Region Of Subthalamic Nucleus Research Articles

Parkinson Disease: Pattern of Functional MR Imaging Activation during Deep Brain Stimulation of Subthalamic Nucleus—Initial Experience

To prospectively determine the pattern of functional magnetic resonance (MR) imaging activation at 3 T produced by deep brain stimulation (DBS) of subthalamic nucleus (STN) for treatment of Parkinson disease and to determine the safety of DBS electrode stimulation during functional MR imaging at 3 T. Informed consent was obtained from all subjects participating in the study, and the study protocol was approved by the institutional review board at the Cleveland Clinic Foundation and was HIPAA compliant. After extensive phantom safety testing of DBS lead systems, five patients (three men, two women; mean age, 49.4 years +/- 14.5 [standard deviation]; range, 31-74 years) with percutaneously extended bilateral DBS electrodes placed in the STN for treatment of Parkinson disease were examined at 3 T on the 1st or 2nd postoperative day. Imaging consisted of a three-dimensional anatomic data set with leads disconnected and a blood oxygen level-dependent functional MR image with a single lead connected to the external pulse generator in the MR imaging control room by using stimulation parameters previously determined to produce optimal stimulation for alleviation of symptoms. A total of nine leads were tested with the functional MR imaging protocol. Subjects underwent neurologic examination immediately before and after MR imaging. All five patients completed the study without change in their neurologic examination and with activation seen in eight of nine electrodes stimulated. Activation was seen in the ipsilateral basal ganglia in all subjects and ipsilateral thalamus in six of the electrodes tested. Two of the electrode stimulations demonstrated additional activation in the STN and/or substantia nigra region adjacent to the electrode tip. For three electrode stimulations, activation was seen in the contralateral superior cerebellum. Therapeutically effective DBS of STN can be performed safely during functional MR imaging at 3 T and produces a consistent pattern of ipsilateral activation of deep brain motor structures.

Modulation of beta oscillations in the subthalamic area during motor imagery in Parkinson's disease

Activation of the basal ganglia has been shown during the preparation and execution of movement. However, the extent to which the activation during movement is related to efferent processes or feedback-related motor control remains unclear. We used motor imagery (MI), which eliminates peripheral feedback, to further investigate the role of the subthalamic area in the feedforward organization of movement. We recorded local field potential (LPF) activity from the region of the subthalamic nucleus (STN) in eight patients with Parkinson's disease off dopaminergic medication during performance of a warned reaction time task. Patients were instructed to either extend the wrist [motor execution (ME)], to imagine performing the same task without any overt movement (MI), or, in a subgroup, to perform a non-motor visual imagery (VI) task. MI led to event-related desynchronization (ERD) of oscillatory beta activity in the region of the STN in all patients that was similar in frequency, time course and degree to the ERD occurring during ME. The degree of ERD during MI correlated with the ERD in trials of ME and, like ME, was accompanied by a decrease in cortico-STN coherence, so that STN LFP activity during MI was similar to that in ME. The ERD in ME and MI were both significantly larger than the ERD in VI. In contrast, event-related synchronization (ERS) was significantly smaller in trials of MI, and even smaller in trials of VI, than during ME. The data suggest that the activity in the region of the human STN indexed by the ERD during movement is related to the feedforward organization of movement and is relatively independent of peripheral feedback. In contrast, sensorimotor feedback is an important factor in the ERS occurring in the STN area after completion of movement, consistent with a role for this region in trial-to-trial motor learning or the re-establishment of postural set following movements.

Emotionally Arousing Visual Stimuli Modulate Oscillatory alpha Activity Recorded from STN Area in PD Patients

High frequency stimulation (HFS) of the subthalamic nucleus (STN) has become a widely accepted therapy to treat motor symptoms in PD patients. In some patients however, stimulation may be accompanied by behavioral and cognitive side effects drawing attention to a possible influence of HFS on associative and limbic circuits within the STN area. To further elucidate the involvement of the human STN region in the processing of emotional information we investigated changes in oscillatory activity within the STN area in response to emotionally arousing visual stimuli. Local field potentials (LFP) were recorded through deep brain macroelectrodes (Medtronic, model 3389) from the STN area in 10 PD patients (6 men, 4 women; age 53.2±3.8 years; 19 sides) during a 1 second presentation of emotionally arousing stimuli (selected from the International Affective Picture System). Data were digitally pass-band filtered in the alpha (8–12Hz) range, squared and responses averaged across pleasant, unpleasant and neutral stimuli. Changes in alpha activity were defined as the percentage decrease (event-related desynchronization-ERD) or increase in band power during the test interval (0.5s to 3s post-stimulus) in comparison to the baseline period (2s before stimulus presentation) for each emotional category. A significant decrease in alpha power was found for all stimulus categories starting at about 0.5s after stimulus presentation. During the post-stimulus time period from 1–2s the ERD was significantly larger in trials of pleasant (mean ERD 21.6%±2.8; p<0.001) and unpleasant (mean ERD 15.0%±4.2; p=0.002) stimuli compared to neutral (mean ERD 4.4%±4.2). The modulation of late alpha activity recorded from the STN area in PD may reflect processing of emotional arousal as it followed both pleasant and unpleasant stimuli. These findings suggest that „limbic“ processing occurs in the region of STN and may offer an explanation for why STN-HFS may be complicated by affective disorders in PD patients.

Identification of target areas for deep brain stimulation in human basal ganglia substructures based on median nerve sensory evoked potential criteria

Objective: In the interventional treatment of movement disorders, the thalamic ventral intermediate nucleus (VIM) and the subthalamic nucleus (STN) are the most relevant electrode targets for deep brain stimulation (DBS)....

Oscillatory Local Field Potentials Recorded from the Subthalamic Nucleus of the Alert Rat

Hitherto, high-frequency local field potential oscillations in the upper γ frequency band (40–80 Hz) have been recorded only from the region of subthalamic nucleus (STN) in parkinsonian patients treated with levodopa. Here we show that local field potentials recorded from the STN in the healthy alert rat also have a spectral peak in the upper γ band (mean 53 Hz, range 46–70 Hz). The power of this high-frequency oscillatory activity was increased by 30 ± 4% (±SEM) during motor activity compared to periods of alert immobility. It was also increased by 86 ± 36% by systemic injection of the D2 dopamine receptor agonist quinpirole. The similarities between the high-frequency activities in the STN of the healthy rat and in the levodopa-treated parkinsonian human argue that this oscillatory activity may be physiological in nature and not a consequence of the parkinsonian state.

Intraoperative micro- and macrostimulation of the subthalamic nucleus in Parkinson's disease.

Studying the clinical effects induced by electrical stimulation of the subthalamic nucleus (STN) area in a parkinsonian patient under local anesthesia is a mandatory step to determine the precise location of the final chronic electrode. Using multiple microelectrodes, preferably in a concentric parallel array allows a precise mapping of the STN region. The most reliable features to determine the suitable target are stimulation-induced dyskinesias and rigidity decrease at a low intensity without adverse effects or only at far higher intensities. New skills are needed to assess all stimulation-induced effects and interpret them in anatomo-functional terms.