Tactile Speed Scaling: Contributions of Time and Space

2008 ◽  
Vol 99 (3) ◽  
pp. 1422-1434 ◽  
Author(s):  
Alexandra Dépeault ◽  
El-Mehdi Meftah ◽  
C. Elaine Chapman
Keyword(s):  
Cortical Neurons ◽  
Temporal Frequency ◽  
Critical Role ◽  
Critical Factor ◽  
Scanning Speed ◽  
Spatial Period ◽  
Textured Surfaces ◽  
Stimulus Motion ◽  
Tactile Stimuli ◽  
Speed Perception

A major challenge for the brain is to extract precise information about the attributes of tactile stimuli from signals that co-vary with multiple parameters, e.g., speed and texture in the case of scanning movements. We determined the ability of humans to estimate the tangential speed of surfaces moved under the stationary fingertip and the extent to which the physical characteristics of the surfaces modify speed perception. Scanning speed ranged from 33 to 110 mm/s (duration of motion constant). Subjects could scale tactile scanning speed, but surface structure was essential because the subjects were poor at scaling the speed of a moving smooth surface. For textured surfaces, subjective magnitude estimates increased linearly across the range of speeds tested. The spatial characteristics of the surfaces influenced speed perception, with the roughest surface (8 mm spatial period, SP) being perceived as moving 15% slower than the smoother, textured surfaces (2–3 mm SP). Neither dot disposition (periodic, non periodic) nor dot density contributed to the results, suggesting that the critical factor was dot spacing in the direction of the scan. A single monotonic relation between subjective speed and temporal frequency (speed/SP) was obtained when the ratings were normalized for SP. This provides clear predictions for identifying those cortical neurons that play a critical role in tactile motion perception and the underlying neuronal code. Finally, the results were consistent with observations in the visual system (decreased subjective speed with a decrease in spatial frequency, 1/SP), suggesting that stimulus motion is processed similarly in both sensory systems.

scholarly journals When brain damage “improves” perception: neglect patients can localize motion-shifted probes better than controls

2015 ◽  
Vol 114 (6) ◽  
pp. 3351-3358 ◽  
Author(s):  
Stefania de Vito ◽  
Marine Lunven ◽  
Clémence Bourlon ◽  
Christophe Duret ◽  
Patrick Cavanagh ◽  
...  
Keyword(s):  
Right Hemisphere ◽  
Visual Fields ◽  
Critical Factor ◽  
Significant Shift ◽  
Stimulus Motion ◽  
Attentional Processes ◽  
Position Shift ◽  
The Right ◽  
High Level ◽  
Better Than

When we look at bars flashed against a moving background, we see them displaced in the direction of the upcoming motion (flash-grab illusion). It is still debated whether these motion-induced position shifts are low-level, reflexive consequences of stimulus motion or high-level compensation engaged only when the stimulus is tracked with attention. To investigate whether attention is a causal factor for this striking illusory position shift, we evaluated the flash-grab illusion in six patients with damaged attentional networks in the right hemisphere and signs of left visual neglect and six age-matched controls. With stimuli in the top, right, and bottom visual fields, neglect patients experienced the same amount of illusion as controls. However, patients showed no significant shift when the test was presented in their left hemifield, despite having equally precise judgments. Thus, paradoxically, neglect patients perceived the position of the flash more veridically in their neglected hemifield. These results suggest that impaired attentional processes can reduce the interaction between a moving background and a superimposed stationary flash, and indicate that attention is a critical factor in generating the illusory motion-induced shifts of location.

Juggling on the line

2015 ◽  
Vol 37 (4) ◽  
pp. 459-474 ◽  
Author(s):  
Samantha Evans
Keyword(s):  
Critical Role ◽  
Case Study Research ◽  
Critical Factor ◽  
Employee Relations ◽  
Front Line ◽  
Structured Interviews ◽  
Line Managers ◽  
Content Type ◽  
Nuanced Understanding ◽  
High Level

Purpose – The purpose of this paper is to examine the interplay between the role of front line managers (FLMs) and their contribution to the reported gap between intended and actual human resource management (HRM). Design/methodology/approach – The findings draw on case study research using 51 semi-structured interviews with managers across two UK retail organisations between 2012 and 2013. Findings – This paper argues that FLMs are key agents in people management and play a critical role in the gap between intended and actual employee relations (ER) and HRM. The research found that these managers held a high level of responsibility for people management, but experienced a lack of institutional support, monitoring or incentives to implement according to central policy. This provided an opportunity for them to modify or resist intended policy and the tensions inherent in their role were a critical factor in this manipulation of their people management responsibilities. Research limitations/implications – The data were collected from only one industry and two organisations so the conclusions need to be considered within these limitations. Practical implications – Efforts to address the gap between intended and actual ER/HRM within organisations will need to consider the role tensions of both front line and middle managers. Originality/value – This research provides a more nuanced understanding of the interplay between FLMs and the gap between intended and actual HRM within organisations. It addresses the issue of FLMs receiving less attention in the HRM-line management literature and the call to research their role in the translation of policy into practice.

scholarly journals PSYCHOGEOGRAPHICAL EXPERIENCE BETWEEN THE SELF AND THE PLACE

2022 ◽  
Vol 7 (1) ◽  
pp. 243-263
Author(s):  
Mohd Fadhli Shah Khaidzir ◽  
Ruzy Suliza Hashim ◽  
Noraini Md. Yusof
Keyword(s):  
Critical Role ◽  
Critical Factor ◽  
The Self ◽  
Future Research ◽  
Future Studies ◽  
Place Meaning ◽  
Solid Foundation ◽  
Self Discovery ◽  
Attachment Place

Background and Purpose: The absence of psychogeographical awareness is a critical factor contributing to the lackadaisical attitudes towards the place and its environment. As a result, it enables an individual to fully experience a location, both physically and intellectually, while also gaining a feeling of self-discovery and self-realisation.   Methodology: The purpose of this study was to examine the responses of a group of individuals who participated in a field observation. 40 participants from a Malaysian university's foundation level were brought to Malacca to experience the environment's geographical scenery at their own leisure. The survey data was then manually transcribed and analysed in accordance with the study's aim.   Findings: Interactions with individuals and observation of features in the countryside and urban surroundings enabled participants to go on a psychogeographical journey that influenced their way of thinking and behaving. All participants felt that the journey had influenced their experiences and perspectives on their thinking and behaviour, highlighting the critical role of this notion in establishing the connection between place and self.   Contributions:  The findings of this study provide a solid foundation for future research in the field of psychogeography. The data may be used as a baseline for future studies to determine whether a comparable impact exists in other locations, with or without significant features like those found in Malacca.   Keywords: Psychogeography, place attachment, place meaning, self-discovery, Malacca.   Cite as: Khaidzir, M. F. S., Hashim, R. S., & Md. Yusof, N. (2022). Psychogeographical experience between the self and the place.  Journal of Nusantara Studies, 7(1), 243-263. http://dx.doi.org/10.24200/jonus.vol7iss1pp243-263

scholarly journals Dopamine receptors mediate strategy abandoning via modulation of a specific prelimbic cortex–nucleus accumbens pathway in mice

2018 ◽  
Vol 115 (21) ◽  
pp. E4890-E4899 ◽  
Author(s):  
Qiaoling Cui ◽  
Qian Li ◽  
Hongyan Geng ◽  
Lei Chen ◽  
Nancy Y. Ip ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Dopamine Receptors ◽  
Cortical Neurons ◽  
Critical Role ◽  
D2 Receptor ◽  
Receptor Activation ◽  
Prelimbic Cortex ◽  
Dopamine Depletion ◽  
Dopaminergic Tone ◽  
Type Receptor

The ability to abandon old strategies and adopt new ones is essential for survival in a constantly changing environment. While previous studies suggest the importance of the prefrontal cortex and some subcortical areas in the generation of strategy-switching flexibility, the fine neural circuitry and receptor mechanisms involved are not fully understood. In this study, we showed that optogenetic excitation and inhibition of the prelimbic cortex–nucleus accumbens (NAc) pathway in the mouse respectively enhances and suppresses strategy-switching ability in a cross-modal spatial-egocentric task. This ability is dependent on an intact dopaminergic tone in the NAc, as local dopamine denervation impaired the performance of the animal in the switching of tasks. In addition, based on a brain-slice preparation obtained from Drd2-EGFP BAC transgenic mice, we demonstrated direct innervation of D2 receptor-expressing medium spiny neurons (D2-MSNs) in the NAc by prelimbic cortical neurons, which is under the regulation by presynaptic dopamine receptors. While presynaptic D1-type receptor activation enhances the glutamatergic transmission from the prelimbic cortex to D2-MSNs, D2-type receptor activation suppresses this synaptic connection. Furthermore, manipulation of this pathway by optogenetic activation or administration of a D1-type agonist or a D2-type antagonist could restore impaired task-switching flexibility in mice with local NAc dopamine depletion; this restoration is consistent with the effects of knocking down the expression of specific dopamine receptors in the pathway. Our results point to a critical role of a specific prelimbic cortex–NAc subpathway in mediating strategy abandoning, allowing the switching from one strategy to another in problem solving.

scholarly journals Emergence of an invariant representation of texture in primate somatosensory cortex

2019 ◽  
Author(s):  
Justin D. Lieber ◽  
Sliman J. Bensmaia
Keyword(s):  
Cortical Neurons ◽  
Rhesus Macaques ◽  
Scanning Speed ◽  
Nerve Fibers ◽  
Invariant Representation ◽  
Major Function ◽  
Neural Representations ◽  
Wide Range ◽  
Sensory Modalities ◽  
Exploratory Movements

ABSTRACTA major function of sensory processing is to achieve neural representations of objects that are stable across changes in context and perspective. Small changes in exploratory behavior can lead to large changes in signals at the sensory periphery, thus resulting in ambiguous neural representations of objects. Overcoming this ambiguity is a hallmark of human object recognition across sensory modalities. Here, we investigate how the perception of tactile texture remains stable across exploratory movements of the hand, including changes in scanning speed, despite the concomitant changes in afferent responses. To this end, we scanned a wide range of everyday textures across the fingertips of Rhesus macaques at multiple speeds and recorded the responses evoked in tactile nerve fibers and somatosensory cortical neurons. We found that individual cortical neurons exhibit a wider range of speed-sensitivities than do nerve fibers. The resulting representations of speed and texture in cortex are more independent than are their counterparts in the nerve and account for speed-invariant perception of texture. We demonstrate that this separation of speed and texture information is a natural consequence of previously described cortical computations.

scholarly journals Peripersonal Space and Bodily Self-Consciousness: Implications for Psychological Trauma-Related Disorders

2020 ◽  
Vol 14 ◽  
Author(s):  
Daniela Rabellino ◽  
Paul A. Frewen ◽  
Margaret C. McKinnon ◽  
Ruth A. Lanius
Keyword(s):  
Multisensory Processing ◽  
Premotor Cortex ◽  
Critical Role ◽  
Psychological Trauma ◽  
Peripersonal Space ◽  
The Body ◽  
Future Research ◽  
Altered States ◽  
Tactile Stimuli ◽  
Defensive Role

Peripersonal space (PPS) is defined as the space surrounding the body where we can reach or be reached by external entities, including objects or other individuals. PPS is an essential component of bodily self-consciousness that allows us to perform actions in the world (e.g., grasping and manipulating objects) and protect our body while interacting with the surrounding environment. Multisensory processing plays a critical role in PPS representation, facilitating not only to situate ourselves in space but also assisting in the localization of external entities at a close distance from our bodies. Such abilities appear especially crucial when an external entity (a sound, an object, or a person) is approaching us, thereby allowing the assessment of the salience of a potential incoming threat. Accordingly, PPS represents a key aspect of social cognitive processes operational when we interact with other people (for example, in a dynamic dyad). The underpinnings of PPS have been investigated largely in human models and in animals and include the operation of dedicated multimodal neurons (neurons that respond specifically to co-occurring stimuli from different perceptive modalities, e.g., auditory and tactile stimuli) within brain regions involved in sensorimotor processing (ventral intraparietal sulcus, ventral premotor cortex), interoception (insula), and visual recognition (lateral occipital cortex). Although the defensive role of the PPS has been observed in psychopathology (e.g., in phobias) the relation between PPS and altered states of bodily consciousness remains largely unexplored. Specifically, PPS representation in trauma-related disorders, where altered states of consciousness can involve dissociation from the body and its surroundings, have not been investigated. Accordingly, we review here: (1) the behavioral and neurobiological literature surrounding trauma-related disorders and its relevance to PPS; and (2) outline future research directions aimed at examining altered states of bodily self-consciousness in trauma related-disorders.

scholarly journals Abstract goal representation in visual search by neurons in the human pre-supplementary motor area

Brain ◽  
2019 ◽  
Vol 142 (11) ◽  
pp. 3530-3549 ◽  
Author(s):  
Shuo Wang ◽  
Adam N Mamelak ◽  
Ralph Adolphs ◽  
Ueli Rutishauser
Keyword(s):  
Visual Search ◽  
Cognitive Deficits ◽  
Supplementary Motor Area ◽  
Critical Role ◽  
Critical Factor ◽  
Motor Area ◽  
Button Press ◽  
Independent Manner ◽  
Search Tasks ◽  
Goal Representation

Abstract The medial frontal cortex is important for goal-directed behaviours such as visual search. The pre-supplementary motor area (pre-SMA) plays a critical role in linking higher-level goals to actions, but little is known about the responses of individual cells in this area in humans. Pre-SMA dysfunction is thought to be a critical factor in the cognitive deficits that are observed in diseases such as Parkinson’s disease and schizophrenia, making it important to develop a better mechanistic understanding of the pre-SMA’s role in cognition. We simultaneously recorded single neurons in the human pre-SMA and eye movements while subjects performed goal-directed visual search tasks. We characterized two groups of neurons in the pre-SMA. First, 40% of neurons changed their firing rate whenever a fixation landed on the search target. These neurons responded to targets in an abstract manner across several conditions and tasks. Responses were invariant to motor output (i.e. button press or not), and to different ways of defining the search target (by instruction or pop-out). Second, ∼50% of neurons changed their response as a function of fixation order. Together, our results show that human pre-SMA neurons carry abstract signals during visual search that indicate whether a goal was reached in an action- and cue-independent manner. This suggests that the pre-SMA contributes to goal-directed behaviour by flexibly signalling goal detection and time elapsed since start of the search, and this process occurs regardless of task. These observations provide insights into how pre-SMA dysfunction might impact cognitive function.

scholarly journals Selection of Unmanned Aerial Vehicles by Using Multicriteria Decision-Making for Defence

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Mustafa Hamurcu ◽  
Tamer Eren
Keyword(s):  
Decision Making ◽  
Unmanned Aerial Vehicles ◽  
Selection Process ◽  
Critical Role ◽  
Multicriteria Decision Making ◽  
Critical Factor ◽  
Unmanned Systems ◽  
Multicriteria Decision ◽  
Aerial Vehicles ◽  
Selection Of

The unmanned systems have been seeing a significant boom in the last ten years in different areas together with technological developments. One of the unmanned systems is unmanned aerial vehicles (UAVs). UAVs are used for reconnaissance and observation in the military areas and play critical role in attack and destroy missions. These vehicles have been winning more features together with developing technology in todays world. In addition, they have been varying with different features. A systematic and efficient approach for the selection of the UAV is necessary to choose a best alternative for the critical tasks under consideration. The multicriteria decision-making (MCDM) approaches that are analytic processes are well suited to deal intricacy in selection of alternative vehicles. This study also proposes an integrated methodology based on the analytic hierarch process (AHP) and technique for order preference by similarity to ideal solution (TOPSIS) to evaluate UAV alternatives for selection process. Firstly, AHP, a MCDM method, is used to determine the weights of each critical factor. Subsequently, it is utilized with the TOPSIS approach to rank the vehicle alternatives in the decision problem. Result of the study shows that UAV-1 was selected as the most suitable vehicle. In results, it is seen that the weights of the evaluation criteria found by using AHP affect the decision-making process. Finally, the validation and sensitivity analysis of the solution are made and discussed.

scholarly journals Kinematics of unconstrained tactile texture exploration

2015 ◽  
Vol 113 (7) ◽  
pp. 3013-3020 ◽  
Author(s):  
Thierri Callier ◽  
Hannes P. Saal ◽  
Elizabeth C. Davis-Berg ◽  
Sliman J. Bensmaia
Keyword(s):  
Neural Coding ◽  
Scanning Speed ◽  
Perceptual Task ◽  
Textured Surfaces ◽  
Cutaneous Mechanoreceptors ◽  
Texture Information ◽  
Different Types ◽  
Exploratory Movements

A hallmark of tactile texture exploration is that it involves movement between skin and surface. When we scan a surface, small texture-specific vibrations are produced in the skin, and specialized cutaneous mechanoreceptors convert these vibrations into highly repeatable, precise, and informative temporal spiking patterns in tactile afferents. Both texture-elicited vibrations and afferent responses are highly dependent on exploratory kinematics, however; indeed, these dilate or contract systematically with decreases or increases in scanning speed, respectively. These profound changes in the peripheral response that accompany changes in scanning speed and other parameters of texture scanning raise the question as to whether exploratory behaviors change depending on what surface is explored or what information is sought about that surface. To address this question, we measure and analyze the kinematics as subjects explore textured surfaces to evaluate different types of texture information, namely the textures' roughness, hardness, and slipperiness. We find that the exploratory movements are dependent both on the perceptual task, as has been previously shown, but also on the texture that is scanned. We discuss the implications of our findings regarding the neural coding and perception of texture.

Astrocyte-neuron crosstalk through Hedgehog signaling mediates cortical circuit assembly

2020 ◽  
Author(s):  
Yajun Xie ◽  
Aaron T. Kuan ◽  
Wengang Wang ◽  
Zachary T. Herbert ◽  
Olivia Mosto ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Molecular Mechanisms ◽  
Synapse Formation ◽  
Critical Role ◽  
Shh Signaling ◽  
Shh Pathway ◽  
Cortical Astrocytes ◽  
Functional Features ◽  
And Function ◽  
Circuit Assembly

SUMMARYNeuron-glia relationships play a critical role in the regulation of synapse formation and neuronal specification. The cellular and molecular mechanisms by which neurons and astrocytes communicate and coordinate are not well understood. Here we demonstrate that the canonical Sonic hedgehog (Shh) pathway is active in cortical astrocytes, where it acts to coordinate layer-specific synaptic connectivity and functional circuit development. We show that Ptch1 is a Shh receptor that is expressed by cortical astrocytes during development and that Shh signaling is necessary and sufficient to promote the expression of layer-specific astrocyte genes involved in regulating synapse formation and function. Loss of Shh in layer V neurons reduces astrocyte complexity and coverage by astrocytic processes in tripartite synapses, moreover, cell-autonomous activation of Shh signaling in astrocytes promotes cortical excitatory synapse formation. Together, these results suggest that Shh secreted from deep layer cortical neurons acts to specialize the molecular and functional features of astrocytes during development to shape circuit assembly and function.

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