Anli Liu

• MD MA
• Professor (Associate) at NYU Langone Medical Center

Transcranial electric stimulation aims to stimulate the brain by applying weak electrical currents at the scalp. However, the magnitude and spatial distribution of electric fields in the human brain are unknown. Here we measure electric potentials intracranially in ten epilepsy patients and estimate electric fields across the entire brain by levera...

Transcranial electrical stimulation has widespread clinical and research applications, yet its effect on ongoing neural activity in humans is not well established. Previous reports argue that transcranial alternating current stimulation (tACS) can entrain and enhance neural rhythms related to memory, but the evidence from non-invasive recordings ha...

Noninvasive brain stimulation techniques are used in experimental and clinical fields for their potential effects on brain network dynamics and behavior. Transcranial electrical stimulation (TES), including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), has gained popularity because of its co...

Direct recordings from the human brain have historically involved epilepsy patients undergoing invasive electroencephalography (iEEG) for surgery. However, these measurements are temporally limited and affected by clinical variables. The RNS System (NeuroPace, Inc.) is a chronic, closed-loop electrographic seizure detection and stimulation system....

Sensory input arrives in continuous sequences that humans experience as units, e.g., words and events. The brain’s ability to discover extrinsic regularities is called statistical learning. Structure can be represented at multiple levels, including transitional probabilities, ordinal position, and identity of units. To investigate sequence encoding...

Hippocampal sharp-wave ripples (SPW-Rs) are high-frequency oscillations critical for memory consolidation in mammals. Despite extensive characterization in rodents, their application as biomarkers to track and treat memory dysfunction in humans is limited by coarse spatial sampling, interference from interictal epileptiform discharges (IEDs), and l...

Background Alzheimer's disease is associated with neurotoxic amyloid‐beta (Aβ) plaques. Studies in mice demonstrated that cerebrospinal fluid (CSF) clearance, if impaired, reduces Aβ clearance by 70% and that sleep enhances CSF clearance via expanding extracellular space by 60%. However, the impact of sleep on extracellular volume in human remains...

In medication-resistant epilepsy, the goal of epilepsy surgery is to make a patient seizure free with a resection/ablation that is as small as possible to minimize morbidity. The standard of care in planning the margins of epilepsy surgery involves electroclinical delineation of the seizure onset zone (SOZ) and incorporation of neuroimaging finding...

In medication-resistant epilepsy, the goal of epilepsy surgery is to make a patient seizure free with a resection/ablation that is as small as possible to minimize morbidity. The standard of care in planning the margins of epilepsy surgery involves electroclinical delineation of the seizure onset zone (SOZ) and incorporation of neuroimaging finding...

Objective and Background Epilepsy patients rank memory problems as their most significant cognitive comorbidity. Current clinical assessments are laborious to administer and score and may not always detect subtle memory decline. The Famous Faces Task (FF) has robustly demonstrated that left temporal lobe epilepsy (LTLE) patients remember fewer name...

Resecting cortical tissue generating high-frequency oscillations (HFOs) has been investigated as a more efficacious alternative to resecting the clinically defined seizure onset zone (SOZ). In this study, we asked if seizure freedom would be achieved using virtual resections of fast ripple (FR) networks. We compared these virtual resections to the...

Due to shared hippocampal dysfunction, patients with Alzheimer’s dementia and late-onset epilepsy (LOE) report memory decline. Multiple studies have described the epidemiological, pathological, neurophysiological, and behavioral overlap between Alzheimer’s Disease and LOE, implying a bi-directional relationship. We describe the neurobiological decl...

Decades of rodent research have established the role of hippocampal sharp wave ripples (SPW-Rs) in consolidating and guiding experience. More recently, intracranial recordings in humans have suggested their role in episodic and semantic memory. Yet, common standards for recording, detection, and reporting do not exist. Here, we outline the methodol...

Religious experiences in epilepsy patients have provoked much interest with suggestions that hyperreligiosity is associated with temporal lobe seizures. Extreme varieties of religious behavior may be more frequent in epilepsy patients during ictal activity or during post-ictal psychotic episodes. We report a 75 year-old man with epilepsy who develo...

Interictal epileptiform discharges (IEDs) can impair memory. The properties of IEDs most detrimental to memory, however, are undefined. We studied the impact of temporal and spatial characteristics of IEDs on list learning. Subjects completed a memory task during intracranial EEG recordings including hippocampal depth and temporal neocortical subdu...

Research has shown that sleep is beneficial for the long-term retention of memories. According to theories of memory consolidation, memories are gradually reorganized, becoming supported by widespread, distributed cortical networks, particularly during postencoding periods of sleep. However, the effects of sleep on the organization of memories in t...

Purpose: Brain responsive neurostimulation (NeuroPace) treats patients with refractory focal epilepsy and provides chronic electrocorticography (ECoG). We explored how machine learning algorithms applied to interictal ECoG could assess clinical response to changes in neurostimulation parameters. Methods: We identified five responsive neurostimul...

We describe the spatiotemporal course of cortical high-gamma activity, hippocampal ripple activity and interictal epileptiform discharges during an associative memory task in 15 epilepsy patients undergoing invasive EEG. Successful encoding trials manifested significantly greater high-gamma activity in hippocampus and frontal regions. Successful cu...

Sensory input arrives in continuous sequences that humans experience as segmented units, e.g., words and events. The brain’s ability to discover regularities is called statistical learning. Structure can be represented at multiple levels, including transitional probabilities, ordinal position, and identity of units. To investigate sequence encoding...

Objective Neuropsychologists labor over scoring the Rey Complex Figure Test (RCFT), a measure of visuospatial functioning and nonverbal memory. Compelling arguments suggest that pathognomonic signs of the RCFT are observable to the “naked eye.” Standard scoring systems are insensitive to lateralizing temporal lobe epilepsy (TLE) and alternative “qu...

We describe the spatiotemporal course of cortical high-gamma activity (HGA), hippocampal ripple activity and interictal epileptiform discharges (IEDs) during an associative memory task in 15 epilepsy patients undergoing invasive electroencephalography. Successful encoding trials manifested significantly greater HGA in hippocampus and frontal region...

Purpose A phase I feasibility study to determine the accuracy of identifying seizures based on audio recordings. Methods We systematically generated 166 audio clips of 30 seconds duration from 83 patients admitted to an epilepsy monitoring unit between 1/2015 and 12/2016, with one clip during a seizure period and one clip during a non-seizure cont...

Objective To describe seizure outcomes in patients with medically refractory epilepsy who had evidence of bilateral mesial temporal lobe (MTL) seizure onsets and underwent MTL resection based on chronic ambulatory intracranial EEG (ICEEG) data from a direct brain‐responsive neurostimulator (RNS) system. Methods We retrospectively identified all pa...

Memory consolidation is hypothesized to involve the distribution and restructuring of memory representations across hippocampal and cortical regions. Theories suggest that, through extended hippocampal-cortical interactions, cortical ensembles come to represent more integrated, or overlapping, memory traces that prioritize commonalities across rela...

Background: Early accounts of forced thought were reported at the onset of a focal seizure, and characterized as vague, repetitive, and involuntary intellectual auras distinct from perceptual or psychic hallucinations or illusions. Here, we examine the neural underpinnings involved in conceptual thought by presenting a series of 3 patients with ep...

Careful study of the clinical outcomes of temporal lobe epilepsy (TLE) surgery has greatly advanced our knowledge of the neuroanatomy of human memory. After early cases resulted in profound amnesia, the critical role of the hippocampus and associated medial temporal lobe (MTL) structures to declarative memory became evident. Surgical approaches qui...

Slow oscillations and spindle activity during non-rapid eye movement sleep have been implicated in memory consolidation. Closed-loop acoustic stimulation has previously been shown to enhance slow oscillations and spindle activity during sleep and improve verbal associative memory. We assessed the effect of closed-loop acoustic stimulation during a...

Magnetic resonance imaging (MRI)-negative temporal lobe epilepsy (TLE) may be a distinct syndrome from TLE with mesial temporal sclerosis (TLE-MTS). Imaging and neuropsychological features of TLE-MTS are well-known; yet, these features are only beginning to be described in MRI-negative TLE. This study examined whether a quantitative measure of cort...

Noninvasive transcranial brain stimulation has been widely used in experimental and clinical applications to perturb the brain activity, aiming at promoting synaptic plasticity or enhancing functional connectivity within targeted brain regions. However, there are different types of neurostimulations and various choices of stimulation parameters; ho...

Objective. Sleep spindles have been implicated in memory consolidation and synaptic plasticity during NREM sleep. Detection accuracy and latency in automatic spindle detection are critical for real-time applications. Approach. Here we propose a novel deep learning strategy (SpindleNet) to detect sleep spindles based on a single EEG channel. While t...

Some patients with medically refractory focal epilepsy are chronically implanted with a brain-responsive neurostimulation device (the RNS ® System), permitting neurophysiological measurements at millisecond resolution. This clinical device can be adapted to measure hippocampal dynamics time-locked to cognitive tasks. We illustrate the technique wit...

It has come to our attention that we did not specify whether the stimulation magnitudes we report in this Article are peak amplitudes or peak-to-peak. All references to intensity given in mA in the manuscript refer to peak-to-peak amplitudes, except in Fig. 2, where the model is calibrated to 1 mA peak amplitude, as stated. In the original version...

Background: Parkinson's disease (PD) is predominantly recognized for its motor symptoms, but patients struggle from a morbid and heterogeneous collection of non-motor symptoms (NMS-PD) that can affect their quality of life even more. NMS-PD is a rather generalized term and the heterogeneity and non-specific nature of many symptoms poses a clinical...

Fig. S1 (A) Postoperative skull X‐ray scan showing cortical strip leads (temporal, frontal, parietal) and one insular depth electrode. (B) Reconstruction MRI showing the depth electrode in the insula. (C and D) One seizure originating from the insula (channel 2 insular contact 3–4) recorded by RNS.

While RNS is approved for treatment of resistant focal epilepsy in adults, little is known about response to treatment of specific cortical targets. We describe the experience of RNS targeting the insular lobe. We identified patients who had RNS implantation with at least one electrode within the insula between 4/2014 and 10/2015. We performed a re...

The differential contribution of medial-temporal lobe regions to verbal declarative memory is debated within the neuroscience, neuropsychology, and cognitive psychology communities. We evaluate whether the extent of surgical resection within medial-temporal regions predicts longitudinal verbal learning and memory outcomes. This single-center retros...

Introduction: Depression and memory dysfunction significantly impact the quality of life of patients with epilepsy. Current therapies for these cognitive and psychiatric comorbidities are limited. We explored the efficacy and safety of transcranial direct current stimulation (TDCS) for treating depression and memory dysfunction in patients with te...

Transcranial magnetic stimulation (TMS) holds great potential in the treatment of a host of neurological conditions due to its ability to focally modulate—suppress or enhance—activity in targeted cortical brain regions and modify activity across specific brain networks. Results from early trials in a number of neurological indications are presented...

To examine the efficacy and safety profile of antiepileptic repetitive transcranial magnetic stimulation (rTMS) for refractory status epilepticus (RSE) in the intensive care unit (ICU) setting. In addition, hypothetical concerns about electrical interference of rTMS with ICU equipment have been previously raised. We describe two cases of RSE treate...

Since the introduction of highly active antiretroviral therapy in 1996, the epidemiologic profile of HIV-associated neurocognitive disorder (HAND) has shifted drastically. Although HIV-associated dementia has nearly disappeared from clinical practice, presymptomatic and milder variants of HAND affect up to 50% of patients on chronic antiretroviral...

Gemcitabine potential myotoxicity has been described in several cases of radiation recall and in patients treated with gemcitabine alone or in combination with other chemotherapy agents. We report two cases of gemcitabine related myositis identified at our institution, and perform a literature review of cases which meet the criteria for gemcitabine...

Patient telephone calls are a major form of unreimbursed healthcare utilization in Parkinson's disease (PD), yet little is known about potential risk factors for frequent calling behavior. Prospective cohort study of 175 non-demented outpatients with PD. Our primary outcome measure was the frequency of patient telephone calls over a three-month per...

Patients presenting with left-sided FTLD syndromes sometimes develop a new preoccupation with art, greater attention to visual stimuli, and increased visual creativity. We describe the case of a 53-year-old, right-handed man with a history of bipolar disorder who presented with language and behavior impairments characteristic of FTLD, then develope...

This chapter articulates the state of the research on visuospatial perception, visual imagery, motor memory, and interest as it applies to the artistic process, through the lens of lesion studies and different categories of neurodegenerative illness. The chapter also discusses the visual systems used by artists as they conceptualize and then produc...

In studies comparing clinical practice to evidence-based standards, researchers have found that quality of care is inconsistently provided to different segments of the population in both developing and developed countries. To test the hypothesis that quality of care varies widely within different countries, we conducted a prospectively designed eva...

To characterize dementia-induced changes in visual art production. Although case studies show altered visual artistic production in some patients with neurodegenerative disease, no case-controlled studies have quantified this phenomenon across groups of patients. Forty-nine subjects [18 Alzheimer disease, 9 frontotemporal dementia (FTD), 9 semantic...