori hypotheses regarding how depressed patients with atypical features (n = 130) would differ from those without atypical features (n = 449). In addition, we tested the strength of the associations between each of the 5 atypical symptoms. RESULTS: Although many of the predicted hypotheses were substantiated, an equal number were not. Correlation analyses revealed modest associations between several of the atypical symptoms, but mood reactivity was not associated with any of the other symptom criteria. CONCLUSION: Our results provide partial support for the validity of the atypical features subtype of major depressive disorder.     

A comparison of quantitative EEG features for neonatal seizure detection.

OBJECTIVE: This study was undertaken to identify the best performing quantitative EEG features for neonatal seizures detection from a test set of 21. METHODS: Each feature was evaluated on 1-min, artefact-free segments of seizure and non-seizure neonatal EEG recordings. The potential utility of each feature for neonatal seizure detection was determined using receiver operating characteristic analysis and repeated measures t-tests. A performance estimate of the feature set was obtained using a cross-fold validation and combining all features together into a linear discriminant classifier model. RESULTS: Significant differences between seizure and non-seizure segments were found in 19 features for 17 patients. The best performing features for this application were the RMS amplitude, the line length and the number of local maxima and minima. An estimate of the patient independent classifier performance yielded a sensitivity of 81.08% and specificity of 82.23%. CONCLUSIONS: The individual performances of 21 quantitative EEG features in detecting electrographic seizure in the neonate were compared and numerically quantified. Combining all features together into a classifier model led to superior performance than that provided by any individual feature taken alone. SIGNIFICANCE: The results documented in this study may provide a reference for the optimum quantitative EEG features to use in developing and enhancing neonatal seizure detection algorithms.     

Serum concentrations of CRP, IL-6, TNF-α and cortisol in major depressive disorder with melancholic or atypical features

The aim of the present study was to explore possible differences between serum C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and cortisol concentration in patients with major depressive disorder (MDD) with melancholic features, and MDD with atypical features. As secondary aim, we investigated possible associations with clinical features such as suicidal ideation, number of episodes, duration of depression and symptomatology severity. We included 55 MDD patients (32 with melancholic features and 23 with atypical features) and 18 healthy controls. When compared to healthy controls, MDD with melancholic or atypical features showed higher CRP and IL-6, but not TNF-α. Cortisol concentration was higher in MDD with melancholic type, in comparison to the atypical type of MDD or controls. A positive correlation was found between the severity of depressive symptoms, concentrations of IL-6 and cortisol in the MDD group with melancholic features, while a negative correlation was observed between IL-6 and CRP in the MDD group with atypical feature. Also, in the MDD group with atypical features, there was a correlation between the severity of anxiety symptoms based on the Hamilton Rating Scale for Anxiety (HARS), concentration of CRP, and the duration of symptoms. In conclusion, we observed several differences in serum CRP, IL-6, and cortisol concentrations in MDD patients considering clinical features as well.     

Dorsal hippocampus is necessary for visual categorization in rats

The hippocampus may play a role in categorization because of the need to differentiate stimulus categories (pattern separation) and to recognize category membership of stimuli from partial information (pattern completion). We hypothesized that the hippocampus would be more crucial for categorization of low‐density (few relevant features) stimuli–due to the higher demand on pattern separation and pattern completion–than for categorization of high‐density (many relevant features) stimuli. Using a touchscreen apparatus, rats were trained to categorize multiple abstract stimuli into two different categories. Each stimulus was a pentagonal configuration of five visual features; some of the visual features were relevant for defining the category whereas others were irrelevant. Two groups of rats were trained with either a high (dense, n = 8) or low (sparse, n = 8) number of category‐relevant features. Upon reaching criterion discrimination (≥75% correct, on 2 consecutive days), bilateral cannulas were implanted in the dorsal hippocampus. The rats were then given either vehicle or muscimol infusions into the hippocampus just prior to various testing sessions. They were tested with: the previously trained stimuli (trained), novel stimuli involving new irrelevant features (novel), stimuli involving relocated features (relocation), and a single relevant feature (singleton). In training, the dense group reached criterion faster than the sparse group, indicating that the sparse task was more difficult than the dense task. In testing, accuracy of both groups was equally high for trained and novel stimuli. However, both groups showed impaired accuracy in the relocation and singleton conditions, with a greater deficit in the sparse group. The testing data indicate that rats encode both the relevant features and the spatial locations of the features. Hippocampal inactivation impaired visual categorization regardless of the density of the category‐relevant features for the trained, novel, relocation, and singleton stimuli. Hippocampus‐mediated pattern completion and pattern separation mechanisms may be necessary for visual categorization involving overlapping irrelevant features.     

Aspects of non-native pronunciation in a case of altered accent following stroke (foreign accent syndrome)

Foreign accent syndrome (FAS) refers to a disorder that involves foreign sounding speech, usually following stroke. This paper presents a case study of an English patient allegedly speaking with a Scottish English accent after right-hemisphere stroke. The results of detailed impressionistic and acoustic analyses are reported, based on a direct comparison of the patient's pre-stroke and post-stroke speech samples. The emphasis is on a comparison of the typical features of Scottish English and phonetic features actually found in the patient's post-stroke speech. The respective roles of prosodic and segmental features in the post-stroke speech sample are also discussed. Rather untypically, prosodic features seem to be affected to a much lesser extent than segmental phonetic features in the patient's post-stroke speech. They are, therefore, less likely to contribute to the perception of a foreign accent.