Thursday 8th Nov, 2012, 14:00-16:50
Whole-cell patch-clampingSingle neurons
MicrostimulationSingle units / multi-units
MacrostimulationNuclei / large areas (e.g., deep brain stimulation (DBS)
CoolingArea near cooling probes
PharmacologyArea/neurons/receptors exposed to or affected by drugs
Transcranial electrical stimulation (TES)Brain areas between electrodes
Transcranial magnetic stimulation (TMS)Brain areas ~1cm diameter
Transcranial direct current stimulation (TDCS)Brain areas between electrodes
Transcranial random noise stimulation (TRNS)Not sure yet...
(Transcutaneous) Peripheral nerve stimulation (PNS)Single nerves
Static magnetic stimulation~5cm of brain
Cohen D (1984). Feasibility of a magnetic stimulator for the brain. In Biomagnetism: applications and theory. Editors: Weinberg H, Stroink G & Katila T. Pergamon press, p. 466-470.
Barker AT, Jalinous R & Freeston I (1985). Non-invasive magnetic stimulation of the human motor cortex. Lancet 1:1106-1107.
Ueno S, Tashiro T & Harada K (1988). Localized stimulation of neural tissue in the brain by means of a paired configuration of time-varying magnetic fields. J Appl. Physics 64:5862-5864.
1987/88 Cadwell Laboratories Inc., repetitive stimulation with water-cooled coil
Orientationaligned with axons
Frequencylow <=1Hz vs high >1Hz
Patternlength & separation of pulse trains
Strong, rapidly-alternating magnetic fields have the potential to induce seizures, both in healthy and in seizure-prone people.
All possible precautions must be taken to screen-out anyone to whom TMS presents an increased risk:
Required reading for all TMS users. Describes different methods & clinical uses of TMS. Collates all known data on adverse reactions to TMS. Attempts to standardise terminology. Sets safety guidelines.
Redrawn from Rossi et al. (2009)
TMS (& PNS) has been used most for studying cortico-motor transduction - the transmission of motor signals from primary motor cortex to muscles
And sensory-motor interactions
The key techniques are:
MEP amplitude & latency tell you about the level of excitability in the cortico-motor pathway and the speed of conduction
FDI muscle, right hand
Size (& variability) of MEPs varies with:
The size & latency of M-waves and H-reflexes can tell you about peripheral nerve-spine conduction
ppTMS comes in two forms: Two pulses from the same coil or two pulses from different coils
Two different coils:
And people are doing triple- and quadri- and other coil combinations now
One coil, two pulses, close together (e.g., 1-50ms)
There's also LICI, LICF, and interactions among all these acronymns - see R Chen's work
Two main kinds:
Supposedly results in decreased activity of the brain area.
Effects supposed to last about half as long as the stimulation.
In long trains, supposedly results in increased activity of the brain area.
In short trains, for interfering with a task during its performance: e.g., 2-5 pulses at 10-20Hz during your task.
TMS pulses are delivered in repeated trains of a certain frequency.
Each train has a certain duration.
Trains are separated by a certain duration.
Theta-burst stimulation is the most popular...
Designed to mimic the tetanic stimulation that is most effective at inducing long term potentiation (LTP) and depression (LTD) in neurons of hippocampal slices
Similar effects shown in human motor cortex by Huang et al., 2005; N=9)
A more recent article from the same group suggests that these effects depend on the subjects... (Hamada et al., 2013; N=56)
Chen, R. (2004). Interactions between inhibitory and excitatory circuits in the human motor cortex. Experimental Brain Research, 154(1), 1–10. [NB]
Classen, J., Steinfelder, B., Liepert, J., Stefan, K., Celnik, P. A., Cohen, L. G., Hess, A., Kunesch, E., & Chen, R. (2000). Cutaneomotor integration in humans is somatotopically organized at various levels of the nervous system and is task dependent. Experimental Brain Research, 130(1), 48–59. [NB]
Funke, K., & Benali, A. (2011). Modulation of cortical inhibition by rtms – findings obtained from animal models. Journal of Physiology, 589(18), 4423–4435. [NB]
Koch, G., Del Olmo, M. F., Cheeran, B. J., Ruge, D., Schippling, S., Caltagirone, C., & Rothwell, J. C. (2007). Focal stimulation of the posterior parietal cortex increases the excitability of the ipsilateral motor cortex. Journal of Neuroscience, 27(25), 6815–6822. [NB]
Mars, R. B., Klein, M. C., Neubert, F., Olivier, E., Buch, E. R., Boorman, E. D., & Rushworth, M. F. S. (2009). Short-latency influence of medial frontal cortex on primary motor cortex during action selection under conflict. Journal of Neuroscience, 29(21), 6926–6931. [NB]
Neubert, F., Mars, R. B., Buch, E. R., Olivier, E., & Rushworth, M. F. S. (2010). Cortical and subcortical interactions during action reprogramming and their related white matter pathways. Proceedings of the National Academy of Sciences USA, 107(30), 13240–13245. [NB]
Oliviero, A., Mordillo-Mateos, L., Arias, P., Panyavin, I., Foffani, G., & Aguilar, J. (2011). Transcranial static magnetic field stimulation of the human motor cortex. Journal of Physiology, 589(20), 4949–4958. [NB]
Rossi, S., Hallett, M., Rossini, P. M., Pascual-Leone, A., & The Safety of TMS Consensus Group, . (2009). Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research. Clinical Neurophysiology, 120(12), 2008–2039. [NB]
Rossini, P. M., Burke, D., Chen, R., Cohen, L. G., Daskalakis, Z. J., Di Iorio, R., di Lazzaro, V., Ferreri, F., Fitzgerald, P. B., George, M. S., Hallett, M., Lefaucheur, J. '., Langguth, B., Matsumoto, H., Miniussi, C., Nitsche, M. A., Pascual-Leone, A., Paulus, W. E., Rossi, S., Rothwell, J. C., Siebner, H. R., Ugawa, Y., Walsh, V. Z., & Ziemann, U. (2015). Non-invasive electrical and magnetic stimulation of the brain, spinal cord, roots and peripheral nerves: basic principles and procedures for routine clinical and research application. an updated report from an i.f.c.n. committee. Clinical Neurophysiology, 126(6), 1071–1107. [NB]
Rothwell, J. C., Day, B. L., Thompson, P. D., & Kujirai, T. (2009). Short latency intracortical inhibition: One of the most popular tools in human motor neurophysiology. Journal of Physiology, 587(1), 11–122. [NB]
Ueno, S., Tashiro, T., & Harada, K. (1988). Localised stimulation of neural tissue in the brain by means of a paired configuration of time-varying magnetic fields. Journal of Applied Physics, 64, 5862–5864. [NB]
Vucic, S., Cheah, B. C., & Kiernan, M. C. (2009b). Defining the mechanisms that underlie cortical hyperexcitability in amyotrophic lateral sclerosis. Experimental Neurology, 220(1), 177–182. [NB]
Walsh, V. Z., & Cowey, A. (2000). Transcranial magnetic stimulation and cognitive neuroscience. Nature Reviews Neuroscience, 1(1), 73–79. [NB]