Deep brain stimulation for phantom perceptions

Characteristics of neurons in auditory cortex of monkeys performing a simple auditory task.

Reliability and Representational Bandwidth in the Auditory Cortex

Exploring magneto-electric nanoparticles (MENPs): a platform for implanted deep brain stimulation

EP 50. High frequency stimulation of the rat dorsal cochlear nucleus inhibits tinnitus

SUMMARYNeuronal oscillations are suggested to play an important role in auditory working memory (WM), but their contribution to content-specific representations has remained unclear. Here, we measure magnetoencephalography during a retro-cueing task with parametric ripple-sound stimuli, which are spectrotemporally similar to speech but resist non-auditory memory strategies. Using machine learning analyses, with rigorous between-subject cross-validation and non-parametric permutation testing, we show that memorized sound content is strongly represented in phase-synchronization patterns between subregions of auditory and frontoparietal cortices. These phase-synchronization patterns predict the memorized sound content steadily across the studied maintenance period. In addition to connectivity-based representations, there are indices of more local, “activity silent” representations in auditory cortices, where the decoding accuracy of WM content significantly increases after task-irrelevant “impulse stimuli.” Our results demonstrate that synchronization patterns across auditory sensory and association areas orchestrate neuronal coding of auditory WM content. This connectivity-based coding scheme could also extend beyond the auditory domain.

10. Central physiology of dystonia – Insights from deep brain recordings

Restoring the firing activity of ventral tegmental area neurons by lateral hypothalamic deep brain stimulation following morphine administration in rats

INTRODUCTION Brain circuit dysfunction in Parkinson's disease (PD) involves an extensive global network. A distinctive basal ganglia resting-state functional connectivity (rsFC) pattern has been linked with the ranked response to L-DOPA. We therefore sought to investigate global rsFC patterns associated with response to L-DOPA and to subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with advanced PD. METHODS A total of 19 patients underwent 3-Tesla resting-state functional magnetic resonance imaging (rsfMRI) in the ON-medication state prior to STN DBS. Improvement in UPDRS-III hemibody scores were assessed following L-DOPA therapy and STN DBS. Global rsFC was measured between regions-of-interest (ROIs) defined by the Automated Anatomical Labeling (AAL) atlas and the Montreal Neurologic Institute (MNI) PD25 subcortical atlas. Seed- and network-level correlations were made with an FDR-P < .005. Graph theoretical analysis was performed with an analysis threshold of FDR-P < .005; and then looking at the top 15% of edges. RESULTS Response to L-DOPA and to DBS displayed cerebellar desynchronization with bilateral thalami and synchronization with bilateral ventromedial prefrontal cortices (vmPFC). L-DOPA response was additionally associated with desynchronization between the vmPFC and the fusiform gyrus. Meanwhile, DBS response was associated with more widespread areas, which have been implicated in visuomotor control and planning. Graph theory analysis revealed that DBS response was inversely related to global efficiency of the thalamus and putamen bilaterally. No significant graph metrics were found relative to L-DOPA response. CONCLUSION Response to DBS and to L-DOPA share similar characteristics, particularly in cerebello-thalamo-cortical circuits, including those that play a role in planning, learning, decision-making, and reward-based behavior. Preservation of distributed networks involved in visuomotor control and network integration of striatothalamocortical circuits appear to predict DBS response. These findings shed a light on the mechanism of action of DBS and L-DOPA and may help serve as useful treatment response biomarkers.

External pallidal stimulation improves parkinsonian motor signs and modulates neuronal activity throughout the basal ganglia thalamic network

EP 141. Physiological effects of subthreshold conditioning TMS anterior of the primary motor cortex

Control of thalamic transmission by corticofugal and ascending reticular pathways in the visual system.

1. Echo-location of blinded Yuma bats (Myotis yumanensis) was studied after ablation of the auditory cortex (A.C.). A task of obstacle-avoidance was given to the bats. Hits and misses of strands were counted, and orientation sounds emitted by the bats during flight were recorded.2. After bilateral ablation of A.C., two bats out of six failed to avoid even large obstacles such as 3.7 mm strands and wall. These bats emitted orientation sounds at a rate of 10-15/sec during flight, but did not change that rate before crossing the obstacles and crashed into them. In these bats, other cortical areas in addition to A.C. were probably ablated.3. In three bats out of six, obstacle-avoidance performance was quite normal. These bats avoided even 0.2 mm strands with orientation sounds, the repetition rate of which was systematically increased before crossing the obstacles. In two of them, the dorsal half of the inferior colliculus (I.C.) was bilaterally ablated in addition to A.C. But ability to avoid the obstacles was not impaired at all. Their cerebral cortices did not show the normal positive-negative diphasic potential change in response to tonal stimuli, although the normal diphasic potential change was retained in A.C. of bats which could not echo-locate as a result of bilateral ablation of the main nucleus of I.C. A.C. appeared to be not essential for echo-location.4. Unilateral ablation of A.C. and the internal capsule had no effect on echo-location, but bilateral ablation of them usually resulted in death from operational trauma.5. It was suggested that A.C. was less important for sound localization in bats than in cats.

Deep Brain Stimulation and Movement Disorder Treatment

Deep brain stimulation (DBS), a proven treatment for movement disorders, also holds promise for the treatment of psychiatric and cognitive conditions. However, for DBS to be clinically effective, it may require DBS technology that can alter or trigger stimulation in response to changes in biomarkers sensed from the patient's brain. A growing body of evidence suggests that such adaptive DBS is feasible, it might achieve clinical effects that are not possible with standard continuous DBS and that some of the best biomarkers are signals from the cerebral cortex. Yet capturing those markers requires the placement of cortex-optimized electrodes in addition to standard electrodes for DBS. In this Perspective we argue that the need for cortical biomarkers in adaptive DBS and the unfortunate convergence of regulatory and financial factors underpinning the unavailability of cortical electrodes for chronic uses threatens to slow down or stall research on adaptive DBS and propose public-private partnerships as a potential solution to such a critical technological gap.

The akinesia symptoms for Parkinson’s disease (PD) is characterized by the abnormal beta (13-30Hz) oscillations in the basal ganglia. Deep brain stimulation (DBS) can alleviate the movement disorders by targeting include thalamic ventralis intermedius nucleus, subthalamic nucleus, and globus pallidus. Here, we construct a computational model, an inhibitory loop between the striatum and globus pallidus externa (GPe). We present the firing pattern and spectral characteristics of striatal neurons and GPe neurons in simulated healthy and Parkinsonian states. Our model predicts that DBS can be applied to striatum neurons to inhibit beta oscillations. We show that the beta frequency activity of the GPe neurons is reduced when DBS is added to the medium spiny neuron (MSN) in the striatum. In particular, as the frequency of DBS becomes higher, the inhibition of beta oscillations in GPe neurons is better. Our model presents new predictions about the target of DBS for PD treatment.