Ward Ã¢ÂÂO,Ã¢ÂÂ Children's Ward, circa 1880-1900Boston City Ã°ÂÂÂ¥...
Ward Ã¢ÂÂO,Ã¢ÂÂ Children's Ward, circa 1880-1900Boston City Ã°ÂÂÂ¥ collection (7020.001), Box 47, Boston City Archives
Ecrit le 21/10 23:31Deep Ã°ÂÂÂ¤ Maintains the Learning Efficiency of the BrainOn...
Most people know from their own experience that just a single sleepless night can lead to difficulty in mastering mental tasks the next day. Researchers assume that deep Ã°ÂÂÂ¤ is essential for maintaining the learning efficiency of the human brain in the long term. While we are awake, we constantly receive impressions from our environment, whereby numerous connections between the nerve cells Ã¢ÂÂ so-called synapses Ã¢ÂÂ are Ã°ÂÂÂ and intensified at times. The excitation of the synapses does not normalize again until we fall Ã°ÂÂ'. Without a recovery phase, many synapses remain maximally Ã°ÂÂÂ, which means that changes in the system are no longer possible: Learning efficiency is blocked.
Causal connection between deep Ã°ÂÂÂ¤ and learning efficiency
The connection between deep Ã°ÂÂÂ¤ and learning efficiency has long been known and proven. Now, researchers at the University of Zurich (UZH) and the Swiss Federal Institute of Technology (ETH) in Zurich have been able to demonstrate a causal connection within the human brain for the first time. Reto Huber, professor at the University Children's Ã°ÂÂÂ¥ Zurich and of Ã°ÂÂÂ¶ and Adolescent Psychiatry at UZH, and Nicole Wenderoth, professor in the Department of Health Sciences and Technology at the ETH Zurich, have succeeded in manipulating the deep Ã°ÂÂÂ¤ of test subjects in targeted areas. Ã¢ÂÂWe have developed a method that lets us reduce the Ã°ÂÂÂ¤ depth in a certain part of the brain and therefore prove the causal connection between deep Ã°ÂÂÂ¤ and learning efficiency,Ã¢ÂÂ says Reto Huber.
Subjective Ã°ÂÂÂ¤ quality was not impaired
In the two-part experiment with six women and seven men, the test subjects had to master three different motoric tasks. The concrete assignment was to learn various sequences of finger movements throughout the day. At night, the brain activity of the test subjects during Ã°ÂÂÂ¤ was monitored by EEG. While the test subjects were able to Ã°ÂÂÂ¤ without disturbance after the learning phase on the first day, their Ã°ÂÂÂ¤ was manipulated in a targeted manner on the second day of the experiment Ã¢ÂÂ using acoustic stimulation during the deep Ã°ÂÂÂ¤ phase. To do so, the researchers localized precisely that part of the brain responsible for learning the abovementioned finger movements, i.e., for the control of motor skills (motor cortex). The test subjects were not aware of this manipulation; to them, the Ã°ÂÂÂ¤ quality of both experimental phases was comparable on the following day.
Deep Ã°ÂÂÂ¤ disturbances impair learning efficiency
In a second step, researchers tested how the manipulation of deep Ã°ÂÂÂ¤ affected the motoric learning tasks on the following day. Here, they observed how the learning and performance curves of the test subjects changed over the course of the experiment. As expected, the participants were particularly able to learn the motoric task well in the morning. As the day went on, however, the rate of mistakes Ã°ÂÂÂ¹. After Ã°ÂÂÂ¤, the learning efficiency considerably improved again. This was not the case after the night with the manipulated Ã°ÂÂÂ¤ phase. Here, clear performance losses and difficulties in learning the finger movements were revealed. Learning efficiency was similarly as weak as on the evening of the first day of the experiment. Through the manipulation of the motor cortex, the excitability of the corresponding synapses was not reduced during Ã°ÂÂÂ¤. Ã¢ÂÂIn the strongly Ã°ÂÂÂ region of the brain, learning efficiency was saturated and could no longer be changed, which inhibited the learning of motor skills,Ã¢ÂÂ Nicole Wenderoth explains.
In a controlled experiment with the same task assignment, researchers manipulated another region of the brain during Ã°ÂÂÂ¤. In this case, however, this manipulation had no effect on the learning efficiency of the test subjects.
Use in clinical studies planned
The newly gained knowledge is an important step in researching human Ã°ÂÂÂ¤. The objective of the scientists is to use this knowledge in clinical studies. Ã¢ÂÂMany diseases manifest in Ã°ÂÂÂ¤ as well, such as epilepsy,Ã¢ÂÂ Reto Huber explains. Ã¢ÂÂUsing the new method, we hope to be able to manipulate those specific brain regions that are directly connected with the disease.Ã¢ÂÂ This could help improve the condition of affected patients.
Ecrit le 21/10 23:25RRR 1909 #histmed
RRR 1909 #histmed
Ecrit le 04/10 13:01Douche de Vichy. Fig. 449. Dr Galtier-BoissiÃ¨re. Dictionnaire...
Douche de Vichy. Fig. 449. Dr Galtier-BoissiÃ¨re. Dictionnaire illustrÃ© de mÃ©decine usuelle, Librairie Larousse, Paris, 1918. #histmed
Ecrit le 01/10 02:37Ten Principal Causes of Death in Boston 1937 Ã¢ÂÂ 1943 One of our...
Ten Principal Causes of Death in Boston 1937 Ã¢ÂÂ 1943
One of our most popular collections at the City Archives are are Departmental Annual reports. This chart from the city's 1943 Health Department report shows common causes of death in the city. It compares causes of death in 1943 to causes of death prior to World War II.
This chart, also from the 1943 Health Department report, tracks deaths from tuberculosis by neighborhood. In 1943, Bostonians living in the South End were were more than twice as likely to die from tuberculosis as Bostonians living in other neighborhoods.
Annual Report of the Health Department, 1943, Collection 7000.002, Boston City Archives.
Ecrit le 01/10 00:12Home-based versus centre-based cardiac...
Home-based versus centre-based cardiac rehabilitation
Ecrit le 29/09 23:11Plate XLIV. Ã¢ÂÂStructure of nerves.Ã¢ÂÂ Illustrations of the...
Plate XLIV. Ã¢ÂÂStructure of nerves.Ã¢ÂÂ Illustrations of the microscopic anatomy of the human body in health and disease. Arthur Hill Hassall, Henry Vanarsdale, New York, 1869.
Ecrit le 25/09 10:54Brain stimulation could restore memory during...
(Image caption: A team of University of Pennsylvania neuroscientists showed for the first time that electrical stimulation delivered when memory is predicted to fail can improve memory function in the human brain. Here, the blue dots indicate overall electrode placement; the yellow dot (top-right corner) indicates the electrode used to stimulate the subject's brain to increase memory performance. Credit: Joel Stein and Youssef Ezzyat)
A team of neuroscientists at the University of Pennsylvania has shown for the first time that electrical stimulation delivered when memory is predicted to fail can improve memory function in the human brain. That same stimulation generally becomes disruptive when electrical pulses arrive during periods of effective memory function.
Ã¢ÂÂÃ¢ÂÂÃ¢ÂÂÃ¢ÂÂÃ¢ÂÂÃ¢ÂÂÃ¢ÂÂThe research team included Michael Kahana, professor of psychology and principal investigator of the Defense Advanced Research Projects Agency's Restoring Active Memory program; Youssef Ezzyat, a senior data scientist in Kahana's lab; and Daniel Rizzuto, director of cognitive neuromodulation at Penn. They published their findings in the journal Current Biology. Â
This work is an important step toward the long-term goal of Restoring Active Memory, a four-year Department of Defense project aimed at developing next-generation technologies that improve memory function in people who suffer from memory loss. It illustrates an important link between appropriately timed deep-brain stimulation and its potential therapeutic benefits.
To get to this point, the Penn team first had to understand and decode signaling patterns that correspond to highs and lows of memory function.
Ã¢ÂÂBy applying machine-learning methods to electrical signals measured at widespread locations throughout the human brain,Ã¢ÂÂ said Ezzyat, lead paper author, Ã¢ÂÂwe are able to identify neural activity that indicates when a given patient will have lapses of memory encoding.Ã¢ÂÂ
Using this model, Kahana's team examined how the effects of stimulation differ during poor versus effective memory function. The study involved neurosurgical patients receiving treatment for epilepsy at the Hospital of the University of Pennsylvania, the Thomas Jefferson University Hospital, the Dartmouth-Hitchcock Medical Center, the Emory University Hospital, the University of Texas Southwestern, the Mayo Clinic, Columbia University, the National Institutes of Health Clinical Center and the University of Washington. Participants were asked to study and recall lists of common words while receiving safe levels of brain stimulation.
During this process, the Penn team recorded electrical activity from electrodes implanted in the patients' brains as part of routine clinical care. These recordings identified the biomarkers of successful memory function, activity patterns that occur when the brain effectively creates new memories.
Ã¢ÂÂWe found that, when electrical stimulation arrives during periods of effective memory, memory worsens,Ã¢ÂÂ Kahana said. Ã¢ÂÂBut when the electrical stimulation arrives at times of poor function, memory is significantly improved.Ã¢ÂÂ
Kahana likens it to traffic patterns in the brain: Stimulating the brain during a backup restores the normal flow of traffic.
Gaining insight into this process could improve the lives of many types of patients, particularly those with traumatic brain injury or neurological diseases, such as Alzheimer's. Ã¢ÂÂTechnology based on this type of stimulation,Ã¢ÂÂ Rizzuto said, Ã¢ÂÂcould produce meaningful gains in memory performance, but more work is needed to move from proof-of-concept to an actual therapeutic platform.Ã¢ÂÂ
This past November, the RAM team publicly released an extensive intracranial brain recording and stimulation dataset that included more than 1,000 hours of data from 150 patients performing memory tasks.
Ecrit le 25/09 10:45Plate XII. Different kinds of Cataract. Essays on the morbid...
Plate XII. Different kinds of Cataract. Essays on the morbid anatomy of the human eye. James Wardrop. 1808.
Ecrit le 18/09 09:38Blood vessels of the foot. Anatomical description of the...
Blood vessels of the foot. Anatomical description of the arteries of the human body. By various authors, illustrations by: Josiah F. Flagg (Josiah Foster), 1813. Plate XIV. (Enlarge: https://www.pinterest.fr/pin/287386019949897962/)
Ecrit le 18/09 09:30John and Charles Bell. Ã¢ÂÂSketch, representing the back part of...
John and Charles Bell. Ã¢ÂÂSketch, representing the back part of the heart.Ã¢ÂÂ The anatomy and physiology of the human body (6th edition). 1826.Â
Ecrit le 09/09 02:15Muscles de l'oeil (Eye muscles), p. 30. La perception visuelle...
Muscles de l'oeil (Eye muscles), p. 30. La perception visuelle de l'espace. Benjamin Boudon. Paris,Â 1902.Â
Ecrit le 06/09 08:36Anatomy class 1920Source: Aalto University CommonsVia Â Â Â Â Â ...
Source: Aalto University Commons
Ecrit le 04/09 21:49nemfrog: Pregnant women playing in Summer heat. Five heads with...
Ecrit le 03/09 19:37nemfrog: nemfrog: A young girl gets advice from a skeleton on...
Growing big and strong. 1939.Â
Ecrit le 03/09 19:33
- Iroises 7104g.4