Developmental Regulation of Plasticity in the Forepaw Representation of Ferret Somatosensory Cortex

2003 ◽  
Vol 89 (4) ◽  
pp. 2289-2298 ◽  
Author(s):  
Debra F. McLaughlin ◽  
Sharon L. Juliano
Keyword(s):  
Spatial Distribution ◽  
Somatosensory Cortex ◽  
Ulnar Nerve ◽  
Cortical Activity ◽  
Cortical Response ◽  
Nerve Lesions ◽  
Long Latency ◽  
Cortical Responses ◽  
Layer 4 ◽  
Neonatal Lesions

This study characterized the spatiotemporal responses in ferret somatosensory cortex after sensory deprivation at different phases of cortical development. We hypothesized that cortical responses to stimulation of intact superficial radial nerve in adults will vary systematically according to maturation of thalamocortical relationships at the time of an ulnar nerve transection. Depending on the age of the animal at the time of the lesion, we found differential effects on the spatial distribution of the short- and long-latency components of the cortical response. In animals lesioned at postnatal days 5–7, when thalamic projections are not yet stabilized and layer 4 is not yet formed, we found that initial (short-latency) cortical responses are widespread and fragmented. Ulnar nerve transections performed at postnatal day 20 or 21, when thalamocortical afferents are more stabilized and layer 4 is clearly identifiable, yield moderate expansions in the distribution of short- and long-latency components of the cortical response. Nerve lesions in adults lead to a wider distribution of long-latency cortical activity. Neonatal lesions broaden the spatial distribution and increase the latency of the initial cortical response; interruption of nerve input in older juveniles alters both the early and later components; and nerve lesions in adult animals expand the distribution of later cortical activity only. These findings demonstrate correlation between developmental phase at the time sensory input is interrupted and the latency of affected components of the cortical response. This supports the hypothesis that differential response changes are regulated by functional reorganization of thalamocortical connections after neonatal lesions and alteration of corticocortical dynamics after adult lesions.

Human cortical potentials evoked by stimulation of the median nerve. II. Cytoarchitectonic areas generating long-latency activity

1989 ◽  
Vol 62 (3) ◽  
pp. 711-722 ◽  
Author(s):  
T. Allison ◽  
G. McCarthy ◽  
C. C. Wood ◽  
P. D. Williamson ◽  
D. D. Spencer
Keyword(s):  
Spatial Distribution ◽  
Median Nerve ◽  
Somatosensory Cortex ◽  
Sensorimotor Cortex ◽  
Preceding Paper ◽  
Short Latency ◽  
Cortical Surface ◽  
Long Latency ◽  
Area 3B ◽  
Stimulation Of

1. The anatomic generators of human median nerve somatosensory evoked potentials (SEPs) in the 40 to 250-ms latency range were investigated in 54 patients by means of cortical-surface and transcortical recordings obtained during neurosurgery. 2. Contralateral stimulation evoked three groups of SEPs recorded from the hand representation area of sensorimotor cortex: P45-N80-P180, recorded anterior to the central sulcus (CS) and maximal on the precentral gyrus; N45-P80-N180, recorded posterior to the CS and maximal on the postcentral gyrus; and P50-N90-P190, recorded near and on either side of the CS. 3. P45-N80-P180 inverted in polarity to N45-P80-N180 across the CS but was similar in polarity from the cortical surface and white matter in transcortical recordings. These spatial distributions were similar to those of the short-latency P20-N30 and N20-P30 potentials described in the preceding paper, suggesting that these long-latency potentials are generated in area 3b of somatosensory cortex. 4. P50-N90-P190 was largest over the anterior one-half of somatosensory cortex and did not show polarity inversion across the CS. This spatial distribution was similar to that of the short-latency P25-N35 potentials described in the preceding paper and, together with our and Goldring et al. 1970; Stohr and Goldring 1969 transcortical recordings, suggest that these long-latency potentials are generated in area 1 of somatosensory cortex. 5. SEPs of apparently local origin were recorded from several regions of sensorimotor cortex to stimulation of the ipsilateral median nerve. Surface and transcortical recordings suggest that the ipsilateral potentials are generated not in area 3b, but rather in other regions of sensorimotor cortex perhaps including areas 4, 1, 2, and 7. This spatial distribution suggests that the ipsilateral potentials are generated by transcallosal input from the contralateral hemisphere. 6. Recordings from the periSylvian region were characterized by P100 and N100, recorded above and below the Sylvian sulcus (SS) respectively. This distribution suggests a tangential generator located in the upper wall of the SS in the second somatosensory area (SII). In addition, N125 and P200, recorded near and on either side of the SS, suggest a radial generator in a portion of SII located in surface cortex above the SS. 7. In comparison with the short-latency SEPs described in the preceding paper, the long-latency potentials were more variable and were more affected by intraoperative conditions.

scholarly journals Short- and long-latency somatosensory neuronal responses reveal selective brain injury and effect of hypothermia in global hypoxic ischemia

2012 ◽  
Vol 107 (4) ◽  
pp. 1164-1171 ◽  
Author(s):  
Dan Wu ◽  
Wei Xiong ◽  
Xiaofeng Jia ◽  
Romergryko G. Geocadin ◽  
Nitish V. Thakor
Keyword(s):  
Brain Injury ◽  
Somatosensory Cortex ◽  
Field Potential ◽  
Cortical Activity ◽  
Neuronal Responses ◽  
Early Recovery ◽  
Long Latency Responses ◽  
Long Latency ◽  
Hypoxic Ischemia ◽  
Somatosensory Neurons

Evoked potentials recorded from the somatosensory cortex have been shown to be an electrophysiological marker of brain injury in global hypoxic ischemia (HI). The evoked responses in somatosensory neurons carry information pertaining to signal from the ascending pathway in both the subcortical and cortical areas. In this study, origins of the subcortical and cortical signals are explored by decomposing the evoked neuronal activities into short- and long-latency responses (SLR and LLR), respectively. We evaluated the effect of therapeutic hypothermia on SLR and LLR during early recovery from cardiac arrest (CA)-induced HI in a rodent model. Twelve rats were subjected to CA, after which half of them were treated with hypothermia (32–34°C) and the rest were kept at normal temperature (36–37°C). Evoked neuronal activities from the primary somatosensory cortex, including multiunit activity (MUA) and local field potential (LFP), were continuously recorded during injury and early recovery. Results showed that upon initiation of injury, LLR disappeared first, followed by the disappearance of SLR, and after a period of isoelectric silence SLR reappeared prior to LLR. This suggests that cortical activity, which primarily underlies the LLR, may be more vulnerable to ischemic injury than SLR, which relates to subcortical activity. Hypothermia potentiated the SLR but suppressed the LLR by delaying its recovery after CA (hypothermia: 38.83 ± 5.86 min, normothermia: 23.33 ± 1.15 min; P < 0.05) and attenuating its amplitude, suggesting that hypothermia may selectively downregulate cortical activity as an approach to preserve the cerebral cortex. In summary, our study reveals the vulnerability of the somatosensory neural structures to global HI and the differential effects of hypothermia on these structures.

Human cortical potentials evoked by stimulation of the median nerve. II. Cytoarchitectonic areas generating short-latency activity

1989 ◽  
Vol 62 (3) ◽  
pp. 694-710 ◽  
Author(s):  
T. Allison ◽  
G. McCarthy ◽  
C. C. Wood ◽  
T. M. Darcey ◽  
D. D. Spencer ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Median Nerve ◽  
Somatosensory Cortex ◽  
Sensorimotor Cortex ◽  
Preceding Paper ◽  
Short Latency ◽  
Cortical Surface ◽  
Long Latency ◽  
Area 3B ◽  
Stimulation Of

1. The anatomic generators of human median nerve somatosensory evoked potentials (SEPs) in the 40 to 250-ms latency range were investigated in 54 patients by means of cortical-surface and transcortical recordings obtained during neurosurgery. 2. Contralateral stimulation evoked three groups of SEPs recorded from the hand representation area of sensorimotor cortex: P45-N80-P180, recorded anterior to the central sulcus (CS) and maximal on the precentral gyrus; N45-P80-N180, recorded posterior to the CS and maximal on the postcentral gyrus; and P50-N90-P190, recorded near and on either side of the CS. 3. P45-N80-P180 inverted in polarity to N45-P80-N180 across the CS but was similar in polarity from the cortical surface and white matter in transcortical recordings. These spatial distributions were similar to those of the short-latency P20-N30 and N20-P30 potentials described in the preceding paper, suggesting that these long-latency potentials are generated in area 3b of somatosensory cortex. 4. P50-N90-P190 was largest over the anterior one-half of somatosensory cortex and did not show polarity inversion across the CS. This spatial distribution was similar to that of the short-latency P25-N35 potentials described in the preceding paper and, together with our and Goldring et al. 1970; Stohr and Goldring 1969 transcortical recordings, suggest that these long-latency potentials are generated in area 1 of somatosensory cortex. 5. SEPs of apparently local origin were recorded from several regions of sensorimotor cortex to stimulation of the ipsilateral median nerve. Surface and transcortical recordings suggest that the ipsilateral potentials are generated not in area 3b, but rather in other regions of sensorimotor cortex perhaps including areas 4, 1, 2, and 7. This spatial distribution suggests that the ipsilateral potentials are generated by transcallosal input from the contralateral hemisphere. 6. Recordings from the periSylvian region were characterized by P100 and N100, recorded above and below the Sylvian sulcus (SS) respectively. This distribution suggests a tangential generator located in the upper wall of the SS in the second somatosensory area (SII). In addition, N125 and P200, recorded near and on either side of the SS, suggest a radial generator in a portion of SII located in surface cortex above the SS. 7. In comparison with the short-latency SEPs described in the preceding paper, the long-latency potentials were more variable and were more affected by intraoperative conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Seasonal plasticity in the adult somatosensory cortex

2020 ◽  
Vol 117 (50) ◽  
pp. 32136-32144
Author(s):  
Saikat Ray ◽  
Miao Li ◽  
Stefan Paul Koch ◽  
Susanne Mueller ◽  
Philipp Boehm-Sturm ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Activity Patterns ◽  
Adaptive Plasticity ◽  
Neural Systems ◽  
Mammalian Brain ◽  
Sensory Stimuli ◽  
Seasonal Plasticity ◽  
Layer 4 ◽  
Life On Earth

Seasonal cycles govern life on earth, from setting the time for the mating season to influencing migrations and governing physiological conditions like hibernation. The effect of such changing conditions on behavior is well-appreciated, but their impact on the brain remains virtually unknown. We investigate long-term seasonal changes in the mammalian brain, known as Dehnel’s effect, where animals exhibit plasticity in body and brain sizes to counter metabolic demands in winter. We find large seasonal variation in cellular architecture and neuronal activity in the smallest terrestrial mammal, the Etruscan shrew, Suncus etruscus. Their brain, and specifically their neocortex, shrinks in winter. Shrews are tactile hunters, and information from whiskers first reaches the somatosensory cortex layer 4, which exhibits a reduced width (−28%) in winter. Layer 4 width (+29%) and neuron number (+42%) increase the following summer. Activity patterns in the somatosensory cortex show a prominent reduction of touch-suppressed neurons in layer 4 (−55%), the most metabolically active layer. Loss of inhibitory gating occurs with a reduction in parvalbumin-positive interneurons, one of the most active neuronal subtypes and the main regulators of inhibition in layer 4. Thus, a reduction in neurons in layer 4 and particularly parvalbumin-positive interneurons may incur direct metabolic benefits. However, changes in cortical balance can also affect the threshold for detecting sensory stimuli and impact prey choice, as observed in wild shrews. Thus, seasonal neural adaptation can offer synergistic metabolic and behavioral benefits to the organism and offer insights on how neural systems show adaptive plasticity in response to ecological demands.

Layer 4 organization and respiration locking in the rodent nose somatosensory cortex

2020 ◽  
Vol 124 (3) ◽  
pp. 822-832 ◽  
Author(s):  
Eduard Maier ◽  
Simon Lauer ◽  
Michael Brecht
Keyword(s):  
Somatosensory Cortex ◽  
Neural Activity ◽  
Field Recordings ◽  
Physiological Properties ◽  
Sensory Modalities ◽  
Layer 4

We characterized the rodent nose somatosensory cortex. The nostril representation appeared as a kind of “hole” (i.e., as a stripe-like recess of layer 4) in tangential cortical sections. Neural activity in nose somatosensory cortex was locked to respiration and simultaneous field recordings indicate that this locking was specific to this region. Our results reveal previously unknown cytoarchitectonic and physiological properties of the rodent nose somatosensory cortex, potentially enabling it to integrate multiple sensory modalities.

Evaluation of experimental spinal cord injury using cortical evoked potentials

1973 ◽  
Vol 39 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Stephen H. Martin ◽  
James R. Bloedel
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cortical Response ◽  
Neurological Deficits ◽  
Cystic Degeneration ◽  
Post Injury ◽  
Content Type ◽  
Cord Injury ◽  
Cortical Responses ◽  
Control Response

✓ Experiments were performed to determine if changes in cortical evoked responses could be used to predict the extent of the neurological deficits following spinal cord injury by sudden inflation of a Fogarty balloon in the epidural space cephalad to a laminectomy. The cortical responses to stimulation of the posterior tibial nerve were recorded over the sigmoid gyrus at various times following the lesion and compared with the control response. Severe, irreversible neurological deficits occurred in cats in which the cortical response either could not be evoked immediately after injury or disappeared rapidly during this period. At the end of at least 6 weeks following injury, all of these animals were paraplegic and showed severe cystic degeneration of the spinal cord. In animals in which the post-injury cortical response did not completely disappear, only mild changes were observed in a spinal cord 6 weeks following injury. This technique may be helpful in ascertaining the severity and irreversibility of a traumatic spinal cord lesion; because the technique is simple, the method may prove helpful in the clinical management of patients with spinal cord injury.

scholarly journals Long-latency suppression of auditory and somatosensory change-related cortical responses

PLoS ONE ◽  
2018 ◽  
Vol 13 (6) ◽  
pp. e0199614 ◽  
Author(s):  
Nobuyuki Takeuchi ◽  
Shunsuke Sugiyama ◽  
Koji Inui ◽  
Kousuke Kanemoto ◽  
Makoto Nishihara
Keyword(s):  
Long Latency ◽  
Cortical Responses

Development of metabolic activity patterns in the somatosensory cortex of cats

1993 ◽  
Vol 70 (5) ◽  
pp. 2117-2127 ◽  
Author(s):  
S. L. Juliano ◽  
R. A. Code ◽  
M. Tommerdahl ◽  
D. E. Eslin
Keyword(s):  
Somatosensory Cortex ◽  
Metabolic Activity ◽  
Activity Patterns ◽  
Vertical Displacement ◽  
Two Dimensional ◽  
Small Spot ◽  
Cortical Responses ◽  
Different Ages ◽  
Evoked Activity ◽  
The Individual

1. The development of cortical responses to somatic stimulation was studied in kittens 2-5 wk of age using the 2-deoxyglucose (2DG) technique. During the 2DG experiment each kitten received an innocuous intermittent vertical displacement stimulus to the forepaw. 2. The pattern of metabolic activity was substantially different in young animals compared with adults. In the individual autoradiographs of the 2-wk-old kittens stimulus-evoked 2DG uptake in primary somatosensory cortex was localized to a small spot in the upper portion of the cortex, whereas in the adult the label extended vertically through the cortical layers and appeared more column-like. Individual patches of label were substantially smaller and less dense in young animals. Over a period of several weeks the evoked activity evolved to the more extensive adult pattern. The 2DG uptake displayed a mature distribution by approximately 4-5 wk of age. During this period, the cortical architecture also evolved from an immature to a mature arrangement. 3. The evoked activity was reconstructed into two-dimensional maps; the distribution of label > or = 1.5 SD above background was considered to be stimulus related. In the adult, the pattern appeared as a strip or strips of increased metabolic activity that extended in the rostrocaudal direction for approximately 1 mm. In contrast, the activity pattern in animals 2-4 wk old was less discretely organized into "strips" and was more diffusely spread over several mms of somatosensory cortex. The two-dimensional pattern gradually coalesced into a more localized strip by approximately 4-5 wk of age. Although the pattern of label was more widespread in the young animals, the absolute distance of the spread of activity did not vary substantially, regardless of the age of the animal. 4. Other measurements regarding the distribution of activity at different ages indicate that the amount of cortex activated increases in absolute terms, although the percent of cortex activated by the stimulus decreases. The overall intensity of the 2DG uptake as measured on the two-dimensional maps increases with age, as does the variability of the 2DG uptake; a wider range of intensity values is seen in the adult. Plots created from the individual two-dimensional reconstructions allowed a measure of "patch strength" at different ages. These histograms relate the most intense region of uptake in a given map to the spatial distribution of activity spreading in the medial and lateral directions.(ABSTRACT TRUNCATED AT 400 WORDS)

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