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Patch-clamp recordings of rat neurons from acute brain slices of the somatosensory cortex during magnetic stimulation.

Pashut T, Magidov D, Ben-Porat H, Wolfus S, Friedman A, Perel E, Lavidor M, Bar-Gad I, Yeshurun Y, Korngreen A - Front Cell Neurosci (2014)

Bottom Line: Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood.In agreement with the modeling, our recordings demonstrate the dependence of magnetic stimulation-triggered action potentials on the type and state of the neuron and its orientation within the magnetic field.Our results suggest that the observed effects of TMS are deeply rooted in the biophysical properties of single neurons in the central nervous system and provide a framework both for interpreting existing TMS data and developing new simulation-based tools and therapies.

View Article: PubMed Central - PubMed

Affiliation: The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University Ramat-Gan, Israel.

ABSTRACT
Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood. We have previously predicted, using compartmental modeling, that magnetic stimulation of central nervous system neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. The simulations also predict that neurons with low current threshold are more susceptible to magnetic stimulation. Here we tested these theoretical predictions by combining in vitro patch-clamp recordings from rat brain slices with magnetic stimulation and compartmental modeling. In agreement with the modeling, our recordings demonstrate the dependence of magnetic stimulation-triggered action potentials on the type and state of the neuron and its orientation within the magnetic field. Our results suggest that the observed effects of TMS are deeply rooted in the biophysical properties of single neurons in the central nervous system and provide a framework both for interpreting existing TMS data and developing new simulation-based tools and therapies.

No MeSH data available.


Related in: MedlinePlus

Magnetic threshold was dependent on coil orientation. (A) Schematic drawing of the simulated and experimental settings showing the calculated induced electric field and two pyramidal neurons, one shifted by 1 cm in the x direction and one shifted by 1 cm in the y direction from the center of the coil. (B) Box plot of the simulated magnetic threshold ratio. The magnetic threshold (MT) was simulated once when the neuron was shifted in the x direction and once in the y direction. The ratio was obtained by dividing the MTx by MTy. (C) representative reconstructions of three L5 pyramidal neurons and three low threshold interneurons used in the simulations presented in (B). The apical dendrite of the pyramidal neurons was truncated to allow using the same scale for both neuronal types. (D) Box plot of the measured magnetic threshold ratio recorded from low threshold interneurons. (E) Box plot of the latency between the magnetic stimulus and the action potential recorded during the experiments in (C).
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Figure 6: Magnetic threshold was dependent on coil orientation. (A) Schematic drawing of the simulated and experimental settings showing the calculated induced electric field and two pyramidal neurons, one shifted by 1 cm in the x direction and one shifted by 1 cm in the y direction from the center of the coil. (B) Box plot of the simulated magnetic threshold ratio. The magnetic threshold (MT) was simulated once when the neuron was shifted in the x direction and once in the y direction. The ratio was obtained by dividing the MTx by MTy. (C) representative reconstructions of three L5 pyramidal neurons and three low threshold interneurons used in the simulations presented in (B). The apical dendrite of the pyramidal neurons was truncated to allow using the same scale for both neuronal types. (D) Box plot of the measured magnetic threshold ratio recorded from low threshold interneurons. (E) Box plot of the latency between the magnetic stimulus and the action potential recorded during the experiments in (C).

Mentions: The magnetic field was assessed using Vector Fields finite elements simulation software (Cobham Technical Services). The electric field induced in the plane of the brain slice was calculated using MATLAB (MATLAB 2007B, Mathworks, Natick, MA, USA) for a magnetic coil with a mean radius of 1 cm (Figure 6B), using the formulae (Tofts, 1990):


Patch-clamp recordings of rat neurons from acute brain slices of the somatosensory cortex during magnetic stimulation.

Pashut T, Magidov D, Ben-Porat H, Wolfus S, Friedman A, Perel E, Lavidor M, Bar-Gad I, Yeshurun Y, Korngreen A - Front Cell Neurosci (2014)

Magnetic threshold was dependent on coil orientation. (A) Schematic drawing of the simulated and experimental settings showing the calculated induced electric field and two pyramidal neurons, one shifted by 1 cm in the x direction and one shifted by 1 cm in the y direction from the center of the coil. (B) Box plot of the simulated magnetic threshold ratio. The magnetic threshold (MT) was simulated once when the neuron was shifted in the x direction and once in the y direction. The ratio was obtained by dividing the MTx by MTy. (C) representative reconstructions of three L5 pyramidal neurons and three low threshold interneurons used in the simulations presented in (B). The apical dendrite of the pyramidal neurons was truncated to allow using the same scale for both neuronal types. (D) Box plot of the measured magnetic threshold ratio recorded from low threshold interneurons. (E) Box plot of the latency between the magnetic stimulus and the action potential recorded during the experiments in (C).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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Figure 6: Magnetic threshold was dependent on coil orientation. (A) Schematic drawing of the simulated and experimental settings showing the calculated induced electric field and two pyramidal neurons, one shifted by 1 cm in the x direction and one shifted by 1 cm in the y direction from the center of the coil. (B) Box plot of the simulated magnetic threshold ratio. The magnetic threshold (MT) was simulated once when the neuron was shifted in the x direction and once in the y direction. The ratio was obtained by dividing the MTx by MTy. (C) representative reconstructions of three L5 pyramidal neurons and three low threshold interneurons used in the simulations presented in (B). The apical dendrite of the pyramidal neurons was truncated to allow using the same scale for both neuronal types. (D) Box plot of the measured magnetic threshold ratio recorded from low threshold interneurons. (E) Box plot of the latency between the magnetic stimulus and the action potential recorded during the experiments in (C).
Mentions: The magnetic field was assessed using Vector Fields finite elements simulation software (Cobham Technical Services). The electric field induced in the plane of the brain slice was calculated using MATLAB (MATLAB 2007B, Mathworks, Natick, MA, USA) for a magnetic coil with a mean radius of 1 cm (Figure 6B), using the formulae (Tofts, 1990):

Bottom Line: Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood.In agreement with the modeling, our recordings demonstrate the dependence of magnetic stimulation-triggered action potentials on the type and state of the neuron and its orientation within the magnetic field.Our results suggest that the observed effects of TMS are deeply rooted in the biophysical properties of single neurons in the central nervous system and provide a framework both for interpreting existing TMS data and developing new simulation-based tools and therapies.

View Article: PubMed Central - PubMed

Affiliation: The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University Ramat-Gan, Israel.

ABSTRACT
Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood. We have previously predicted, using compartmental modeling, that magnetic stimulation of central nervous system neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. The simulations also predict that neurons with low current threshold are more susceptible to magnetic stimulation. Here we tested these theoretical predictions by combining in vitro patch-clamp recordings from rat brain slices with magnetic stimulation and compartmental modeling. In agreement with the modeling, our recordings demonstrate the dependence of magnetic stimulation-triggered action potentials on the type and state of the neuron and its orientation within the magnetic field. Our results suggest that the observed effects of TMS are deeply rooted in the biophysical properties of single neurons in the central nervous system and provide a framework both for interpreting existing TMS data and developing new simulation-based tools and therapies.

No MeSH data available.


Related in: MedlinePlus