Changes in the response properties of neurons in the ventroposterior lateral thalamic nucleus of the raccoon after peripheral deafferentation

1996 ◽  
Vol 75 (6) ◽  
pp. 2441-2450 ◽  
Author(s):  
D. D. Rasmusson
Keyword(s):  
Receptive Field ◽  
Thalamic Nucleus ◽  
Receptive Fields ◽  
Field Size ◽  
Mechanical Stimuli ◽  
Sensory Pathways ◽  
Average Latency ◽  
Somatotopic Map ◽  
Almost All ◽  
Stimulation Of

1. Single neurons in the ventroposterior lateral thalamic nucleus were studied in 10 anesthetized raccoons, 4 of which had undergone amputation of the fourth digit 4-5 mo before recording. Neurons with receptive fields on the glabrous skin of a forepaw digit were examined in response to electrical stimulation of the “on-focus” digit that contained the neuron's receptive field and stimulation of an adjacent, “off-focus” digit. 2. In normal raccoons all neurons responded to on-focus stimulation with an excitation at a short latency (mean 13 ms), whereas only 63% of the neurons responded to off-focus digit stimulation. The off-focus responses had a longer latency (mean 27.2 ms) and a higher threshold than the on-focus responses (800 and 452 microA, respectively). Only 3 of 32 neurons tested with off-focus stimulation had both a latency and a threshold within the range of on-focus values. Inhibition following the excitation was seen in the majority of neurons with both types of stimulation. 3. In the raccoons with digit removal, the region of the thalamus that had lost its major peripheral input (the “deafferented” region) was distinguished from the normal third and fifth digit regions on the basis of the sequence of neuronal receptive fields within a penetration and receptive field size as described previously. 4. Almost all of the neurons in the deafferented region (91%) were excited by stimulation of one or both adjacent digits. The average latency for these responses was shorter (15.3 ms) and the threshold was lower than was the case with off-focus stimulation in control animals. These values were not significantly different from the responses to on-focus stimulation in the animals with digit amputation. 5. These results confirm that reorganization of sensory pathways can be observed at the thalamic level. In addition to the changes in the somatotopic map that have been shown previously with the use of mechanical stimuli, the present paper demonstrates an improvement in several quantitative measures of single-unit responses. Many of these changes suggest that this reorganization could be explained by an increased effectiveness of preexisting, weak connections from the off-focus digits; however, the increase in the proportion of neurons responding to stimulation of adjacent digits may indicate that sprouting of new connections also occurs.

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.

Prenatal development of the receptive fields of individual trigeminal ganglion cells in the rat

1993 ◽  
Vol 69 (4) ◽  
pp. 1171-1180 ◽  
Author(s):  
N. L. Chiaia ◽  
W. R. Bauer ◽  
R. W. Rhoades
Keyword(s):  
Receptive Field ◽  
Ganglion Cells ◽  
Receptive Fields ◽  
Prenatal Development ◽  
Primary Afferents ◽  
Field Size ◽  
Mechanical Stimuli ◽  
Unit Recording ◽  
Tactile Stimuli ◽  
Fetal Rats

1. Extracellular single-unit recording and receptive-field mapping techniques were used to evaluate the response characteristics of trigeminal (V) ganglion cells in unanesthetized, decerebrate, fetal rats between the ages of embryonic (E-) day 15 and E-20 (E-0 is the day of conception). 2. The receptive-field properties of the cells (n = 282) recorded at all of these ages except E-15 were remarkably similar; V primary afferents were generally silent in the absence of peripheral stimulation (94.3%) and gave rapidly adapting responses to innocuous tactile stimuli (97.5%). Rapid response decrements to repeated stimuli were observed in 9 of the 14 cells (64%) tested. 3. None of the cells recorded were activated by either heat or cold. No attempt was made to evaluate responses to noxious mechanical stimuli. 4. Particular attention was paid to neurons whose receptive fields involved mystacial vibrissae follicles. At all ages, neurons were recorded that responded to indentation of the skin at the base of the vibrissae, but vibrissa deflection was not an adequate stimulus for any of the cells tested. At all ages, nearly all (89.0%) of the 127 cells with vibrissa-related receptive fields responded to indentation of one and only one follicle. 5. These results indicate that the response properties (e.g., adaptation characteristics, ability to respond to repeated stimuli) of V primary afferents in fetal rats differ substantially from those of V ganglion cells in adult animals, but that the receptive-field size for these neurons in prenatal rats is, with very rare exceptions, adult-like from the earliest age at which they can be recorded. 6. These results, when considered together with the results of previous retrograde tracing experiments in fetal animals, suggest that the initial projections of V primary afferents to their peripheral targets may be quite accurate.

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.

scholarly journals Visual performance in behaving cats after prenatal unilateral enucleation

1993 ◽  
Vol 90 (23) ◽  
pp. 11142-11146 ◽  
Author(s):  
S Bisti ◽  
C Trimarchi
Keyword(s):  
Visual Acuity ◽  
Visual Field ◽  
Receptive Field ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Visual Performance ◽  
Field Size ◽  
Electrophysiological Recordings ◽  
Severe Impairment ◽  
Orientation Columns

Prenatal unilateral enucleation in mammals causes an extensive anatomical reorganization of visual pathways. The remaining eye innervates the entire extent of visual subcortical and cortical areas. Electrophysiological recordings have shown that the retino-geniculate connections are retinotopically organized and geniculate neurones have normal receptive field properties. In area 17 all neurons respond to stimulation of the remaining eye and retinotopy, orientation columns, and direction selectivity are maintained. The only detectable change is a reduction in receptive field size. Are these changes reflected in the visual behavior? We studied visual performance in cats unilaterally enucleated 3 weeks before birth (gestational age at enucleation, 39-42 days). We tested behaviorally the development of visual acuity and, in the adult, the extension of the visual field and the contrast sensitivity. We found no difference between prenatal monocularly enucleated cats and controls in their ability to orient to targets in different positions of the visual field or in their visual acuity (at any age). The major difference between enucleated and control animals was in contrast sensitivity:prenatal enucleated cats present a loss in sensitivity for gratings of low spatial frequency (below 0.5 cycle per degree) as well as a slight increase in sensitivity at middle frequencies. We conclude that prenatal unilateral enucleation causes a selective change in the spatial performance of the remaining eye. We suggest that this change is the result of a reduction in the number of neurones with large receptive fields, possibly due to a severe impairment of the Y system.

Receptive Field Size and Response Latency Are Correlated Within the Cat Visual Thalamus

2005 ◽  
Vol 93 (6) ◽  
pp. 3537-3547 ◽  
Author(s):  
Chong Weng ◽  
Chun-I Yeh ◽  
Carl R. Stoelzel ◽  
Jose-Manuel Alonso
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Response Latency ◽  
Time Course ◽  
Frequency Tuning ◽  
Receptive Fields ◽  
Cortical Cell ◽  
Field Size ◽  
Receptive Field Size ◽  
Spatial Frequency Tuning

Each point in visual space is encoded at the level of the thalamus by a group of neighboring cells with overlapping receptive fields. Here we show that the receptive fields of these cells differ in size and response latency but not at random. We have found that in the cat lateral geniculate nucleus (LGN) the receptive field size and response latency of neighboring neurons are significantly correlated: the larger the receptive field, the faster the response to visual stimuli. This correlation is widespread in LGN. It is found in groups of cells belonging to the same type (e.g., Y cells), and of different types (i.e., X and Y), within a specific layer or across different layers. These results indicate that the inputs from the multiple geniculate afferents that converge onto a cortical cell (approximately 30) are likely to arrive in a sequence determined by the receptive field size of the geniculate afferents. Recent studies have shown that the peak of the spatial frequency tuning of a cortical cell shifts toward higher frequencies as the response progresses in time. Our results are consistent with the idea that these shifts in spatial frequency tuning arise from differences in the response time course of the thalamic inputs.

Responses of Medullary Dorsal Horn Neurons to Corneal Stimulation by CO2 Pulses in the Rat

1999 ◽  
Vol 82 (5) ◽  
pp. 2092-2107 ◽  
Author(s):  
Harumitsu Hirata ◽  
James W. Hu ◽  
David A. Bereiter
Keyword(s):  
Thalamic Nucleus ◽  
Receptive Fields ◽  
Male Rats ◽  
Cervical Cord ◽  
Type I ◽  
Type Ii ◽  
Upper Cervical ◽  
The Difference ◽  
Evoked Activity ◽  
Stimulation Of

Corneal-responsive neurons were recorded extracellularly in two regions of the spinal trigeminal nucleus, subnucleus interpolaris/caudalis (Vi/Vc) and subnucleus caudalis/upper cervical cord (Vc/C1) transition regions, from methohexital-anesthetized male rats. Thirty-nine Vi/Vc and 26 Vc/C1 neurons that responded to mechanical and electrical stimulation of the cornea were examined for convergent cutaneous receptive fields, responses to natural stimulation of the corneal surface by CO2 pulses (0, 30, 60, 80, and 95%), effects of morphine, and projections to the contralateral thalamus. Forty-six percent of mechanically sensitive Vi/Vc neurons and 58% of Vc/C1 neurons were excited by CO2 stimulation. The evoked activity of most cells occurred at 60% CO2 after a delay of 7–22 s. At the Vi/Vc transition three response patterns were seen. Type I cells ( n = 11) displayed an increase in activity with increasing CO2 concentration. Type II cells ( n = 7) displayed a biphasic response, an initial inhibition followed by excitation in which the magnitude of the excitatory phase was dependent on CO2 concentration. A third category of Vi/Vc cells (type III, n = 3) responded to CO2 pulses only after morphine administration (>1.0 mg/kg). At the Vc/C1 transition, all CO2-responsive cells ( n = 15) displayed an increase in firing rates with greater CO2 concentration, similar to the pattern of type I Vi/Vc cells. Comparisons of the effects of CO2 pulses on Vi/Vc type I units, Vi/Vc type II units, and Vc/C1 corneal units revealed no significant differences in threshold intensity, stimulus encoding, or latency to sustained firing. Morphine (0.5–3.5 mg/kg iv) enhanced the CO2-evoked activity of 50% of Vi/Vc neurons tested, whereas all Vc/C1 cells were inhibited in a dose-dependent, naloxone-reversible manner. Stimulation of the contralateral posterior thalamic nucleus antidromically activated 37% of Vc/C1 corneal units; however, no effective sites were found within the ventral posteromedial thalamic nucleus or nucleus submedius. None of the Vi/Vc corneal units tested were antidromically activated from sites within these thalamic regions. Corneal-responsive neurons in the Vi/Vc and Vc/C1 regions likely serve different functions in ocular nociception, a conclusion reflected more by the difference in sensitivity to analgesic drugs and efferent projection targets than by the CO2 stimulus intensity encoding functions. Collectively, the properties of Vc/C1 corneal neurons were consistent with a role in the sensory-discriminative aspects of ocular pain due to chemical irritation. The unique and heterogeneous properties of Vi/Vc corneal neurons suggested involvement in more specialized ocular functions such as reflex control of tear formation or eye blinks or recruitment of antinociceptive control pathways.

Two-dimensional receptive-field organization in striate cortical neurons of the cat

1994 ◽  
Vol 11 (4) ◽  
pp. 703-720 ◽  
Author(s):  
Ming Sun ◽  
A. B. Bonds
Keyword(s):  
Receptive Field ◽  
Cortical Neurons ◽  
Ocular Dominance ◽  
Receptive Fields ◽  
Field Size ◽  
Two Dimensional ◽  
Cortical Layers ◽  
Field Organization ◽  
Receptive Field Organization ◽  
Cortical Receptive Fields

AbstractThe two-dimensional organization of receptive fields (RFs) of 44 cells in the cat visual cortex and four cells from the cat LGN was measured by stimulation with either dots or bars of light. The light bars were presented in different positions and orientations centered on the RFs. The RFs found were arbitrarily divided into four general types: Punctate, resembling DOG filters (11%); those resembling Gabor filters (9%); elongate (36%); and multipeaked-type (44%). Elongate RFs, usually found in simple cells, could show more than one excitatory band or bifurcation of excitatory regions. Although regions inhibitory to a given stimulus transition (e.g. ON) often coincided with regions excitatory to the opposite transition (e.g. OFF), this was by no means the rule. Measurements were highly repeatable and stable over periods of at least 1 h. A comparison between measurements made with dots and with bars showed reasonable matches in about 40% of the cases. In general, bar-based measurements revealed larger RFs with more structure, especially with respect to inhibitory regions. Inactivation of lower cortical layers (V-VI) by local GABA injection was found to reduce sharpness of detail and to increase both receptive-field size and noise in upper layer cells, suggesting vertically organized RF mechanisms. Across the population, some cells bore close resemblance to theoretically proposed filters, while others had a complexity that was clearly not generalizable, to the extent that they seemed more suited to detection of specific structures. We would speculate that the broadly varying forms of cat cortical receptive fields result from developmental processes akin to those that form ocular-dominance columns, but on a smaller scale.

Hebb-Type Dynamics is Sufficient to Account for the Inverse Magnification Rule in Cortical Somatotopy

1990 ◽  
Vol 2 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Kamil A. Grajski ◽  
Michael M. Merzenich
Keyword(s):  
Computer Simulation ◽  
Receptive Field ◽  
Cortical Neuron ◽  
Inverse Relationship ◽  
Unit Area ◽  
Skin Surface ◽  
Field Size ◽  
Synaptic Modification ◽  
Somatotopic Map ◽  
Cortical Magnification

The inverse magnification rule in cortical somatotopy is the experimentally derived inverse relationship between cortical magnification (area of somatotopic map representing a unit area of skin surface) and receptive field size (area of restricted skin surface driving a cortical neuron). We show by computer simulation of a simple, multilayer model that Hebb-type synaptic modification subject to competitive constraints is sufficient to account for the inverse magnification rule.

Unmyelinated nociceptors of rat paraspinal tissues

1995 ◽  
Vol 73 (5) ◽  
pp. 1752-1762 ◽  
Author(s):  
G. M. Bove ◽  
A. R. Light
Keyword(s):  
Lumbar Spine ◽  
Intact Animal ◽  
Receptive Fields ◽  
Clinical Importance ◽  
Mechanical Stimuli ◽  
Peripheral Neuropathies ◽  
Deep Tissue ◽  
Surrounding Connective Tissue ◽  
Thermal Stimuli ◽  
Stimulation Of

1. We made recordings from rat dorsal root filaments to study unmyelinated afferent units (conduction velocity < or = 1.5 m/s) associated with deep paraspinal tissues of the dorsal sacrum and proximal tail. Data from 57 unmyelinated units were analyzed in 47 experiments. Receptive fields were identified in intact animals and then surgically isolated using microdissection. Units were characterized using mechanical, noxious chemical, and thermal stimuli. 2. These recordings revealed innervation of the nerve sheaths and surrounding connective tissue, muscles, tendons, and tissue apposed to the undersurface of the skin. No units were found with receptive fields directly on joint capsular tissue. The receptive fields of the units were often multiple and located in more than one tissue; 31 of 57 units showed convergence from different tissues. 3. The units with receptive fields on neurovascular bundles shared sensitivities with other deep tissue units described in this and other reports. These units may have clinical importance in pain due to peripheral neuropathies. 4. The units initially responded to strong mechanical stimulation of the intact animal and often to noxious stretch of the tail. Once surgically isolated, an individual unit's threshold to mechanical stimuli appeared lower. 5. Capsaicin (0.001%-0.1%) elicited responses in 81% (17 of 21) of the units tested. Bradykinin (20 micrograms/ml) elicited responses in 45% (10 of 22) of the units tested. Noxious cold (4-10 degrees C) and hot (55 degrees C) stimulation elicited discharges from 33% (5 of 15) and 25% (5 of 20) of the units tested, respectively. 6. The unmyelinated units had similar mechanical, chemical, and thermal sensitivities. These similarities and the observed convergence only allowed separation of units by the tissue in which the ending was found, and did not allow further classification. 7. The prevalence of background discharge suggested that many units were sensitized during the experiments. 8. The sensitivities of these paraspinal units were similar to those reported for other tissues. Because of the anatomic similarity of the paraspinal tissues of the proximal tail and the lumbar spine, the conclusions of the present study can be related to the lumbar spine. These afferent units are thought to participate in nociception from the deep paraspinal tissues.

scholarly journals Cutaneous stimulation evokes long-lasting excitation of spinal interneurons in the turtle

1990 ◽  
Vol 64 (4) ◽  
pp. 1134-1148 ◽  
Author(s):  
S. N. Currie ◽  
P. S. Stein
Keyword(s):  
Spinal Cord ◽  
Receptive Field ◽  
Action Potential ◽  
Receptive Fields ◽  
Neural Mechanisms ◽  
Cutaneous Afferents ◽  
Cutaneous Stimulation ◽  
Single Action ◽  
Single Action Potential ◽  
Stimulation Of

1. We demonstrated multisecond increases in the excitability of the rostral-scratch reflex in the turtle by electrically stimulating the shell at sites within the rostral-scratch receptive field. To examine the cellular mechanisms for these multisecond increases in scratch excitability, we recorded from single cutaneous afferents and sensory interneurons that responded to stimulation of the shell within the rostral-scratch receptive field. A single segment of the midbody spinal cord (D4, the 4th postcervical segment) was isolated in situ by transecting the spinal cord at the segment's anterior and posterior borders. The isolated segment was left attached to its peripheral nerve that innervates part of the rostral-scratch receptive field. A microsuction electrode (4-5 microns ID) was used to record extracellularly from the descending axons of cutaneous afferents and interneurons in the spinal white matter at the posterior end of the D4 segment. 2. The turtle shell is innervated by slowly and rapidly adapting cutaneous afferents. All cutaneous afferents responded to a single electrical stimulus to the shell with a single action potential. Maintained mechanical stimulation applied to the receptive field of some slowly adapting afferents produced several seconds of afterdischarge at stimulus offset. We refer to the cutaneous afferent afterdischarge caused by mechanical stimulation of the shell as "peripheral afterdischarge." 3. Within the D4 spinal segment there were some interneurons that responded to a brief mechanical stimulus within their receptive fields on the shell with short afterdischarge and others that responded with long afterdischarge. Short-afterdischarge interneurons responded to a single electrical pulse to a site in their receptive fields either with a brief train of action potentials or with a single action potential. Long-afterdischarge interneurons responded to a single electrical shell stimulus with up to 30 s of afterdischarge. Long-afterdischarge interneurons also exhibited strong temporal summation in response to a pair of electrical shell stimuli delivered up to several seconds apart. Because all cutaneous afferents responded to an electrical shell stimulus with a single action potential, we conclude that electrically evoked afterdischarge in interneurons was produced by neural mechanisms in the spinal cord; we refer to this type of afterdischarge as "central afterdischarge." 4. These results demonstrate that neural mechanisms for long-lasting excitability changes in response to cutaneous stimulation reside in a single segment of the spinal cord. Cutaneous interneurons with long afterdischarge may serve as cellular loci for multise

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