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Title: Neural representation of movements : insights from neural activity and from behaviour
Author: Kobak, Eva-Maria
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2013
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It is long known that the motor cortex is involved in the execution of movements. However, how exactly movements are represented in the brain remains largely unknown. In this thesis, I adopt two different approaches to study natural control of movements. In the first approach, neural signals in the motor cortex are analysed and brought in relation to concurrent movements. In the second approach the behaviour of subjects is observed to deduce characteristics of the underlying neural representations. For the analysis of neural signals, I had access to multi-electrode recordings from motor cortex of behaving monkeys. In the phase of local field potentials, a spatiotemporal pattern resembling a propagating wave can be observed. On a single trial basis, I could show that this pattern is present over a very broad frequency range (0.3???90 Hz) throughout which the wavelength stays relatively constant, causing a linear increase in propagation speed with frequency. Two models, a travelling wavepacket and a dipole model, will be discussed as possible sources of the observed pattern. Additionally, I investigated the information content of the phases of LFP signals with regards to movement direction, which could potentially have implications for the application in a brain machine interface. The behaviour of human subjects was studied in a motor-psychophysical experiment in which a reaching movement was performed under a visuomotor rotation. The two parts of the movement, reaching forward to the target and returning to the starting location, were analysed separately and subjects were prevented from learning the rotation directly in the latter. Thereby, I could estimate the influence of proprioception on backward motor control, and could demonstrate that there is learning transfer between forward and backward movements.
Supervisor: Mehring, Carsten Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available