Mechanisms Underlying Decision-Making as Revealed by Deep-Brain Stimulation in Patients with Parkinson's Disease.

Herz DM
Little S
Pedrosa D
Tinkhauser G
Cheeran B
Foltynie T
Bogacz R
Brown P

Here, we studied how electrical activity in a part of the brain called the subthalamic nucleus is involved in making a decision. We show that a precisely-timed burst of electrical waves in the subthalamic nucleus determines whether or not people take time to consider the options when making a decision.

Scientific Abstract

To optimally balance opposing demands of speed and accuracy during decision-making, we must flexibly adapt how much evidence we require before making a choice. Such adjustments in decision thresholds have been linked to the subthalamic nucleus (STN), and therapeutic STN deep-brain stimulation (DBS) has been shown to interfere with this function. Here, we performed continuous as well as closed-loop DBS of the STN while Parkinson's disease patients performed a perceptual decision-making task. Closed-loop STN DBS allowed temporally patterned STN stimulation and simultaneous recordings of STN activity. This revealed that DBS only affected patients' ability to adjust decision thresholds if applied in a specific temporally confined time window during deliberation. Only stimulation in that window diminished the normal slowing of response times that occurred on difficult trials when DBS was turned off. Furthermore, DBS eliminated a relative, time-specific increase in STN beta oscillations and compromised its functional relationship with trial-by-trial adjustments in decision thresholds. Together, these results provide causal evidence that the STN is involved in adjusting decision thresholds in distinct, time-limited processing windows during deliberation.

In this experiment, we were able to establish a causal link between deep brain rhythms and delaying decisions. We were able to do this by directly recording beta-frequency electrical activity in the subthalamic nucleus in people with Parkinson’s disease and then interfering with this activity through closed-loop Deep Brain Stimulation. Participants engaged in a task in which they had to decide on the predominant direction of movement of a cloud of moving dots presented on a screen.
In this experiment, we were able to establish a causal link between deep brain rhythms and delaying decisions. We were able to do this by directly recording beta-frequency electrical activity in the subthalamic nucleus in people with Parkinson’s disease and then interfering with this activity through closed-loop Deep Brain Stimulation. Participants engaged in a task in which they had to decide on the predominant direction of movement of a cloud of moving dots presented on a screen.
Citation

2018.Curr. Biol., 28(8):1169-1178.e6.

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