Improving efficacy of repetitive transcranial magnetic stimulation for treatment of Parkinson disease gait disorders.

Parkinson disease (PD) is a neurodegenerative disorder that causes motor and cognitive deficits, presenting complex challenges for therapeutic interventions. Repetitive transcranial magnetic stimulation (rTMS) is a type of neuromodulation that can produce plastic changes in neural activity. rTMS has been trialed as a therapy to treat motor and non-motor symptoms in persons with Parkinson disease (PwP), particularly treatment-refractory postural instability and gait difficulties such as Freezing of Gait (FoG), but clinical outcomes have been variable.

Evidence for a Causal Dissociation of the McGurk Effect and Congruent Audiovisual Speech Perception via TMS to the Left pSTS.

Congruent visual speech improves speech perception accuracy, particularly in noisy environments. Conversely, mismatched visual speech can alter what is heard, leading to an illusory percept that differs from the auditory and visual components, known as the McGurk effect. While prior transcranial magnetic stimulation (TMS) and neuroimaging studies have identified the left posterior superior temporal sulcus (pSTS) as a causal region involved in the generation of the McGurk effect, it remains unclear whether this region is critical only for this illusion or also for the more general benefits of congruent visual speech (e.

Repeated spaced cortical paired associative stimulation promotes additive plasticity in the human parietal-motor circuit.

Objective: Repeated spaced sessions of repetitive transcranial magnetic stimulation (TMS) to the human primary motor cortex can lead to dose-dependent increases in motor cortical excitability. However, this has yet to be demonstrated in a defined cortical circuit. We aimed to examine the effects of repeated spaced cortical paired associative stimulation (cPAS) on excitability in the motor cortex.

People are more error-prone after committing an error.

Humans tend to slow down after making an error. A longstanding account of this post-error slowing is that people are simply more cautious. However, accuracy typically does not improve following an error, leading some researchers to suggest that an initial 'orienting' response may initially impair performance immediately following error.

Evidence for a Causal Dissociation of the McGurk Effect and Congruent Audiovisual Speech Perception via TMS.

Congruent visual speech improves speech perception accuracy, particularly in noisy environments. Conversely, mismatched visual speech can alter what is heard, leading to an illusory percept known as the McGurk effect. This illusion has been widely used to study audiovisual speech integration, illustrating that auditory and visual cues are combined in the brain to generate a single coherent percept.

Motivational Vigor in Parkinson's Disease Requires the Short and Long Duration Response to Levodopa.

Background: Impaired movement vigor (bradykinesia) is a cardinal feature of Parkinson's disease (PD) and hypothesized to result from abnormal motivational processes-impaired motivation-vigor coupling. Dopamine replacement therapy (DRT) improves bradykinesia, but the response to DRT is multifaceted, comprising a short-duration response (SDR) and a long-duration response (LDR) only manifesting with chronic treatment. Prior experiments assessing motivation-vigor coupling in PD used chronically treated subjects, obscuring the roles of the SDR and LDR.

The behavioral and neural effects of parietal theta burst stimulation on the grasp network are stronger during a grasping task than at rest.

Repetitive transcranial magnetic stimulation (TMS) is widely used in neuroscience and clinical settings to modulate human cortical activity. The effects of TMS on neural activity depend on the excitability of specific neural populations at the time of stimulation. Accordingly, the brain state at the time of stimulation may influence the persistent effects of repetitive TMS on distal brain activity and associated behaviors.

Lateral Prefrontal Stimulation of Active Cortex With Theta Burst Transcranial Magnetic Stimulation Affects Subsequent Engagement of the Frontoparietal Network.

Background: A critical unanswered question about therapeutic transcranial magnetic stimulation is what patients should do during treatment to optimize its effectiveness. Here, we address this lack of knowledge in healthy participants, testing the hypotheses that stimulating the left dorsolateral prefrontal cortex (dlPFC) while participants perform a working memory task will provide stronger effects on subsequent activation, perfusion, connectivity, and performance than stimulating resting dlPFC.

Methods: After a baseline functional magnetic resonance imaging session to localize dlPFC activation and the associated frontoparietal network (FPN) engaged by an n-back task, healthy participants (N = 40, 67.

Reward Accelerates the Preparation of Goal-directed Actions under Conflict.

Our goals sometimes conflict with our prepotent habitual responses, which often leads to impaired performance on a variety of tasks. People are better at exerting cognitive control to overcome prepotent and automatic responses when they are motivated by the prospect of reward. The standard experimental paradigms used to study this phenomenon examine free RTs that allow participants to select a variety of response strategies including delaying response initiation to avoid committing errors.

Influence of goals on modular brain network organization during working memory.

Introduction: Top-down control underlies our ability to attend relevant stimuli while ignoring irrelevant, distracting stimuli and is a critical process for prioritizing information in working memory (WM). Prior work has demonstrated that top-down biasing signals modulate sensory-selective cortical areas during WM, and that the large-scale organization of the brain reconfigures due to WM demands alone; however, it is not yet understood how brain networks reconfigure between the processing of relevant versus irrelevant information in the service of WM.

Methods: Here, we investigated the effects of task goals on brain network organization while participants performed a WM task that required participants to detect repetitions (e.

Reward influences the allocation but not the availability of resources in visual working memory.

Visual working memory possesses capacity constraints limiting the availability of resources for encoding and maintaining information. Studies have shown that prospective rewards improve performance on visual working memory tasks, but it remains unclear whether rewards increase total resource availability or simply influence the allocation of resources. Participants performed a continuous report visual working memory task with oriented grating stimuli.

Continuous Theta Burst Stimulation to the Secondary Visual Cortex at 80% Active Motor Threshold Does Not Impair Central Vision in Humans During a Simple Detection Task.

Continuous theta burst stimulation (cTBS) is a powerful form of repetitive transcranial magnetic stimulation capable of suppressing cortical excitability for up to 50 min. A growing number of studies have applied cTBS to the visual cortex in human subjects to investigate the neural dynamics of visual processing, but few have specifically examined its effects on central vision, which has crucial implications for safety and inference on downstream cognitive effects. The present study assessed the safety of offline, neuronavigated cTBS to V2 by examining its effects on central vision performance.

Heuristics contribute to sensorimotor decision-making under risk.

Research in psychophysics argues that incentivized sensorimotor decisions (such as deciding where to reach to get a reward) maximize expected gain, suggesting that these decisions may be impervious to cognitive biases and heuristics. We tested this hypothesis in two experiments, directly comparing the predictive accuracy of an optimal model and plausible suboptimal models. We obtained strong evidence that people deviated from the optimal strategy by excessively avoiding loss regions when the potential loss was zero and failing to shift far enough away from loss regions when potential losses outweighed the potential gains.

Interactive effects of incentive value and valence on the performance of discrete action sequences.

Incentives can be used to increase motivation, leading to better learning and performance on skilled motor tasks. Prior work has shown that monetary punishments enhance on-line performance while equivalent monetary rewards enhance off-line skill retention. However, a large body of literature on loss aversion has shown that losses are treated as larger than equivalent gains.

Reward modulates cortical representations of action.

People are capable of rapid improvements in performance when they are offered a reward. The neural mechanism by which this performance enhancement occurs remains unclear. We investigated this phenomenon by offering people monetary reward for successful performance in a sequence production task.

Theta Burst Transcranial Magnetic Stimulation of Fronto-Parietal Networks: Modulation by Mental State.

Unlabelled: Transcranial magnetic stimulation (TMS) treats neuropsychiatric disorders, but effects of stimulation are highly state-dependent and in most therapeutic applications, mental state is not controlled. This exploratory proposal will test the broad hypothesis that when TMS, specifically intermittent theta burst stimulation (iTBS), is applied during a controlled mental state, network changes will be facilitated, compared to stimulation when mental state is uncontrolled. We will focus on the dorsolateral prefrontal cortex (dlPFC) and the associated fronto-parietal network (FPN), which subserves cognitive control, an important neural and behavioral target of therapeutic TMS.

Rewards interact with explicit knowledge to enhance skilled motor performance.

From typing on a keyboard to playing the piano, many everyday skills require the ability to quickly and accurately perform sequential movements. It is well known that the availability of rewards leads to increases in motivational vigor whereby people enhance both the speed and force of their movements. However, in the context of motor skills, it is unclear whether rewards also lead to more effective motor planning and action selection.

Limiting motor skill knowledge via incidental training protects against choking under pressure.

The paradoxical harmful effects of motivation and incentives on skilled performance ("choking under pressure") are observed in a wide variety of motor tasks. Two theories of this phenomenon suggest that choking under pressure occurs due to maladaptive attention and top-down control, either through distraction away from the task or interference via an overreliance on controlled processing of a skilled task. A third theory, overmotivation (or overarousal), suggests that under pressure, "instinctive" or Pavlovian approach/withdrawal responses compete with the desired response.

Coupling between Theta Oscillations and Cognitive Control Network during Cross-Modal Visual and Auditory Attention: Supramodal vs Modality-Specific Mechanisms.

Cortical theta band oscillations (4-8 Hz) in EEG signals have been shown to be important for a variety of different cognitive control operations in visual attention paradigms. However the synchronization source of these signals as defined by fMRI BOLD activity and the extent to which theta oscillations play a role in multimodal attention remains unknown. Here we investigated the extent to which cross-modal visual and auditory attention impacts theta oscillations.

The Effect of Disruption of Prefrontal Cortical Function with Transcranial Magnetic Stimulation on Visual Working Memory.

It is proposed that feedback signals from the prefrontal cortex (PFC) to extrastriate cortex are essential for goal-directed processing, maintenance, and selection of information in visual working memory (VWM). In a previous study, we found that disruption of PFC function with transcranial magnetic stimulation (TMS) in healthy individuals impaired behavioral performance on a face/scene matching task and decreased category-specific tuning in extrastriate cortex as measured with functional magnetic resonance imaging (fMRI). In this study, we investigated the effect of disruption of left inferior frontal gyrus (IFG) function on the fidelity of neural representations of two distinct information codes: (1) the stimulus category and (2) the goal-relevance of viewed stimuli.

Out of control: diminished prefrontal activity coincides with impaired motor performance due to choking under pressure.

There are three non-exclusive theoretical explanations for the paradoxical collapse of performance due to large financial incentives. It has been proposed that "choking under pressure" is either due to distraction, interference via an increase in top-down control and performance monitoring, or excessive levels of arousal in the face of large losses. Given the known neural architecture involved in executive control and reward, we used fMRI of human participants during incentivized motor performance to provide evidence to support and/or reconcile these competing models in a visuomotor task.

Quantifying the reconfiguration of intrinsic networks during working memory.

Rapid, flexible reconfiguration of connections across brain regions is thought to underlie successful cognitive control. Two intrinsic networks in particular, the cingulo-opercular (CO) and fronto-parietal (FP), are thought to underlie two operations critical for cognitive control: task-set maintenance/tonic alertness and adaptive, trial-by-trial updating. Using functional magnetic resonance imaging, we directly tested whether the functional connectivity of the CO and FP networks was related to cognitive demands and behavior.