Quantitative Comparison Between Functional Imaging and Single-Unit Spiking in Rat Somatosensory Cortex

2003 ◽  
Vol 89 (3) ◽  
pp. 1702-1712 ◽  
Author(s):  
Susan A. Masino
Keyword(s):  
Somatosensory Cortex ◽  
Functional Imaging ◽  
Cortical Neurons ◽  
Quantitative Comparison ◽  
Evoked Response ◽  
Cortical Surface ◽  
Sodium Pentobarbital ◽  
Intrinsic Signal ◽  
Rat Somatosensory Cortex ◽  
Stimulation Of

The profile of activity across rat somatosensory cortex on stimulation of a single whisker was examined using both intrinsic signal imaging and electrophysiological recording. In the same animals, under sodium pentobarbital anesthesia, the intrinsic signal response to a 5-Hz stimulation of whisker C2 was recorded through a thinned skull. Subsequently, the thinned skull was removed, and individual cortical neurons were recorded at multiple locations and in all cortical layers in response to the same whisker stimulation paradigm. The amplitude of the evoked response obtained with both techniques was quantified across the cortical surface with respect to distance (≤1.6 mm) from the peak intrinsic signal activity. Cortical neurons were rated as having a significant or nonsignificant whisker-evoked response as compared with a baseline period of spontaneous firing; a minority of neurons exhibited a small but significant increase in neuronal spiking even at long distances (>1.6 mm) from the optically determined peak of activity. Overall, this analysis shows a significant correlation between the two techniques in terms of the profile of evoked activity across the cortical surface. Furthermore, this data set affords a detailed and quantitative comparison between the two activity-dependent techniques—one measuring an intrinsic decrease in light reflectance based largely on metabolic changes and one measuring neuronal firing patterns. Studies such as this, comparing directly between imaging and detailed electrophysiology, may influence the interpretation of the extent of the activated area as assessed with in vivo functional imaging techniques.

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 Smoothened receptor signaling regulates the developmental shift of GABA polarity in rat somatosensory cortex

2020 ◽  
Vol 133 (20) ◽  
pp. jcs247700
Author(s):  
Quentin Delmotte ◽  
Mira Hamze ◽  
Igor Medina ◽  
Emmanuelle Buhler ◽  
Jinwei Zhang ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Cortical Neurons ◽  
Functional Expression ◽  
Brain Maturation ◽  
Surface Stability ◽  
Chloride Homeostasis ◽  
Cell Proliferation And Differentiation ◽  
Developmental Shift ◽  
Proliferation And Differentiation ◽  
Rat Somatosensory Cortex

ABSTRACTSonic hedgehog (Shh) and its patched–smoothened receptor complex control a variety of functions in the developing central nervous system, 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 negative-phenotype forms of the Shh signal transducer 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 a manner dependent on functional expression of potassium–chloride cotransporter type 2 (KCC2, also known as SLC12A5). On the other hand, blocking Smo activity maintains the GABA response in a depolarizing state in mature cortical neurons, resulting in altered chloride homeostasis and increased seizure susceptibility. This study reveals unexpected functions of Smo signaling in the regulation of chloride homeostasis, through control of KCC2 cell-surface stability, and the timing of the GABA excitatory-to-inhibitory shift in brain maturation.

Intrinsic discharge patterns and somatosensory inputs for neurons in raccoon primary somatosensory cortex

1994 ◽  
Vol 72 (6) ◽  
pp. 2827-2839 ◽  
Author(s):  
P. J. Istvan ◽  
P. Zarzecki
Keyword(s):  
Somatosensory Cortex ◽  
Cortical Neurons ◽  
Primary Somatosensory Cortex ◽  
Membrane Properties ◽  
Postsynaptic Potentials ◽  
Synaptic Inputs ◽  
Ionic Conductances ◽  
Discharge Patterns ◽  
Intrinsic Membrane Properties ◽  
Stimulation Of

1. Discharge patterns of neurons are regulated by synaptic inputs and by intrinsic membrane properties such as their complement of ionic conductances. Discharge patterns evoked by synaptic inputs are often used to identify the source and modality of sensory input. However, the interpretation of these discharge patterns may be complicated if different neurons respond to the same synaptic input with a variety of discharge patterns due to differences in intrinsic membrane properties. The purposes of this study were 1) to investigate intrinsic discharge patterns of neurons in primary somatosensory cortex of raccoon in vivo and 2) to use somatosensory postsynaptic potentials evoked by stimulation of forepaw digits to determine thalamocortical connectivity for the same neurons. 2. Conventional intracellular recordings with sharp electrodes were made from 121 neurons in the cortical representation of glabrous skin of digit four (d4). Intracellular injection of identical current pulses (100-120 ms in duration) elicited various patterns of discharge in different neurons. Neurons were classified on the basis of these intrinsic patterns of discharge, rates of spike adaptation, and characteristics of spike waveforms. Three main groups were identified: regular spiking (RS) neurons, intrinsic bursting (IB) neurons, and fast spiking (FS) neurons. Subclasses were identified for the RS and IB groups. 3. Neurons were tested for somatosensory inputs by stimulating electrically d3, d4, and d5. Excitatory postsynaptic potentials (EPSPs) were elicited in 100% of the neurons by electrical stimulation of d4, the "on-focus" digit. EPSPs were usually followed by inhibitory postsynaptic potentials (IPSPs). Many neurons (41%) responded with EPSP-IPSP sequences after stimulation of d3 or d5, the "off-focus" digits. 4. Latencies of somatosensory EPSPs and IPSPs were used to determine the synaptic order in the cortical circuitry of RS, IB, and FS neurons. EPSPs with monosynaptic thalamocortical latencies were recorded in RS, IB, and FS neurons. 5. We conclude that precise patterns of neural discharge in primary somatosensory cortex cannot be reliable estimates of sensory inputs reaching these neurons because patterns of discharge are so strongly influenced by intrinsic membrane properties. Ionic conductances governing patterns of neuronal discharge seem almost identical in intact cortex of raccoon, rat, and cat, and in slices of rodent cortex, because similar patterns of discharge are found. The consistency of patterns of discharge across species and types of preparation suggests that these intrinsic membrane properties are a general property of cerebral cortical neurons and should be considered when evaluation sensory coding by these neurons.

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.

Recording High Frequency Neural Signals Using Conformable and Low-Impedance ECoG Electrodes Arrays Coated with PEDOT-PSS-PEG

2016 ◽  
Vol 102 ◽  
pp. 77-85 ◽  
Author(s):  
Elisa Castagnola ◽  
Marco Marrani ◽  
Emma Maggiolini ◽  
Francesco Maita ◽  
Luca Pazzini ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
High Frequency ◽  
Cortical Neurons ◽  
Ad Hoc ◽  
Ionic Conductivities ◽  
Neural Signals ◽  
Brain Surface ◽  
Small Neuron ◽  
Rat Somatosensory Cortex

Electrocorticography (ECoG) is receiving growing attention for both clinical and research applications thanks to its reduced invasiveness and ability of addressing large cortical areas. These benefits come with a main drawback, i.e. a limited frequency bandwidth. However, recent studies have shown that spiking activity from cortical neurons can be recorded when the ECoG grids present the following combined properties: (I) conformable substrate, (II) small neuron-sized electrodes with (III) low-impedance interfaces. We introduce here an ad-hoc designed ECoG device for investigating how electrode size, interface material composition and electrochemical properties affect the capability to record evoked and spontaneous neural signals from the rat somatosensory cortex and influence the ability to record high frequency neural signal components.Contact diameter reduction down to 8 μm was possible thanks to a specific coating of a (3,4-ethylenedioxytiophene)-poly (styrenesulfonate)-poly-(ethyleneglycol) (PEDOT-PSS-PEG) composite that drastically reduces impedance and increases electrical and ionic conductivities. In addition, the extreme thinness of the polyimide substrate (6 - 8 μm) and the presence of multiple perforations through the device ensure an effective contact with the brain surface and the free flow of cerebrospinal fluid. In-vivo validation was performed on rat somatosensory cortex.

Stimulation of the rat somatosensory cortex at different frequencies and pulse widths

2006 ◽  
Vol 19 (1) ◽  
pp. 10-17 ◽  
Author(s):  
N. Van Camp ◽  
M. Verhoye ◽  
A. Van der Linden
Keyword(s):  
Somatosensory Cortex ◽  
Rat Somatosensory Cortex ◽  
Stimulation Of

scholarly journals Augmentation of Plasticity of the Central Auditory System by the Basal Forebrain and/or Somatosensory Cortex

2003 ◽  
Vol 89 (1) ◽  
pp. 90-103 ◽  
Author(s):  
Xiaofeng Ma ◽  
Nobuo Suga
Keyword(s):  
Somatosensory Cortex ◽  
Auditory System ◽  
Basal Forebrain ◽  
Cortical Neurons ◽  
Electric Stimulation ◽  
Cortical Plasticity ◽  
Frequency Tuning ◽  
Cortical Stimulation ◽  
Cholinergic Basal Forebrain ◽  
Stimulation Of

Auditory conditioning (associative learning) or focal electric stimulation of the primary auditory cortex (AC) evokes reorganization (plasticity) of the cochleotopic (frequency) map of the inferior colliculus (IC) as well as that of the AC. The reorganization results from shifts in the best frequencies (BFs) and frequency-tuning curves of single neurons. Since the importance of the cholinergic basal forebrain for cortical plasticity and the importance of the somatosensory cortex and the corticofugal auditory system for collicular and cortical plasticity have been demonstrated, Gao and Suga proposed a hypothesis that states that the AC and corticofugal system play an important role in evoking auditory collicular and cortical plasticity and that auditory and somatosensory signals from the cerebral cortex to the basal forebrain play an important role in augmenting collicular and cortical plasticity. To test their hypothesis, we studied whether the amount and the duration of plasticity of both collicular and cortical neurons evoked by electric stimulation of the AC or by acoustic stimulation were increased by electric stimulation of the basal forebrain and/or the somatosensory cortex. In adult big brown bats ( Eptesicus fuscus), we made the following major findings. 1) Collicular and cortical plasticity evoked by electric stimulation of the AC is augmented by electric stimulation of the basal forebrain. The amount of augmentation is larger for cortical plasticity than for collicular plasticity. 2) Collicular and cortical plasticity evoked by AC stimulation is augmented by somatosensory cortical stimulation mimicking fear conditioning. The amount of augmentation is larger for cortical plasticity than for collicular plasticity. 3) Collicular and cortical plasticity evoked by both AC and basal forebrain stimulations is further augmented by somatosensory cortical stimulation. 4) A lesion of the basal forebrain tends to reduce collicular and cortical plasticity evoked by AC stimulation. The reduction is small and statistically insignificant for collicular plasticity but significant for cortical plasticity. 5) The lesion of the basal forebrain eliminates the augmentation of collicular and cortical plasticity that otherwise would be evoked by somatosensory cortical stimulation. 6) Collicular and cortical plasticity evoked by repetitive acoustic stimuli is augmented by basal forebrain and/or somatosensory cortical stimulation. However, the lesion of the basal forebrain eliminates the augmentation of collicular and cortical plasticity that otherwise would be evoked by somatosensory cortical stimulation. These findings support the hypothesis proposed by Gao and Suga.

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