These days, it sounds a bit old-fashioned to ask the question: â€œWhere is consciousness located in the brain?â€ The prevailing thinking is that consciousness lives in the network, rather than in one particular place. Still, neuroscientists sometimes get an intriguing glimpse of a critical link in the network.
A recent paper in the journal Epilepsy & Behavior describes an epilepsy patient who had electrodes implanted within her brain at Emory University Hospital, because neurologists wanted to understand where her seizures were coming from and plan possible surgery. Medication had not controlled her seizures and previous surgery elsewhere hadÂ not either.
MRI showing electrode placement. Yellow outline indicates the location of the caudate and thalamus. Image from Leeman-Markowsi et al, Epilepsy & Behavior (2015).
During intracranial EEG monitoring, implanted electrodes detected a pattern of signals coming from one part of the thalamus, a central region of the brain. The pattern was present when the patient was conscious, and then stopped as soon as seizure activity made her lose awareness.
The pattern of signals had a characteristic frequency â€“ around 35 times per second â€“ so it helps to think of the signal as an auditory tone. Lead author Beth Leeman-Markowski, director of EUHâ€™s Epilepsy Monitoring Unit at the time when the patient was evaluated, describes the signal as a â€œbuzz.â€
â€œThat buzz has something to do with maintenance of consciousness,â€ she says. Read more
From Emory Medicine, Spring 2013
A small clinical study of clarithromycin for the sleep disorder hypersomnia shows that the antibiotic can combat patients’ subjective experience of sleepiness, but it does not seem to improve reaction time measured in a video-game-type vigilance task.
The effects of clarithromycin in hypersomnia were first observed by Emory doctors when a pioneering patient (Anna Sumner, whose story is told in this Emory Medicine article) unexpectedly experienced sleeplessness when taking it for a respiratory infection.
The results of the study were published online by Annals of Neurology on June 10.
Lynn Marie Trotti, MD, David Rye, MD, PhD and colleagues from the Department of Neurology and Emory Sleep Center conducted the study, which involved 23 patients.
Advantages of clarithromycin:
- It’s inexpensive and widely available.
- It’s an option for people dealing with hypersomnia for whom other medications, such as modafinil, are not helpful or tolerable.
- It represents an alternative to flumazenil, the benzodiazepine antidote that has been shown to help some hypersomnia patients. Flumazenil used to be very scarce, and shortages occur (Hypersomnia Foundation/American Society of Health System Pharmacists).
Disadvantages of clarithromycin:
- It’s an antibiotic, so it probably changes intestinal bacteria.
- Chronic use could promote the growth of antibiotic-resistant bacteria.
- Most patients reported an altered sense of taste or smell. Some describe this as a metallic mouth sensation.
Emory researchers led by neurologist Manuel Yepes, MD have identified a protein released by neurons while the brain is recovering from a stroke.Â The results were published online today inÂ Journal of Neuroscience.
The protein, called urokinase-type plasminogen activator or uPA, has been approved by the FDA to dissolve blood clots in the lungs. It has been tested in clinical trialsÂ in some countriesÂ as a treatment for acute stroke.
The Emory teamâ€™s findings suggest that in stroke, uPAâ€™s benefits may extend beyond the time when doctorsâ€™ principal goal is dissolving the blood clot that is depriving the brain of blood.
Instead, uPA appears to help brain cells recover from the injuries induced by loss of blood flow. Treating mice with uPA after an experimental stroke can improve their recovery of motor function, the researchers found.
It’s not sleep apnea. It’s not narcolepsy. Hypersomnia is a different kind of sleep disorder. There’s even an “apples and oranges” T-shirt (see below) that makes that point.
This weekend, your correspondent attended a patient-organized Living with Hypersomnia conference. One of the main purposes of the conference was to update sufferers and supporters on the state of research at Emory and elsewhere, but there was also a lot of community building — hence the T-shirts.
The story of how sleep took over one young lawyer’s life, and how her life was then transformed by flumazenil, a scarce antidote to sleeping pills she was not taking, has received plenty of attention.
Now an increasing number of people are emerging who have a condition similar to Anna Sumner’s, and several questions need answers. Read more