Deep brain stimulation of the ventrointermediate nucleus of the thalamus to treat essential tremor improves motor sequence learning

Abstract:

The network of brain structures engaged in motor sequence learning comprises the same structures as those involved in tremor, including basal ganglia, cerebellum, thalamus, and motor cortex. Deep brain stimulation (DBS) of the ventrointermediate nucleus of the thalamus (VIM) reduces tremor, but the effects on motor sequence learning are unknown. We investigated whether VIM stimulation has an impact on motor sequence learning and hypothesized that stimulation effects depend on the laterality of electrode location. Twenty patients (age: 38–81 years; 12 female) withVIM electrodes implanted to treat essential tremor (ET) successfully performed a serial reaction time task, varying whether the stimuli followed a repeating pattern or were selected at random, during which VIM-DBS was either on or off. Analyses of variance were applied to evaluate motor sequence learning performance according to reaction times (RTs) and accuracy. An interaction was observed between whether the sequence was repeated or random and whether VIM-DBS was on or off (F[1,18]=7.89,p=.012). Motor sequence learning, reflected by reduced RTs for repeated sequences, was greater with DBS on than off (T[19]=2.34,p=.031). Stimulation location correlated with the degree of motor learning, with greater motor learning when stimulation targeted the lateral VIM (n=23,ρ=0.46;p=.027).These results demonstrate the beneficial effects of VIM-DBS on motor sequence learning in ET patients, particularly with lateral VIM electrode location, and provide evidence for a role for the VIM in motor sequence learning.

Authors:

• Laila Terzic

• Angela Voegtle

• Amr Farahat

• Nanna Hartong

• Imke Galazky

• Slawomir J. Nasuto

• Adriano de Oliveira Andrade

• Robert T. Knight

• Richard B. Ivry

• Jürgen Voges

• Lars Buentjen

• Catherine M. Sweeney-Reed

Date: 2022

DOI: 10.1002/hbm.25989

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Predictive value of novel stimuli modifies visual event-related potentials and behavior

Authors:

• Shugo Suwazono

• Liana Machado

• Robert T. Knight

Date: 1999

PubMed: 10656508

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Abstract:

Objective: We examined how behavioral context in ̄uences novelty processing by varying the degree that a novel event predicted the occurrence of a subsequent target stimulus. Methods: Visual event-related potentials (ERPs) and reaction times (RTs) were recorded in 3 detection experiments (23 subjects). The predictive value of a novel stimulus on the occurrence of a subsequent target was varied as was novel-target pairing intervals (200±900 ms). In Experiment 1, novel stimuli always preceded a target, in Experiment 2, 40% of novel stimuli were followed by a target, and in Experiment 3, novel stimuli occurred randomly. Results: In Experiment 1, RTs following 100% predictive novels were shortened for targets at all spatial locations and novel-target pairing intervals. Novel stimuli predicting a target generated a central negativity peaking at 300 ms and reduced P3a and P3b ERPs. In Experiments 2 and 3, target RTs were prolonged only when novel and target stimuli were presented in the same spatial location at short ISIs (200 ms). The central novel N2 was smaller in amplitude in comparison to Experiment 1, and novelty P3a and target extrastriate N2 and posterior scalp P3b ERPs were enhanced. Conclusions: The enhanced N2 for100% predictive novel stimuli appears to index an alerting system facilitating behavioral detection. The same novel stimuli with no predictive value distract attention and generate a different ERP pattern characterized by increased novelty P3a and target P3b responses. The results indicate that behavioral context determines how novel stimuli are processed and in ̄uence behavior.

Association Cortex Contributions to the Human P3

ABSTRACT

Event-related potentials (ERPs) assess the timing and neurophysiological basis of cognition in humans. The P3 ERP component (Desmedt et al., 1965; Sutton et al., 1965) has been associated with psychological constructs including orientation, attention, stimulus evaluation, and memory. The functional significance and neural generators of the P3 are under active investigation (Desmedt et al., 1979; Donchin, 1979; Hillyard and Picton, 1987).

AUTHORS

• Shuhei Yamaguchi

• Robert T. Knight

Date: 1993

DOI: doi.org/10.1007/978-1-4757-1379-4_6

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