Breaking News
February 19, 2018 - Russian researchers develop new multi-layered biodegradable scaffolds
February 19, 2018 - Are ‘Vaccine Skeptics’ Responsible for Flu Deaths?
February 19, 2018 - Hidden genetic effects behind immune diseases may be missed, study suggests
February 19, 2018 - Study sheds light on biology that guides behavior across different stages of life
February 19, 2018 - Morning Break: Transgender Breast Feeding; Brazilian ‘Pro-Vaxxers’; Post-Stroke Exercise
February 19, 2018 - Meningitis vaccination strategy in Africa found to be effective, economical
February 19, 2018 - Researchers uncover how excess calcium may influence development of Parkinson’s disease
February 19, 2018 - Psoriasis drug also effective at reducing aortic inflammation
February 19, 2018 - Excess emissions can make serious contributions to air pollution, study shows
February 19, 2018 - Diabetes Drugs Differ on HF; School-Based Obesity Program Flop; Plaque Type in ACS
February 19, 2018 - Surgical infections linked to drug-resistant bugs, study suggests
February 19, 2018 - Poor awareness may hinder a child’s early dental care
February 19, 2018 - Researchers uncover Ras protein’s role in uncontrolled cancer growth
February 19, 2018 - FDA Approves Apalutamide (Erleada) to Help Curb a Tough-to-Treat Prostate Cancer
February 19, 2018 - Educational Tool Boosts Cervical Length Screening
February 19, 2018 - Spider’s web inspires removable implant that may control type 1 diabetes
February 19, 2018 - Scientists develop fluorescent probe to identify cancer stem cells
February 19, 2018 - University Hospital of Santiago de Compostela participates in large pancreatic cancer study
February 19, 2018 - New blood test shows promise to revolutionize diagnosis of tick-borne diseases
February 19, 2018 - Report: Use, Not Price, Drives State Health Costs
February 19, 2018 - Emergency services crews often unprepared for diabetic crises
February 19, 2018 - Scientists in Sweden create DNA nanowires that offer hope for treatment of diseases
February 19, 2018 - ID Break: Clean Hands, Fewer Abx; $11 Million HIV Cure?; MenB Vax for Kids
February 19, 2018 - Patient exposure to X-rays depends on how dentists are paid
February 19, 2018 - Study reveals parents’ views toward children’s tanning bed use
February 19, 2018 - Shot may help reduce risk of shingles
February 19, 2018 - FDA approves first treatment to reduce risk of NSCLC progression
February 19, 2018 - FDA Expands Approval of Imfinzi (durvalumab) to Reduce the Risk of Non-Small Cell Lung Cancer Progressing
February 19, 2018 - D.C. Week: Congress Passes Spending Bill
February 19, 2018 - Heart-muscle patches made with human cells improve heart attack recovery
February 19, 2018 - FDA Approves First Blood Test to Detect Concussions
February 19, 2018 - Survival Bump in Bladder Cancer with Keytruda
February 18, 2018 - Scientists describe the mechanism of heart regeneration in the zebrafish
February 18, 2018 - Scientists uncover the structure of microtubule motor proteins
February 18, 2018 - Light-activated cancer drugs without toxic side effects are closer to becoming reality
February 18, 2018 - Pioneering research could provide novel insight into how genomic information is read
February 18, 2018 - Pearls From: David Putrino, PhD
February 18, 2018 - Researchers uncover how cancer stem cells drive triple-negative breast cancer
February 18, 2018 - Morning Break: Anti-Anti-Vaxxers; Private Piercings Prohibited; A Case for Pelvic Massage
February 18, 2018 - Lower-dose radiation effective, safe for HPV+ head and neck cancer after induction chemo
February 18, 2018 - Specialist residential service for adults with autism opens in Swansea
February 18, 2018 - FDA Moves to Limit Loperamide Doses per Package
February 18, 2018 - Alcohol use disorder – Genetics Home Reference
February 18, 2018 - Autism might be better detected using new two-minute questionnaire
February 18, 2018 - Hand hygiene-intervention practices may reduce risk of infection among nursing home patients
February 18, 2018 - Researchers develop most sophisticated mini-livers to date
February 18, 2018 - Obamacare Helped More Young Women Get Prenatal Care: Study
February 18, 2018 - School-Based Program Fails to Dent Kids’ Obesity
February 18, 2018 - Research compares neural activity in children with and without autism spectrum disorder
February 18, 2018 - Poor fitness levels increase the risk dementia, concludes study
February 18, 2018 - Risk Score May Reveal if Kids are Victims of Ill-Treatment
February 18, 2018 - Adding Folic Acid to Corn Masa Flour May Prevent Birth Defects
February 18, 2018 - Acute treatment suppresses posttraumatic arthritis in ankle injury
February 18, 2018 - A Role for Budesonide in Autoimmune Hepatitis?
February 18, 2018 - Lupus patients exhibit altered cell proteins, a discovery with potential implications for diagnostics
February 18, 2018 - Muscle plays vital role in regulating heat loss from the hands
February 18, 2018 - High-tech brain scans can provide new way to define intelligence
February 18, 2018 - Study reveals the association between ultra-processed foods and cancer
February 18, 2018 - Prescription Opioid Use Tied to Higher Pneumonia Risk
February 18, 2018 - A non-invasive method to detect Alzheimer’s disease
February 18, 2018 - Deletion of specific enzyme leads to improvement in memory and cognitive functions
February 18, 2018 - Amyloid protein may be transmitted through neurosurgical instruments, study suggests
February 18, 2018 - Electric brain signals of males and females show differences
February 18, 2018 - American Heart Association commends McDonald’s for offering healthier menu in kids’ meals
February 18, 2018 - Parents Find Kids’ Weight Report Cards Hard to Swallow
February 18, 2018 - Does a Financial Conflict of Interest Ever Expire?
February 18, 2018 - Exercise can improve Alzheimer’s symptoms
February 18, 2018 - Scientists develop green chemistry method to improve pharmaceutical manufacturing efficiency
February 17, 2018 - ‘A Time Clock to a Tissue Clock’ for Acute Stroke Care
February 17, 2018 - Cancer Care Gets Personal | NIH News in Health
February 17, 2018 - Do more youth use or do youth use more?
February 17, 2018 - Eating faster linked to obesity
February 17, 2018 - Who’s Still Smoking? ACS Report Highlights Most Vulnerable Adults
February 17, 2018 - Study of smoking and genetics illuminates complexities of blood pressure
February 17, 2018 - Study reveals new link between bone cells and blood glucose level
February 17, 2018 - Children with reading challenges may have lower than expected binocular vision test results
February 17, 2018 - Mass Shootings Trigger Change for Emergency Medicine
February 17, 2018 - ECMO helps revive woman thought to be drowned
February 17, 2018 - Learning stress-reducing techniques may benefit people with epilepsy
February 17, 2018 - Shedding Pounds Before Weight-Loss Surgery a Smart Move
Deep brain stimulation at low frequencies improves cognitive performance of PD patients

Deep brain stimulation at low frequencies improves cognitive performance of PD patients

image_pdfDownload PDFimage_print

A multidisciplinary neuroscience study using rare, intraoperative brain recordings suggests that low frequency stimulation of a deep brain region may be able to improve cognitive function in patients with Parkinson’s disease (PD). The study findings, published Nov. 28 online in the journal Brain, also hint at the broader potential of brain stimulation for treating other cognitive diseases.

The new work by neurologists and neurosurgeons with the Iowa Neuroscience Institute at the University of Iowa provides the first direct evidence of a connection in the human brain between the thinking region of the brain (the frontal cortex) and a deeper structure called the subthalamic nucleus (STN) that is involved in controlling movement. The study also shows that stimulation of the STN at low frequencies improves the performance of PD patients on a simple cognitive task that is usually disrupted by PD.

“It’s not very often that you identify a new connection in the human brain,” says Nandakumar Narayanan, MD, PhD, UI assistant professor of neurology in the UI Carver College of Medicine and senior study author. “The existence of this hyperdirect pathway from the prefrontal cortex to the STN has been bandied about for around a decade, but this is the first time we’ve experimentally shown that it exists and functions in people.

“We were also able to show that if we stimulate the STN, we change the frontal cortical activity and we think it’s by this pathway,” he adds. “And if we stimulate the STN and change cortical activity, we can actually change behavior in a beneficial way, improving the patients’ cognitive performance.”

Parkinson’s disease is a progressive neurodegenerative condition that affects about one million people in the United States. Deep brain stimulation of the STN at high frequencies is already approved to treat movement problems in some patients with PD. In addition to causing movement problems, however, PD also affects thinking. The new findings raise the possibility that STN deep brain stimulation at a different (low) frequency might also improve cognitive symptoms in PD, and possibly even in other neurologic and psychiatric diseases.

Listening in on the brain

The team was able to map the STN-cortex connection by “listening in” on brain activity during surgeries to implant deep brain stimulation (DBS) electrodes in patients with PD.

UI neurosurgeon Jeremy Greenlee, MD, conducts more than 30 such surgeries every year and his expertise was vital to the mapping experiment. Using specialized recording electrodes placed inside the patients’ brains, Greenlee listens in on brain activity in order to accurately place the DBS device. Those electrodes also allow direct recording of brain activity for experimental purposes in patients who are awake during the procedure without adding any risk. This kind of intraoperative recordings is not very common, but Greenlee and his UI colleagues have a long history of expertise in the technique.

During the surgery, the patients did a simple cognitive task as a way of stimulating one part of the brain while recording electrical activity from other parts that are connected. Listening to the neural activity during the task allowed the team to map the connection.

“We were able to evoke a response to show the functional connection,” Greenlee explains. “The very fast response suggests a single, direct synaptic connection – that is what hyperdirect means.”

Stimulation improves cognitive performance

Having established the existence of the hyperdirect connection, the researchers next investigated the effect of low frequency STN stimulation on cognitive abilities. Narayanan’s team uses a very simple thinking task–accurately estimating the passage of a short interval of time–to study cognitive impairment in PD patients and animal models of PD.

During post-surgery follow up visits, the researchers had the patients do the interval timing task with the DBS stimulator set to one of three settings: high frequency (normal for controlling movement), no stimulation, or a low frequency setting of 4 Hz. Only the 4 Hz stimulation improved the patients’ performance on the timing test.

Previous research from Narayanan’s labs has shown that people with PD and rodent models of the disease are missing a specific brain wave known as the delta wave in their frontal cortex while they are doing the timing task. The delta wave cycles at a frequency of about 4 Hz.

“When we stimulate the STN at 4 Hz, the delta wave is restored in the mid frontal cortex,” Narayanan says. “By stimulating the STN we can rescue cortical activity (which is disrupted in PD) and we can improve cognitive behavior.”

The researchers think that the frequencies are like communication channels between networks. If two networks are working together at the same frequency, that might be a unique way that the networks interact and information is transmitted.

“The fact that we are able to test a lot of our ideas (that come from the rodent studies) about how the neural networks work in awake behaving humans, is something I never dreamed I’d be able to do, but it enables us to ask questions that might actually help a lot of people,” Narayanan says.

“It is exciting to potentially have a way to improve cognition that could be life changing for patients,” Greenlee adds.

Tagged with:

About author

Related Articles