scholarly journals Widespread Decoding of Tactile Input Patterns Among Thalamic Neurons

2021 ◽  
Vol 15 ◽  
Author(s):  
Anders Wahlbom ◽  
Jonas M. D. Enander ◽  
Henrik Jörntell
Keyword(s):  
Response Latency ◽  
Cortical Neurons ◽  
Tactile Stimulation ◽  
Single Pulse ◽  
Afferent Input ◽  
Skin Area ◽  
Tactile Information ◽  
Thalamic Neurons ◽  
Activation Patterns ◽  
Tactile Input

Whereas, there is data to support that cuneothalamic projections predominantly reach a topographically confined volume of the rat thalamus, the ventroposterior lateral (VPL) nucleus, recent findings show that cortical neurons that process tactile inputs are widely distributed across the neocortex. Since cortical neurons project back to the thalamus, the latter observation would suggest that thalamic neurons could contain information about tactile inputs, in principle regardless of where in the thalamus they are located. Here we use a previously introduced electrotactile interface for producing sets of highly reproducible tactile afferent spatiotemporal activation patterns from the tip of digit 2 and record neurons throughout widespread parts of the thalamus of the anesthetized rat. We find that a majority of thalamic neurons, regardless of location, respond to single pulse tactile inputs and generate spike responses to such tactile stimulation patterns that can be used to identify which of the inputs that was provided, at above-chance decoding performance levels. Thalamic neurons with short response latency times, compatible with a direct tactile afferent input via the cuneate nucleus, were typically among the best decoders. Thalamic neurons with longer response latency times as a rule were also found to be able to decode the digit 2 inputs, though typically at a lower decoding performance than the thalamic neurons with presumed direct cuneate inputs. These findings provide support for that tactile information arising from any specific skin area is widely available in the thalamocortical circuitry.

Input-output relationships of the primary face motor cortex in the monkey (Macaca fascicularis)

1989 ◽  
Vol 61 (2) ◽  
pp. 350-362 ◽  
Author(s):  
C. S. Huang ◽  
H. Hiraba ◽  
B. J. Sessle
Keyword(s):  
Macaca Fascicularis ◽  
Tactile Stimulation ◽  
Afferent Input ◽  
Upper Lip ◽  
Lower Lip ◽  
Medial Border ◽  
Tactile Input ◽  
Orofacial Region ◽  
Afferent Inputs ◽  
Stimulation Of

1. Somatosensory afferent input and its relationship with efferent output were examined in the primary face motor cortex (MI) and adjacent cerebral cortical areas. Excitatory afferent inputs were tested in a total of 1,654 single neurons recorded in awake or anesthetized monkeys (Macaca fascicularis), and output was characterized in these same monkeys by the movement and EMG responses evoked by intracortical microstimulation (ICMS) at the neuronal recording sites. 2. Most neurons in the MI area responded to light tactile stimulation of the orofacial region, especially the upper lip, lower lip, and tongue. Although contralateral afferent inputs predominated, 21% of the neurons received ipsilateral or bilateral orofacial inputs. The afferent input evoked by tactile stimulation of the upper and lower lips was represented especially at the medial border and the input from the tongue at the lateral border of MI. However, in most regions of MI between the medial and lateral borders, an intermingling of tactile inputs from different orofacial areas occurred. Multiple representation of tactile input from the same orofacial area was found in several, often quite separate, intracortical sites in MI. 3. Only a small proportion of the MI neurons could be activated by the deep stimuli used (e.g., stretch and pressure applied to muscle, passive jaw movement, low-intensity stimulation of hypoglossal nerve) from the orofacial region. Those neurons which did respond to these low-threshold deep inputs were not clearly segregated from those which responded to tactile input, although most of the neurons receiving deep input were located in the rostral part of MI. 4. A somatotopic pattern of representation of orofacial tactile input was more obvious in the primary face somatosensory cortex (SI). At the medial border of SI, the periorbital area was represented, then followed laterally in sequence the tactile representation of the upper lip, lower lip, and intraoral area. Contralateral afferent inputs predominated, but as in MI, a considerable proportion of SI neurons received ipsilateral or bilateral orofacial inputs. Few neurons in the region explored (areas 3b, 1, and 2) responded to deep orofacial stimuli. 5. Tactile input also dominated the input patterns of neurons in the premotor cortex (PM). Most neurons received ipsilateral or bilateral orofacial afferent inputs and no clear somatotopic pattern was noted. Several PM neurons were also activated by visual stimuli. 6. Muscle twitches evoked by ICMS were limited to MI.(ABSTRACT TRUNCATED AT 400 WORDS)

Developmental Expression of Calcium-Binding Protein-Containing Neurons in Neocortical Transplants

1998 ◽  
Vol 7 (2) ◽  
pp. 121-129 ◽  
Author(s):  
Jeffrey M. Rosenstein ◽  
Newton S. More ◽  
Nina Mani ◽  
Janette M. Krum
Keyword(s):  
Oxidative Stress ◽  
Cortical Neurons ◽  
Calcium Binding ◽  
Binding Protein ◽  
Substantial Reduction ◽  
Qualitative Change ◽  
Afferent Input ◽  
Calcium Binding Protein ◽  
Developmental Expression ◽  
Parvalbumin Neurons

The present study examined the development of calcium binding protein-containing neurons in a timed series of fetal neocortical transplants. The immunoexpression of parvalbumin and calbindin, which are subpopulations of GABAergic neurons, have been widely studied in normal development and in disease and injury states. Because of their purported resistance to oxidative injury by their ability to buffer Ca++ influx, these neurons have been particularly studied following ischemia. Because it is likely that oxidative stress is associated with the grafting procedure, we sought to determine if these neurons displayed enhanced survival characteristics. Normally, parvalbumin and calbindin represent about 5-10% of cortical neurons. Within 2-4 wk after grafting the expression of both proteins increased markedly in that a relatively larger number of neurons (27% for parvalbumin) were immunopositive. This increase was transitory, however, and by 4 mo and beyond, confocal microscopic data showed a reduction of over 50% of parvalbumin (+) neurons and processes. Calbindin (+) processes showed a qualitative change in that they were smaller with less terminal branching. Electron microscopy confirmed a substantial reduction in parvalbumin synaptic contacts. Interestingly, in older grafts, remaining parvalbumin neurons were those that were strongly NSE (+) suggesting a link between normal metabolism and Ca++ buffering in grafted neurons. It is possible that in early grafts certain neuronal populations transiently upregulated calcium binding proteins as a defensive mechanism against Ca++ influx associated with oxidative stress. Over time, however, following physiological normalization within grafts, the calcium binding protein (+) neurons are diminished, possibly due to lack of appropriate afferent input to the interneuronal pool.

Olfactory modulation of barrel cortex activity during active whisking and passive whisker stimulation

2021 ◽  
Author(s):  
Anthony Renard ◽  
Evan Harrell ◽  
Brice Bathallier
Keyword(s):  
Facial Nerve ◽  
Calcium Imaging ◽  
Tactile Stimulation ◽  
Barrel Cortex ◽  
Neuronal Responses ◽  
Population Activity ◽  
Tactile Information ◽  
Large Populations ◽  
Whisker Stimulation ◽  
The Impact

Abstract Rodents depend on olfaction and touch to meet many of their fundamental needs. The joint significance of these sensory systems is underscored by an intricate coupling between sniffing and whisking. However, the impact of simultaneous olfactory and tactile inputs on sensory representations in the cortex remains elusive. To study these interactions, we recorded large populations of barrel cortex neurons using 2-photon calcium imaging in head-fixed mice during olfactory and tactile stimulation. We find that odors alter barrel cortex activity in at least two ways, first by enhancing whisking, and second by central cross-talk that persists after whisking is abolished by facial nerve sectioning. Odors can either enhance or suppress barrel cortex neuronal responses, and while odor identity can be decoded from population activity, it does not interfere with the tactile representation. Thus, barrel cortex represents olfactory information which, in the absence of learned associations, is coded independently of tactile information.

scholarly journals Widely Different Correlation Patterns Between Pairs of Adjacent Thalamic Neurons In vivo

2021 ◽  
Vol 15 ◽  
Author(s):  
Anders Wahlbom ◽  
Hannes Mogensen ◽  
Henrik Jörntell
Keyword(s):  
Cortical Neurons ◽  
Pyramidal Neurons ◽  
Thalamic Nuclei ◽  
Thalamic Neurons ◽  
Low Weight ◽  
Afferent Inputs ◽  
Cortical Inputs ◽  
Unique Relationship ◽  
Spike Firing

We have previously reported different spike firing correlation patterns among pairs of adjacent pyramidal neurons within the same layer of S1 cortex in vivo, which was argued to suggest that acquired synaptic weight modifications would tend to differentiate adjacent cortical neurons despite them having access to near-identical afferent inputs. Here we made simultaneous single-electrode loose patch-clamp recordings from 14 pairs of adjacent neurons in the lateral thalamus of the ketamine-xylazine anesthetized rat in vivo to study the correlation patterns in their spike firing. As the synapses on thalamic neurons are dominated by a high number of low weight cortical inputs, which would be expected to be shared for two adjacent neurons, and as far as thalamic neurons have homogenous membrane physiology and spike generation, they would be expected to have overall similar spike firing and therefore also correlation patterns. However, we find that across a variety of thalamic nuclei the correlation patterns between pairs of adjacent thalamic neurons vary widely. The findings suggest that the connectivity and cellular physiology of the thalamocortical circuitry, in contrast to what would be expected from a straightforward interpretation of corticothalamic maps and uniform intrinsic cellular neurophysiology, has been shaped by learning to the extent that each pair of thalamic neuron has a unique relationship in their spike firing activity.

scholarly journals 6B4 proteoglycan/phosphacan is a repulsive substratum but promotes morphological differentiation of cortical neurons

Development ◽  
1996 ◽  
Vol 122 (2) ◽  
pp. 647-658
Author(s):  
N. Maeda ◽  
M. Noda
Keyword(s):  
Cell Adhesion ◽  
Neurite Outgrowth ◽  
Cortical Neurons ◽  
Tyrosine Phosphatase ◽  
Neuronal Cell ◽  
Morphological Differentiation ◽  
Cell Types ◽  
Thalamic Neurons ◽  
Neurite Extension ◽  
The Brain

6B4 proteoglycan/phosphacan is one of the major phosphate-buffered saline-soluble chondroitin sulfate proteoglycans of the brain. Recently, this molecule has been demonstrated to be an extracellular variant of the proteoglycan-type protein tyrosine phosphatase, PTPzeta (RPTPbeta). The influence of the 6B4 proteoglycan, adsorbed onto the substratum, on cell adhesion and neurite outgrowth was studied using dissociated neurons from the cerebral cortex and thalamus. 6B4 proteoglycan adsorbed onto plastic tissue culture dishes did not support neuronal cell adhesion, but rather exerted repulsive effects on cortical and thalamic neurons. When neurons were densely seeded on patterned substrata consisting of a grid-like structure of alternating poly-L-lysine and 6B4 proteoglycan-coated poly-L-lysine domains, they were concentrated on the poly-L-lysine domains. However, 6B4 proteoglycan did not retard the differentiation of neurons but rather promoted neurite outgrowth and development of the dendrites of cortical neurons, when neurons were sparsely seeded on poly-L-lysine-conditioned coverslips continuously coated with 6B4 proteoglycan. This effect of 6B4 proteoglycan on the neurite extension of cortical neurons was apparent even on coverslips co-coated with fibronectin or tenascin. By contrast, the neurite extension of thalamic neurons was not modified by 6B4 proteoglycan. Chondroitinase ABC or keratanase digestion of 6B4 proteoglycan did not affect its neurite outgrowth promoting activity, but a polyclonal antibody against 6B4 proteoglycan completely suppressed this activity, suggesting that a protein moiety is responsible for the activity. 6B4 proteoglycan transiently promoted tyrosine phosphorylation of an 85x10(3) Mr protein in the cortical neurons, which correlated with the induction of neurite outgrowth. These results suggest that 6B4 proteoglycan/phosphacan modulates morphogenesis and differentiation of neurons dependent on its spatiotemporal distribution and the cell types in the brain.

scholarly journals Development of Thalamocortical Response Transformations in the Rat Whisker-Barrel System

2008 ◽  
Vol 99 (1) ◽  
pp. 356-366 ◽  
Author(s):  
Michael Shoykhet ◽  
Daniel J. Simons
Keyword(s):  
Cortical Neurons ◽  
Time Course ◽  
Receptive Fields ◽  
Second Phase ◽  
Adult Rats ◽  
Response Latencies ◽  
Thalamic Neurons ◽  
Response Properties ◽  
Temporal Domain

Extracellular single-unit recordings were used to characterize responses of thalamic barreloid and cortical barrel neurons to controlled whisker deflections in 2, 3-, and 4-wk-old and adult rats in vivo under fentanyl analgesia. Results indicate that response properties of thalamic and cortical neurons diverge during development. Responses to deflection onsets and offsets among thalamic neurons mature in parallel, whereas among cortical neurons responses to deflection offsets become disproportionately smaller with age. Thalamic neuron receptive fields become more multiwhisker, whereas those of cortical neurons become more single-whisker. Thalamic neurons develop a higher degree of angular selectivity, whereas that of cortical neurons remains constant. In the temporal domain, response latencies decrease both in thalamic and cortical neurons, but the maturation time-course differs between the two populations. Response latencies of thalamic cells decrease primarily between 2 and 3 wk of life, whereas response latencies of cortical neurons decrease in two distinct steps—the first between 2 and 3 wk of life and the second between the fourth postnatal week and adulthood. Although the first step likely reflects similar subcortical changes, the second phase likely corresponds to developmental myelination of thalamocortical fibers. Divergent development of thalamic and cortical response properties indicates that thalamocortical circuits in the whisker-to-barrel pathway undergo protracted maturation after 2 wk of life and provides a potential substrate for experience-dependent plasticity during this time.

Spike-Wave Complexes and Fast Components of Cortically Generated Seizures. IV. Paroxysmal Fast Runs in Cortical and Thalamic Neurons

1998 ◽  
Vol 80 (3) ◽  
pp. 1495-1513 ◽  
Author(s):  
Igor Timofeev ◽  
François Grenier ◽  
Mircea Steriade
Keyword(s):  
Electrical Stimulation ◽  
High Frequency ◽  
Cortical Neurons ◽  
Field Potential ◽  
Thalamic Nuclei ◽  
Experimental Conditions ◽  
Thalamic Neurons ◽  
Single Action ◽  
Spike Bursts ◽  
Spike Wave

Timofeev, Igor, François Grenier, and Mircea Steriade. Spike-wave complexes and fast components of cortically generated seizures. IV. Paroxysmal fast runs in cortical and thalamic neurons. J. Neurophysiol. 80: 1495–1513, 1998. In the preceding papers of this series, we have analyzed the cellular patterns and synchronization of neocortical seizures occurring spontaneously or induced by electrical stimulation or cortical infusion of bicuculline under a variety of experimental conditions, including natural states of vigilance in behaving animals and acute preparations under different anesthetics. The seizures consisted of two distinct components: spike-wave (SW) or polyspike-wave (PSW) at 2–3 Hz and fast runs at 10–15 Hz. Because the thalamus is an input source and target of cortical neurons, we investigated here the seizure behavior of thalamic reticular (RE) and thalamocortical (TC) neurons, two major cellular classes that have often been implicated in the generation of paroxysmal episodes. We performed single and dual simultaneous intracellular recordings, in conjunction with multisite field potential and extracellular unit recordings, from neocortical areas and RE and/or dorsal thalamic nuclei under ketamine-xylazine and barbiturate anesthesia. Both components of seizures were analyzed, but emphasis was placed on the fast runs because of their recent investigation at the cellular level. 1) The fast runs occurred at slightly different frequencies and, therefore, were asynchronous in various cortical neuronal pools. Consequently, dorsal thalamic nuclei, although receiving convergent inputs from different neocortical areas involved in seizure, did not express strongly synchronized fast runs. 2) Both RE and TC cells were hyperpolarized during seizure episodes with SW/PSW complexes and relatively depolarized during the fast runs. As known, hyperpolarization of thalamic neurons deinactivates a low-threshold conductance that generates high-frequency spike bursts. Accordingly, RE neurons discharged prolonged high-frequency spike bursts in close time relation with the spiky component of cortical SW/PSW complexes, whereas they fired single action potentials, spike doublets, or triplets during the fast runs. In TC cells, the cortical fast runs were reflected as excitatory postsynaptic potentials appearing after short latencies that were compatible with monosynaptic activation through corticothalamic pathways. 3) The above data suggested the cortical origin of these seizures. To further test this hypothesis, we performed experiments on completely isolated cortical slabs from suprasylvian areas 5 or 7 and demonstrated that electrical stimulation within the slab induces seizures with fast runs and SW/PSW complexes, virtually identical to those elicited in intact-brain animals. The conclusion of all papers in this series is that complex seizure patterns, resembling those described at the electroencephalogram level in different forms of clinical seizures with SW/PSW complexes and, particularly, in the Lennox-Gastaut syndrome of humans, are generated in neocortex. Thalamic neurons reflect cortical events as a function of membrane potential in RE/TC cells and degree of synchronization in cortical neuronal networks.

Functional properties of single neurons in the face primary motor cortex of the primate. II. Relations with trained orofacial motor behavior

1992 ◽  
Vol 67 (3) ◽  
pp. 759-774 ◽  
Author(s):  
G. M. Murray ◽  
B. J. Sessle
Keyword(s):  
Motor Cortex ◽  
Cortical Neurons ◽  
Primary Motor Cortex ◽  
Motor Behavior ◽  
Afferent Input ◽  
Single Neurons ◽  
Tongue Protrusion ◽  
Input And Output ◽  
The Face ◽  
Tongue Movements

1. The previous paper has described in detail the input and output features of single neurons located at sites within primate face motor cortex from which intracortical microstimulation (ICMS, less than or equal to 20 microA) evoked tongue movements at the lowest threshold ("tongue-MI" sites); for comparative purposes, we also reported on the input and output features of a smaller number of neurons recorded at sites from which ICMS could evoke jaw movements ("jaw-MI" sites), facial movements ("face-MI" sites), or, at a few sites, tongue movements and, at the same threshold intensity, either a jaw movement or a facial movement. 2. Our findings of an extensive and diverse representation of sites within face motor cortex of monkeys for the generation of elemental components of tongue movement, and the relatively few sites from which jaw-closing movements could be evoked, were consistent with our recent observations that reversible, cooling-induced inactivation of the face motor cortex severely impaired the performance by monkeys of a tongue-protrusion task but had only relatively minor effects on the performance of a biting task. In an attempt to establish a neuronal correlate for these different behavioral relations, the present study has documented the task-related activities of those single neurons that were characterized in the previous paper in terms of afferent input and ICMS-defined output features. 3. Each task required the development and maintenance by each monkey of a fixed force level for a minimum period of time to obtain a fruit-juice reward. During one or both of these tasks, we characterized the activities of 231 single face motor cortical neurons that were located at the above-mentioned ICMS-defined sites. Neurons were said to be related to a particular task if they showed statistically significant differences in firing rates during the task in comparison with a control pretrial period (PTP). 4. In tongue-MI, there was a significantly higher proportion of neurons (63% of 156 neurons tested) that were related to the tongue-protrusion task than to the biting task (15% of 65). However, in jaw-MI the proportion of neurons that were biting task-related (63% of 19) was significantly higher than the proportion related to the tongue-protrusion task (11% of 9); the proportion of biting task-related neurons at ICMS-defined jaw-closing sites was also higher than that at jaw-opening sites.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals The Effect of Limb Position on a Static Knee Extension Task can be Explained with a Simple Spinal Cord Circuit Model

2021 ◽  
Author(s):  
Gareth James Richard York ◽  
Hugh Osborne ◽  
Piyanee Sriya ◽  
Sarah Astill ◽  
Marc de Kamps ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Muscle Activity ◽  
Neural Circuits ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Afferent Input ◽  
Muscle Synergy ◽  
Knee Angle ◽  
Activation Patterns ◽  
Isometric Knee Extension

The influence of proprioceptive feedback on muscle activity during isometric tasks is the subject of conflicting studies. We performed an isometric knee extension task experiment based on two common clinical tests for mobility and flexibility. The task was carried out at four pre-set angles of the knee and we recorded from five muscles for two different hip positions. We applied muscle synergy analysis using non-negative matrix factorisation on surface electromyograph recordings to identify patterns in the data which changed with internal knee angle, suggesting a link between proprioception and muscle activity. We hypothesised that such patterns arise from the way proprioceptive and cortical signals are integrated in neural circuits of the spinal cord. Using the MIIND neural simulation platform, we developed a computational model based on current understanding of spinal circuits with an adjustable afferent input. The model produces the same synergy trends as observed in the data, driven by changes in the afferent input. In order to match the activation patterns from each knee angle and position of the experiment, the model predicts the need for three distinct inputs: two to control a non-linear bias towards the extensors and against the flexors, and a further input to control additional inhibition of rectus femoris. The results show that proprioception may be involved in modulating muscle synergies encoded in cortical or spinal neural circuits.

Sign in / Sign up

Export Citation Format

Share Document