Methods Series

WIPS

Closed-loop transcranial magnetic stimulation for the treatment of tremor

V.Mancini, N. Shackle, A. Sharrott, K. Wendt, T. Denison, C. Stagg, H. Cagnan, A. Oswal

Tremor can be both physically and socially challenging. By far the two commonest causes are Essential tremor (ET) and Parkinson’s disease (PD). There is a need for less invasive stimulation approaches than deep brain stimulation for tremor treatment, and the goal of this study is to investigate the potential of cortical interventions. We plan to test transcranial magnetic stimulation based on the principle of phase interference. The non-invasive stimulation being applied here will be timed to catch the neural oscillation responsible for tremor at the phase which leads to a decrease in amplitude. Stimulation of the motor cortex at approximately tremor frequency (5 Hz) has already been shown to lead to a modest, acute improvement of Parkinsonism, including rest tremor, even when no attempt is made to deliver stimulation at the most sensitive tremor phase for suppression. We predict that treatment effects on tremor will be much greater if amplitude suppressing phases in the tremor cycle are systematically and consistently targeted. This is because we have reason to believe that TMS of the motor cortex can have phase dependent effects on tremor and that the effects of consistent phase-locked stimulation may be cumulative.

Oscillatory signatures underlying impaired hippocampal learning in psychosis

V.Mancini, H.Barron C. Stagg

Schizophrenia has the greatest impact on the quality of life and life expectancy of affected individuals among
the psychiatric disorders. This disability results mainly from the treatment-refractory cognitive symptoms. For
this reason, there is a great need for studies exploring the neural circuits underlying cognitive deficits in
schizophrenia. Several lines of research converge on the impairment of hippocampal-related functions, and
inhibitory neural circuits underlying high-frequency neural oscillations (gamma-band oscillations, >30 Hz) in
schizophrenia. However, there is limited evidence for reduced gamma-band response in the hippocampus
during long-term memory tasks in psychotic patients. Here, we propose to investigate the oscillatory signatures
underlying hippocampal learning in psychotic patients as compared to a control group by leveraging advanced
magnetoencephalography (MEG) techniques and employing a task that selectively engages the hippocampus.
Furthermore, we aim to probe the contribution of the excitatory-inhibitory (EI) balance to the psychotic
phenotype by manipulating cortical EI balance in a second control group, to address the hypothesis that this
manipulation will lead to neuroimaging and behavioural outcomes similar to the psychotic group.

WIN Methods Series

Aaron Hess

Human 7T MRI has promised much since the first machine in 1995. Its wrapper promised double the signal and better BOLD/T1/T2 contrast; 20 years of development is bringing this potential into reach. In this talk, I will address how MRI technology has evolved and how it will continue to evolve to cater for the unique challenges of 7T. Clinical benefits have given rise to new 7T products – such as the recently upgraded FMRIB 7T, and a fully featured clinical 7T product (Terra X).  These will be discussed in the presentation.