The Unversity of Ottawa is pleased to invite qualified proponents to submit a proposal for a Transcranial Magnetic Brain Stimulation Platform. The overarching objective of this research program is to improve our understanding of the brain mechanisms underlying the inability to turn the intention to be physically active into actions. To reach this objective, the relationship between effort overestimation and physical inactivity will be investigated using transcranial magnetic stimulation (TMS). Two types of approaches based on motor-evoked potentials (MEPs) –electrical signals, recorded from muscles, that result from the stimulation of motor pathways within the brain– will be used to probe the primary motor cortex (M1) physiology. First, single-pulse TMS will be used to assess the overall excitability of the motor system. Second, paired-pulse TMS will be used to probe the activity of targeted M1 intracortical circuits: short- and long-interval intracortical inhibition (SICI, LICI) as well as intracortical facilitation (ICF). Dual-site paired-pulse TMS will be exploited to test if an alteration of effective connectivity between M1 and the prefrontal cortex is associated with increased effort overestimation and increased automatic tendencies toward sedentary behavior. This TMS protocol isolates the influence of a targeted cortical area on M1. Repetitive TMS (rTMS) –a method that transiently alters cortical excitability through short trains of magnetic stimuli at high frequency – will be used to decrease the cortical excitability of brain areas beyond the stimulation period.
General Description:
The project requires state-of-the-art and gold standard transcranial magnetic equipment. Single and paired-pulse transcranial magnetic stimulators will allow for probing the excitability of the brain, mapping out networks of interest and identifying biomarkers. Repetitive transcranial magnetic stimulation will allow for the neuromodulation of the mechanisms involved in effort overestimation. The cooled coil will provide cooling so that longer repetitive stimulation protocols can be used without the concern of coils overheating part way through test protocols. The non-cooled coils will allow for single- and paired-pulse stimulation to be implemented in single or dual-coil protocols. Interface modules are integral to the measurement of physiologic responses and the understanding of the impacts of magnetic stimulation on the potential treatments being investigated by synchronizing the TMS devices to other recording devices like electromyography, electroencephalography, or other devices that provide visual, audio or proprioception stimulation to a subject or patient.
Mandatory Requirements:
1. Repetitive transcranial magnetic stimulator
1.1 Must employ biphasic waveforms
1.2 Must eliminate pulse decay and roll-off at high frequencies of stimulation (i.e., higher than 40 Hz)
1.3 At high frequencies of stimulation (i.e., higher than 40 Hz), every single pulse must be of the same intensity.
1.4 Must provide repetitive protocols ranging from 1 to 100 Hz stimulation at 1 Hz increments.
1.5 Must be able to provide 5 Hz bursts of 3 pulses, which are provided at 50 Hz (intermittent theta burst stimulation) without pulse decay and roll-off.
1.6 Must include an EMG amplifier and oscilloscope with at least two channels that allows for display and measurement of collected motor evoked potentials.
1.7 Must include a stimulator cart with an incorporated coil arm and holder.
2. Single-pulse transcranial magnetic stimulators for paired-pulse stimulators
2.1 Must include two inter-connected single-pulse monophasic stimulators that allow for up to 100% output for each pulse in the pair.
2.2 It must be possible to control each stimulator externally via trigger in capability.
2.3 It must be possible to decouple the stimulators and use each one independently or to allow for two site stimulations (e.g., bi-hemispheric).
2.4 It must be possible to have inter-pulse intervals of 1 millisecond or less.
2.5 Must include a stimulator cart.
3. Interface modules
3.1 Must include 3 interface modules that allow for trigger in and trigger out capabilities into and out of all the stimulators.
3.2 The interface modules must allow for the synchronization of the stimulators (repetitive stimulator and single-pulse stimulators) to other devices like electromyography, electroencephalography, or other devices that provide visual, audio, or proprioception stimulation.
4. Coils
4.1 Must include a 70-mm figure-of-eight flat coil with a cooling system.
4.2 Must include a 70-mm figure-of-eight flat coil without cooling system and two 40-mm figure-of-eight flat coils without cooling system
5. Other Requirements
5.1 Installation and training must be included.
5.2 Must be capable of providing up to a total of 5 years of warranty
