Layer 6 ensembles can selectively regulate the behavioral impact and layer-specific representation of sensory deviants

Predictive models can enhance the salience of unanticipated input. Here, we tested a key potential node in neocortical model formation in this process, layer (L) 6, using behavioral, electrophysiological and imaging methods in mouse primary somatosensory neocortex. We found that deviant stimuli enhanced tactile detection and were encoded in L2/3 neural tuning. To test the contribution of L6, we applied weak optogenetic drive that changed which L6 neurons were sensory responsive, without affecting overall firing rates in L6 or L2/3. This stimulation selectively suppressed behavioral sensitivity to deviant stimuli, without impacting baseline performance. This stimulation also eliminated deviance encoding in L2/3 but did not impair basic stimulus responses across layers. In contrast, stronger L6 drive inhibited firing and suppressed overall sensory function. These findings indicate that, despite their sparse activity, specific ensembles of stimulus driven L6 neurons are required to form neocortical predictions, and to realize their behavioral benefit.

Can Signal Delay be Functional? Including Delay in Evolved Robot Controllers

Engineers, control theorists, and neuroscientists often view the delay imposed by finite signal propagation velocities as a problem that needs to be compensated for or avoided. In this article, we consider the alternative possibility that in some cases, signal delay can be used functionally, that is, as an essential component of a cognitive system. To investigate this idea, we evolve a minimal robot controller to solve a basic stimulus-distinction task. The controller is constrained so that the solution must utilize a delayed recurrent signal. Different from previous evolutionary robotics studies, our controller is modeled using delay differential equations, which (unlike the ordinary differential equations of conventional continuous-time recurrent neural networks) can accurately capture delays in signal propagation. We analyze the evolved controller and its interaction with its environment using classical dynamical systems techniques. The analysis shows what kinds of invariant sets underlie the various successful and unsuccessful performances of the robot, and what kinds of bifurcations produce these invariant sets. In the second phase of our analysis, we turn our attention to the parameter θ, which describes the amount of signal delay included in the model. We show how the delay destabilizes certain attractors that would exist if there were no delay and creates other stable attractors, resulting in an agent that performs well at the target task.

Studying Human Habits in Societal Context: Examining Support for a Basic Stimulus–Response Mechanism

Human habits are considered to be an important root of societal problems. The significance of habits has been demonstrated for a variety of behaviors in different domains, such as work, transportation, health, and ecology, suggesting that habits have a pervasive impact on human life. Studying and changing habits in societal context requires a broad view of behavior, which poses a challenge for applying basic models to complex human habits. We address the conceptualization and operationalization of habits in the current literature and note that claims about the role of habits in societal context rarely agree with the basic definition of habits as goal-independent behavior. We consider future directions that are important for making progress in the study of habit change in societal context.

The Effects of Blur and Inversion on the Recognition of Ambient Face Images

When viewing unfamiliar faces that vary in expressions, angles, and image quality, observers make many recognition errors. Specifically, in unconstrained identity-sorting tasks, observers struggle to cope with variation across different images of the same person while succeeding at telling different people apart. The use of ambient face images in this simple card-sorting task reveals the magnitude of these face recognition errors and suggests a useful platform to reexamine the nature of face processing using naturalistic stimuli. In the present study, we chose to investigate the impact of two basic stimulus manipulations (image blur and face inversion) on identity sorting with ambient images. Although these manipulations are both known to affect face processing when well-controlled, frontally viewed face images are used, examining how they affect performance for ambient images is an important step toward linking the large body of research using controlled face images to more ecologically valid viewing conditions. Briefly, we observed a high cost of image blur regardless of blur magnitude, and a strong inversion effect that affected observers’ sensitivity to extrapersonal variability but did not affect the number of unique identities they estimated were present in the set of images presented to them.

The effects of blur and inversion on the recognition of ambient face images

When viewing unfamiliar faces that vary in expressions, angles, and image quality, observers make many recognition errors (Jenkins et al., 2011). Specifically, in unconstrained identity-sorting tasks, observers struggle to cope with variation across different images of the same person while succeeding at telling different people apart. The use of ambient face images in this simple card sorting task reveals the magnitude of these face recognition errors, and suggests a useful platform to re-examine the nature of face processing using naturalistic stimuli. In the present study, we chose to investigate the impact of two basic stimulus manipulations (image blur and face inversion) on identity sorting with ambient images. Though these manipulations are both known to affect face processing when well-controlled, frontally viewed face images are used, examining how they affect performance for ambient images is an important step towards linking the large body of research using controlled face images to more ecologically valid viewing conditions. Briefly, we observed a high cost of image blur regardless of blur magnitude, and a strong inversion effect that affected observers’ sensitivity to extra-personal variability but did not affect the number of unique identities they estimated were present in the set of images presented to them.

Implicit Attitudes and the Architecture of the Mind

This chapter argues that the co-activating FTBA components of spontaneous inclinations make up a unified and sui generis mental kind, namely, an implicit attitude. After making some clarifying remarks about terminology, I begin by ruling out more mundane possibilities. First, I argue that implicit attitudes are not basic stimulus-response reflexes. Nor are they mere mental associations that are explainable in terms of the laws of spatiotemporal contiguity. Neither are they best understood as beliefs or as traits. While they are closest to what Gendler calls “aliefs,” implicit attitudes are distinct from these as well. The chapter concludes with considerations that favor interpreting implicit attitudes as a unified mental kind.

Decoding the orientation of contrast edges from MEG evoked and induced responses

1AbstractVisual gamma oscillations have been proposed to subserve perceptual binding, but their strong modulation by diverse stimulus features confounds interpretations of their precise functional role. Overcoming this challenge necessitates a comprehensive account of the relationship between gamma responses and stimulus features. Here we used multivariate pattern analyses on human MEG data to characterize the relationships between gamma responses and one basic stimulus feature, the orientation of contrast edges. Our findings confirmed we could decode orientation information from induced responses in two dominant frequency bands at 24-32 Hz and 50-58 Hz. Decoding was higher for cardinal than oblique orientations, with similar results also obtained for evoked MEG responses. In contrast to multivariate analyses, orientation information was mostly absent in univariate signals: evoked and induced responses in early visual cortex were similar in all orientations, with only exception an inverse oblique effect observed in induced responses, such that cardinal orientations produced weaker oscillatory signals than oblique orientations. Taken together, our results showed multivariate methods are well suited for the analysis of gamma oscillations, with multivariate patterns robustly encoding orientation information and predominantly discriminating cardinal from oblique stimuli.

Influence Of The Number Of Platelets And Hemoglobin Concentrations In Predicting The Development Of Proteinuria Induced By The Administration Of Bevacizumab

Bevacizumab neutralizes a key stimulation factor in tumour angiogenesis - vascular endothelial growth factor (VEGF). The origin of VEGF is related to platelets, and the basic stimulus for its production is hypoxia. By neutralizing VEGF, changes occur in the blood that are manifested at the platelet and haemoglobin levels. Study results indicate that proteinuria is a side effect of bevacizumab treatment. The aim of the present study was to examine the percentages of proteinuria in patients with metastatic colorectal cancer after the administration of bevacizumab. The correlation between the degree of proteinuria and changes in the number of platelets and concentration of haemoglobin in patients, as well as in relation to the age (< 60 i ≥ 60) and gender of the patients, was examined. The study group of respondents included 20 patients with metastatic colorectal cancer (9 men and 11 women) ranging in age from 43 to 73 years. Proteinuria was tested using “Laboquick” test strips. The levels of platelets and haemoglobin were measured using an autoanalyser, the type Cell Dyn 3700 – Abbott, according to the protocol prescribed by The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). Statistically significant differences were recorded for the platelet measurements before and after therapy in the overall group of respondents (p= 0.025). Statistically significant decreases in platelet counts and increases in haemoglobin concentrations were also noted in women (Plt: p=0.0036; Hb: p=0.0286) and in patients < 60 years old (Plt: p=0.0270; Hb: p=0.0553). No significant differences were identified in men or in patients ≥ 60 years of age. Proteinuria was detected in one case in which demonstrating an increase in only the recorded number of platelets and a decrease in the level of haemoglobin. Platelets and haemoglobin may serve as prognostic biomarkers of the risk of proteinuria. Based on the initial values of these parameters, we can predict the target group, in terms of gender and age, that may obtain the most benefit from bevacizumab therapy.