The distribution of intrinsic cortical axons in area 3b of cat primary somatosensory cortex

1989 ◽  
Vol 78 (3) ◽  
Author(s):  
H.D. Schwark ◽  
E.G. Jones
Keyword(s):  
Somatosensory Cortex ◽  
Primary Somatosensory Cortex ◽  
Area 3B

scholarly journals Stimulus-Rate Sensitivity Discerns Area 3b of the Human Primary Somatosensory Cortex

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0128462 ◽  
Author(s):  
Yevhen Hlushchuk ◽  
Cristina Simões-Franklin ◽  
Cathy Nangini ◽  
Riitta Hari
Keyword(s):  
Somatosensory Cortex ◽  
Rate Sensitivity ◽  
Primary Somatosensory Cortex ◽  
Stimulus Rate ◽  
Area 3B

Cortical mechanisms underlying tactile discrimination in the monkey. I. Role of primary somatosensory cortex in passive texture discrimination

1996 ◽  
Vol 76 (5) ◽  
pp. 3382-3403 ◽  
Author(s):  
F. Tremblay ◽  
S. A. Ageranioti-Belanger ◽  
C. E. Chapman
Keyword(s):  
Somatosensory Cortex ◽  
Contact Force ◽  
Discharge Rate ◽  
The Other ◽  
Primary Somatosensory Cortex ◽  
Spatial Period ◽  
Motor Speed ◽  
Texture Discrimination ◽  
Significant Difference ◽  
Area 3B

1. The discharge patterns of 359 single neurons in the hand representation of primary somatosensory cortex (SI) of two monkeys (Macaca mulatta) were recorded during the performance of a passive texture discrimination task with the contralateral hand (104 in area 3b, 149 in area 1, and 106 in area 2). Three nyloprint surfaces were mounted on a drum that was rotated under the digit tips. One surface was entirely smooth, whereas the other two were smooth over the first half and rough over the second half (smooth/ rough) (raised dots, 1 mm high and 1 mm diam, in a rectangular array; spatial period of 3 mm across the rows and columns for most recordings; 9 mm between columns for selected recordings). The monkeys were trained to distinguish between the smooth and smooth/rough surfaces. After the surface presentation, the monkey indicated the texture of the second half of the surface by pushing or pulling, respectively, on a lever with the other arm. For most recordings an average tangential speed of 49 mm/s was tested. For selected recordings motor speed was incremented (63, 75, or 89 mm/s). 2. Two hundred eighty-three neurons had a cutaneous receptive field (RF) on the hand (96 in area 3b, 120 in area 1, and 67 in area 2). Thirty-five neurons had a deep RF (4 in area 3b, 15 in area 1, and 16 in area 2). Seven neurons had mixed cutaneous and deep RFs (4 in area 1, 3 in area 2). Thirty-four neurons had no identifiable RF (4 in area 3b, 10 in area 1, and 20 in area 2). 3. The discharge of 185 of 359 neurons was significantly modulated during the presentation of one or both surfaces compared with the discharge at rest. Cells with a cutaneous RF that included part or all of the distal phalangeal pads of the digits used in the task (usually digits III and IV) were more likely to be modulated during surface presentation (132 of 179, 74%) than those with a cutaneous RF not in contact with the surfaces (24 of 104, 23%). The remaining neurons (mixed, deep, or no RF) were also infrequently modulated (29 of 76, 38%). 4. Of the 185 modulated units, 118 cells were classified as texture related because there was a significant difference in the discharge rate evoked by the smooth/rough and smooth surfaces. Cells with a cutaneous RF that included the digital pads in contact with the surfaces were frequently texture related (100 of 132, 76%). Texture sensitivity was less frequently observed in the remaining modulated neurons (18 of 53, 34%: cutaneous RF not in contact with the surfaces, deep RF, mixed cutaneous and deep RF, no identifiable RF). 5. Texture-related neurons were found in areas 3b, 1, and 2. Two patterns of texture-related responses were observed in the 100 cutaneous units with an RF in contact with the surfaces. Thirty-one units were classified as showing a phasic response at the time the digits encountered the leading edge of the rough half of the surface. Fifty-eight cells were classified as phasic-tonic (or sometimes tonic at the slowest motor speeds) because the response lasted for the duration of the presentation of the rough portion of the surface. The remaining 11 neurons could not be readily classified into one or the other category and, indeed, generally showed clear texture-related responses only at higher motor speeds (> 49 mm/s, 9 of 11). 6. Speed sensitivity was systematically evaluated in 41 of 100 texture-related units with a cutaneous RF in contact with the surfaces. The discharge of 66% of the units (27 of 41) varied significantly with the speed of surface presentation, with discharge increasing at higher speeds. Speed sensitivity was found in all three cytoarchitectonic areas (6 of 6 cells in area 3b, 11 of 22 in area 1, and 10 of 13 in area 2). 7. Contact force was also systematically monitored in these experiments (69 of 100 texture-related cells with a cutaneous RF in contact with the surfaces). Linear regression analyses indicated than 22% (15 of 69) of the texture-related units were sensitive to contact force (13

Plasticity of Primary Somatosensory Cortex Paralleling Sensorimotor Skill Recovery From Stroke in Adult Monkeys

1998 ◽  
Vol 79 (4) ◽  
pp. 2119-2148 ◽  
Author(s):  
Christian Xerri ◽  
Michael M. Merzenich ◽  
Bret E. Peterson ◽  
William Jenkins
Keyword(s):  
Somatosensory Cortex ◽  
Skill Acquisition ◽  
Cortical Area ◽  
Receptive Fields ◽  
Field Size ◽  
Primary Somatosensory Cortex ◽  
Small Object ◽  
Object Retrieval ◽  
Area 3A ◽  
Area 3B

Xerri, Christian, Michael M. Merzenich, Bret E. Peterson, and William Jenkins. Plasticity of primary somatosensory cortex paralleling sensorimotor skill recovery from stroke in adult monkeys. J. Neurophysiol. 79: 2119–2148, 1998. Adult owl and squirrel monkeys were trained to master a small-object retrieval sensorimotor skill. Behavioral observations along with positive changes in the cortical area 3b representations of specific skin surfaces implicated specific glabrous finger inputs as important contributors to skill acquisition. The area 3b zones over which behaviorally important surfaces were represented were destroyed by microlesions, which resulted in a degradation of movements that had been developed in the earlier skill acquisition. Monkeys were then retrained at the same behavioral task. They could initially perform it reasonably well using the stereotyped movements that they had learned in prelesion training, although they acted as if key finger surfaces were insensate. However, monkeys soon initiated alternative strategies for small object retrieval that resulted in a performance drop. Over several- to many-week-long period, monkeys again used the fingers for object retrieval that had been used successfully before the lesion, and reacquired the sensorimotor skill. Detailed maps of the representations of the hands in SI somatosensory cortical fields 3b, 3a, and 1 were derived after postlesion functional recovery. Control maps were derived in the same hemispheres before lesions, and in opposite hemispheres. Among other findings, these studies revealed the following 1) there was a postlesion reemergence of the representation of the fingertips engaged in the behavior in novel locations in area 3b in two of five monkeys and a less substantial change in the representation of the hand in the intact parts of area 3b in three of five monkeys. 2) There was a striking emergence of a new representation of the cutaneous fingertips in area 3a in four of five monkeys, predominantly within zones that had formerly been excited only by proprioceptive inputs. This new cutaneous fingertip representation disproportionately represented behaviorally crucial fingertips. 3) There was an approximately two times enlargement of the representation of the fingers recorded in cortical area 1 in postlesion monkeys. The specific finger surfaces employed in small-object retrieval were differentially enlarged in representation. 4) Multiple-digit receptive fields were recorded at a majority of emergent, cutaneous area 3a sites in all monkeys and at a substantial number of area 1 sites in three of five postlesion monkeys. Such fields were uncommon in area 1 in control maps. 5) Single receptive fields and the component fields of multiple-digit fields in postlesion representations were within normal receptive field size ranges. 6) No significant changes were recorded in the SI hand representations in the opposite (untrained, intact) control hemisphere. These findings are consistent with “substitution” and “vicariation” (adaptive plasticity) models of recovery from brain damage and stroke.

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 Modular Processing in the Hand Representation of Primate Primary Somatosensory Cortex Coexists With Widespread Activation

2010 ◽  
Vol 104 (6) ◽  
pp. 3136-3145 ◽  
Author(s):  
Jamie L. Reed ◽  
Hui-Xin Qi ◽  
Pierre Pouget ◽  
Mark J. Burish ◽  
A. B. Bonds ◽  
...  
Keyword(s):  
Firing Rate ◽  
Somatosensory Cortex ◽  
Receptive Fields ◽  
Electrode Array ◽  
Electrode Site ◽  
Primary Somatosensory Cortex ◽  
Local Processing ◽  
Firing Rates ◽  
Area 3B ◽  
Activation Site

Neurons in the hand representation of primary somatosensory cortex (area 3b) are known to have discretely localized receptive fields; and these neurons form modules that can be visualized histologically as distinct digit and palm representations. Despite these indicators of the importance of local processing in area 3b, widespread interactions between stimuli presented to locations across the hand have been reported. We investigated the relationship of neuron firing rate with distance from the site of maximum activation in cortex by recording from a 100-electrode array with electrodes spaced 400 μm apart, implanted into the area 3b hand representation in anesthetized owl monkeys. For each stimulated location on the hand, the electrode site where neurons had the highest peak firing rate was defined as the peak activation site. The lesser firing rates of neurons at all other electrode sites in the grid were compared with the firing rates of neurons at the peak activation site. On average, peak firing rates of neurons decreased rapidly with distance away from the peak activation site. The effect of distance on the variance of firing rates was highly significant ( P < 0.0001). However, individual neurons retained high firing rates for distances over 3 mm. The clear decline in firing rate with distance from the most activated location indicates that local processing is emphasized in area 3b, while the distance of neurons with reduced but maintained firing rates ≤3–4 mm from the site of best activation demonstrated widespread activation in primary somatosensory cortex.

scholarly journals Tactile texture signals in primate primary somatosensory cortex and their relation to subjective roughness intensity

2016 ◽  
Vol 115 (4) ◽  
pp. 1767-1785 ◽  
Author(s):  
Stéphanie Bourgeon ◽  
Alexandra Dépeault ◽  
El-Mehdi Meftah ◽  
C. Elaine Chapman
Keyword(s):  
Firing Rate ◽  
Somatosensory Cortex ◽  
Discharge Rate ◽  
Scanning Speed ◽  
Primary Somatosensory Cortex ◽  
Small Range ◽  
Monotonic Increase ◽  
Wide Range ◽  
Texture Sensitivity ◽  
Area 3B

This study investigated the hypothesis that a simple intensive code, based on mean firing rate, could explain the cortical representation of subjective roughness intensity and its invariance with scanning speed. We examined the sensitivity of neurons in the cutaneous, finger representation of primary somatosensory cortex (S1) to a wide range of textures [1 mm high, raised-dot surfaces; spatial periods (SPs), 1.5–8.5 mm], scanned under the digit tips at different speeds (40–115 mm/s). Since subjective roughness estimates show a monotonic increase over this range and are independent of speed, we predicted that the mean firing rate of a subgroup of S1 neurons would share these properties. Single-unit recordings were made in four alert macaques (areas 3b, 1 and 2). Cells whose discharge rate showed a monotonic increase with SP, independent of speed, were particularly concentrated in area 3b. Area 2 was characterized by a high proportion of cells sensitive to speed, with or without texture sensitivity. Area 1 had intermediate properties. We suggest that area 3b and most likely area 1 play a key role in signaling roughness intensity, and that a mean rate code, signaled by both slowly and rapidly adapting neurons, is present at the level of area 3b. Finally, the substantial proportion of neurons that showed a monotonic change in discharge limited to a small range of SPs (often independent of response saturation) could play a role in discriminating smaller changes in SP.

scholarly journals A computational view of area 3b of primary somatosensory cortex

2013 ◽  
Vol 14 (S1) ◽  
Author(s):  
Georgios IS Detorakis ◽  
Nicolas P Rougier
Keyword(s):  
Somatosensory Cortex ◽  
Primary Somatosensory Cortex ◽  
Area 3B
Sign in / Sign up

Export Citation Format

Share Document