<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom" ><generator uri="https://jekyllrb.com/" version="3.10.0">Jekyll</generator><link href="/feed.xml" rel="self" type="application/atom+xml" /><link href="/" rel="alternate" type="text/html" /><updated>2024-10-08T15:33:37+00:00</updated><id>/feed.xml</id><title type="html">Alan Degenhart, Ph.D.</title><subtitle>My personal website. Contains information about my research, publications, and other projects. Views expressed are my own.</subtitle><entry><title type="html">‘Monkeys exhibit a paradoxical decrease in performance in high-stakes scenarios’ published in PNAS</title><link href="/2021/09/07/pnas-choking.html" rel="alternate" type="text/html" title="‘Monkeys exhibit a paradoxical decrease in performance in high-stakes scenarios’ published in PNAS" /><published>2021-09-07T00:00:00+00:00</published><updated>2021-09-07T00:00:00+00:00</updated><id>/2021/09/07/pnas-choking</id><content type="html" xml:base="/2021/09/07/pnas-choking.html"><![CDATA[<p>Our paper “Monkeys exhibit a paradoxical decrease in performance in high-stakes scenarios” was recently published in the Proceedings of the National Academy of Sciences (PNAS).  From the article:</p>

<blockquote>
  <p><strong>Significance.</strong> Choking under pressure is a frustrating phenomenon experienced sometimes by skilled performers as well as during everyday life. The phenomenon has been extensively studied in humans, but it has not been previously shown whether animals also choke under pressure. Here we report that rhesus monkeys also choke under pressure. This indicates that there may be shared neural mechanisms that underlie the behavior in both humans and monkeys. Introducing an animal model for choking under pressure allows for opportunities to study the neural causes of this paradoxical behavior.</p>
</blockquote>

<blockquote>
  <p><strong>Abstract.</strong>  In high-stakes situations, people sometimes exhibit a frustrating phenomenon known as “choking under pressure.” Usually, we perform better when the potential payoff is larger. However, once potential rewards get too high, performance paradoxically decreases—we “choke.” Why do we choke under pressure? An animal model of choking would facilitate the investigation of its neural basis. However, it could be that choking is a uniquely human occurrence. To determine whether animals also choke, we trained three rhesus monkeys to perform a difficult reaching task in which they knew in advance the amount of reward to be given upon successful completion. Like humans, monkeys performed worse when potential rewards were exceptionally valuable. Failures that occurred at the highest level of reward were due to overly cautious reaching, in line with the psychological theory that explicit monitoring of behavior leads to choking. Our results demonstrate that choking under pressure is not unique to humans, and thus, its neural basis might be conserved across species.</p>
</blockquote>

<p>Contrats to all of the authors:  Adam Smoulder, Nick Pavlosky, Patrick Marino, Nicole McClain, Aaron Batista, and Steve Chase.</p>

<p>Associated press/news:</p>
<ul>
  <li>PNAS Commentary: <a href="https://doi.org/10.1073/pnas.2113777118">https://doi.org/10.1073/pnas.2113777118</a></li>
  <li><a href="https://www.wired.com/story/youre-not-alone-monkeys-choke-under-pressure-too/">You’re Not Alone: Monkeys Choke Under Pressure Too (Wired)</a></li>
  <li><a href="https://engineering.cmu.edu/news-events/news/2021/08/24-performance-under-pressure.html">Research sheds new light on decreased performance under pressure (CMU press release)</a></li>
</ul>

<p><strong>Full citation:</strong>  Smoulder, A.L.*, Pavlosky, N.P.*, Marino, P.J.*, Degenhart, A.D., McClain, N.T., Batista, A.P.^, Chase, S.M.^  Monkeys exhibit a paradoxical decrease in performance in high-stakes scenarios.  Proceedings of the National Academy of Sciences (2021).  (*,^: denotes equal contributions)  https://doi.org/10.1073/pnas.2109643118</p>]]></content><author><name></name></author><summary type="html"><![CDATA[Our paper “Monkeys exhibit a paradoxical decrease in performance in high-stakes scenarios” was recently published in the Proceedings of the National Academy of Sciences (PNAS). From the article:]]></summary></entry><entry><title type="html">Started position at the Allen Institute for Brain Science</title><link href="/2020/10/01/allen-institute.html" rel="alternate" type="text/html" title="Started position at the Allen Institute for Brain Science" /><published>2020-10-01T00:00:00+00:00</published><updated>2020-10-01T00:00:00+00:00</updated><id>/2020/10/01/allen-institute</id><content type="html" xml:base="/2020/10/01/allen-institute.html"><![CDATA[<p>I’m happy to announce that I’ve started a new position at the <a href="https://alleninstitute.org">Allen Institute for Brain Science</a>.  As a Scientist in the MindScope Program, I’ll be using computational techniques to investigate coding properties of neural populations in the visual system.  I’m looking forward to be a part of the Institute’s vision of conducting large-scale, multidisciplinary neuroscience research.</p>

<p>Some recent examples of work coming out of the Allen Institute:</p>
<ul>
  <li><a href="https://www.nature.com/articles/s41593-019-0550-9">A large-scale standardized physiological survey reveals functional organization of the mouse visual cortex</a></li>
  <li><a href="https://www.nature.com/articles/s41586-020-03171-x">Survey of spiking in the mouse visual system reveals functional hierarchy</a></li>
  <li><a href="https://www.nature.com/articles/s41586-018-0654-5">Shared and distinct transcriptomic cell types across neocortical areas</a></li>
</ul>]]></content><author><name></name></author><summary type="html"><![CDATA[I’m happy to announce that I’ve started a new position at the Allen Institute for Brain Science. As a Scientist in the MindScope Program, I’ll be using computational techniques to investigate coding properties of neural populations in the visual system. I’m looking forward to be a part of the Institute’s vision of conducting large-scale, multidisciplinary neuroscience research.]]></summary></entry><entry><title type="html">‘Stabilization of a brain-computer interface via the alignment of low-dimensional spaces of neural activity’ published in Nature Biomedical Engineering</title><link href="/2020/05/02/nature-bme-paper.html" rel="alternate" type="text/html" title="‘Stabilization of a brain-computer interface via the alignment of low-dimensional spaces of neural activity’ published in Nature Biomedical Engineering" /><published>2020-05-02T00:00:00+00:00</published><updated>2020-05-02T00:00:00+00:00</updated><id>/2020/05/02/nature-bme-paper</id><content type="html" xml:base="/2020/05/02/nature-bme-paper.html"><![CDATA[<p>Our paper “Stabilization of a brain–computer interface via the alignment of low-dimensional spaces of neural activity” was published today in Nature Biomedical Engineering. In it, we present a stabilized brain-computer interface (BCI) system that addresses the problem of neural recording instabilities. These instabilities, if left unchecked, can quickly lead BCIs to become uncontrollable.</p>

<p>To address this problem, we developed a <em>manifold-based stabilizer</em> that extracts a stable representation of neural activity from neural recordings where instabilities may be present. Our technique leverages the concept of a “neural manifold”: a low-dimensional space that captures specific correlation patterns across neurons. By aligning estimates of the neural manifold made at different points in time, we can stabilize the inputs to the BCI system, thus allowing control to proceed unimpeded. We hope that this work will help to improve the clinical viability of BCIs.</p>

<p>This work was the result of a collaboration between researchers at Carnegie Mellon University and the University of Pittsburgh, including myself, William Bishop, Emily Oby, Elizabeth Tyler-Kabara, MD, PhD, Steven Chase, Aaron Batista, and Byron Yu.</p>

<p>Link to full article: <a href="https://www.nature.com/articles/s41551-020-0542-9">https://www.nature.com/articles/s41551-020-0542-9</a></p>]]></content><author><name></name></author><summary type="html"><![CDATA[Our paper “Stabilization of a brain–computer interface via the alignment of low-dimensional spaces of neural activity” was published today in Nature Biomedical Engineering. In it, we present a stabilized brain-computer interface (BCI) system that addresses the problem of neural recording instabilities. These instabilities, if left unchecked, can quickly lead BCIs to become uncontrollable.]]></summary></entry><entry><title type="html">New website</title><link href="/2020/04/16/welcome.html" rel="alternate" type="text/html" title="New website" /><published>2020-04-16T18:38:47+00:00</published><updated>2020-04-16T18:38:47+00:00</updated><id>/2020/04/16/welcome</id><content type="html" xml:base="/2020/04/16/welcome.html"><![CDATA[<p>I’m currently in the process of migrating content from my old website to this one.
I’m hoping that this new site, which is based on Jekyll and GitHub Pages, will be
easier to edit and maintain moving forward.</p>]]></content><author><name></name></author><summary type="html"><![CDATA[I’m currently in the process of migrating content from my old website to this one. I’m hoping that this new site, which is based on Jekyll and GitHub Pages, will be easier to edit and maintain moving forward.]]></summary></entry><entry><title type="html">‘New neural activity patterns emerge with long-term learning’ published in PNAS</title><link href="/2019/06/12/omp-learning.html" rel="alternate" type="text/html" title="‘New neural activity patterns emerge with long-term learning’ published in PNAS" /><published>2019-06-12T00:00:00+00:00</published><updated>2019-06-12T00:00:00+00:00</updated><id>/2019/06/12/omp-learning</id><content type="html" xml:base="/2019/06/12/omp-learning.html"><![CDATA[<p>Emily Oby’s work investigating the formation of new neural activity patterns during long-term learning was just published in the Proceedings of the National Academy of Sciences (PNAS).  From the article:</p>

<blockquote>
  <p>Consider a skill you would like to learn, like playing the piano. How do you progress from “Chopsticks” to Chopin? As you learn to do something new with your hands, does the brain also do something new? We found that monkeys learned new skilled behavior by generating new neural activity patterns. We used a brain–computer interface (BCI), which directly links neural activity to movement of a computer cursor, to encourage animals to generate new neural activity patterns. Over several days, the animals began to exhibit new patterns of neural activity that enabled them to control the BCI cursor. This suggests that learning to play the piano and other skills might also involve the generation of new neural activity patterns.</p>
</blockquote>

<p>These experiments were incredibly to conduct, involving training animals to perform a difficult brain-computer interface task across multiple days.  Kudos to her for all of the hard work!</p>

<p>The full article is available here:</p>

<p><a href="https://www.pnas.org/content/early/2019/06/06/1820296116">https://www.pnas.org/content/early/2019/06/06/1820296116</a></p>

<p>Oby, E. R., Golub, M. D., Hennig, J. A., Degenhart, A. D., Tyler-Kabara, E. C., Yu, B. M., Chase, S. M., Batista, A. B.  New neural activity patterns emerge with long-term learning.  <em>Proceedings of the National Academy of Sciences (PNAS)</em>, (2019).</p>]]></content><author><name></name></author><summary type="html"><![CDATA[Emily Oby’s work investigating the formation of new neural activity patterns during long-term learning was just published in the Proceedings of the National Academy of Sciences (PNAS).  From the article:]]></summary></entry><entry><title type="html">‘Remapping cortical modulation for electrocorticographic brain–computer interfaces’ published in the Journal of Neural Engineering</title><link href="/2018/02/15/somatotopy-paper.html" rel="alternate" type="text/html" title="‘Remapping cortical modulation for electrocorticographic brain–computer interfaces’ published in the Journal of Neural Engineering" /><published>2018-02-15T00:00:00+00:00</published><updated>2018-02-15T00:00:00+00:00</updated><id>/2018/02/15/somatotopy-paper</id><content type="html" xml:base="/2018/02/15/somatotopy-paper.html"><![CDATA[<p>The paper summarizing the main body of my graduate research has just been published in the Journal of Neural Engineering!  This work describes our efforts to achieve three-dimensional brain-computer interface control using electrocorticography with 3 individuals with upper-limb paralysis.</p>

<p><strong>Degenhart, AD</strong> et al., 2017. “Remapping Cortical Modulation for Electrocorticographic Brain-Computer Interfaces: a Somatotopy-Based Approach in Individuals with Upper-Limb Paralysis..” <em>Journal of Neural Engineering</em> 15 (2). IOP Publishing: 026021. doi:10.1088/1741-2552/aa9bfb. <a href="http://iopscience.iop.org/article/10.1088/1741-2552/aa9bfb">http://iopscience.iop.org/article/10.1088/1741-2552/aa9bfb</a></p>

<blockquote>
  <p><strong>Objective</strong>. Brain–computer interface (BCI) technology aims to provide individuals with paralysis a means to restore function. Electrocorticography (ECoG) uses disc electrodes placed on either the surface of the dura or the cortex to record field potential activity. ECoG has been proposed as a viable neural recording modality for BCI systems, potentially providing stable, long-term recordings of cortical activity with high spatial and temporal resolution. Previously we have demonstrated that a subject with spinal cord injury (SCI) could control an ECoG-based BCI system with up to three degrees of freedom (Wang et al. 2013 PLoS One). Here, we expand upon these findings by including brain-control results from two additional subjects with upper-limb paralysis due to amyotrophic lateral sclerosis and brachial plexus injury, and investigate the potential of motor and somatosensory cortical areas to enable BCI control. <em>Approach</em>. Individuals were implanted with high-density ECoG electrode grids over sensorimotor cortical areas for less than 30 d. Subjects were trained to control a BCI by employing a somatotopic control strategy where high-gamma activity from attempted arm and hand movements drove the velocity of a cursor. <strong>Main results</strong>. Participants were capable of generating robust cortical modulation that was differentiable across attempted arm and hand movements of their paralyzed limb. Furthermore, all subjects were capable of voluntarily modulating this activity to control movement of a computer cursor with up to three degrees of freedom using the somatotopic control strategy. Additionally, for those subjects with electrode coverage of somatosensory cortex, we found that somatosensory cortex was capable of supporting ECoG-based BCI control. <strong>Significance</strong>. These results demonstrate the feasibility of ECoG-based BCI systems for individuals with paralysis as well as highlight some of the key challenges that must be overcome before such systems are translated to the clinical realm. ClinicalTrials.gov Identifier: NCT01393444.</p>
</blockquote>]]></content><author><name></name></author><summary type="html"><![CDATA[The paper summarizing the main body of my graduate research has just been published in the Journal of Neural Engineering!  This work describes our efforts to achieve three-dimensional brain-computer interface control using electrocorticography with 3 individuals with upper-limb paralysis.]]></summary></entry></feed>