Prescott, T.J.; González, F.M.M.; Gurney, K.; Humphries, M.D.; Redgrave, P. Simulated Dopamine Modulation of a Neurorobotic Model of the Basal Ganglia. Biomimetics2024, 9, 139.
Prescott, T.J.; González, F.M.M.; Gurney, K.; Humphries, M.D.; Redgrave, P. Simulated Dopamine Modulation of a Neurorobotic Model of the Basal Ganglia. Biomimetics 2024, 9, 139.
Prescott, T.J.; González, F.M.M.; Gurney, K.; Humphries, M.D.; Redgrave, P. Simulated Dopamine Modulation of a Neurorobotic Model of the Basal Ganglia. Biomimetics2024, 9, 139.
Prescott, T.J.; González, F.M.M.; Gurney, K.; Humphries, M.D.; Redgrave, P. Simulated Dopamine Modulation of a Neurorobotic Model of the Basal Ganglia. Biomimetics 2024, 9, 139.
Abstract
The vertebrate basal ganglia are thought to play an important role in action selection—the resolution of conflicts between alternative motor programs. The effective operation of basal ganglia circuitry is also known to rely on appropriate levels of tonic dopamine transmission. We show that when the tonic level of simulated dopamine in a robotic model of the basal ganglia is significantly reduced or increased, relative to an effective operating baseline, a variety of behavioral outcomes are observed that provide interesting comparisons with the results of human and animal studies. The main findings were that progressive reductions in the levels of simulated dopamine caused a slowing of the robot’s movements and eventually an inability to initiate movement. These states were partially relieved at increased salience levels (stronger sensory/motivational input). Conversely, increased levels of simulated dopamine could cause distortion of the robot’s motor acts through partially-expressed motor activity relating to losing actions; this could also lead to increased frequency of switching between behaviors. Levels of simulated dopamine that were either significantly lower or higher than baseline could cause changes to the timing of behavior switching that could cause a loss of behavioral integration, sometimes leaving the robot in a ‘behavioral trap’. That some analogous traits are observed in animals and humans affected by dopamine dysregulation suggests that embodied (robotic) models could prove useful in understanding the role of dopamine neurotransmission in basal ganglia function and dysfunction. That the effects of simulated dopamine on robot action selection were partially, but not fully, predictable from the selection properties of the non-embodied basal ganglia model, also points to the added value of using robotic models to explore the relationship between brain activity and behavior.
Biology and Life Sciences, Neuroscience and Neurology
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