Time course of deficits in finger use induced by muscimol injection into the first somatosensory cortex of awake monkeys

1990 ◽  
Vol 11 ◽  
pp. S134
Author(s):  
Yoshiaki Iwamura ◽  
Michio Tanaka
Keyword(s):  
Somatosensory Cortex ◽  
Time Course ◽  
Finger Use

scholarly journals Metaplasticity in human primary somatosensory cortex: effects on physiology and tactile perception

2016 ◽  
Vol 115 (5) ◽  
pp. 2681-2691 ◽  
Author(s):  
Christina B. Jones ◽  
Tea Lulic ◽  
Aaron Z. Bailey ◽  
Tanner N. Mackenzie ◽  
Yi Qun Mi ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Time Course ◽  
Primary Motor Cortex ◽  
Temporal Order Judgment ◽  
Intracortical Inhibition ◽  
Primary Somatosensory Cortex ◽  
Theta Burst Stimulation ◽  
Median Nerve Stimulation ◽  
Pulse Ratio ◽  
Theta Burst

Theta-burst stimulation (TBS) over human primary motor cortex evokes plasticity and metaplasticity, the latter contributing to the homeostatic balance of excitation and inhibition. Our knowledge of TBS-induced effects on primary somatosensory cortex (SI) is limited, and it is unknown whether TBS induces metaplasticity within human SI. Sixteen right-handed participants (6 females, mean age 23 yr) received two TBS protocols [continuous TBS (cTBS) and intermittent TBS (iTBS)] delivered in six different combinations over SI in separate sessions. TBS protocols were delivered at 30 Hz and were as follows: a single cTBS protocol, a single iTBS protocol, cTBS followed by cTBS, iTBS followed by iTBS, cTBS followed by iTBS, and iTBS followed by cTBS. Measures included the amplitudes of the first and second somatosensory evoked potentials (SEPs) via median nerve stimulation, their paired-pulse ratio (PPR), and temporal order judgment (TOJ). Dependent measures were obtained before TBS and at 5, 25, 50, and 90 min following stimulation. Results indicate similar effects following cTBS and iTBS; increased amplitudes of the second SEP and PPR without amplitude changes to SEP 1, and impairments in TOJ. Metaplasticity was observed such that TOJ impairments following a single cTBS protocol were abolished following consecutive cTBS protocols. Additionally, consecutive iTBS protocols altered the time course of effects when compared with a single iTBS protocol. In conclusion, 30-Hz cTBS and iTBS protocols delivered in isolation induce effects consistent with a TBS-induced reduction in intracortical inhibition within SI. Furthermore, cTBS- and iTBS-induced metaplasticity appear to follow homeostatic and nonhomeostatic rules, respectively.

Plasticity of Bat's Central Auditory System Evoked by Focal Electric Stimulation of Auditory and/or Somatosensory Cortices

2001 ◽  
Vol 85 (3) ◽  
pp. 1078-1087 ◽  
Author(s):  
Xiaofeng Ma ◽  
Nobuo Suga
Keyword(s):  
Electrical Stimulation ◽  
Somatosensory Cortex ◽  
Cortical Neurons ◽  
Electric Stimulation ◽  
Time Course ◽  
Recovery Period ◽  
Acoustic Stimulus ◽  
Acoustic Parameter ◽  
Response Curves ◽  
Stimulation Of

Recent findings indicate that the corticofugal system would play an important role in cortical plasticity as well as collicular plasticity. To understand the role of the corticofugal system in plasticity, therefore, we studied the amount and the time course of plasticity in the inferior colliculus (IC) and auditory cortex (AC) evoked by focal electrical stimulation of the AC and also the effect of electrical stimulation of the somatosensory cortex on the plasticity evoked by the stimulation of the AC. In adult big brown bats ( Eptesicus fuscus), we made the following major findings. 1) Electric stimulation of the AC evokes best frequency (BF) shifts, i.e., shifts in frequency-response curves of collicular and cortical neurons. These BF shifts start to occur within 2 min, reach a maximum (or plateau) at 30 min, and then recover ∼180 min after a 30-min-long stimulus session. When the stimulus session is lengthened from 30 to 90 min, the plateau lasts ∼60 min, but BF shifts recover ∼180 min after the session. 2) The electric stimulation of the somatosensory cortex delivered immediately after that of the AC, as in fear conditioning, evokes a dramatic lengthening of the recovery period of the cortical BF shifts but not that of the collicular BF shift. The electric stimulation of the somatosensory cortex delivered before that of the AC, as in backward conditioning, has no effect on the collicular and cortical BF shifts. 3) Electric stimulation of the AC evokes BF shifts not only in the ipsilateral IC and AC but also in the contralateral IC and AC. BF shifts are smaller in amount and shorter in recovery time for contralateral collicular and cortical neurons than for ipsilateral ones. Our findings support the hypothesis that the AC and the corticofugal system have an intrinsic mechanism for reorganization of the IC and AC, that the reorganization is highly specific to a value of an acoustic parameter (frequency), and that the reorganization is augmented by excitation of nonauditory sensory cortex that makes the acoustic stimulus behaviorally relevant to the animal through associative learning.

scholarly journals Smoothened receptor Signaling regulates the developmental shift of GABA polarity in rat somatosensory cortex

2019 ◽  
Author(s):  
Quentin Delmotte ◽  
Igor Medina ◽  
Mira Hamze ◽  
Emmanuelle Buhler ◽  
Jinwei Zhang ◽  
...  
Keyword(s):  
Potassium Chloride ◽  
Somatosensory Cortex ◽  
Cortical Neurons ◽  
Time Course ◽  
Functional Expression ◽  
Dominant Negative ◽  
Brain Maturation ◽  
Surface Stability ◽  
Chloride Homeostasis

ABSTRACTSonic Hedgehog (Shh) and its patched-smoothened receptor complex control a variety of functions in the developing central nervous system (CNS) such as neural cell proliferation and differentiation. Recently, Shh signaling components have been found to be expressed at the synaptic level in the postnatal brain, suggesting a potential role in the regulation of synaptic transmission. Using in utero electroporation of constitutively active and dominant-negative forms of the Shh co-receptor smoothened (Smo), we studied the role of Smo signaling in the development and maturation of GABAergic transmission in the somatosensory cortex. Our results show that enhancing Smo activity during development accelerates the shift from depolarizing to hyperpolarizing GABA in dependence on functional expression of potassium-chloride cotransporter type 2 (KCC2). On the other hand, blocking Smo activity maintains GABA response in a depolarizing state in mature cortical neurons resulting in altered chloride homeostasis and increased seizure susceptibility. This study reveals an unexpected function of Smo signaling on the regulation of chloride homeostasis through the control of KCC2 cell surface stability and on the timing of the GABA inhibitory/excitatory shift in brain maturation.Summary statementThe smoothened receptor controls the time course of inhibitory transmission through the stability of the potassium-chloride cotransporter type 2 at the plasma membrane.

scholarly journals The time course of the tonic oculomotor proprioceptive signal in area 3a of somatosensory cortex

2011 ◽  
Vol 106 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Yixing Xu ◽  
Xiaolan Wang ◽  
Christopher Peck ◽  
Michael E. Goldberg
Keyword(s):  
Somatosensory Cortex ◽  
Visual Processing ◽  
Time Course ◽  
Temporal Dynamics ◽  
Eye Position ◽  
Phasic Response ◽  
Tonic Response ◽  
Proprioceptive Signal ◽  
Position Signal ◽  
Area 3A

A proprioceptive representation of eye position exists in area 3a of primate somatosensory cortex (Wang X, Zhang M, Cohen IS, Goldberg ME. Nat Neurosci 10: 640–646, 2007). This eye position signal is consistent with a fusimotor response (Taylor A, Durbaba R, Ellaway PH, Rawlinson S. J Physiol 571: 711–723, 2006) and has two components during a visually guided saccade task: a short-latency phasic response followed by a tonic response. While the early phasic response can be excitatory or inhibitory, it does not accurately reflect the eye's orbital position. The late tonic response appears to carry the proprioceptive eye position signal, but it is not clear when this component emerges and whether the onset of this signal is reliable. To test the temporal dynamics of the tonic proprioceptive signal, we used an oculomotor smooth pursuit task in which saccadic eye movements and phasic proprioceptive responses are suppressed. Our results show that the tonic proprioceptive eye position signal consistently lags the actual eye position in the orbit by ∼60 ms under a variety of eye movement conditions. To confirm the proprioceptive nature of this signal, we also studied the responses of neurons in a vestibuloocular reflex (VOR) task in which the direction of gaze was held constant; response profiles and delay times were similar in this task, suggesting that this signal does not represent angle of gaze and does not receive visual or vestibular inputs. The length of the delay suggests that the proprioceptive eye position signal is unlikely to be used for online visual processing for action, although it could be used to calibrate an efference copy signal.

Sharp, Local Synchrony Among Putative Feed-Forward Inhibitory Interneurons of Rabbit Somatosensory Cortex

1998 ◽  
Vol 79 (2) ◽  
pp. 567-582 ◽  
Author(s):  
Harvey A. Swadlow ◽  
Irina N. Beloozerova ◽  
Mikhail G. Sirota
Keyword(s):  
Somatosensory Cortex ◽  
Short Duration ◽  
Action Potentials ◽  
Time Course ◽  
Target Cells ◽  
Inhibitory Interneurons ◽  
Antidromic Activation ◽  
Feed Forward ◽  
Thalamic Input ◽  
Peripheral Stimulation

Swadlow, Harvey A., Irina N. Beloozerova, and Mikhail G. Sirota. Sharp, local synchrony among putative feed-forward inhibitory interneurons of rabbit somatosensory cortex. J. Neurophysiol. 79: 567–582, 1998. Many suspected inhibitory interneurons (SINs) of primary somatosensory cortex (S1) receive a potent monosynaptic thalamic input (thalamocortical SINs, SINstc). It has been proposed that nearly all such SINstc of a S1 barrel column (BC) receive excitatory synaptic input from each member of a subpopulation of neurons within the topographically aligned ventrobasal (VB) thalamic barreloid. Such a divergent and convergent network leads to several testable predictions: sharply synchronous activity should occur between SINstc of a BC, sharp synchrony should not occur between SINstc of neighboring BCs, and sharp synchrony should not occur between SINs or other neurons of the same BC that do not receive potent monosynaptic thalamic input. These predictions were tested by cross-correlating the activity of SINstc of the same and neighboring BCs. Correlations among descending corticofugal neurons of layer 5 (CF-5 neurons, identified by antidromic activation) and other neurons that receive little or no monosynaptic VB input also were examined. SINs were identified by a high-frequency (>600 Hz) burst of three or more spikes elicited by VB stimulation and had action potentials of short duration. SINstc were further differentiated by short synaptic latencies to electrical stimulation of VB thalamus (<1.7 ms) and to peripheral stimulation (<7.5 ms). The above predictions were confirmed fully. 1) Sharp synchrony (±1 ms) was seen between all SINstc recorded within the same BC (a mean of 4.26% of the spikes of each SINtc were synchronized sharply with the spikes of the paired SINtc). Sharp synchrony was not dependent on peripheral stimulation, was not oscillatory, and survived general anesthesia. Sharp synchrony was superimposed on a broader synchrony, with a time course of tens of milliseconds. 2) Little or no sharp synchrony was seen when CF-5 neurons were paired with SINstc or other neurons of the same BC. 3) Little or no sharp synchrony was seen when SINstc were paired with other SINstc located in neighboring BCs. Intracellular recordings obtained from three SINs in the fully awake state supported the assertion that SINs are GABAergic interneurons. Each of these cells met our extracellular criteria for identification as a SIN, each had a spike of short duration (0.4–0.5 ms), and each responded to a depolarizing current pulse with a nonadapting train of action potentials. These results support the proposed network linking VB barreloid neurons with SINstc within the topographically aligned BC. We suggest that sharp synchrony among SINstc results in highly synchronous inhibitory postsynpatic potentials (IPSPs)in the target neurons of these cells and that these summated IPSPs may be especially effective when excitatory drive to target cells is weak and asynchronous.

scholarly journals Functional Increases in Cerebral Blood Volume over Somatosensory Cortex

1995 ◽  
Vol 15 (5) ◽  
pp. 754-765 ◽  
Author(s):  
Sanjiv M. Narayan ◽  
Pooneh Esfahani ◽  
Anne J. Blood ◽  
Lucia Sikkens ◽  
Arthur W. Toga
Keyword(s):  
Somatosensory Cortex ◽  
Blood Volume ◽  
Single Unit ◽  
Time Course ◽  
Cerebral Blood Volume ◽  
Receptive Fields ◽  
Cortical Layer ◽  
Sprague Dawley ◽  
Optical Reflectance ◽  
Sprague Dawley Rats

We have examined the relationship between cerebral blood volume (CBV) and electrophysiology over primary somatosensory cortex (S-I) in the rat. We did this by comparing the spatial characteristics and time course of activity-related changes in plasma fluorescence, intrinsic optical reflectance signals, and single unit electrophysiology in S-I to identical stimuli. S-Is of urethane-anesthetized male Sprague–Dawley rats were exposed, and fluorescent Texas Red dextran dye (MW 70,000) was administered intravenously. Subsequently, foredigit electroshock or vibrissal deflection was associated with fluorescence increases over contralateral forelimb or posteromedial barrel subfield cortex. Fluorescence was delayed and prolonged, indicating that CBV increases at 1–1.5 s and peaks 2–2.5 s after the onset of stimulation in both regions. When stimulus intensity was adjusted to produce barely detectable fluorescence foci (10% above background), significant electrophysiologic spiking was seen. At these parameters, fluorescence change overlay areas of increased cortical layer III cell firing on single unit recordings. However, surface boundaries of the smallest observable fluorescence foci at their peak spatial extents consistently overspilled electrophysiologic center receptive fields. Corresponding intrinsic optical reflectance decreases were seen at 610 and 850 nm, exhibiting similar timing and colocalizing closely with fluorescence increase at both wavelengths after identical stimuli. These signals similarly overspilled electrophysiologic activity. Thus, we observed delayed increases in vascular fluorescence (related to CBV) over activated cortex. The smallest detectable fluorescence changes overspilled the center receptive field boundaries and were associated with appreciable electrophysiologic firing. In addition, the striking spatial and temporal similarity between intrinsic optical reflectance and fluorescence activity suggests that changes in intrinsic cortical reflectance are strongly related to changes in CBV.

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