An infrequent change to an otherwise repetitive sequence of stimuli leads to the generation of mismatch negativity (MMN), even in the absence of attention. This evoked negative response occurs in the scalp-recorded electroencephalogram (EEG) over the temporal and frontal cortices, 100-250 ms after onset of the deviant stimulus. The MMN is used to detect sensory information processing. The aim of our study was to investigate whether MMN can be recorded in the subthalamic nuclei (STN) as evidence of auditory information processing on an unconscious level within this structure. To our knowledge, MMN has never been recorded in the human STN. We recorded intracerebral EEG using a MMN paradigm in five patients with Parkinson's disease (PD) who were implanted with depth electrodes in the subthalamic nuclei (STN). We found far-field MMN when intracerebral contacts were connected to an extracranial reference electrode. In all five PD patients (and nine of ten intracerebral electrodes), we also found near-field MMN-like potentials when intracerebral contacts were referenced to one another, and in some electrodes, we observed phase reversals in these potentials. The mean time-to-peak latency of the intracerebral MMN-like potentials was 214 ± 38 ms (median 219 ms). We reveal MMN-like potentials in bilateral STN. This finding provides evidence that STN receives sensory (auditory) information from other structures. The question for further research is whether STN receives such signals through a previously described hyperdirect pathway between STN and frontal cortex (a known generator of the MMN potential) and if the STN contributes to sensorimotor integration.

• MeSH
• Acoustic Stimulation MeSH
• Electroencephalography MeSH
• Functional Laterality MeSH
• Contingent Negative Variation physiology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Magnetic Resonance Imaging MeSH
• Neuropsychological Tests MeSH
• Subthalamic Nucleus physiopathology   MeSH
• Parkinson Disease complications   pathology   MeSH
• Reaction Time physiology   MeSH
• Aged MeSH
• Evoked Potentials, Auditory physiology   MeSH
• Severity of Illness Index MeSH
• Tomography Scanners, X-Ray Computed MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

We studied the appearance of broadband oscillatory changes (ranging 2-45 Hz) induced by a cognitive task with two levels of complexity. The event-related de/synchronizations (ERD/S) in the subthalamic nucleus (STN) and in the anterior cingulate cortex (ACC) were evaluated in an executive function test. Four epilepsy surgery candidates with intracerebral electrodes implanted in the ACC and three Parkinson's disease patients with externalized deep brain stimulation electrodes implanted in the STN participated in the study. A Flanker test (FT) with visual stimuli (arrows) was performed. Subjects reacted to four types of stimuli presented on the monitor by pushing the right or left button: congruent arrows to the right or left side (simple task) and incongruent arrows to the right or left side (more difficult complex task). We explored the activation of STN and the activation of the ACC while processing the FT. Both conditions, i.e. congruent and incongruent, induced oscillatory changes in the ACC and also STN with significantly higher activation during incongruent trial. At variance with the ACC, in the STN not only the ERD beta but also the ERD alpha activity was significantly more activated by the incongruent condition. In line with our earlier studies, the STN appears to be involved in activities linked with increased cognitive load. The specificity and complexity of task-related activation of the STN might indicate the involvement of the STN in processes controlling human behaviour, e.g. in the selection and inhibition of competing alternatives.

• MeSH
• Gyrus Cinguli physiology   MeSH
• Adult MeSH
• Electroencephalography MeSH
• Epilepsy physiopathology   MeSH
• Executive Function physiology   MeSH
• Deep Brain Stimulation MeSH
• Electrodes, Implanted MeSH
• Cognition physiology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Magnetic Resonance Imaging MeSH
• Neuropsychological Tests MeSH
• Subthalamic Nucleus physiology   MeSH
• Parkinson Disease physiopathology   therapy   MeSH
• Signal Processing, Computer-Assisted MeSH
• Psychomotor Performance physiology   MeSH
• Photic Stimulation MeSH
• Visual Perception physiology   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH