A5001946095- Memory and Neural Mechanisms
- Neuroscience and Neuropharmacology Research
- Neural dynamics and brain function
- Glioma Diagnosis and Treatment
- Traumatic Brain Injury and Neurovascular Disturbances
- Neuroscience and Neural Engineering
- Meningioma and schwannoma management
- Neonatal Respiratory Health Research
- Congenital Diaphragmatic Hernia Studies
- Cell Image Analysis Techniques
- Intraoperative Neuromonitoring and Anesthetic Effects
- Neurosurgical Procedures and Complications
- Respiratory Support and Mechanisms
- Spinal Fractures and Fixation Techniques
- Neurofibromatosis and Schwannoma Cases
- Educational Technology and Pedagogy
- Intracerebral and Subarachnoid Hemorrhage Research
- Pituitary Gland Disorders and Treatments
- Machine Learning in Materials Science
- Neuroscience and Music Perception
- Natural Language Processing Techniques
- Functional Brain Connectivity Studies
- Cancer, Stress, Anesthesia, and Immune Response
- Brain Tumor Detection and Classification
- CCD and CMOS Imaging Sensors
Neurological Surgery
2018-2024
University of California, San Francisco
2022-2024
San Francisco General Hospital
2022-2023
City College of San Francisco
2022-2023
The University of Texas Southwestern Medical Center
2018-2022
Southwestern University
2021
Center for Excellence in Education
2020
Stanford University
2017-2020
University of Utah
2020
Southwestern Medical Center
2019
Significance Time cells are neurons in the hippocampus and entorhinal cortex that fire at specific moments within a cognitive task or experience. While many prominent theories of memory encoding offer time as source temporal component to memory, they have never been observed human recordings. We identify cell populations medial lobe humans during retrieval. Further, we demonstrate stability signal provided by influences ability temporally order memories
Abstract The organization of temporal information is critical for the encoding and retrieval episodic memories. In rodent hippocampus entorhinal cortex, recent evidence suggests that encoded by a population “time cells.” We identify time cells in humans using intracranial microelectrode recordings obtained from 27 human epilepsy patients who performed an memory task. show cell activity predicts A significant portion these exhibits phase precession, key phenomenon not previously seen...
Pulmonary angiogenesis is a key driver of alveolarization. Our prior studies showed that NF-κB promotes pulmonary during early However, the mechanisms regulating temporal-specific activation in vasculature are unknown. To identify activate proangiogenic signaling developing vasculature, proteomic analysis lung secretome was performed using two-dimensional difference gel electrophoresis. and angiogenic function assessed primary endothelial cells (PECs) TGFBI (transforming growth...
Hospital length of stay (HLOS) after traumatic brain injury (TBI) is an important metric severity, resource utilization, and access to post-acute care services. Risk factors for protracted HLOS TBI require further characterization.
A necessary condition for forming episodic memories is the construction of specific episodes demarcated from other in space and time. Evidence studies memory formation using rodent models suggest that medial temporal lobe (MTL) supports representation boundary information. Building on recent work human microelectrode recordings as well, we hypothesized MTL neurons with firing rates sensitive to We identified 27 out 736 single recorded across subjects. Firing these increased at beginning end...
Introduction: Neuroworsening may be a sign of progressive brain injury and is factor for treatment traumatic (TBI) in intensive care settings. The implications neuroworsening clinical management long-term sequelae TBI the emergency department (ED) require characterization. Methods: Adult subjects from prospective Transforming Research Clinical Knowledge Traumatic Brain Injury Pilot Study with ED admission disposition Glasgow Coma Scale (GCS) scores were extracted. All patients received head...
Episodic memories, or consciously accessible memories of unique events, represent a key aspect human cognition. Evidence from rodent models suggests that the neural representation these complex requires cooperative firing groups neurons on short time scales, organized by gamma oscillations. These co-firing groups, termed "neuronal assemblies," fundamental neurophysiological unit supporting memory. Using microelectrode data neurosurgical patients, we identify neuronal assemblies in MTL and...
Abstract The question of whether the anterior and posterior hippocampus serve different or complementary functional roles during episodic memory processing has been motivated by noteworthy findings in rodent experiments from noninvasive studies humans. Researchers have synthesized these data to postulate several models specialization, However, issue not explored detail using direct brain recordings. We recently published evidence that theta power increases encoding occur In our current...
Episodic memory requires associating items with temporal context, a process for which the medial lobe (MTL) is critical. This study uses recordings from 27 human subjects who were undergoing surgical intervention intractable epilepsy. These same data also utilized in Umbach et al. (2020). We identify 103 memory-sensitive neurons hippocampus and entorhinal cortex, whose firing rates predicted successful episodic encoding as performed verbal free recall task. exhibit important properties....
The question of longitudinal hippocampal functional specialization is critical to human episodic memory because an accurate understanding this phenomenon would impact theories mnemonic function and entail practical consequences for the clinical management patients undergoing temporal lobe surgery. implementation robotically assisted stereo electroencephalography technique seizure mapping has provided our group with opportunity obtain recordings simultaneously from anterior posterior...
BACKGROUND AND OBJECTIVES: Meningiomas are the most common primary intracranial tumors and among only that can form lamellar, hyperostotic bone in tumor microenvironment. Little is known about epidemiology or molecular features of meningiomas. METHODS: Using a retrospective database 342 meningiomas treated with surgery at single institution, we correlated clinical, tumor-related, targeted next-generation DNA sequencing (n = 39 total, 16 meningioma-induced hyperostosis [MIH]), surgical...
Background: Postoperative hyponatremia is a known complication of intracranial surgery, which can present with depressed mental status. Hyponatremia resulting in focal neurologic deficits less frequently described. Case Description: We describe patient who, after bifrontal craniotomy for olfactory groove meningioma, developed acute overnight decline status from Glasgow coma scale (GCS) score 15 to GCS 7 and unilateral fixed dilated pupil. Head computed tomography showed expected...
BACKGROUND AND OBJECTIVES: Although diffuse gliomas in the primary somatosensory cortex (S1) are often considered resectable, motor require mapping to preserve function. Recent evidence indicates that some neurons may trigger responses, necessitating refined techniques. METHODS: Using piezoelectric tactile stimulators on patients' faces and hands, we delivered 25 Hz vibrations prompted patients discriminate between dermatomes. Testing included areas contralateral tumor-infiltrated...
Abstract OBJECTIVE Significant advancements in neurosurgical planning, approach, and practice over the past five decades have improved surgical management of diffuse low high-grade gliomas. We sought to evaluate extent which LGG survival outcomes evolved fifty years using glioma registry datasets with histopathological groups defined by WHO diagnostic criteria supplemented next generation genome-sequencing. METHODS Three (SEER, TCGA, GENIE) were used trends prognosis following diagnosis...
Abstract Specialized neocortical circuits selectively organize neuronal signals and encode features of cognitive processing via local long-range connections. Since glioma-infiltrated cortex is excitable can participate in processing, the underlying laminar structure functionality may still be preserved despite infiltration. Moreover, since glioma cells remodel existing neural microenvironmental factors drive invasion proliferation, neuron-glioma interactions demonstrate layer specificity. As...
OBJECTIVE There is a high prevalence of cervical myelopathy that requires surgery; as such, it important to identify how different groups benefit from surgery. The American Association Neurological Surgeons launched the Quality Outcomes Database (QOD), prospective longitudinal registry, includes demographic, clinical, and patient-reported outcome data measure safety quality neurosurgical procedures. In this study, authors assessed impact gender on outcomes in patients who underwent surgery...
Abstract The representation of episodes is a fundamental requirement for forming episodic memories, but the specific electrophysiological mechanisms supporting episode construction in human hippocampus remain unknown. Experiments rodent models indicate that population neurons sensitive to edges an environment, termed border or boundary spatial navigation, fulfills role analogous demarcation. We hypothesized such could be identified mesial temporal lobe, with firing rates specifically...
Mathematical reasoning is central to everyday life. Lesion data and functional MRI studies suggest that even simple arithmetic involves the coordination of multiple spatially diverse brain regions, but date, math processing has not been well characterized using direct recordings, especially outside parietal cortex. To address this, we utilized an unparalleled set 310 subjects implanted with intracranial electrodes investigate spatial temporal dynamics reasoning. Our support importance...
Abstract Rationale Pulmonary angiogenesis is a key driver of alveolarization. Our prior studies showed that nuclear factor kappa-B (NFκB) promotes pulmonary during early However, the mechanisms regulating temporal-specific NFκB activation in vasculature are unknown. Objectives To identify activate pro-angiogenic signaling developing vasculature. Methods Proteomic analysis lung secretome was performed using 2D-DIGE. and angiogenic function assessed primary endothelial cells (PEC)...
Traumatic subdural hematomas (SDH) can have devastating neurologic consequences. Acute-on-chronic SDHs are more frequent in the elderly, who increased comorbidities and perioperative risks. The evacuation port system (SEPS) procedure consists of a twist drill hole connected to single drain on suction, which be performed at bedside evacuate without requiring general anesthesia. However, SEPS limited due inability across septations between different ages.We present our knowledge first case...