Perception Of Sensory Signals Research Articles

Spécificités intéroceptives chez les enfants et adolescents qui présentent un trouble à symptomatologie somatique : étude descriptive sur dix-neuf patients

IntroductionDespite the high rate of somatic symptom disorder (TSS) in the pediatric population, etiological mechanisms remain poorly understood. Previous studies conducted in youths with anxiety, eating disorder, or autistic disorder support a relation between difficulties in the perception of sensory signals (i.e., interoception) and difficulties in identifying emotions. MethodA cross-sectional study was carried out at the University Hospital of Amiens-Picardie in 19 young people aged 9 to 17 hospitalized in the pediatric ward for TSS. A mental heartbeat tracking task was used to assess interoceptive accuracy, awareness and sensibility. The Porges Body Perception Questionnaire (PBPQ) was used to assess interoceptive attention. Other questionnaires were used to assess associated clinical dimensions such as depression, anxiety, emotional dysregulation and alexithymia. ResultsThe mean interoceptive accuracy score was lower in TSS subjects compared to expected scores in the general population (33% error vs. 20%). A statistically significant correlation was found between, on the one hand, interoceptive sensibility and the “avoidance” subscore of the ECAP (r=0.51) and, on the other hand, between interoceptive awareness and the total score of the Child Depression Inventory (r=0.51). A significant relationship was found between the PBPQ scale total score and the Children-Toronto Alexithymia Scale total score (r=0.42), in particular with the “difficulty expressing emotions” subscore (r=0.62). ConclusionThis study confirms that interoceptive difficulties occur in young patients with severe TSS. Our finding adds empirical evidence supporting the relations between interoceptive difficulties, alexithymia and somatic symptoms in children and adolescents.

Oscillatory Activity and Cross-Frequency Interactions in the Hippocampus and Connected Brain Structures during Sensory Information Processing

It has been suggested that oscillations, or rhythms, are required for the execution of many cognitive functions, as they support rapid and flexible interactions between neurons in different brain structures [Livanov, 1977; Fries, 2005; Womelsdorf et al., 2007]. Until recently, little attention was focused on the question of how different types of oscillations are synchronized during the processing of information arriving in the brain. We report here an analysis of the extent and correlations of rhythmic activity in the θ, α, and γ ranges in animals in two behavioral states: during calm consciousness and during the perception of sensory signals. Local field potentials (LFP) were recorded in eight brain structures (cortical and subcortical). Many areas showed increases in oscillatory activity in different frequency bands on delivery of sensory stimuli. The main result of this study was a sharp increase in the cross-frequency interactions of all rhythms in both cortical and subcortical structures during sensory information processing. We suggest that the increase in interfrequency interactions between different rhythms in different parts of the brain is required for detailed assessment of environmental signals and their registration in the memory system.

Context Dependent Encoding Using Convolutional Dynamic Networks.

Perception of sensory signals is strongly influenced by their context, both in space and time. In this paper, we propose a novel hierarchical model, called convolutional dynamic networks, that effectively utilizes this contextual information, while inferring the representations of the visual inputs. We build this model based on a predictive coding framework and use the idea of empirical priors to incorporate recurrent and top-down connections. These connections endow the model with contextual information coming from temporal as well as abstract knowledge from higher layers. To perform inference efficiently in this hierarchical model, we rely on a novel scheme based on a smoothing proximal gradient method. When trained on unlabeled video sequences, the model learns a hierarchy of stable attractors, representing low-level to high-level parts of the objects. We demonstrate that the model effectively utilizes contextual information to produce robust and stable representations for object recognition in video sequences, even in case of highly corrupted inputs.

Brain processes during the perception of sensory signals in men with high and low output α-frequencies.

Human functional capabilities largely depend upon genetic qualities of person's nervous system. The registration of the spontaneous electroencephalogram (EEG) is among the physiological technigues allowing making a direct estimation of specific features of the nervous system, in particular, the human brain activity. The study is devoted to the investigation of brain processes in men with high and low levels of individual α-frequency determined in a quiescent state during the perception of sensory signals. A test group consisting of 104 right-hand healthy men from the ages of 19 to 21 was divided into two groups according to the magnitude of their individual α- frequency (IAF) median - groups with high (n = 53, IA ≥ 10,04 Hz) and low (n = 51, IAF≤10,03 Hz) levels of IAF. The power and coherence of the electrical activity of the cerebral cortex as well as inter group differences were evaluated in a quiescent state and during the perception of sensory signals by Subjects. A localized power increase of the EEG α1-waves are registered in frontal areas, β1, β2- oscillations - in the anterior cortex, γ- activity - around the scalp and its decrease is present in the posterior temporal, parietal and occipital cortex leads, especially in the α- and β- frequency spectrum during the perception of sensory signals in men with a high IAF. The generalized depression of the θ-, α- and β- activity of the cortex is fixed in individuals with a low IAF while the expression of γ- waves is more local. The generalized increase of data in EEG coherence fluctuations throughout the frequency spectrum of the EEG in the cortex is set in all Subjects. The dextrocerebral preponderance is observable in posterior structures of the Subjects' right hemisphere. A localized decrease of the coherence concerning θ-, α1-, α3-, β- and γ- oscillations are traced in the frontal and anterior temporal areas of the left hemisphere. We are of the opinion that the establishment of such common factors in the studied groups is an important step towards the release of the clear prognostic criteria for the functionality of men in the sensory area according to the congenital features of brain function.

Inhibition Mediates Top-Down Control of Sensory Processing

In this issue of Neuron, Hamilton et al. (2013) stimulate identified inhibitory interneurons with optogenetics, revealing powerful control of the flow of sensory responses across cortical layers. During natural behavior, these influences may mediate the rapid adaptive abilities necessary for detection and perception of sensory signals in noisy environments.