duke medicine

anonymous asked:

All of them (Heathers) start to carry tissues in their purses and start strategically placing boxes of tissues around the house.

Duke carries around allergy medicine bc she knows Ronnie doesn’t take it, Chandler is constantly berating her for not taking better care of herself, and McNamara becomes a tissue ninja. Any time she sneezes, McNamara is there, with a tissue and a hug.

Hi everyone, I’m Elena!

I’ve been studyblr-ing for a few months now and finally decided to post a formal introduction. This blog was initially just a place for me to organize all of the studyblr/bujo posts I was saving, but since experiencing so much encouragement and love from the studyblr community, I’ve decided to become a more active part! 

Some facts about me:

  • I’m 23 years old and am currently in a gap year between undergrad and graduate studies 
  • I received my B.S. In Biology with a minor in Neuroscience and a focus in Pre-Med curriculum in May of 2016 
  • I was accepted to a graduate program at my dream school, Duke University School of Medicine, but had to defer for a year when I was diagnosed with Stage 3 Hodgkin’s Lymphoma this last summer 😢  buuuut I went through six months of chemotherapy and, thankfully, am currently in remission! 
  • I’m currently studying for the MCAT, which I’ll be taking in May! I’m also hoping to let lots of shadowing hours in once my immune system is fully recovered
  • I’ll begin the Master’s of Biomedical Sciences program at Duke in July and could not be more excited 💙  
  • My long-term goal is to become an emergency physician, and eventually enter medical academia or healthcare advocacy and policy. 
  • I live in the PNW and love being outdoors– hiking, biking, fishing, kayaking, backpacking, skiing, I love all of it! I also love cooking, consignment stores, doggos of all shapes and sizes, photo editing, creating my bullet journal, getting lost in Spotify, The Office, Harry Potter, most Netflix original series, and learning to watercolor. 

A few of my favorite studyblr’s are: (shout out, you guys are great and have already saved my butt on multiple occasions)

@bookmrk @studylustre @way-to-study @study-harder @wolftramp @carriestudies @studycine @bookmocha@studylikeasurgeon @loverssweets

Tags I follow: 

 #studyblr #desk aesthetic #desk #grad school #medblr #bullet journal #bujo #study tips 

I tag my original posts with #mine so I take credit for none of these posts unless you see that tag! I’m looking forward to connecting with all of you lovely study bloggers and definitely follow back! ☺️

Brain Regions of PTSD Patients Show Differences During Fear Responses

Regions of the brain function differently among people with post-traumatic stress disorder, causing them to generalize non-threatening events as if they were the original trauma, according to new research from Duke Medicine and the Durham VA Medical Center.

Using functional MRI, the researchers detected unusual activity in several regions of the brain when people with PTSD were shown images that were only vaguely similar to the trauma underlying the disorder. The findings, reported in the Dec. 15, 2015, issue of the journal Translational Psychiatry, suggest that exposure-based PTSD treatment strategies might be improved by focusing on tangential triggers to the initial event.

“We know that PTSD patients tend to generalize their fear in response to cues that merely resemble the feared object but are still distinct from it,” said Rajendra A. Morey, M.D., an associate professor in the Department of Psychiatry and Behavioral Sciences at Duke and director of the Neuroimaging Lab at the Durham VA Medical Center. “This generalization process leads to a proliferation of symptoms over time as patients generalize to a variety of new triggers. Our research maps this in the brain, identifying the regions of the brain involved with these behavioral changes.”

Morey and colleagues enrolled 67 military veterans who had been deployed to conflict zones in Iraq or Afghanistan after Sept. 11, 2001, and who had been involved in traumatic events. Thirty-two were diagnosed with PTSD and 35 did not have the disorder.

All patients were showed a series of five facial images, depicting a range of emotions from neutral to frightened, while undergoing a functional MRI. The scans showed no dissimilarities between those with PTSD and those unaffected.

Outside the MRI, the participants were shown the images again and given a mild electrical shock when viewing the middle image – the face showing moderate fear.  

The patients then underwent another MRI scan as they viewed all five faces. People with PTSD showed heightened brain activity when they saw the most fearful face and associated it with the electric shock, even though they had actually experienced shocks when the middle, less fearful face appeared. Brain activity was heightened for the non-PTSD group when participants saw the correctly associated middle face.

“The PTSD patients remembered incorrectly and generalized their anxiety to the image showing the most fearful expression,” Morey said. “This phenomenon was captured in MRI scans, showing where the PTSD group had heightened activity.

“The amygdala, which is an important region in responding to threat, did not show a bias in activation to any particular face,” Morey said. “But there was a definite bias of heightened activity in response to the most frightened expression in brain regions such as the fusiform gyrus, insula, primary visual cortex, locus coeruleus and thalamus.”

Morey said the visual cortex was significant because it is not only doing visual processing, but also assessing threats. He said the locus coeruleus is responsible for triggering the release of adrenaline during stress or serious threat.

These functional brain differences provide a neurobiological model for fear generalization in which PTSD symptoms are triggered by things that merely resemble the source of original trauma.

“People with posttraumatic stress disorder grow anxious based on reminders of past trauma, and generalize that fear to a variety of triggers that resemble the initial trauma,” Morey said. “Current fear conditioning therapies are limited by repeated use of the same cue to trigger the initial trauma, but they might be enhanced by including cues that resemble, but are not identical to, cues in the original trauma.”

New role for immature brain neurons in the dentate gyrus identified

University of Alabama at Birmingham researchers have proposed a model that resolves a seeming paradox in one of the most intriguing areas of the brain — the dentate gyrus.

This region helps form memories such as where you parked your car, and it also is one of only two areas of the brain that continuously produces new nerve cells throughout life.

“So the big question,” said Linda Overstreet-Wadiche, Ph.D., associate professor in the UAB Department of Neurobiology, “is why does this happen in this brain region? Entirely new neurons are being made. What is their role?”

In a paper published in Nature Communications on April 20, Overstreet-Wadiche and colleagues at UAB; the University of Perugia, Italy; Sandia National Laboratories, Albuquerque, New Mexico; and Duke University School of Medicine; present data and a simple statistical network model that describe an unanticipated property of newly formed, immature neurons in the dentate gyrus.

These immature granule cell neurons are thought to increase pattern discrimination, even though they are a small proportion of the granule cells in the dentate gyrus. But it is not clear how they contribute.

This work is one small step — along with other steps taken in a multitude of labs worldwide — towards cracking the neural code, one of the great biological challenges in research. As Eric Kandel and co-authors write in Principles of Neural Science, “The ultimate goal of neural science is to understand how the flow of electrical signals through neural circuits gives rise to the mind — to how we perceive, act, think, learn and remember.”

Newly formed granule cells can take six-to-eight weeks to mature in adult mice. Researchers wondered if the immature cells had properties that made them different. More than 10 years ago, researchers found one difference — the cells showed high excitability, meaning that even small electrical pulses made the immature cells fire their own electrical spikes. Thus they were seen as “highly excitable young neurons,” as described by Alejandro Schinder and others in the field.

But this created a paradox. Under the neural coding hypothesis, high excitability should degrade the ability of the dentate gyrus — an important processing center in the brain — to perceive the small differences in input patterns that are crucial in memory, to know your spatial location or the location of your car.

“The dentate gyrus is very sensitive to pattern differences,” Overstreet-Wadiche said. “It takes an input and accentuates the differences. This is called pattern separation.”

The dentate gyrus receives input from the entorhinal cortex, a part of the brain that processes sensory and spatial input from other regions of the brain. The dentate gyrus then sends output to the hippocampus, which helps form short- and long-term memories and helps you navigate your environment.

In their mouse brain slice experiments, Overstreet-Wadiche and colleagues did not directly stimulate the immature granule cells. They instead stimulated neurons of the entorhinal cortex.

“We tried to mimic a more physiological situation by stimulating the upstream neurons far away from the granule cells,” she said.

Use of this weaker and more diffuse stimulation revealed a new, previously underappreciated role for the immature dentate gyrus granule cells. Since these cells have fewer synaptic connections with the entorhinal cortex cells, as compared with mature granule cells, this lower connectivity meant that a lower signaling drive reached the immature granule cells when stimulation was applied at the entorhinal cortex.

The experiments by Overstreet-Wadiche and colleagues show that this low excitatory drive make the immature granule cells less — not more — likely to fire than mature granule cells. Less firing is known in computational neuroscience as sparse coding, which allows finer discrimination among many different patterns.

“This is potentially a way that immature granule cells can enhance pattern separation,” Overstreet-Wadiche said. “Because the immature cells have fewer synapses, they can be more selective.”

Seven years ago, paper co-author James Aimone, Ph.D., of Sandia National Laboratories, had developed a realistic network model for the immature granule cells, a model that incorporated their high intrinsic excitability. When he ran that model, the immature cells degraded, rather than improved, overall dentate gyrus pattern separation. For the current Overstreet-Wadiche paper, Aimone revised a simpler model incorporating the new findings of his colleagues. This time, the statistical network model showed a more complex result — immature granule cells with high excitability and low connectivity were able to broaden the range of input levels from the entorhinal cortex that could still create well-separated output representations.

In other words, the balance between low synaptic connectivity and high intrinsic excitability could enhance the capabilities of the network even with very few immature cells.

“The main idea is that as the cells develop, they have a different function,” Overstreet-Wadiche said. “It’s almost like they are a different neuron for a little while that is more excitable but also potentially more selective.”

The proposed role of the immature granule cells by Overstreet-Wadiche and colleagues meshes with prior experiments by other researchers who found that precise removal of immature granule cells of a rodent, using genetic manipulations, creates difficulty in distinguishing small differences in contexts of sensory cues. Thus, removal of this small number of cells degrades pattern separation.