Understanding the human conflict processing network: A review of the literature on direct neural recordings during performance of a modified stroop task.

The Stroop Task is a well-known neuropsychological task developed to investigate conflict processing in the human brain. Our group has utilized direct intracranial neural recordings in various brain regions during performance of a modified color-word Stroop Task to gain a mechanistic understanding of non-emotional human conflict processing. The purpose of this review article is to: 1) synthesize our own studies into a model of human conflict processing, 2) review the current literature on the Stroop Task and other conflict tasks to put our research in context, and 3) describe how these studies define a network in conflict processing.

Stereotactic Frame-Based Electrode Insertion: The Accuracy of Increasingly Oblique Insertion Angles.

Aim: To investigate the relationship between planned drill approach angle and angular deviation of the stereotactically placed intracranial electrode tips.

Material And Methods: Stereotactic electrode implantation was performed in 13 patients with drug resistant epilepsy. A total of 136 electrodes were included in our analysis.

A review of neurophysiological effects and efficiency of waveform parameters in deep brain stimulation.

Neurostimulation has diverse clinical applications and potential as a treatment for medically refractory movement disorders, epilepsy, and other neurological disorders. However, the parameters used to program electrodes-polarity, pulse width, amplitude, and frequency-and how they are adjusted have remained largely untouched since the 1970 s. This review summarizes the state-of-the-art in Deep Brain Stimulation (DBS) and highlights the need for further research to uncover the physiological mechanisms of neurostimulation.

Validation of Myc-Associated Protein X (MAX) regulation in growth hormone secreting and nonfunctional pituitary adenoma.

Introduction: Many patients with growth hormone-secreting pituitary adenoma (GHPA) fail to achieve biochemical remission, warranting investigation into epigenetic and molecular signatures associated with tumorigenesis and hormonal secretion. Prior work exploring the DNA methylome showed Myc-Associated Protein X (MAX), a transcription factor involved in cell cycle regulation, was differentially methylated between GHPA and nonfunctional pituitary adenoma (NFPA). We aimed to validate the differential DNA methylation and related MAX protein expression profiles between NFPA and GHPA.

Neuromodulation in Beta-Band Power Between Movement Execution and Inhibition in the Human Hippocampus.

Introduction: The hippocampus is thought to be involved in movement, but its precise role in movement execution and inhibition has not been well studied. Previous work with direct neural recordings has found beta-band (13-30 Hz) modulation in both movement execution and inhibition throughout the motor system, but the role of beta-band modulation in the hippocampus during movement inhibition is not well understood. Here, we perform a Go/No-Go reaching task in ten patients with medically refractory epilepsy to study human hippocampal beta-power changes during movement.

Amygdaloid theta-band power increases during conflict processing in humans.

The amygdala is a medial temporal lobe structure known to be involved in processing emotional conflict. However, its role in processing non-emotional conflict is not well understood. Previous studies have utilized the Stroop Task to examine brain modulation of humans under the color-word conflict scenario, which is non-emotional conflict processing, and found hippocampal theta-band (4-7 Hz) modulation.

Beta-band modulation in the human hippocampus during a conflict response task.

. Identify the role of beta-band (13-30 Hz) power modulation in the human hippocampus during conflict processing..

Stereotactic Radiosurgery for Residual and Recurrent Nonfunctioning Pituitary Adenomas: A Contemporary Case Series of GammaKnife and CyberKnife Radiosurgery.

Background: In patients with residual or recurrent nonfunctioning pituitary adenomas (NFPAs) after transsphenoidal resection, both GammaKnife (GKRS) and CyberKnife (CKRS) stereotactic radiosurgery (SRS) are viable treatment options.

Objectives: We report a retrospective single center series comparing assessing the effectiveness and complications from of these 2 commonly used SRS techniques.

Methods: A total of 53 patients with prior surgical resection and residual or recurrent NFPAs who underwent GKRS or CKRS and minimum 3-month follow-up between January 2002 and February 2017 at a single center were identified.

Beta-band power modulation in the human hippocampus during a reaching task.

Objective: Characterize the role of the beta-band (13-30 Hz) in the human hippocampus during the execution of voluntary movement.

Approach: We recorded electrophysiological activity in human hippocampus during a reach task using stereotactic electroencephalography (SEEG). SEEG has previously been utilized to study the theta band (3-8 Hz) in conflict processing and spatial navigation, but most studies of hippocampal activity during movement have used noninvasive measures such as fMRI.

A Phantom Study of the Spatial Precision and Accuracy of Stereotactic Localization Using Computed Tomography Imaging with the Leksell Stereotactic System.

Background: Stereotactic localization of neurosurgical targets traditionally relies on computed tomography (CT), which is considered the optimal imaging modality for geometric accuracy. However, in-depth investigations that characterize the precision and accuracy of CT images are lacking. We used a CT phantom to examine interscanner precision and interprotocol accuracy in coordinate localization.

Mapping of primary somatosensory cortex of the hand area using a high-density electrocorticography grid for closed-loop brain computer interface.

The ideal modality for generating sensation in sensorimotor brain computer interfaces (BCI) has not been determined. Here we report the feasibility of using a high-density 'mini'-electrocorticography (mECoG) grid in a somatosensory BCI system.Thirteen subjects with intractable epilepsy underwent standard clinical implantation of subdural electrodes for the purpose of seizure localization.

Utility and lower limits of frequency detection in surface electrode stimulation for somatosensory brain-computer interface in humans.

Objective: Stimulation of the primary somatosensory cortex (S1) has been successful in evoking artificial somatosensation in both humans and animals, but much is unknown about the optimal stimulation parameters needed to generate robust percepts of somatosensation. In this study, the authors investigated frequency as an adjustable stimulation parameter for artificial somatosensation in a closed-loop brain-computer interface (BCI) system.

Methods: Three epilepsy patients with subdural mini-electrocorticography grids over the hand area of S1 were asked to compare the percepts elicited with different stimulation frequencies.

Functional Frequency Discrimination From Cortical Somatosensory Stimulation in Humans.

Recently, efforts to produce artificial sensation through cortical stimulation of primary somatosensory cortex (PSC) in humans have proven safe and reliable. Changes in stimulation parameters like frequency and amplitude have been shown to elicit different percepts, but without clearly defined psychometric profiles. This study investigates the functionally useful limits of frequency changes on the percepts felt by three epilepsy patients with subdural electrocorticography (ECoG) grids.

Dual responsive neurostimulation implants for epilepsy.

Closed-loop brain-responsive neurostimulation via the RNS System is a treatment option for adults with medically refractory focal epilepsy. Using a novel technique, 2 RNS Systems (2 neurostimulators and 4 leads) were successfully implanted in a single patient with bilateral parietal epileptogenic zones. In patients with multiple epileptogenic zones, this technique allows for additional treatment options.

Long-Term Tumor Control Rates Following Gamma Knife Radiosurgery for Acoustic Neuroma.

Background: Acoustic neuromas (ANs) are benign intracranial tumors that arise from myelin-forming Schwann cells surrounding the vestibular branch of the vestibulocochlear nerve (cranial nerve VIII). Treatment options for AN include observation, radiosurgery, and microsurgical resection. Gamma Knife radiosurgery (GKRS) for AN has well-documented short-term safety and efficacy for carefully selected patients.

Utilizing Light-field Imaging Technology in Neurosurgery.

Traditional still cameras can only focus on a single plane for each image while rendering everything outside of that plane out of focus. However, new light-field imaging technology makes it possible to adjust the focus plane after an image has already been captured. This technology allows the viewer to interactively explore an image with objects and anatomy at varying depths and clearly focus on any feature of interest by selecting that location during post-capture viewing.