Force information integration in the primate fronto-parietal reach network
by Julia Nowak
Date of Examination:2022-11-24
Date of issue:2023-11-10
Advisor:Prof. Dr. Alexander Gail
Referee:Prof. Dr. Alexander Gail
Referee:Dr. Igor Kagan
Persistent Address:
http://dx.doi.org/10.53846/goediss-10193
Files in this item
Name:Dissertation_JuliaNowak.pdf
Size:5.02Mb
Format:PDF
The following license files are associated with this item:
Abstract
English
The primate sensorimotor system relies on force predictions, when executing a motor command with a certain force. Yet it remains unclear if the sensorimotor system uses these force predictions to prepare a motor command according to the force the command will be executed with. We conducted two studies that investigate if the sensorimotor system uses force predictions when preparing a motor command (action-context) or when selecting between motor commands (action selection-context). The first study investigated if areas in the fronto-parietal reach network encode the force of reach movement during movement preparation (action-context). We trained two macaque monkeys to perform a reach task, where reaches had to be conducted, against alternating resistive forces, toward a reach goal. In most trials the resistive force of the previous trial was predictive of the resistive force monkeys encountered in the present trial. While the monkeys performed the reach task, we recorded the neural activity in three areas of the fronto-parietal reach network: the arm area of the primary motor cortex (M1), the dorsal premotor cortex (PMd) and the parietal reach region (PRR). Results from our first study suggest that M1, PMd and PRR do not encode the force of reach movement during movement preparation but do so during movement execution. The second study investigated if the same areas in the fronto-parietal reach network encode the force when selecting between reach movements (action selection-context). We trained a macaque monkey to perform an effort-guided reach selection task, where reaches had to be conducted, against alternating resistive forces, toward one of two reach goals. Again, in most trials the resistive force of the previous trial was predictive of the resistive force monkeys encountered in the present trial, but this time the resistive force was only applied when reaches were conducted toward one of the two reach goals. While the monkey performed the reach selection task, we recorded the neural activity in M1, PMd and PRR. Results from our second study suggest that PMd, and to an extent M1, encode the force when selecting between reach movements and M1, PMd and PRR encode the force once the selection was made and the movement executed. The results from our studies suggest that the primate sensorimotor system uses force predictions when selecting between motor commands (action selection-context) but not when preparing a motor command (action-context). Therefore, we conclude that the use of force predictions prior to movement execution might be context dependent in the primate sensorimotor system.
Keywords: sensorimotor control; action and action selection; force; neuroscience; non-human primates
