6,998 research outputs found
Can't touch this: the first-person perspective provides privileged access to predictions of sensory action outcomes.
RCUK Open Access funded. ESRC ES/J019178/1Previous studies have shown that viewing others in pain activates cortical somatosensory processing areas and facilitates the detection of tactile targets. It has been suggested that such shared representations have evolved to enable us to better understand the actions and intentions of others. If this is the case, the effects of observing others in pain should be obtained from a range of viewing perspectives. Therefore, the current study examined the behavioral effects of observed grasps of painful and nonpainful objects from both a first- and third-person perspective. In the first-person perspective, a participant was faster to detect a tactile target delivered to their own hand when viewing painful grasping actions, compared with all nonpainful actions. However, this effect was not revealed in the third-person perspective. The combination of action and object information to predict the painful consequences of another person's actions when viewed from the first-person perspective, but not the third-person perspective, argues against a mechanism ostensibly evolved to understand the actions of others
Review: Do the Different Sensory Areas within the Cat Anterior Ectosylvian Sulcal Cortex Collectively Represent a Network Multisensory Hub?
Current theory supports that the numerous functional areas of the cerebral cortex are organized and function as a network. Using connectional databases and computational approaches, the cerebral network has been demonstrated to exhibit a hierarchical structure composed of areas, clusters and, ultimately, hubs. Hubs are highly connected, higher-order regions that also facilitate communication between different sensory modalities. One region computationally identified network hub is the visual area of the Anterior Ectosylvian Sulcal cortex (AESc) of the cat. The Anterior Ectosylvian Visual area (AEV) is but one component of the AESc that also includes the auditory (Field of the Anterior Ectosylvian Sulcus - FAES) and somatosensory (Fourth somatosensory representation - SIV). To better understand the nature of cortical network hubs, the present report reviews the biological features of the AESc. Within the AESc, each area has extensive external cortical connections as well as among one another. Each of these core representations is separated by a transition zone characterized by bimodal neurons that share sensory properties of both adjoining core areas. Finally, core and transition zones are underlain by a continuous sheet of layer 5 neurons that project to common output structures. Altogether, these shared properties suggest that the collective AESc region represents a multiple sensory/multisensory cortical network hub. Ultimately, such an interconnected, composite structure adds complexity and biological detail to the understanding of cortical network hubs and their function in cortical processing
Evaluation of behavior in transgenic mouse models to understand human congenital pain conditions
BACKGROUND: Containing a brain for signal processing and decision making, and a peripheral component for sensation and response, the nervous system provides higher organisms a powerful method of interacting with their environment. The specific neurons involved in pain sensation are known as nociceptors and are the source of normal nociceptive pain signaling to prompt appropriate responses. Though acute hypersensitization can be advantageous by encouraging an organism to allow an injured area to heal, chronic pain conditions can be pathological and can markedly reduce quality of life. While a variety of genes have been associated with congenital pain conditions, two rare cases examined in this study have not had their mutated genes identified. Potassium voltage-gated channel subfamily H member 8, or KCNH8, is involved in regulating action potential production and propagation, and has not been linked with pain processing of any kind to date. Here, a male patient evaluated at Boston Childrenâs Hospital contains a novel single-base KCNH8 mutation and possesses an extremely low sensitivity to cold temperatures and mechanical pain, but a higher sensitivity to warmer temperatures. A separate protein, intersectin-2, or ITSN2, normally functions in clathrin-mediated endocytosis and exocytosis. A second patient at Boston Childrenâs Hospital expresses a previously-unseen point mutation in ITSN2 and experiences erythromelalgia, characterized by episodes of intense pain and red, swollen limbs during ambient warm temperatures. Through the use of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 genome editing, this study will produce these specific genetic mutations in mouse lines to explore their effects on mammalian behavior.
OBJECTIVES: This project employs two transgenic mouse models to study the behavioral phenotypes associated with rare potentially damaging mutations in KCNH8 and ITSN2 exhibited in the human patients. Through these experiments, a greater understanding of neural pain signaling and sensitivity changes can occur.
METHODS: The differences in temperature preference of KCNH8 and ITSN2 mutant mice compared to wild type mice lacking these mutations was studied using thermal plates under cold and warm conditions. Direct application of acetone and von Frey filaments to mouse paws was used to study cold and mechanical sensitivity. Further testing of stamina, anxiety, coordination, and strength were also evaluated.
RESULTS: A marked decrease in sensitivity to von Frey stimulation (p<0.01) and acetone administration (p<0.05) was observed in KCNH8 mutant mice. Thermal preference testing demonstrated a decreased preference for warmer temperatures as compared to wild type mice. In addition, anxiety levels were also observed to be slightly higher in these mutant KCNH8 mice (p<0.05). The mutant ITSN2 mice spent less time at cooler temperatures, though surprisingly they significantly preferred warmer conditions as compared to their wild type littermates. A full and partial reversal of these temperature preferences was demonstrated in cold and heat thermal conditions respectively after intraperitoneal gabapentin injection, which normalized the mice toward wild type behavior.
CONCLUSIONS: Data from the KCNH8 mutant mouse model indicates an aversion to warmer temperatures and a decreased ability to detect cold or mechanical pressure, much like the human patient. The mutant ITSN2 mice were less likely to spend time at cooler temperatures, indicating heightened sensory sensitivity, but their preference for warmer temperatures suggests a possible desensitization of the affected nociceptors. These results often mirror the patientâs phenotype, but the preference for ambient warmer environments appears opposite to the patient. As the ITSN2 mice feel discomfort at cooler temperatures, a proposed desensitization at warmer temperatures would result in a more comfortable environment and could explain the observed preference. The trends toward normal neural firing rates achieved through gabapentin injection suggest that the aberrant responses in mutant ITSN2 mice is due to altered sensitization, but additional examination under these conditions with a larger group of mice is necessary to further unravel these signaling pathways. However, these extremely encouraging data introduce two new molecular targets for acute pain control
Engineering data compendium. Human perception and performance. User's guide
The concept underlying the Engineering Data Compendium was the product of a research and development program (Integrated Perceptual Information for Designers project) aimed at facilitating the application of basic research findings in human performance to the design and military crew systems. The principal objective was to develop a workable strategy for: (1) identifying and distilling information of potential value to system design from the existing research literature, and (2) presenting this technical information in a way that would aid its accessibility, interpretability, and applicability by systems designers. The present four volumes of the Engineering Data Compendium represent the first implementation of this strategy. This is the first volume, the User's Guide, containing a description of the program and instructions for its use
Sensory coding in supragranular cells of the vibrissal cortex in anesthetized and awake mice
Sensory perception entails reliable representation of the
external stimuli as impulse activity of individual neurons (i.e.
spikes) and neuronal populations in the sensory area. An ongoing
challenge in neuroscience is to identify and characterize the
features of the stimuli which are relevant to a specific sensory
modality and neuronal strategies to effectively and efficiently
encode those features. It is widely hypothesized that the
neuronal populations employ âsparse codingâ strategies to
optimize the stimulus representations with a low energetic cost
(i.e. low impulse activity). In the past two decades, a wealth of
experimental evidence has supported this hypothesis by showing
spatiotemporally sparse activity in sensory area. Despite
numerous studies, the extent of sparse coding and its underlying
mechanisms are not fully understood, especially in primary
vibrissal somatosensory cortex (vS1), which is a key model system
in sensory neuroscience. Importantly, it is not clear yet whether
sparse activation of supragranular vS1 is due to insufficient
synaptic input to the majority of the cells or the absence of
effective stimulus features.
In this thesis, first we asked how the choice of stimulus could
affect the degree of sparseness and/or the overall fraction of
the responsive vS1 neurons. We presented whisker deflections
spanning a broad range of intensities, including âstandard
stimuliâ and a high-velocity, âsharpâ stimulus, which
simulated the fast slip events that occur during whisker mediated
object palpation. We used whole-cell and cell-attached recording
and calcium imaging to characterize the neuronal responses to
these stimuli. Consistent with previous literature, whole-cell
recording revealed a sparse response to the standard range of
velocities: although all recorded cells showed tuning to velocity
in their postsynaptic potentials, only a small fraction produced
stimulus-evoked spikes. In contrast, the sharp stimulus evoked
reliable spiking in a large fraction of regular spiking neurons
in the supragranular vS1. Spiking responses to the sharp stimulus
were binary and precisely timed, with minimum trial-to-trial
variability. Interestingly, we also observed that the sharp
stimulus produced a consistent and significant reduction in
action potential threshold.
In the second step we asked whether the stimulus dependent sparse
and dense activations we found in anesthetized condition would
generalize to the awake condition. We employed cell-attached
recordings in head-fixed awake mice to explore the degree of
sparseness in awake cortex. Although, stimuli delivered by a
piezo-electric actuator evoked significant response in a small
fraction of regular spiking supragranular neurons (16%-29%), we
observed that a majority of neurons (84%) were driven by manual
probing of whiskers. Our results demonstrate that despite sparse
activity, the majority of neurons in the superficial layers of
vS1 contribute to coding by representing a specific feature of
the tactile stimulus.
Thesis outline: Chapter 1 provides a review of the current
knowledge on sparse coding and an overview of the whisker-sensory
pathway. Chapter 2 represents our published results regarding
sparse and dense coding in vS1 of anesthetized mice
(Ranjbar-Slamloo and Arabzadeh 2017). Chapter 3 represents our
pending manuscript with results obtained with piezo and manual
stimulation in awake mice. Finally, in Chapter 4 we discuss and
conclude our findings in the context of the literature. The
appendix provides unpublished results related to Chapter 2. This
section is referenced in the final chapter for further
discussion
Electroencephalographic Responses to Frictional Stimuli: Measurement Setup and Processing Pipeline
Tactility is a key sense in the human interaction with the environment. The understanding of
tactile perception has become an exciting area in industrial, medical and scienti c research with an
emphasis on the development of new haptic technologies. Surprisingly, the quanti cation of tactile
perception has, compared to other senses, only recently become a eld of scienti c investigation.
The overall goal of this emerging scienti c discipline is an understanding of the causal chain
from the contact of the skin with materials to the brain dynamics representing recognition of
and emotional reaction to the materials. Each link in this chain depends on individual and
environmental factors ranging from the in uence of humidity on contact formation to the role of
attention for the perception of touch.
This thesis reports on the research of neural correlates to the frictional stimulation of the human
ngertip. Event-related electroencephalographic potentials (ERPs) upon the change in ngertip
friction are measured and studied, when pins of a programmable Braille-display were brought into
skin contact. In order to contribute to the understanding of the causal chain mentioned above,
this work combines two research areas which are usually not connected to each other, namely
tribology and neuroscience. The goal of the study is to evaluate contributions of friction to the
process of haptic perception. Key contributions of this thesis are:
1) Development of a setup to simultaneously record physical forces and ERPs upon tactile
stimulation.
2) Implementation of a dedicated signal processing pipeline for the statistical analysis of ERP
-amplitudes, -latencies and -instantaneous phases.
3) Interpretation of skin friction data and extraction of neural correlates with respect to varying
friction intensities.
The tactile stimulation of the ngertip upon raising and lowering of di erent lines of Braille-pins
(one, three and ve) caused pronounced N50 and P100 components in the event-related ERPsequences,
which is in line with the current literature. Friction between the ngertip and the
Braille-system exhibited a characteristic temporal development which is attributed to viscoelastic
skin relaxation. Although the force stimuli varied by a factor of two between the di erent Braillepatterns,
no signi cant di erences were observed between the amplitudes and latencies of ERPs
after standard across-trial averaging. Thus, for the rst time a phase measure for estimating singletrial
interactions of somatosensory potentials is proposed. Results show that instantaneous phase
coherency is evoked by friction, and that higher friction induces stronger and more time-localized
phase coherencyDie Taktilität ist ein zentraler Sinn in der Interaktion mit unserer Umwelt. Das Bestreben,
fundierte Erkenntnisse hinsichtlich der taktilenWahrnehmung zu gewinnen erhält groÿen Zuspruch
in der industriellen, medizinischen und wissenschaftlichen Forschung, meist mit einem Fokus auf
der Entwicklung von haptischen Technologien. Erstaunlicherweise ist jedoch die wissenschaftliche
Quanti zierung der taktilen Wahrnehmung, verglichen mit anderen Sinnesmodalitäten, erst seit
kurzem ein sich entwickelnder Forschungsbereich. Fokus dieser Disziplin ist es, die kognitive und
emotionale Reaktion nach physischem Kontakt mit Materialien zu beschreiben, und die kausale
Wirkungskette von der BerĂźhrung bis zur Reaktion zu verstehen. Dabei unterliegen die einzelnen
Faktoren dieser Kette sowohl individuellen als auch externen Ein Ăźssen, welche von der Luftfeuchtigkeit
während des Kontaktes bis hin zur Rolle der Aufmerksamkeit fßr die Wahrnehmung
reichen.
Die vorliegende Arbeit beschäftigt sich mit der Untersuchung von neuronalen Korrelaten nach
Reibungsstimulation des menschlichen Fingers. Dazu wurden Reibungsänderungen, welche durch
den Kontakt der menschlichen Fingerspitze mit schaltbaren Stiften eines Braille-Display erzeugt
wurden, untersucht und die entsprechenden neuronalen Korrelate aufgezeichnet. Um zu dem Verst
ändnis der oben erwähnten Wirkungskette beizutragen, werden Ansätze aus zwei fßr gewÜhnlich
nicht zusammenhängenden Forschungsbereichen, nämlich der Tribologie und der Neurowissenschaft,
kombiniert. Folgende Beiträge sind Hauptbestandteile dieser Arbeit:
1) Realisierung einer Messumgebung zur simultanen Ableitung von Kräften und ereigniskorrelierten
Potentialen nach taktiler Stimulation der Fingerspitze.
2) Aufbau einer speziellen Signalverarbeitungskette zur statistischen Analyse von stimulationsabh
ängigen EEG -Amplituden, -Latenzen und -instantanen Phasen.
3) Interpretation der erhobenen Reibungsdaten und Extraktion neuronaler Korrelate hinsichtlich
variierender Stimulationsintensitäten.
Unsere Resultate zeigen, dass die taktile Stimulation der Fingerspitze nach Anheben und Senken
von Braille-Stiften zu signi kanten N50 und P100 Komponenten in den ereigniskorrelierten Potentialen
fĂźhrt, im Einklang mit der aktuellen Literatur. Die Reibung zwischen der Fingerspitze
und dem Braille-System zeigte einen charakteristischen Signalverlauf, welcher auf viskoelastische
Hautrelaxation zurĂźckzufĂźhren ist. Trotz der um einen Faktor zwei verschiedenen Intensit
ätsunterschiede zwischen den Stimulationsmustern zeigten sich keine signi kanten Unterschiede
zwischen den einfach gemittelten Amplituden der evozierten Potentialen. Erstmalig wurde ein
Phasen-MaĂż zur Identi zierung von Unterschieden zwischen somatosensorischen "single-trial" Interaktionen
angewandt. Diese Phasenanalyse zeigte, im Gegensatz zur Amplituden- und Latenzanalyse,
deutlichere und signi kantere Unterschiede zwischen den Stimulationsparadigmen. Es
wird gefolgert, dass Kohärenz zwischen den Momentanphasen durch Reibungsereignisse herbeigef
ßhrt wird und dass durch stärkere Reibung diese Kohärenz, im zeitlichen Verlauf, stärker und
lokalisierter wird
Perception of patterned vibratory stimulation: An evaluation of the tactile vision substitution system
Sensory substitution--The replacing of an impaired sensory channel by a properly functioning one--is possibly best manifested today in attempts to provide visual aids for the blind. The tactile vision substitution system (T.V.S.S.) is an example of one such visual aid. The system presents patterned tactile stimulation to the skin of the observer provided by the output of a closed-circuit television system. Research conducted with congenitally blind Ss in evaluation of the T.V.S.S. has provided useful information concerning the potentialities and limitations of the prototype systems, similarities and differences between tactile and visual perception, and the development of visual perception in the congenitally blind
Investigation demonstrated that the congenitally blind Ss can learn to make valid judgements of three-dimensional displays with the T.V.S.S. Such judgements are made on the basis of properties contained in the proximal stimulation properties analogous to the monocular clues of depth presence in vision, such as linear-perspective, apparent elevation in the visual field, size change as a function of distance, occlusion, and texural gradients.
Similarities have been noted between judgements made by sighted Ss using vision and by blind Ss using the T.V.S.S. on comparable tasks. A display consisting of two slightly displaced alternating lights is perceived in both situations as a single spot of light moving back-and-forth between two display boundaries. A rotating drum made up of alternate black and white stripes is, when stopped, perceived as briefly moving in the opposite direction. External localization of the source of stimulation also occurs with both sensory inputs.
The major differences between the visual and tactile inputs that have been noted have occurred in form recognition tacks. Although blind Ss using the patterned tactile stimulation are able to identify both geometric forms and abstract patterns, accuracy is consistently lower than that of sighted Ss using vision, and the latencies for the blind Ss are significantly longer. It is hypothesized that the longer latencies for the blind Ss using the T.V.S.S. can be accounted for primarily by the need to hand-position the television camera during scanning. A major factor in the lower accuracy for the tactile group is the noted difficulty in detecting and identifying display features located within a mass of stimulation. This difficulty with internal display detail may be a function of sensory inhibition and/or masking.
The research findings support a concept of sensory substitution as well as a theory of perception which stresses the modality of many qualities contained in visible displays. Further research is needed to determine the significance of sensor movement--either eye movements or camera manipulation--in the perceptual process
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