Face identification in the near-absence of focal attention.
(49/196)
In contrast to artificial geometric shapes, natural scenes and face-gender can be processed even when spatial attention is not fully available. In this study, we investigate whether a finer discrimination, at the level of the individual, is possible in the near-absence of focal attention. Using the paradigm, subjects performed face identification on faces of celebrities and relatively unfamiliar individuals, along with a task that is known to engage spatial attention. We find that face-identification performance is only modestly impaired under dual-task conditions. These results suggest that the visual system is well able to make complex judgments of natural stimuli, even when attention is not fully available. (+info)
Flash-lag chimeras: the role of perceived alignment in the composite face effect.
(50/196)
Spatial alignment of different face halves results in a configuration that mars the recognition of the identity of either face half (). What would happen to the recognition performance for face halves that were aligned on the retina but were perceived as misaligned, or were misaligned on the retina but were perceived as aligned? We used the 'flash-lag' effect () to address these questions. We created chimeras consisting of a stationary top half-face initially aligned with a moving bottom half-face. Flash-lag chimeras were better recognized than their stationary counterparts. However when flashed face halves were presented physically ahead of moving halves thereby nulling the flash-lag effect, recognition was impaired. This counters the notion that relative movement between the two face halves per se is sufficient to explain better recognition of flash-lag chimeras. Thus, the perceived spatial alignment of face halves (despite retinal misalignment) impairs recognition, while perceived misalignment (despite retinal alignment) does not. (+info)
Konorski and conditional reflexes: a historical summary and an addendum.
(51/196)
There have been four major pioneers from Eastern Europe in the neuroscientific study of memory and learning: Pavlov, Bekhterev, Beritashvili and Konorski. The thinking of each evolved with the progress of neuroscientific knowledge throughout the world, and save for Pavlov, each encountered governmental opposition to their views. Among the clues largely overlooked in their examination of conditional reflexes was the fact that the animal appreciates not only its own appetitive state but its immersion in the experimental setting. The latter in itself must require considerable, ongoing neuronal activity to sustain it. There is also the question as to whether "motivation" is an essential feature for the formation of conditional connections; and in cases where it is seemingly absent, as in recognition memory, the processes that underlie the astonishing efficacy of such memory formation remain almost wholly obscure. Finally, it is remarked that the cerebral cortex, as initially supposed, may indeed be the governing locus, even of such simple effects as habituation. (+info)
Cerebral cortex astroglia and the brain of a genius: a propos of A. Einstein's.
(52/196)
The glial fibrillary acidic protein immunoreactive astroglial layout of the cerebral cortex from Albert Einstein and other four age-matched human cases lacking any known neurological disease was analyzed using quantification of geometrical features mathematically defined. Several parameters (parallelism, relative depth, tortuosity) describing the primate-specific interlaminar glial processes did not show individually distinctive characteristics in any of the samples analyzed. However, A. Einstein's astrocytic processes showed larger sizes and higher numbers of interlaminar terminal masses, reaching sizes of 15 microm in diameter. These bulbous endings are of unknown significance and they have been described occurring in Alzheimer's disease. These observations are placed in the context of the general discussion regarding the proposal--by other authors--that structural, postmortem characteristics of the aged brain of Albert Einstein may serve as markers of his cognitive performance, a proposal to which the authors of this paper do not subscribe, and argue against. (+info)
Language and memory disorder in the case of Jonathan Swift: considerations on retrospective diagnosis.
(53/196)
The cause of behavioural changes described by Alzheimer for his original case, Auguste D., has been recently reconfirmed by histological examination. However, there has been active speculation regarding the cause of behavioural changes exhibited by the political satirist Jonathan Swift (1667-1745) during the final three years of his life for over 250 years. Swift's symptoms of cognitive changes, memory impairment, personality alterations, language disorder and facial paralysis have all been apportioned differing levels of significance in various attempts at retrospective diagnosis. The various medical arguments put forward from the 18th through 20th centuries will be critically examined. The diagnoses considered refer to evolving theories of insanity, phrenology, localization of cortical function, hydrocephalus, psychoanalysis, aphasia, dementia and depression in ageing. Re-consideration of the attempts to re-diagnose Swift's final mental state by the leading neurological thinkers of the day, including Wilde (The Closing Years of Dean Swift's Life. Dublin: Hodges and Smith, 1849), Bucknill (1882), Osler [Osler's textbook Principles and Practice of Medicine (1892); published in St Thomas's Hospital Gazette (London) 1902; 12: 59-60), Brain (Irish Med J 1952: 320-1 and 337-346) and Boller and Forbes (J Neurol Sci 1998; 158: 125-133) reveal the changing attitudes regarding the significance of behavioural symptoms to neurological diagnosis from the 18th century to the present day. (+info)
Bend it like Beckham: embodying the motor skills of famous athletes.
(54/196)
Observing an action activates the same representations as does the actual performance of the action. Here we show for the first time that the action system can also be activated in the complete absence of action perception. When the participants had to identify the faces of famous athletes, the responses were influenced by their similarity to the motor skills of the athletes. Thus, the motor skills of the viewed athletes were retrieved automatically during person identification and had a direct influence on the action system of the observer. However, our results also indicated that motor behaviours that are implicit characteristics of other people are represented differently from when actions are directly observed. That is, unlike the facilitatory effects reported when actions were seen, the embodiment of the motor behaviour that is not concurrently perceived gave rise to contrast effects where responses similar to the behaviour of the athletes were inhibited. (+info)
Multi-element screening by ICP-MS of two specimens of Napoleon's hair.
(55/196)
Since 1960, it has been demonstrated by various analytical procedures that high concentrations of arsenic were present in Napoleon's hair. Various authors, indicating that the detected arsenic levels are a consequence of external contamination, have challenged the results of these examinations. In order to shed more light on this historical controversy, we have tested two samples of Napoleon's hair by inductively coupled plasma-mass spectrometry (ICP-MS). The samples of hair were decontaminated with acetone and were cut into small segments. For multi-element screening, hair samples were mineralized in concentrated nitric acid for 1 h at 70 degrees C, diluted 1:40 in specific solution with rhodium as an internal standard, and finally analyzed by ICP-MS on a Thermo Electron ICP/MS X7. Multi-element analysis of Napoleon's hair samples revealed massive amounts of arsenic (42.1 and 37.4 ng/mg), antimony (2.1 and 1.8 ng/mg) and elevated levels of mercury (3.3 and 4.7 ng/mg) and lead (229 and 112 ng/mg). In the case of arsenic, these concentrations, 40 times higher than the normal values, confirm the hypothesis of a significant exposure to arsenic. The concentrations of the other elements, in particular antimony and mercury, are in agreement with the data already known about the therapeutic treatments given to Napoleon, which were based on calomel (salt of mercury) and tartar emetic (antimony). (+info)
The leadership principles of Dr. Martin Luther King, Jr. and their relevance to surgery.
(56/196)
In order to face the challenges in healthcare this century, it is essential that surgeons understand modern leadership principles. One of the greatest leaders in history was Dr. Martin Luther King, Jr., who provides a shining example of level-5 leadership for us to study. The study of leadership principles of great leaders can provide us with practical methods of conflict resolution as well as inspiration to keep us engaged and focused. As leaders of the medical community, we face numerous challenges, including discovering and implementing new treatments for disease, providing care for the indigent, overcoming educational challenges such as incorporating the ACGME Core Competencies into our surgical training and promoting diversity in education. Achieving these goals is often hindered by the environment in which we labor-nearly 50 million are uninsured, the rising cost of medical care is currently at 16% of the GNP, and reimbursement rates are falling-which makes the practice of surgery a significant challenge. Effective leadership will be paramount in achieving these goals. In this editorial, which summarizes a presentation given to the Surgical Section of the annual National Medical Association meeting, five important leadership principles that are important for surgeons have been selected and related to the outstanding leadership of Dr. Martin Luther King, Jr. (+info)