Sunday, July 30, 2006

Abstract of the Day: Of Time and the River

Takahashi T. Time-estimation error following Weber-Fechner law may explain subadditive time-discounting.. Medical Hypotheses. 2006 Jul 25; [Epub ahead of print]

Department of Cognitive and Behavioral Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan.

Impulsivity in drug addicts have been associated with impatience in intertemporal choice, i.e., high degrees to which delayed rewards are discounted, indicating the importance of reducing the degree of discounting in drug addicts. Intertemporal choice (delay discounting) has been attracting attention in neuropsychopharmacology and behavioral neuroeconomics. Recently, behavioral economists have reported that impatience/impulsivity in intertemporal choice is increased if a delay period is presented as a sum of divided time-blocks, which is referred to as subadditive discounting (i.e., "total patience" over the delay period is larger than the "sum of patience" over divided delay periods). This finding implies that abstinent drug addicts may more readily relapse into addiction if an abstinence period is presented as a series of shorter abstinent periods, rather than a single block of a long abstinence period. Therefore, understanding of neuropsychological processing underlying subadditive discounting is important for establishing medical treatments of drug addiction, although to date, no study has addressed this question. In this study, we propose that time-estimation following Weber-Fechner law, formerly introduced for explaining hyperbolic discounting, may also explain subadditive discounting. Our present hypothesis also predicts that possibility of relapse into drug dependence can be decreased by helping abstinent patients to perceive time-duration of an abstinence/withdrawal period precisely.

PMID: 16872753 [PubMed - as supplied by publisher]

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Anthony H. Risser | |

Sunday, July 23, 2006

Upcoming Event: Zurich, 26-30 July 2006

International Neuropsychological Society (INS) mid-year conference taking place this week in Zurich, Switzerland. Visit the conference website for more information: website.

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Anthony H. Risser | |

Saturday, July 15, 2006

Virginia Apgar!

Most everyone reading this will have had a closer degree of connection with Virginia Apgar than they know. Who is Virginia Apgar, you ask? When born, most of you will have received an Apgar Score in the delivery room. She created it. Did you know?... (grin)




From an NIH press release on the 13th of July:

Papers of Virginia Apgar Added to National Library of Medicine's Profiles in Science Web Site

Bethesda, Maryland - The National Library of Medicine's Profiles in Science Web site has been enriched by the addition of the papers of Virginia Apgar, M.D., creator of the widely used Apgar Score to evaluate newborns. The Library has collaborated with the Mount Holyoke College Archives and Special Collections to digitize her papers and make them widely available. This brings to 18 the number of notable scientists who have personal and professional records included in Profiles. The site is at http://www.profiles.nlm.nih.gov.

In 1949, faced with unacceptably high newborn mortality rates in her hospital's maternity ward, Virginia Apgar (1909-1974), an anesthesiologist, set out to ensure that newborns in distress got the prompt attention they needed. Using the same signs anesthesiologists monitored during and after surgery - heart rate, respiration, reflex irritability, muscle tone, and color - she developed a simple, rapid method for assessing the medical condition of newborn babies. Quickly adopted by obstetric teams, her method (now known as the Apgar Score) reduced infant mortality and laid the foundations of neonatology.

"Dr. Apgar brought enormous intelligence and energy to everything she did. Her newborn scoring method put neonatology on a firm scientific basis, and she made substantial contributions to anesthesiology and the study of birth defects. I personally found her a memorable and inspiring teacher," said Donald A. B. Lindberg, M.D., Director of the National Library of Medicine.

Born on June 7, 1909, in Westfield, New Jersey, Apgar attended Mount Holyoke College, and then received her M.D. from the Columbia University College of Physicians and Surgeons in 1933. Although she completed a two-year surgical internship at New York's Presbyterian Hospital, her mentor there discouraged her from pursuing a surgical career, noting that women surgeons rarely achieved financial success. Instead he recommended that she enter anesthesiology, then a new medical specialty. Apgar subsequently trained with anesthesiology pioneer Ralph Waters at the University of Wisconsin, and in 1938 returned to Presbyterian Hospital as the director of a new Division of Anesthesia. She transformed the anesthesia service during the next decade, establishing an anesthesiology education program and replacing nurse-anesthetists with physicians.

In 1949, Apgar was appointed a full professor of anesthesiology and she stepped down as director of the Division of Anesthesia. Free of administrative duties, she continued to teach and devoted more time to research in obstetrical anesthesia. Within three years, she developed the Apgar scoring method, and started using score data from thousands of infants to assess the results of obstetric practices, types of maternal pain relief, and effects of resuscitation.

Apgar was a legendary clinical teacher, well known for her fierce dedication to patients of all ages. She kept basic resuscitation equipment with her at all times, both on and off duty, explaining, "Nobody, but nobody is going to stop breathing on me!"

[ .. Read the full release ... ]
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Anthony H. Risser | |

Monday, July 10, 2006

New Books from The Dana Center

I received a couple of new books on neuroethics from The Dana Center. The first one I started to read is Mind Wars: Brain Research and National Defense by bioethicist Jonathan D. Moreno, Ph.D. It's been a fascinating read so far.

The cover blurb points to coverage of how neuroscience may influence warfare and the ethical and policy issues that are likely to be confronted.

I'm curious as to what arguments and points will emerge in Moreno's presentation!

The other book is Hard Science, Hard Choices: Facts, Ethics, and Policies Guiding Brain Science Today by Sandra J. Ackerman.

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Anthony H. Risser | |

Saturday, July 08, 2006

Media: Hemispherectomy in The New Yorker

Last week's issue of The New Yorker (03 July 2006) included an excellent Annals of Medicine essay on hemispherectomy, The Deepest Cut, written by Christine Kenneally. She follows the lives of two individuals, Lacy and Christina, and provides a succinct overview to the indications for this operative procedure and its outcomes.
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Anthony H. Risser | |

Wednesday, July 05, 2006

Abstract of the Day: Alzheimer Disease

Cummings JL, McRae T, & Zhang R. (2006). Effects of donepezil on neuropsychiatric symptoms in patients with dementia and severe behavioral disorders. American Journal of Geriatric Psychiatry, 14(7), 605-612.

Departments of Neurology and Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, California (JLC); and Pfizer, Inc., New York, New York (TM, RZ).

Objective: The objective of this study was to conduct exploratory analyses of data pertaining to the efficacy of donepezil treatment of patients with severe behavioral disturbances. Preliminary studies suggest that cholinesterase inhibitors, including donepezil, may reduce behavioral disturbances in patients with Alzheimer disease (AD). Most patients included in clinical trials have had low levels of psychopathology at baseline, and the effect of cholinesterase inhibitors on patients with more severe behavioral disturbances is unknown. The authors report the effects of donepezil on behavioral disturbances in patients with relatively severe psychopathology at baseline. Methods: This is a hypothesis-driven secondary analysis of a three-phase study involving donepezil and sertraline. In phase 1, psychotropic agents were withdrawn; in phase 2, patients were treated in an open-label fashion with donepezil for 8 weeks; and in phase 3, patients on donepezil were randomized to receive placebo or sertraline for an additional 12 weeks. The data set analyzed is comprised of the patient population treated with donepezil (without sertraline) for 20 weeks. One hundred twenty patients were included in the analyses. Mean age was 76 years, average Mini-Mental State Examination Score was 18, and mean Neuropsychiatric Inventory (NPI) total score was 30. Primary efficacy assessments were the NPI, the Clinical Global Impression-Improvement, and the Clinical Global Impression-Severity scales. Secondary measures included the Behavioral Pathology in Alzheimer's Disease Rating Scale, The Hamilton Depression Rating Scale, and the Alzheimer's Disease Functional Assessment and Change Scale. Results: Excellent concurrent validity was noted between the NPI and the Behavioral Pathology in Alzheimer's Disease Rating Scale. The total score of the NPI was significantly reduced over the 20 weeks of therapy with donepezil. Sixty-two percent of patients had at least a 30% reduction in the total NPI score (significantly greater than the number with no meaningful response). Likewise, more patients had total or partial resolution of depression and delusions than those who had no meaningful change. Factor analysis of baseline NPI data revealed five factors, including a psychosis factor, an agitation factor, mood factor, frontal lobe function factor, and appetite and eating disorders factor. Clinically meaningful treatment effect sizes were notable for the delusion factor (0.340) and the mood factor (0.39). There were significant correlations between the Clinical Global Impression-Improvement and reductions in mood and agitation scores. Conclusion: The results of these analyses suggest that donepezil reduces behavioral symptoms, particularly mood disturbances and delusions, in patients with AD with relatively severe psychopathology.

PMID: 16816014 [PubMed - in process]
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Anthony H. Risser | |

Parkinson Disease

From an NIH press release on 04 July 2006:

Dopamine Drug Leads to New Neurons and Recovery of Function in Rat Model of Parkinson's Disease

In preliminary results, researchers have shown that a drug which mimics the effects of the nerve-signaling chemical dopamine causes new neurons to develop in the part of the brain where cells are lost in Parkinson's disease (PD). The drug also led to long-lasting recovery of function in an animal model of PD. The findings may lead to new ways of treating PD and other neurodegenerative diseases. The study was funded in part by the NIH's National Institute of Neurological Disorders and Stroke (NINDS).

The study suggests that drugs which affect dopamine D3 receptors might trigger new neurons to grow in humans with the disease. Some of these drugs are commonly used to treat PD. The finding also suggests a way to develop new treatments for PD. The results appear in the July 5, 2006, issue of The Journal of Neuroscience.

[snip]

The new study, conducted by Christopher Eckman, Ph.D., and Jackalina Van Kampen, Ph.D., at the Mayo Clinic College of Medicine in Jacksonville, Florida, focused on a second possible way to restore function — prompting stem cells that normally remain dormant in the adult brain to develop into neurons. While most researchers previously believed the adult brain could not develop new neurons, recent studies have shown that the brain contains stem cells and that new neurons can develop in some regions. Studies by Dr. Van Kampen and others also have shown that drugs which affect dopamine D3 receptors can trigger development of new neurons (a process called neurogenesis) in the brains of adult rats. Until now, however, no one had shown that the newly developed neurons could connect with other parts of the brain and restore function.

"This is the first study to show that endogenous neurogenesis [development of new neurons from cells already in the brain] can lead to recovery of function in an animal model of Parkinson's disease," says Dr. Eckman.

[ ... Read the full release ... ]
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Anthony H. Risser | |

Monday, July 03, 2006

Pushing Alzheimer Research Forward

Zach Lynch of Brain Waves points to a recent Op-Ed piece in The Washington Post by the CEO of Wyeth, Robert Essner:

Read the post, with a link to the piece

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Anthony H. Risser | |

Ants!

From the Canadian Broadcasting Corporation (CBC):
Ants walk using internal distance clock: Study
Last Updated Fri, 30 Jun 2006 15:43:19 EDT
CBC News

Desert ants have an internal pedometer that measures how far they've marched, researchers have found.

Foraging Sahara Desert ants wander when searching for food, but take a relatively straight path when heading back to their nests.

To do so, the ants need to judge directions and distances when travelling over flat, sandy terrain without landmarks. Scent trails used by other species won't work because the odours fade in the hot desert.

[...continues...]

[ ... Read the full report ... ]

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Anthony H. Risser | |