scholarly journals Bayesian population receptive field modeling in human somatosensory cortex

2019 ◽  
Author(s):  
Alexander M. Puckett ◽  
Saskia Bollmann ◽  
Keerat Junday ◽  
Markus Barth ◽  
Ross Cunnington
Keyword(s):  
Receptive Field ◽  
Somatosensory Cortex ◽  
Spatial Organization ◽  
Imaging Techniques ◽  
Detailed Examination ◽  
The Body ◽  
Primary Somatosensory Cortex ◽  
Vibrotactile Stimulation ◽  
Modeling Framework ◽  
The Brain

AbstractSomatosensation is fundamental to our ability to sense our body and interact with the world. Our body is continuously sampling the environment using a variety of receptors tuned to different features, and this information is routed up to primary somatosensory cortex. Strikingly, the spatial organization of the peripheral receptors in the body are well maintained, with the resulting representation of the body in the brain being referred to as the somatosensory homunculus. Recent years have seen considerable advancements in the field of high-resolution fMRI, which have enabled an increasingly detailed examination of the organization and properties of this homunculus. Here we combined advanced imaging techniques at ultra-high field (7T) with a recently developed Bayesian population receptive field (pRF) modeling framework to examine pRF properties in primary somatosensory cortex. In each subject, vibrotactile stimulation of the fingertips (i.e., the peripheral mechanoreceptors) modulated the fMRI response along the post-central gyrus and these signals were used to estimate pRFs. We found the pRF center location estimates to be in accord with previous work as well as evidence of other properties in line with the underlying neurobiology. Specifically, as expected from the known properties of cortical magnification, we find a larger representation of the index finger compared to the other stimulated digits (middle, index, little). We also show evidence that the little finger is marked by the largest pRF sizes. The ability to estimate somatosensory pRFs in humans provides an unprecedented opportunity to examine the neural mechanisms underlying somatosensation and is critical for studying how the brain, body, and environment interact to inform perception and action.

scholarly journals A touch of hierarchy: population receptive fields reveal fingertip integration in Brodmann areas in human primary somatosensory cortex

2021 ◽  
Author(s):  
W. Schellekens ◽  
M. Thio ◽  
S. Badde ◽  
J. Winawer ◽  
N. Ramsey ◽  
...  
Keyword(s):  
Receptive Field ◽  
Somatosensory Cortex ◽  
Receptive Fields ◽  
Body Part ◽  
Field Size ◽  
Primary Somatosensory Cortex ◽  
Vibrotactile Stimulation ◽  
Brodmann Areas ◽  
Functional Hierarchy ◽  
Stimulation Of

AbstractSeveral neuroimaging studies have shown the somatotopy of body part representations in primary somatosensory cortex (S1), but the functional hierarchy of distinct subregions in human S1 has not been adequately addressed. The current study investigates the functional hierarchy of cyto-architectonically distinct regions, Brodmann areas BA3, BA1, and BA2, in human S1. During functional MRI experiments, we presented participants with vibrotactile stimulation of the fingertips at three different vibration frequencies. Using population Receptive Field (pRF) modeling of the fMRI BOLD activity, we identified the hand region in S1 and the somatotopy of the fingertips. For each voxel, the pRF center indicates the finger that most effectively drives the BOLD signal, and the pRF size measures the spatial somatic pooling of fingertips. We find a systematic relationship of pRF sizes from lower-order areas to higher-order areas. Specifically, we found that pRF sizes are smallest in BA3, increase slightly towards BA1, and are largest in BA2, paralleling the increase in visual receptive field size as one ascends the visual hierarchy. Additionally, we find that the time-to-peak of the hemodynamic response in BA3 is roughly 0.5 s earlier compared to BA1 and BA2, further supporting the notion of a functional hierarchy of subregions in S1. These results were obtained during stimulation of different mechanoreceptors, suggesting that different afferent fibers leading up to S1 feed into the same cortical hierarchy.

scholarly journals Attenuation of sensory processing in the primary somatosensory cortex during rubber hand illusion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masanori Sakamoto ◽  
Hirotoshi Ifuku
Keyword(s):  
Somatosensory Cortex ◽  
Sensory Processing ◽  
The Body ◽  
Neural Representation ◽  
Rubber Hand Illusion ◽  
Primary Somatosensory Cortex ◽  
Somatosensory Processing ◽  
Rubber Hand ◽  
Factors Influencing ◽  
The Brain

AbstractThe neural representation of the body is easily altered by the integration of multiple sensory signals in the brain. The “rubber hand illusion” (RHI) is one of the most popular experimental paradigms to investigate this phenomenon. During this illusion, a feeling of ownership of the rubber hand is created. Some studies have shown that somatosensory processing in the brain is attenuated when RHI occurs. However, it is unknown where attenuation of somatosensory processing occurs. Here, we show that somatosensory processing is attenuated in the primary somatosensory cortex. We found that the earliest response of somatosensory evoked potentials, which is thought to originate from the primary somatosensory cortex, was attenuated during RHI. Furthermore, this attenuation was observed before the occurrence of the illusion. Our results suggest that attenuation of sensory processing in the primary somatosensory cortex is one of the factors influencing the occurrence of the RHI.

Attenuated Input to the Primary Somatosensory Cortex is Associated with the Occurrence of Rubber Hand Illusion

2021 ◽  
Author(s):  
Masanori Sakamoto ◽  
Hirotoshi Ifuku
Keyword(s):  
Somatosensory Cortex ◽  
Early Response ◽  
The Body ◽  
Neural Representation ◽  
Rubber Hand Illusion ◽  
Primary Somatosensory Cortex ◽  
Somatosensory Processing ◽  
Rubber Hand ◽  
Somatosensory Input ◽  
The Brain

Abstract The neural representation of the body is easily altered by the integration of multiple sensory signals in the brain. The “rubber hand illusion” (RHI) is one of the most popular experimental paradigms to investigate this phenomenon. During this illusion, ownership of the rubber hand is created. Some studies have shown that somatosensory processing in the brain is attenuated when RHI occurs. However, it is unknown where attenuation of somatosensory inputs occurs. Here, we show that somatosensory input from the hand is attenuated at the primary somatosensory cortex. We found that the early response of somatosensory evoked potential, which is thought to originate from the primary somatosensory cortex, was attenuated during RHI. Furthermore, this attenuation was observed before the occurrence of the illusion. Our results suggest that attenuation of somatosensory inputs from the hand to the brain is one of the factors influencing the occurrence of the RHI.

scholarly journals A touch of hierarchy. Population Receptive Fields reveal fingertip integration in Brodmann areas in human primary somatosensory cortex

2021 ◽  
Author(s):  
W. Schellekens ◽  
M. Thio ◽  
S. Badde ◽  
J. Winawer ◽  
N. Ramsey ◽  
...  
Keyword(s):  
Receptive Field ◽  
Somatosensory Cortex ◽  
Receptive Fields ◽  
Body Part ◽  
Field Size ◽  
Primary Somatosensory Cortex ◽  
Vibrotactile Stimulation ◽  
Brodmann Areas ◽  
Functional Hierarchy ◽  
Stimulation Of

AbstractSeveral neuroimaging studies have shown the somatotopy of body part representations in primary somatosensory cortex (S1), but the functional hierarchy of distinct subregions in human S1 has not been adequately addressed. The current study investigates the functional hierarchy of cyto-architectonically distinct regions, Brodmann areas BA3, BA1, and BA2, in human S1. During functional MRI experiments, we presented participants with vibrotactile stimulation of the fingertips at 3 different vibration frequencies. Using population Receptive Field (pRF) modeling of the fMRI BOLD activity, we identified the hand region in S1 and the somatotopy of the fingertips. For each voxel, the pRF center indicates the finger that most effectively drives the BOLD signal, and the pRF size measures the spatial somatic pooling of fingertips. We find a systematic relationship of pRF sizes from lower-order areas to higher-order areas. Specifically, we found that pRF sizes are smallest in BA3, increase slightly towards BA1, and are largest in BA2, paralleling the increase in visual receptive field size as one ascends the visual hierarchy. Additionally, we find that the time-to-peak of the hemodynamic response in BA3 is roughly 0.5s earlier compared to BA1 and BA2, further supporting the notion of a functional hierarchy of subregions in S1. These results were obtained during stimulation of different mechanoreceptors, suggesting that different afferent fibers leading up to S1 feed into the same cortical hierarchy.

Spatio-Temporal Subthreshold Receptive Fields in the Vibrissa Representation of Rat Primary Somatosensory Cortex

1998 ◽  
Vol 80 (6) ◽  
pp. 2882-2892 ◽  
Author(s):  
Christopher I. Moore ◽  
Sacha B. Nelson
Keyword(s):  
Receptive Field ◽  
Somatosensory Cortex ◽  
Rise Time ◽  
Cortical Plasticity ◽  
Temporal Dynamics ◽  
Receptive Fields ◽  
Excitatory Input ◽  
Primary Somatosensory Cortex ◽  
Spatio Temporal ◽  
Sensory Evoked

Moore, Christopher I. and Sacha B. Nelson. Spatio-temporal subthreshold receptive fields in the vibrissa representation of rat primary somatosensory cortex. J. Neurophysiol. 80: 2882–2892, 1998. Whole cell recordings of synaptic responses evoked by deflection of individual vibrissa were obtained from neurons within adult rat primary somatosensory cortex. To define the spatial and temporal properties of subthreshold receptive fields, the spread, amplitude, latency to onset, rise time to half peak amplitude, and the balance of excitation and inhibition of subthreshold input were quantified. The convergence of information onto single neurons was found to be extensive: inputs were consistently evoked by vibrissa one- and two-away from the vibrissa that evoked the largest response (the “primary vibrissa”). Latency to onset, rise time, and the incidence and strength of inhibitory postsynaptic potentials (IPSPs) varied as a function of position within the receptive field and the strength of evoked excitatory input. Nonprimary vibrissae evoked smaller amplitude subthreshold responses [primary vibrissa, 9.1 ± 0.84 (SE) mV, n = 14; 1-away, 5.1 ± 0.5 mV, n = 38; 2-away, 3.7 ± 0.59 mV, n = 22; 3-away, 1.3 ± 0.70 mV, n = 8] with longer latencies (primary vibrissa, 10.8 ± 0.80 ms; 1-away, 15.0 ± 1.2 ms; 2-away, 15.7 ± 2.0 ms). Rise times were significantly faster for inputs that could evoke action potential responses (suprathreshold, 4.1 ± 1.3 ms, n = 8; subthreshold, 12.4 ± 1.5 ms, n = 61). In a subset of cells, sensory evoked IPSPs were examined by deflecting vibrissa during injection of hyperpolarizing and depolarizing current. The strongest IPSPs were evoked by the primary vibrissa ( n = 5/5), but smaller IPSPs also were evoked by nonprimary vibrissae ( n = 8/13). Inhibition peaked by 10–20 ms after the onset of the fastest excitatory input to the cortex. This pattern of inhibitory activity led to a functional reversal of the center of the receptive field and to suppression of later-arriving and slower-rising nonprimary inputs. Together, these data demonstrate that subthreshold receptive fields are on average large, and the spatio-temporal dynamics of these receptive fields vary as a function of position within the receptive field and strength of excitatory input. These findings constrain models of suprathreshold receptive field generation, multivibrissa interactions, and cortical plasticity.

scholarly journals Perception of the dynamic visual vertical during sinusoidal linear motion

2017 ◽  
Vol 118 (4) ◽  
pp. 2499-2506 ◽  
Author(s):  
A. Pomante ◽  
L. P. J. Selen ◽  
W. P. Medendorp
Keyword(s):  
Vestibular System ◽  
Spatial Orientation ◽  
Linear Acceleration ◽  
The Body ◽  
Body Motion ◽  
Whole Body ◽  
Linear Motion ◽  
Modeling Framework ◽  
Visual Vertical ◽  
The Brain

The vestibular system provides information for spatial orientation. However, this information is ambiguous: because the otoliths sense the gravitoinertial force, they cannot distinguish gravitational and inertial components. As a consequence, prolonged linear acceleration of the head can be interpreted as tilt, referred to as the somatogravic effect. Previous modeling work suggests that the brain disambiguates the otolith signal according to the rules of Bayesian inference, combining noisy canal cues with the a priori assumption that prolonged linear accelerations are unlikely. Within this modeling framework the noise of the vestibular signals affects the dynamic characteristics of the tilt percept during linear whole-body motion. To test this prediction, we devised a novel paradigm to psychometrically characterize the dynamic visual vertical—as a proxy for the tilt percept—during passive sinusoidal linear motion along the interaural axis (0.33 Hz motion frequency, 1.75 m/s2peak acceleration, 80 cm displacement). While subjects ( n=10) kept fixation on a central body-fixed light, a line was briefly flashed (5 ms) at different phases of the motion, the orientation of which had to be judged relative to gravity. Consistent with the model’s prediction, subjects showed a phase-dependent modulation of the dynamic visual vertical, with a subject-specific phase shift with respect to the imposed acceleration signal. The magnitude of this modulation was smaller than predicted, suggesting a contribution of nonvestibular signals to the dynamic visual vertical. Despite their dampening effect, our findings may point to a link between the noise components in the vestibular system and the characteristics of dynamic visual vertical.NEW & NOTEWORTHY A fundamental question in neuroscience is how the brain processes vestibular signals to infer the orientation of the body and objects in space. We show that, under sinusoidal linear motion, systematic error patterns appear in the disambiguation of linear acceleration and spatial orientation. We discuss the dynamics of these illusory percepts in terms of a dynamic Bayesian model that combines uncertainty in the vestibular signals with priors based on the natural statistics of head motion.

Multiple representations of the body within the primary somatosensory cortex of primates

Science ◽  
1979 ◽  
Vol 204 (4392) ◽  
pp. 521-523 ◽  
Author(s):  
J. Kaas ◽  
R. Nelson ◽  
M Sur ◽  
C. Lin ◽  
M. Merzenich
Keyword(s):  
Somatosensory Cortex ◽  
Multiple Representations ◽  
The Body ◽  
Primary Somatosensory Cortex

Localization of somatosensory function by using positron emission tomography scanning: a comparison with intraoperative cortical stimulation

1999 ◽  
Vol 90 (3) ◽  
pp. 478-483 ◽  
Author(s):  
Richard G. Bittar ◽  
André Olivier ◽  
Abbas F. Sadikot ◽  
Frederick Andermann ◽  
Roch M. Comeau ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Somatosensory Cortex ◽  
Cortical Stimulation ◽  
Emission Tomography ◽  
Primary Somatosensory Cortex ◽  
Vibrotactile Stimulation ◽  
Content Type ◽  
Positron Emission ◽  
Pet Scanning ◽  
Fine Print

Object. To investigate the utility of [15O]H2O positron emission tomography (PET) activation studies in the presurgical mapping of primary somatosensory cortex, the authors compared the magnitude and location of activation foci obtained using PET scanning with the results of intraoperative cortical stimulation (ICS).Methods. The authors used PET scanning and vibrotactile stimulation (of the face, hand, or foot) to localize the primary somatosensory cortex before surgical resection of mass lesions or epileptogenic foci affecting the central area in 20 patients. With the aid of image-guided surgical systems, the locations of significant activation foci on PET scanning were compared with those of positive ICS performed at craniotomy after the patient had received a local anesthetic agent. In addition, the relationship between the magnitude and statistical significance of blood flow changes and the presence of positive ICS was examined.In 22 (95.6%) of 23 statistically significant (p < 0.05) PET activation foci, spatially concordant sites on ICS were also observed. Intraoperative cortical stimulation was positive in 40% of the PET activation studies that did not result in statistically significant activation. In the patients showing these results, there was a clearly identifiable t-statistic peak that was spatially concordant with the site of positive ICS in the sensorimotor area. All PET activation foci with a t statistic greater than 4.75 were associated with spatially concordant sites of positive ICS. All PET activation foci with a t statistic less than 3.2 were associated with negative ICS.Conclusions. Positron emission tomography is an accurate method for mapping the primary somatosensory cortex before surgery. The need for ICS, which requires local anesthesia, may be eliminated when PET foci with high (> 4.75) or low (< 3.20) t-statistic peaks are elicited by vibrotactile stimulation.

scholarly journals The diacylglycerol lipases: structure, regulation and roles in and beyond endocannabinoid signalling

2012 ◽  
Vol 367 (1607) ◽  
pp. 3264-3275 ◽  
Author(s):  
Melina Reisenberg ◽  
Praveen K. Singh ◽  
Gareth Williams ◽  
Patrick Doherty
Keyword(s):  
Dopaminergic Neurons ◽  
Cannabinoid Receptors ◽  
Homology Modelling ◽  
Detailed Examination ◽  
The Body ◽  
Adult Brain ◽  
And Migration ◽  
Regulatory Loop ◽  
Translational Mechanisms ◽  
The Brain

The diacylglycerol lipases (DAGLs) hydrolyse diacylglycerol to generate 2-arachidonoylglycerol (2-AG), the most abundant ligand for the CB 1 and CB 2 cannabinoid receptors in the body. DAGL-dependent endocannabinoid signalling regulates axonal growth and guidance during development, and is required for the generation and migration of new neurons in the adult brain. At developed synapses, 2-AG released from postsynaptic terminals acts back on presynaptic CB 1 receptors to inhibit the secretion of both excitatory and inhibitory neurotransmitters, with this DAGL-dependent synaptic plasticity operating throughout the nervous system. Importantly, the DAGLs have functions that do not involve cannabinoid receptors. For example, 2-AG is the precursor of arachidonic acid in a pathway that maintains the level of this essential lipid in the brain and other organs. This pathway also drives the cyclooxygenase-dependent generation of inflammatory prostaglandins in the brain, which has recently been implicated in the degeneration of dopaminergic neurons in Parkinson's disease. Remarkably, we still know very little about the mechanisms that regulate DAGL activity—however, key insights can be gleaned by homology modelling against other α/β hydrolases and from a detailed examination of published proteomic studies and other databases. These identify a regulatory loop with a highly conserved signature motif, as well as phosphorylation and palmitoylation as post-translational mechanisms likely to regulate function.

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