scholarly journals Four Artists: Angels and Mentors

2022 ◽  
Author(s):  
Polly Barton
Keyword(s):  
Somatosensory Cortex ◽  
The Brain

Interwoven into my life at the loom are the stories of four women: a weaver, a painter, an embroiderer, and a fiber artist. Their histories have guided and pulled me forward in my own growth as an artist. Yet it is to their art that I feel a heartfelt, visceral, and almost spiritual resonance. I would like to present to the TSA conference in 2020 my research into the lives of Sumiko Deguchi (1883-1952), Helen Frankenthaler (1928- 2011), Adya van Rees-Dutilh (1876- 1959), and Pat Hickman (b.1935). As an artist who has wound, tied, dyed, and woven silk into contemporary ikat work for over forty years, I have become fascinated by how the thread reveals a life and encodes memory. There are many questions I would con- sider as I research the lives and work of these four women: • How does connection of fingertips on thread inform and guide the artist? • How does touch inform the somatosensory cortex in the brain? • How are the artist’s spirit and heart strings revealed in a viewer’s kines- thetic response to the luster and tactile presence of fiber? • What draws us to look closely at the intelligence within a textile or a canvas? Including images of the development of my own work, I hope to illustrate how their art has been an inspiration, a consolation, and an integral part of the fabric of my life’s work. Shouldering a vital textile tradition within a historic and vibrant contemporary community of fiber artists has been the thread I follow with my own voice.

scholarly journals Assessing the utility of MAGNETO to control neuronal excitability in the somatosensory cortex

2019 ◽  
Author(s):  
Koen Kole ◽  
Yiping Zhang ◽  
Eric J. R. Jansen ◽  
Terence Brouns ◽  
Ate Bijlsma ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Action Potentials ◽  
Magnetic Stimulation ◽  
Neuronal Excitability ◽  
Neural Interfaces ◽  
Intracellular Recordings ◽  
Membrane Excitability ◽  
Freely Moving ◽  
The Brain

Magnetic neuromodulation has outstanding promise for the development of novel neural interfaces without direct physical intervention with the brain. Here we tested the utility of Magneto in the adult somatosensory cortex by performing whole-cell intracellular recordings in vitro and extracellular recordings in freely moving mice. Results show that magnetic stimulation does not alter subthreshold membrane excitability or contribute to the generation of action potentials in virally transduced neurons expressing Magneto.

scholarly journals Discriminative and affective touch converge: Somatosensory cortex represents A-beta input in a CT-like manner

2021 ◽  
Author(s):  
Annett Schirmer ◽  
Oscar Lai ◽  
Francis McGlone ◽  
Clare Cham ◽  
Darwin Lau
Keyword(s):  
Spinal Cord ◽  
Somatosensory Cortex ◽  
Current Theory ◽  
Affective Touch ◽  
Interpersonal Touch ◽  
Hairy Skin ◽  
C Fiber ◽  
The Brain ◽  
Affective System

Current theory divides the human mechanical sense into discriminative and affective systems. A discriminative system supports tactile exploration and manipulation via fast A-beta signaling, whereas an affective system supports the pleasure of friendly interpersonal touch via slow CT signaling. To probe this system segregation, we recorded the electroencephalogram from participants being stroked and reporting stroke pleasantness. We observed a somatosensory negativity that was maximal for CT optimal as compared with sub-optimal velocities, that predicted subjective pleasantness, and showed only for stroking of hairy skin known to be CT innervated. Importantly, the latency of this negativity preceded C fiber input to the brain by several hundred milliseconds and is best explained by interactions between CT and A-beta processes in the spinal cord. Our data challenge the divide between discriminative and affective touch implying instead that both fast A-beta and slow CT signaling play an important role in tactile pleasure.

Effect of U-92032, T-Type Ca2+ Channel Blocker, on Rats with Genetic Absence Epilepsy

Pharmacology ◽  
2020 ◽  
Vol 105 (9-10) ◽  
pp. 561-567
Author(s):  
Hasan Raci Yananli ◽  
Mahluga Jafarova Demirkapu ◽  
Halil Eren Sakallı ◽  
Rezzan Gülhan ◽  
Filiz Yılmaz Onat
Keyword(s):  
Somatosensory Cortex ◽  
Channel Blocker ◽  
Complete Removal ◽  
Absence Epilepsy ◽  
Primary Somatosensory Cortex ◽  
Cumulative Duration ◽  
Electroencephalogram Eeg ◽  
The Brain ◽  
Field Area ◽  
Recording Electrodes

<b><i>Introduction:</i></b> Absence epilepsy is associated with diffuse spike-and-wave discharges (SWD) on the electroencephalogram (EEG). Recent studies have demonstrated that the primary somatosensory cortex is also implicated in the generation of the SWDs. <b><i>Objective:</i></b> This study investigated the effects of systemic and local administrations of U-92032 into the brain of Genetic Absence Epilepsy Rats from Strasbourg (GAERS). <b><i>Methods:</i></b> GAERS animals underwent stereotaxic surgery for the placement of EEG recording electrodes and guide cannulas for U-92032 administration into the lateral ventricle (intracerebroventricular [i.c.v.]), upper lips area (S1Ulp) or barrel field area (S1B) of primary somatosensory cortex. Following 7 days of recovery, electrical activity was recorded continuously for 1 h before and 6 h after intraperitoneal (0.25; 1; 5 mg/kg i.p.) or local U-92032 or dimethyl sulfoxide (DMSO) injections. <b><i>Results:</i></b> No changes were detected in the cumulative duration, mean duration, and number of SWDs following i.p. U-92032 injections. Local i.c.v. injections of U-92032 caused a significant decrease in the cumulative duration (i.c.v., 50 and 100 nmol/L), mean duration (i.c.v., 50, 100, and 250 nmol/L), and the number (i.c.v., 250 nmol/L) of SWDs compared to DMSO groups. Intra-cortical (S1Ulp and S1B) U-92032 injections caused a significant decrease in all 3 parameters compared to DMSO groups, as well. <b><i>Conclusion:</i></b> Intra-cortical injection of U-92032 caused almost complete removal of SWDs in GAERS and i.c.v. administration resulted in a significant reduction. However, systemic i.p. administration did not cause a significant change with the applied ­doses.

Abstract 66: No Evidence of Functional Peri-Infarct Circuit Remapping in Mouse Somatosensory Cortex After Ischemic Stroke

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
William Zeiger ◽  
Mate Marosi ◽  
Satvir Saggi ◽  
Natalie Noble ◽  
Isa Samad ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Somatosensory Cortex ◽  
Single Neuron ◽  
Direct Evidence ◽  
Individual Layer ◽  
Two Photon ◽  
Whisker Stimulation ◽  
Transcriptomic Changes ◽  
The Brain

Following ischemic stroke, many patients exhibit partial spontaneous recovery, suggesting that the brain has endogenous mechanisms to recover lost functions. Evidence supports a role for peri-infarct cortex in recovery as this area undergoes structural, physiologic, and transcriptomic changes following stroke. It has been hypothesized that these changes promote circuit rewiring, leading spared neurons in the peri-infarct cortex to “remap” and subsume the function previously performed by neurons in the ischemic core. However, direct evidence for remapping at the single neuron level is lacking. To test this, we targeted photothrombotic (PT) strokes to an individual barrel (C1) in the barrel field of mouse primary somatosensory cortex (S1BF). We then performed longitudinal in vivo two-photon (2P) calcium imaging in Thy1 -GCaMP6s transgenic mice and recorded whisker-evoked responses of individual layer 2/3 neurons in the adjacent D3 barrel. Before stroke, ~30% of active neurons in the D3 barrel respond to stimulation of the D3 whisker and ~8% of neurons respond to the C1 whisker. Based on the remapping hypothesis, we predicted that the percentage of C1 whisker-responsive neurons in the spared D3 barrel would increase after stroke; however, we found that only ~2% of neurons in the D3 barrel responded to C1 whisker stimulation one month after stroke. We also tested the effect of forced-use therapy on recovery by plucking all whiskers, except the C1 whisker corresponding to the infarcted barrel, following stroke. Still, we found that forced-use therapy did not lead to an increased percentage of C1 whisker-responsive neurons, but it did enhance the responses to C1 whisker stimulation in surviving C1-responsive neurons in the peri-infarct cortex. These results suggest that at the circuit level recovery may occur through potentiation of spared homotopic neurons rather than remapping of neurons to perform new functions.

Experience-dependent plasticity of neurovascularization

2015 ◽  
Vol 114 (4) ◽  
pp. 2077-2079 ◽  
Author(s):  
Koen Kole
Keyword(s):  
Somatosensory Cortex ◽  
Functional Organization ◽  
Brain Plasticity ◽  
Critical Factor ◽  
Primary Somatosensory Cortex ◽  
Dependent Plasticity ◽  
Cellular Components ◽  
The Brain

Experience powerfully shapes structural and functional organization of neurons during development and in adulthood. Recent experiments in the mouse primary somatosensory cortex now suggest that experience is also a critical factor in shaping neurovasculature and promoting angiogenesis. These results support the universality of brain plasticity and show that all structural cellular components in the brain, from neuron and glia to epithelia, are shaped by experience.

Neuronal correlates of tactile speed in primary somatosensory cortex

2013 ◽  
Vol 110 (7) ◽  
pp. 1554-1566 ◽  
Author(s):  
Alexandra Dépeault ◽  
El-Mehdi Meftah ◽  
C. Elaine Chapman
Keyword(s):  
Somatosensory Cortex ◽  
Cortical Neurons ◽  
Primary Somatosensory Cortex ◽  
Spatial Period ◽  
Speed Scaling ◽  
Brain Extracts ◽  
Texture Sensitivity ◽  
Hand Region ◽  
The Brain ◽  
Area 3B

Moving stimuli activate all of the mechanoreceptive afferents involved in discriminative touch, but their signals covary with several parameters, including texture. Despite this, the brain extracts precise information about tactile speed, and humans can scale the tangential speed of moving surfaces as long as they have some surface texture. Speed estimates, however, vary with texture: lower estimates for rougher surfaces (increased spatial period, SP). We hypothesized that the discharge of cortical neurons playing a role in scaling tactile speed should covary with speed and SP in the same manner. Single-cell recordings ( n = 119) were made in the hand region of primary somatosensory cortex (S1) of awake monkeys while raised-dot surfaces (longitudinal SPs, 2–8 mm; periodic or nonperiodic) were displaced under their fingertips at speeds of 40–105 mm/s. Speed sensitivity was widely distributed (area 3b, 13/25; area 1, 32/51; area 2, 31/43) and almost invariably combined with texture sensitivity (82% of cells). A subset of cells (27/64 fully tested speed-sensitive cells) showed a graded increase in discharge with increasing speed for testing with both sets of surfaces (periodic, nonperiodic), consistent with a role in tactile speed scaling. These cells were almost entirely confined to caudal S1 (areas 1 and 2). None of the speed-sensitive cells, however, showed a pattern of decreased discharge with increased SP, as found for subjective speed estimates in humans. Thus further processing of tactile motion signals, presumably in higher-order areas, is required to explain human tactile speed scaling.

scholarly journals A spatial map in the somatosensory cortex

2018 ◽  
Author(s):  
Xiaoyang Long ◽  
Sheng-Jia Zhang
Keyword(s):  
Somatosensory Cortex ◽  
Spatial Representation ◽  
Hippocampal Formation ◽  
Place Cells ◽  
Border Cells ◽  
Head Direction ◽  
Head Direction Cells ◽  
Sensory Inputs ◽  
Boundary Vector ◽  
The Brain

AbstractSpatially selective firing in the forms of place cells, grid cells, boundary vector/border cells and head direction cells are the basic building blocks of a canonical spatial navigation system centered on the hippocampal-entorhinal complex. While head direction cells can be found throughout the brain, spatial tuning outside the hippocampal formation are often non-specific or conjunctive to other representations such as a reward. Although the precise mechanism of spatially selective activities is not understood, various studies show sensory inputs (particularly vision) heavily modulate spatial representation in the hippocampal-entorhinal circuit. To better understand the contribution from other sensory inputs in shaping spatial representation in the brain, we recorded from the primary somatosensory cortex in foraging rats. To our surprise, we were able to identify the full complement of spatial activity patterns reported in the hippocampal-entorhinal network, namely, place cells, head direction cells, boundary vector/border cells, grid cells and conjunctive cells. These newly identified somatosensory spatial cell types form a spatial map outside the hippocampal formation and support the hypothesis that location information is necessary for body representation in the somatosensory cortex, and may be analogous to spatially tuned representations in the motor cortex relating to the movement of body parts. Our findings are transformative in our understanding of how spatial information is used and utilized in the brain, as well as functional operations of the somatosensory cortex in the context of rehabilitation with brain-machine interfaces.

scholarly journals Finger somatotopy is preserved after tetraplegia but deteriorates over time

2021 ◽  
Author(s):  
Sanne Kikkert ◽  
Dario Pfyffer ◽  
Michaela Verling ◽  
Patrick Freund ◽  
Nicole Wenderoth
Keyword(s):  
Somatosensory Cortex ◽  
Primary Somatosensory Cortex ◽  
Healthy Controls ◽  
Body Parts ◽  
Functional Connection ◽  
Cross Sectional ◽  
Functional Connections ◽  
Cord Injury ◽  
Time Since Injury ◽  
The Brain

AbstractFollowing spinal cord injury (SCI), the motor output flow to the limb(s) and sensory input to the brain is largely lost. While attempted movements with the paralysed and sensory deprived body part can still evoke signals in the sensorimotor system, this task-related “net” brain activity of SCI patients differs substantially from healthy controls. Such reorganised and/or altered activity is thought to reflect abnormal processing. It is however possible that this altered ‘net’ sensorimotor activity in SCI patients conceals preserved somatotopically-specific representations of the paralysed and sensory deprived body parts that could be exploited in a functionally meaningful manner (e.g. via neuroprosthetics).In this cross-sectional study, we investigated whether a functional connection between the periphery and the brain is necessary to maintain somatosensory representations. We used functional MRI and an (attempted) finger movement task to characterise the somatotopic hand layout in the primary somatosensory cortex and structural MRI to assess spared spinal tissue bridges. We tested 14 tetraplegic SCI patients (mean age ± s.e.m.=55 ± 3.6; 1 female) who differed in terms of lesion completeness, retained sensorimotor functioning, and time since injury, as well as 18 healthy control participants (mean age ± s.e.m.=56 ± 3.6 years; 1 female).Our results revealed somatotopically organised representations of patients’ hands in which neighbouring clusters showed selectivity for neighbouring fingers in contralateral S1, qualitatively similar to those observed in healthy controls. To quantify whether these representations were normal in tetraplegic SCI patients we correlated each participant’s intricate representational distance pattern across all fingers (revealed using representational similarity analysis) with a canonical inter-finger distance pattern obtained from an independent sample. The resulting hand representation typicality scores were not significantly different between patients and controls. This was even true when considering two individual patients with no sensory hand functioning, no hand motor functioning, and no spared spinal tissue bridges. However, a correlational analysis revealed that over years since SCI the hand representation typicality in primary somatosensory cortex deteriorates.We show that somatosensory representations can be maintained for several years following SCI even in the absence of perhiperhal inputs. Such preserved cortical hand representations could therefore be exploited in a functionally meaningful way by rehabilitation approaches that attempt to establish new functional connections between the hand and the brain after an SCI (e.g. through neuroprosthetics). However, time since injury may critically influence the somatotopic representations of SCI patients and might thereby impact the success of such rehabilitation approaches.

scholarly journals UP-DOWN cortical dynamics reflect state transitions in a bistable balanced network

2016 ◽  
Author(s):  
Daniel Jercog ◽  
Alex Roxin ◽  
Peter Barthó ◽  
Artur Luczak ◽  
Albert Compte ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
State Transitions ◽  
Quiescent State ◽  
Population Activity ◽  
Cortical Dynamics ◽  
Underlying Mechanisms ◽  
The Brain ◽  
Population Rate ◽  
Low Rate ◽  
Balanced Network

AbstractIn the idling brain, neuronal circuits often exhibit transitions between periods of sustained firing (UP state) and quiescence (DOWN state). Although these dynamics occur across multiple areas and behavioral conditions, the underlying mechanisms remain unclear. Here we analyze spontaneous population activity from the somatosensory cortex of urethane-anesthetized rats. We find that UP and DOWN periods are variable (i.e. non-rhythmic) and that the population rate shows no significant decay during UP periods. We build a network model of excitatory (E) and inhibitory (I) neurons that exhibits a new bistability between a quiescent state and a balanced state of arbitrarily low rate. Fluctuating inputs trigger state transitions. Adaptation in E cells paradoxically causes a marginal decay of E-rate but a marked decay of I-rate, a signature of balanced bistability that we validate experimentally. Our findings provide evidence of a bistable balanced network that exhibits non-rhythmic state transitions when the brain rests.

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