scholarly journals Spatiotemporal Analysis of Category and Target-related Information Processing in the Brain during Object Detection

2018 ◽  
Author(s):  
Hamid Karimi-Rouzbahani ◽  
Ehsan Vahab ◽  
Reza Ebrahimpour ◽  
Mohammad Bagher Menhaj
Keyword(s):  
Object Detection ◽  
Stimulus Presentation ◽  
Occipital Cortex ◽  
Spatiotemporal Analysis ◽  
Target Object ◽  
External Information ◽  
Causality Analysis ◽  
Brain Areas ◽  
Related Information ◽  
The Brain

AbstractTo recognize a target object, the brain implements strategies which involve a combination of externally sensory-driven and internally task-driven mechanisms. While several studies have suggested a role for frontal brain areas in enhancing task-related representations in visual cortices, especially the lateral-occipital cortex, they remained silent about the type of information transferred to visual areas. However, the recently developed method of representational causality analysis, allowed us to track the movement of different types of information in the brain. Accordingly, we designed an EEG object detection experiment and evaluated the spatiotemporal dynamics of category- and target-related information across the brain using. Results showed that the prefrontal area initiated the processing of target-related information. This information was then transferred to posterior brain areas during stimulus presentation to facilitate object detection and to direct the decision-making procedure. We also observed that, as compared to category-related information, the target-related information could predict the behavioral detection performance more accurately, suggesting the dominant representation of internal compared to external information in brain signals. These results provided new evidence about the role of prefrontal cortices in the processing of task-related information the brain during object detection.

scholarly journals Spatiotemporal analysis of category and target-related information processing in the brain during object detection

2019 ◽  
Vol 362 ◽  
pp. 224-239 ◽  
Author(s):  
Hamid Karimi-Rouzbahani ◽  
Ehsan Vahab ◽  
Reza Ebrahimpour ◽  
Mohammad Bagher Menhaj
Keyword(s):  
Information Processing ◽  
Object Detection ◽  
Spatiotemporal Analysis ◽  
Related Information ◽  
The Brain

scholarly journals The different brain areas occupied for integrating information of hierarchical linguistic units: a study based on EEG and TMS

2021 ◽  
Author(s):  
Changfu Pei ◽  
Yuan Qiu ◽  
Fali Li ◽  
Xunan Huang ◽  
Yajing Si ◽  
...  
Keyword(s):  
Sentence Comprehension ◽  
Vital Role ◽  
Brain Areas ◽  
Visual Integration ◽  
Related Information ◽  
Neural Representations ◽  
Monosyllabic Words ◽  
Processing Information ◽  
Linguistic Units ◽  
The Brain

Human linguistic units are hierarchical, and our brain responds differently when processing linguistic units during sentence comprehension, especially when the modality of the received signal is different (auditory, visual, or audio-visual). However, it is unclear how the brain processes and integrates language information at different linguistic units (words, phrases, and sentences) provided simultaneously in audio and visual modalities. To address the issue, we presented participants with sequences of short Chinese sentences through auditory or visual or combined audio-visual modalities, while electroencephalographic responses were recorded. With a frequency tagging approach, we analyzed the neural representations of basic linguistic units (i.e., characters/monosyllabic words) and higher-level linguistic structures (i.e., phrases and sentences) across the three modalities separately. We found that audio-visual integration occurs at all linguistic units, and the brain areas involved in the integration varied across different linguistic levels. In particular, the integration of sentences activated the local left prefrontal area. Therefore, we used continuous theta-burst stimulation (cTBS) to verify that the left prefrontal cortex plays a vital role in the audio-visual integration of sentence information. Our findings suggest the advantage of bimodal language comprehension at hierarchical stages in language-related information processing and provide evidence for the causal role of the left prefrontal regions in processing information of audio-visual sentences.

Sensory evidence integration and action initiation occur in parallel during perceptual decisions

2020 ◽  
Author(s):  
Lluís Hernández-Navarro ◽  
Ainhoa Hermoso-Mendizabal ◽  
Daniel Duque ◽  
Alexandre Hyafil ◽  
Jaime de la Rocha
Keyword(s):  
Time Pressure ◽  
Reaction Times ◽  
Stimulus Presentation ◽  
Perceptual Decision Making ◽  
Evidence Accumulation ◽  
Action Preparation ◽  
Action Model ◽  
The Brain ◽  
Evidence Integration ◽  
Action Initiation

It is commonly assumed that, during perceptual decisions, the brain integrates stimulus evidence until reaching a decision, and then performs the response. There are conditions, however (e.g. time pressure), in which the initiation of the response must be prepared in anticipation of the stimulus presentation. It is therefore not clear when the timing and the choice of perceptual responses depend exclusively on evidence accumulation, or when preparatory motor signals may interfere with this process. Here, we find that, in a free reaction time auditory discrimination task in rats, the timing of fast responses does not depend on the stimulus, although the choices do, suggesting a decoupling of the mechanisms of action initiation and choice selection. This behavior is captured by a novel model, the Parallel Sensory Integration and Action Model (PSIAM), in which response execution is triggered whenever one of two processes, Action Initiation or Evidence Accumulation, reaches a bound, while choice category is always set by the latter. Based on this separation, the model accurately predicts the distribution of reaction times when the stimulus is omitted, advanced or delayed. Furthermore, we show that changes in Action Initiation mediates both post-error slowing and a gradual slowing of the responses within each session. Overall, these results extend the standard models of perceptual decision-making, and shed a new light on the interaction between action preparation and evidence accumulation.

Aetiologies and anatomy of confabulation

2017 ◽  
Author(s):  
Armin Schnider
Keyword(s):  
Brain Damage ◽  
Limbic Encephalitis ◽  
Artery Aneurysm ◽  
Anterior Communicating Artery ◽  
Brain Areas ◽  
Anatomical Basis ◽  
Korsakoff Syndrome ◽  
Hypoxic Brain ◽  
Degenerative Dementia ◽  
The Brain

What diseases cause confabulations and which are the brain areas whose damage is responsible? This chapter reviews the causes, both historic and present, of confabulations and deduces the anatomo-clinical relationships for the four forms of confabulation in the following disorders: alcoholic Korsakoff syndrome, traumatic brain injury, rupture of an anterior communicating artery aneurysm, posterior circulation stroke, herpes and limbic encephalitis, hypoxic brain damage, degenerative dementia, tumours, schizophrenia, and syphilis. Overall, clinically relevant confabulation is rare. Some aetiologies have become more important over time, others have virtually disappeared. While confabulations seem to be more frequent after anterior brain damage, only one form has a distinct anatomical basis.

scholarly journals The brain dynamics of architectural affordances during transition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zakaria Djebbara ◽  
Lars Brorson Fich ◽  
Klaus Gramann
Keyword(s):  
Occipital Cortex ◽  
The Body ◽  
Brain Dynamics ◽  
Alpha Band ◽  
Time Frequency ◽  
Posterior Cingulate ◽  
Sensory Signals ◽  
Event Related Desynchronization ◽  
The Brain ◽  
Attentional Mechanisms

AbstractAction is a medium of collecting sensory information about the environment, which in turn is shaped by architectural affordances. Affordances characterize the fit between the physical structure of the body and capacities for movement and interaction with the environment, thus relying on sensorimotor processes associated with exploring the surroundings. Central to sensorimotor brain dynamics, the attentional mechanisms directing the gating function of sensory signals share neuronal resources with motor-related processes necessary to inferring the external causes of sensory signals. Such a predictive coding approach suggests that sensorimotor dynamics are sensitive to architectural affordances that support or suppress specific kinds of actions for an individual. However, how architectural affordances relate to the attentional mechanisms underlying the gating function for sensory signals remains unknown. Here we demonstrate that event-related desynchronization of alpha-band oscillations in parieto-occipital and medio-temporal regions covary with the architectural affordances. Source-level time–frequency analysis of data recorded in a motor-priming Mobile Brain/Body Imaging experiment revealed strong event-related desynchronization of the alpha band to originate from the posterior cingulate complex, the parahippocampal region as well as the occipital cortex. Our results firstly contribute to the understanding of how the brain resolves architectural affordances relevant to behaviour. Second, our results indicate that the alpha-band originating from the occipital cortex and parahippocampal region covaries with the architectural affordances before participants interact with the environment, whereas during the interaction, the posterior cingulate cortex and motor areas dynamically reflect the affordable behaviour. We conclude that the sensorimotor dynamics reflect behaviour-relevant features in the designed environment.

scholarly journals Limbic Expression of mRNA Coding for Chemoreceptors in Human Brain—Lessons from Brain Atlases

2021 ◽  
Vol 22 (13) ◽  
pp. 6858
Author(s):  
Fanny Gaudel ◽  
Gaëlle Guiraudie-Capraz ◽  
François Féron
Keyword(s):  
G Proteins ◽  
The Body ◽  
Trace Amines ◽  
Chemical Senses ◽  
Brain Areas ◽  
Genes Encoding ◽  
The Central Nervous System ◽  
Human Brains ◽  
The Brain ◽  
Brain Atlases

Animals strongly rely on chemical senses to uncover the outside world and adjust their behaviour. Chemical signals are perceived by facial sensitive chemosensors that can be clustered into three families, namely the gustatory (TASR), olfactory (OR, TAAR) and pheromonal (VNR, FPR) receptors. Over recent decades, chemoreceptors were identified in non-facial parts of the body, including the brain. In order to map chemoreceptors within the encephalon, we performed a study based on four brain atlases. The transcript expression of selected members of the three chemoreceptor families and their canonical partners was analysed in major areas of healthy and demented human brains. Genes encoding all studied chemoreceptors are transcribed in the central nervous system, particularly in the limbic system. RNA of their canonical transduction partners (G proteins, ion channels) are also observed in all studied brain areas, reinforcing the suggestion that cerebral chemoreceptors are functional. In addition, we noticed that: (i) bitterness-associated receptors display an enriched expression, (ii) the brain is equipped to sense trace amines and pheromonal cues and (iii) chemoreceptor RNA expression varies with age, but not dementia or brain trauma. Extensive studies are now required to further understand how the brain makes sense of endogenous chemicals.

scholarly journals Potential for imaging the high-affinity state of the 5-HT1B receptor: a comparison of three PET radioligands with differing intrinsic activity

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anton Lindberg ◽  
Ryosuke Arakawa ◽  
Tsuyoshi Nogami ◽  
Sangram Nag ◽  
Magnus Schou ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Specific Binding ◽  
Occipital Cortex ◽  
Intrinsic Activity ◽  
High Affinity ◽  
G Protein Coupled ◽  
Dose Dependent ◽  
The Brain ◽  
Agonist Affinity States ◽  
Different Doses

Abstract Background Over the last decade, a few radioligands have been developed for PET imaging of brain 5-HT1B receptors. The 5-HT1B receptor is a G-protein-coupled receptor (GPCR) that exists in two different agonist affinity states. An agonist ligand is expected to be more sensitive towards competition from another agonist, such as endogenous 5-HT, than an antagonist ligand. It is of interest to know whether the intrinsic activity of a PET radioligand for the 5-HT1B receptor impacts on its ability to detect changes in endogenous synaptic 5-HT density. Three high-affinity 11C-labeled 5-HT1B PET radioligands with differing intrinsic activity were applied to PET measurements in cynomolgus monkey to evaluate their sensitivity to be displaced within the brain by endogenous 5-HT. For these experiments, fenfluramine was pre-administered at two different doses (1.0 and 5.0 mg/kg, i.v.) to induce synaptic 5-HT release. Results A dose-dependent response to fenfluramine was detected for all three radioligands. At the highest dose of fenfluramine (5.0 mg/kg, i.v.), reductions in specific binding in the occipital cortex increased with radioligand agonist efficacy, reaching 61% for [11C]3. The most antagonistic radioligand showed the lowest reduction in specific binding. Conclusions Three 5-HT1B PET radioligands were identified with differing intrinsic activity that could be used in imaging high- and low-affinity states of 5-HT1B receptors using PET. From this limited study, radioligand sensitivity to endogenous 5-HT appears to depend on agonist efficacy. More extensive studies are required to substantiate this suggestion.

scholarly journals Initiators of Classical and Lectin Complement Pathways Are Differently Engaged after Traumatic Brain Injury—Time-Dependent Changes in the Cortex, Striatum, Thalamus and Hippocampus in a Mouse Model

2020 ◽  
Vol 22 (1) ◽  
pp. 45
Author(s):  
Agata Ciechanowska ◽  
Katarzyna Ciapała ◽  
Katarzyna Pawlik ◽  
Marco Oggioni ◽  
Domenico Mercurio ◽  
...  
Keyword(s):  
Brain Injury ◽  
Microglial Cell ◽  
Lectin Pathway ◽  
Brain Areas ◽  
Mannose Binding ◽  
Primary Microglial Cell ◽  
Cellular Markers ◽  
The Brain ◽  
Binding Lectin ◽  
Complement Pathways

The complement system is involved in promoting secondary injury after traumatic brain injury (TBI), but the roles of the classical and lectin pathways leading to complement activation need to be clarified. To this end, we aimed to determine the ability of the brain to activate the synthesis of classical and lectin pathway initiators in response to TBI and to examine their expression in primary microglial cell cultures. We have modeled TBI in mice by controlled cortical impact (CCI), a clinically relevant experimental model. Using Real-time quantitative polymerase chain reaction (RT-qPCR) we analyzed the expression of initiators of classical the complement component 1q, 1r and 1s (C1q, C1r, and C1s) and lectin (mannose binding lectin A, mannose binding lectin C, collectin 11, ficolin A, and ficolin B) complement pathways and other cellular markers in four brain areas (cortex, striatum, thalamus and hippocampus) of mice exposed to CCI from 24 h and up to 5 weeks. In all murine ipsilateral brain structures assessed, we detected long-lasting, time- and area-dependent significant increases in the mRNA levels of all classical (C1q, C1s, C1r) and some lectin (collectin 11, ficolin A, ficolin B) initiator molecules after TBI. In parallel, we observed significantly enhanced expression of cellular markers for neutrophils (Cd177), T cells (Cd8), astrocytes (glial fibrillary acidic protein—GFAP), microglia/macrophages (allograft inflammatory factor 1—IBA-1), and microglia (transmembrane protein 119—TMEM119); moreover, we detected astrocytes (GFAP) and microglia/macrophages (IBA-1) protein level strong upregulation in all analyzed brain areas. Further, the results obtained in primary microglial cell cultures suggested that these cells may be largely responsible for the biosynthesis of classical pathway initiators. However, microglia are unlikely to be responsible for the production of the lectin pathway initiators. Immunofluorescence analysis confirmed that at the site of brain injury, the C1q is localized in microglia/macrophages and neurons but not in astroglial cells. In sum, the brain strongly reacts to TBI by activating the local synthesis of classical and lectin complement pathway activators. Thus, the brain responds to TBI with a strong, widespread and persistent upregulation of complement components, the targeting of which may provide protection in TBI.

Comparing the brain areas supporting nondeclarative categorization and recognition memory

2002 ◽  
Vol 14 (2) ◽  
pp. 245-257 ◽  
Author(s):  
Paul J Reber ◽  
Eric C Wong ◽  
Richard B Buxton
Keyword(s):  
Recognition Memory ◽  
Brain Areas ◽  
The Brain

Cannabidiol Has a Unique Effect on Global Brain Activity: A Pharmacological, Functional MRI Study in Awake Mice 

2021 ◽  
Author(s):  
Aymen Sadaka ◽  
Ana Ozuna ◽  
Richard Ortiz ◽  
Praveen Kulkarni ◽  
Clare Johnson ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Brain Activity ◽  
Stress Disorders ◽  
Functional Coupling ◽  
Specific Information ◽  
Imaging Data ◽  
Post Traumatic Stress ◽  
Brain Areas ◽  
Dose Dependent ◽  
The Brain

Abstract Background: The phytocannabinoid cannabidiol (CBD) is a potential treatment for post-traumatic stress disorders. How does CBD interact with the brain to alter behavior? We hypothesized that CBD would produce a dose-dependent reduction in brain activity and functional coupling in neural circuitry associated with fear and defense. Methods: During the scanning session awake mice were given vehicle or CBD (3, 10, or 30 mg/kg I.P.) and imaged for 10 min post treatment. Mice were also treated with the 10 mg/kg dose of CBD and imaged one hr later for resting state BOLD functional connectivity (rsFC). Imaging data were registered to a 3D MRI mouse atlas providing site-specific information on 138 different brain areas. Blood samples were collected for CBD measurements.Results: CBD produced a dose-dependent polarization of activation along the rostral-caudal axis of the brain. The olfactory bulb and prefrontal cortex showed an increase in positive BOLD whereas the brainstem and cerebellum showed a decrease in BOLD signal. This negative BOLD affected many areas connected to the ascending reticular activating system (ARAS). The ARAS was decoupled to much of the brain but was hyperconnected to the olfactory system and prefrontal cortex. The pattern of ARAS connectivity closely overlapped with brain areas showing high levels N-acyl-phosphatidylethanolamines-specific phospholipase D (NAPE-PLD) messenger RNA.Conclusion: The CBD-induced decrease in ARAS activity is consistent with an emerging literature suggesting that CBD reduces autonomic arousal under conditions of emotional and physical stress. The putative target and mechanism of action is NAPE-PLD the enzyme responsible for the biosynthesis of lipid signaling molecules like anandamide.

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