The brain is the key organ of the response to stress because it determines what is threatening and, therefore, potentially stressful, as well as the physiological and behavioral responses which can be either adaptive or damaging. Stress involves two-way communication between the brain and the cardiovascular, immune, and other systems via neural and endocrine mechanisms. Beyond the "flight-or-fight" response to acute stress, there are events in daily life that produce a type of chronic stress and lead over time to wear and tear on the body ("allostatic load"). Yet, hormones associated with stress protect the body in the short-run and promote adaptation ("allostasis"). The brain is a target of stress, and the hippocampus was the first brain region, besides the hypothalamus, to be recognized as a target of glucocorticoids. Stress and stress hormones produce both adaptive and maladaptive effects on this brain region throughout the life course. Early life events influence life-long patterns of emotionality and stress responsiveness and alter the rate of brain and body aging. The hippocampus, amygdala, and prefrontal cortex undergo stress-induced structural remodeling, which alters behavioral and physiological responses. As an adjunct to pharmaceutical therapy, social and behavioral interventions such as regular physical activity and social support reduce the chronic stress burden and benefit brain and body health and resilience.

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Physiology and Neurobiology of Stress and Adaptation: Central Role of the Brain

Let's read! We will often find out this sentence everywhere. When still being a kid, mom used to order us to always read, so did the teacher. Some books are fully read in a week and we need the obligation to support reading. What about now? Do you still love reading? Is reading only for you who have obligation? Absolutely not! We here offer you a new book enPDFd the perception of the visual world to read.

The Perception of the Visual World. By James J. Gibson. U.S.A.: Houghton Mifflin Company, 1950 (George Allen & Unwin, Ltd., London). Price 35s.

Mini Mental State

The Organization of Learning そして

Practice guideline for the treatment of patients with obsessive-compulsive disorder.

It has not been established that walking without vision to previewed targets is indeed controlled by perceived distance. To this end, we compared walking and verbal report as distance indicators, looking for a tight covariation in responses that would indicate control by a common variable. Targets from 79-500 cm away were presented under dark and well-lit conditions. Both verbal reports and walking indicated overestimation of near targets and underestimation of far targets under dark viewing conditions. Moreover, the finding that verbally reported distance plotted essentially as a single-valued function of walked distance and vice versa is evidence that both indicators were responding to the same internal variable, ostensibly perceived distance. In addition, binocular parallax, absolute motion parallax, and angular elevation were evaluated as distance cues, and only angular elevation exerted a large influence on perceived distance.

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Comparison of two indicators of perceived egocentric distance under full-cue and reduced-cue conditions

1. C.R. Gallistel, The Organization of Learning (MIT Press, Cambridge, MA, 1990). 2. P.S. Churchland, V.S. Ramachandran, and T.J. Sejnowski, A critique of pure vision, in Large Scale Neuronal Theories of the Brain, C. Koch and J.L. Davis, Eds. (MIT Press, Cambridge, MA, 1994). 3. K. von Frisch, The Dance Language and Ori entation of Bees (Harvard University Press, Cam bridge, MA, 1967). 4. M. Lindauer, Angeborne und erlernte Komponenten in der Sonnenorientierung der Bi enen, Zeitschrift f?r vergleichende Physiologie, 42, 43-62 (1959). 5. F.C. Dyer, Memory and sun compensation by honey bees, Journal of Comparative Physiology A, 160, 621-633 (1987). 6. F.C. Dyer, Nocturnal orientation by the Asian honey bee, Apis dorsata, Animal Behaviour, 33, 769-774 (1985), and publications by Lindauer, Edrich, and Wehner cited therein. 7. D.A.T. New and J.K. New, The dances of honey bees at small zenith distances of the sun, Journal of Experimental Biology, 39, 271-291 (1962); R. Wehner, Himmelsnavigation bei Insekten: Neurophysiologie und Verhalten, Neujahrsblatt der Natur for sehenden Gesellschaft in Z?rich, 184, 1-132 (1982); R. Wehner and B. Lanfranconi, What do ants know about the rotation of the sky? Nature, 293, 731-733 (1981). 8. J.L. Gould, Sun compensation by bees, Sci ence, 207, 545-547 (1980). 9. F.C. Dyer and J.A. Dickinson, Develop ment of sun compensation by honeybees: How partially experienced bees estimate the sun's course, Proceedings of the National Academy of Sci ences, USA, 91, 4471-4474 (1994). 10. R. Wehner and M. M?ller, How do ants acquire their celestial ephemeris function? Natur wissenschaften, 80, 331-333 (1993). 11. P. Marier, Song-learning: The interface be tween behavior and neuroethology, Philosophical Transactions of the Royal Society of London B, 329, 109-114 (1990). 12. S. Pinker, The Language Instinct (MIT Press, Cambridge, MA, 1994); N. Chomsky, On the nature, use, and acquisition of language, in Readings in Philosophy and Cognitive Science, A.I. Goldman, Ed. (MIT Press, Cambridge, MA, 1993). 13. D.F. Sherry, L.F. Jacobs, and S.J. Gaulin, Spatial memory and adaptive specialization of the hippocampus, Trends in Neurosciences, 15, 298-303 (1992). 14. K. Schmidt-Koenig, J.U. Ganzhorn, and R. Ranvaud, The sun compass, in Orientation in Birds, P. Berthold, Ed. (Birkh?user-Verlag, Basel, Switzerland, 1991).

Visual Perception of Location and Distance

We provide experimental evidence that perceived location is an invariant in the control of action, by showing that different actions are directed toward a single visually specified location in space (corresponding to the putative perceived location) and that this single location, although specified by a fixed physical target, varies with the availability of information about the distance of that target. Observers in two conditions varying in the availability of egocentric distance cues viewed targets at 1.5, 3.1, or 6.0 m and then attempted to walk to the target with eyes closed using one of three paths; the path was not specified until after vision was occluded. The observers stopped at about the same location regardless of the path taken, providing evidence that action was being controlled by some invariant, ostensibly visually perceived location. That it was indeed perceived location was indicated by the manipulation of information about target distance—the trajectories in the full-cues condition converged near the physical target locations, whereas those in the reduced-cues condition converged at locations consistent with the usual perceptual errors found when distance cues are impoverished.

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Visually perceived location is an invariant in the control of action.

Three experiments investigated auditory distance perception under natural listening conditions in a large open field. Targets varied in egocentric distance from 3 to 16 m. By presenting visual targets at these same locations on other trials, we were able to compare visual and auditory distance perception under similar circumstances. In some experimental conditions, observers made verbal reports of target distance. In others, observers viewed or listened to the target and then, without further perceptual information about the target, attempted to face the target, walk directly to it, or walk along a two-segment indirect path to it. The primary results were these. First, the verbal and walking responses were largely concordant, with the walking responses exhibiting less between-observer variability. Second, different motoric responses provided consistent estimates of the perceived target locations and, therefore, of the initially perceived distances. Third, under circumstances for which visual targets were perceived more or less correctly in distance using the more precise walking response, auditory targets were generally perceived with considerable systematic error. In particular, the perceived locations of the auditory targets varied only about half as much in distance as did the physical targets; in addition, there was a tendency to underestimate target distance, except for the closest targets.

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Assessing auditory distance perception using perceptually directed action

D. R. Proffitt and colleagues (e. g., D. R. Proffitt, J. Stefanucci, T. Banton, & W. Epstein, 2003) have suggested that objects appear farther away if more effort is required to act upon them (e.g., by having to throw a ball). The authors attempted to replicate several findings supporting this view but found no effort-related effects in a variety of conditions differing in environment, type of effort, and intention to act. Although they did find an effect of effort on verbal reports when participants were instructed to take into account nonvisual (cognitive) factors, no effort-related effect was found under apparent- and objective-distance instruction types. The authors' interpretation is that in the paradigms tested, effort manipulations are prone to influencing response calibration because they encourage participants to take nonperceptual connotations of distance into account while leaving perceived distance itself unaffected. This in no way rules out the possibility that effort influences perception in other contexts, but it does focus attention on the role of response calibration in any verbal distance estimation task.

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John W. Philbeck

Papers

Comparison of two indicators of perceived egocentric distance under full-cue and reduced-cue conditions

Visual Perception of Location and Distance

Visually perceived location is an invariant in the control of action.

Assessing auditory distance perception using perceptually directed action

The Various Perceptions of Distance: An Alternative View of How Effort Affects Distance Judgments