The generalized cone in human spatial organization

The generalized cone is one of the newer concepts useful for describing spatial structures, and it has become popular as a volumetric primitive in models of object recognition. Apart from this use of the concept (or perhaps underlying it), the generalized cone can be considered a species of spatial regularity. In the general definition of symmetry as invariance across transformation, the generalized cone is a combination of translation and dilation symmetry. In such symmetry, there is homogeneity both of the slants of edges and surfaces of an object about an axis and the radial positions of these features about the axis. The results of two research projects are reviewed suggesting that the generalized cone is useful in human spatial organization. In the first instance, each of the three simpler regular polyhedra, the Platonic Solids, are easiest to perceive and imaging when they are organized as generalized cones. In the second instance, people imagine simple rotations best when the symmetric space that would be traced by the motion is aligned with salient spatial reference systems.     

Propagation of various tooth impacts in the human body

The purpose of this study was to investigate how far tooth impacts were propagated in the body and whether the propagation would be influenced by posture. The impacts were propagated to all recording sites on the head and neck of the 10 examinees tested. In the recordings on the limbs, even at the most distal site, the number of examinees detecting the vibration was seven out of nine examinees. These results showed that the impacts exerted on the tooth were propagated to distal sites of limbs through the bones and soft tissues and implied that the propagated vibration would influence the whole of the body. On the other hand, as the amplitude of propagated vibration was influenced by posture and recording site, the posture during jaw functioning appears to be important.     

Genetic features of the spatial organization of the human cerebral cortex

The within-pair similarity of the topographical maps of the spatial synchronization of the cerebral cortical potentials was studied in 11 pairs of monozygotic twins and 20 genetically unrelated subjects in the resting state and during four types of intellectual activity. It was demonstrated that the degree of similarity of the topographical maps is higher in the resting state in the monozygotic twins than in the genetically unrelated subjects. No frequency band of the EEG which exerts a special influence on the formation of the high degree of similarity of the spatial synchronization of the potentials was found. The maximal similarity in the topographical maps of the monozygotic twins is observed in the anterior regions of the left hemisphere and in the temporoparietal regions of the right. Differences between groups are recorded in both regions; however they are especially distinct in the right hemisphere. The data obtained make it possible to draw an inference regarding the influence of a genetic factor not only on individual components of the EEG (which had been previously demonstrated by a number of authors), but also on the systemic organization of the cortical processes. The right-hemispheric activity apparently relates to the most controllable genetic processes. The results of the analysis of the similarity of topographical maps during various types of activity confirm this: the coefficient of similarity reaches the level of significance in the majority of pairs of monozygotic twins only in a "right-hemispheric" test (simultaneous analysis of nonverbal material).     

Variants in the definitive organization of the human thoracic duct from the positions of its preceding origin

The study was performed in 120 corpses of 8.5-36 weeks human fetuses using macro-microscopic methods complex. Thoracic duct definitive organization variants as monotrunk, transitional forms and plexus reflect strong, middle and slight magistralization extent of antevertebral and adjacent plexuses. Peculiarities of the duct regions positions are defined by topographical variants of adaptive reorganizations--left-side, right-side and bilateral ones.     

Perceived life satisfaction and the organization of personal project systems.

A new methodology developed by the 2nd author (see record 1983-26972-001) for the systemic appraisal of personal project systems was used as an approach to understanding perceived life satisfaction. Variables derived from the personal projects matrix were shown to explain variability in reported life satisfaction in 2 separate studies with 178 university students (aged 18–64 yrs) and 72 residents (aged 15–77 yrs) of a rural/suburban community. High life satisfaction was associated with (a) involvement in projects of high short-term importance that were highly enjoyable and moderately difficult and (b) the presence of a social network that shared project involvements and offered social support. A cross-validation analysis revealed that the results obtained with the larger university sample generalized to the community group. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual organization of two-dimensional patterns.

The perceptual organization of image patterns is considered from 2 standpoints. First, a theoretical framework is presented from which computational models of perceptual organization can be constructed and tested. Second, a specific computational model for perceptual organization of line images is described. In this model, input images are first processed by a dense array of neurons that have properties consistent with recent analyses of single-neuron responses in primary visual cortex. Then, complex image structure is discovered by interleaved pattern-matching and grouping processes constrained by a generalized uniqueness principle. A series of 3-pattern grouping experiments was performed to test a restricted version of the model and to estimate critical parameters. Using the estimated parameters, an extended version of the model was tested by generating predictions for a series of "textbook" perceptual organization demonstrations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of spatial organization in prose learning.

In Exp I, 40 undergraduates either did or did not create a map-like representation while learning a passage. Learners who generated a map exhibited significantly greater retention than did control Ss. In Exp II, 120 undergraduates were either forced to study the map, instructed to study, or given no map prior to reading. Learners who were forced to process performed significantly better than other groups on retention measures. Ss not forced to study performed no better than the control group who received no map. Free-recall data showed that forced map study benefited learners with low vocabulary scores more than Ss with higher vocabulary scores. This was not true for multiple-choice or constructed response measures. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of unconscious interoceptive afferentation on the spatial organization of electrical activity in the human cerebral cortex

Toposcopic studies consisting of EEG recording from 24 cortical points was carried out to characterize the spatial organization of the electrical activity of the human cerebral cortex during the action of unconscious interoceptive stimuli arising from biologically active points associated with different internal organs-the heart, lungs, liver, and intestine. When acupuncture had positive effects, reductions in global synchronization of cortical potentials were noted, which were combined with foci of weakening of the linear and nonlinear correlations in the anterior parts of the right hemisphere, as well as in the posterior and temporal parts of the left hemisphere, with increases in coherence in one of the high-frequency subranges of the EEG (21.5-23.0 Hz). Negative effects and absence of effect correlated with significantly less pronounced weakening of global synchronization of potentials, and increases in their coherence in one of the subranges of alpha activity.     

Bistability and hysteresis in the organization of apparent motion patterns.

In a paradigm for which 2 distinct patterns are perceived for the same stimulus, perceptual hysteresis (persistence of a percept despite parameter change to values favoring the alternative pattern) and temporal stability (persistence despite intrinsic propensities toward spontaneous change) are interdependent. Greater persistence during parameter change reduces temporal stability, slowing the rate of parameter change reduces hysteresis by increasing opportunity for spontaneous change, and increasing temporal stability (by enlarging the stimulus) increases hysteresis. Hysteresis results in the perception of parametrically disfavored patterns; a parameter can influence a percept without specifying it. The visual system thus exhibits time-dependent behavior analogous to dynamical behavior observed in other systems, both physical and biological, for which there is competition among alternative patterns that vary in relative stability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of various lithotomy positions on lower-extremity blood pressure

BACKGROUND: Compartment syndrome of a lower extremity from hypoperfusion is a rare but potentially devastating complication of the lithotomy position during surgery. The aim of this study is to determine the effects of various lithotomy positions on lower-extremity blood pressures. METHODS: Blood pressure in eight young, healthy people was studied for 10 lithotomy positions. Blood pressure measurements were taken in both the upper arm (brachial artery) and the lower extremity (dorsalis pedis). The heart-to-ankle height gradient in each position was measured, and a predicted lower-extremity systolic pressure was calculated. The measured and predicted lower-extremity systolic blood pressures were compared with repeated measures analysis of variance. RESULTS: As a group, the mean systolic blood pressures in the lower extremities correlated closely with the predicted values. However, the difference between measured and predicted pressures varied among the 10 positions (P < 0.05). CONCLUSIONS: Although lower-extremity systolic blood pressures in the young, healthy volunteers correlated with predicted values, there was an additional reduction in pressure associated with the lithotomy position. This surprising finding suggests that a lengthy procedure necessitating the use of a lithotomy position for only a portion should be planned so the remainder of the procedure can take place before establishing the position or so the position can be changed to an alternative position when it is no longer needed.     

Contextual organization and intentionality in adults' spatial memory.

Examines the effects of intentionality and attention to contextual organization in spatial memory. Middle-aged and older women were asked either to study the placement of objects in a contextually organized panorama or to engage in incidental orienting activities, which gave them exposure to the array without awareness that subsequent reconstruction would be required. The incidental conditions required differing degrees of attention to contextual spatial relations. The pattern of results was similar for both age groups. Although some spatial location information was remembered without intention, even when subjects were not required to attend to spatial relations in the array, reconstruction was enhanced by intentionality or by the goal-relevant activity of attending to contextual spatial relations. Orienting activities involving attention to contextual spatial organization or relations between items produced better reconstruction than orienting activities requiring attention only to individual items. In fact, the incidental conditions requiring attention to spatial relations produced performance equal to that in the intentional condition. Although intentionality was not necessary for good reconstruction on a contextually organized task, attention to relations between items was necessary. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Imagined spatial transformation of one's body.

This study examined two related phenomena: (a) the judgment of whether a human body part belongs to the left or right half of the body and (b) the imagined spatial transformation of one's body. In three experiments, observers made left–right judgments of a part of a body whose orientation differed from their own by a rotation about one of 13 axes. To do so, they imagined themselves passing to the orientation of the stimulus. Time for (a) left–right judgments and (b) accompanying imagined spatial transformations depended on the extent of the orientation difference (OD) between the observer and stimulus. More important, time for phenomena (a) and (b) depended strongly, and in the same way, on the direction of OD. Further results showed that the rate of imagined spatial transformations can vary strongly for different axes and directions of rotation about an axis. These and other results (e.g., Parsons, 1987a) suggest that temporal and kinematic properties of imagined spatial transformations are more object-specific than could be previously assumed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental change in children's analysis of spatial patterns.

This study examines the early development of spatial pattern analysis and focuses on changes in the way that preschool children (3–5 yr olds) segment and integrate the parts of simple spatial forms. The results from each of the 3 experiments in this study show that young children analyze spatial patterns in ways that differ systematically from that of older children and adults. Changes with development were observed in the parts children segmented out of the forms and in the relations they used to organize the parts forming the overall pattern. The youngest children segmented out simple, well-formed, spatially independent parts and used simple relational structures to bind these parts together. With development, children constructed forms that included increasingly complex parts and relations. These findings were consistent across several different stimuli using 2 construction mediums. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived depth inversion of smoothly curved surfaces due to image orientation.

A relative depth judgment task was used to distinguish perceived reversals in depth due to image orientation from spontaneous reversals such as those observed with a Necker cube. Results demonstrate that inversion effects due to image orientation can occur for several different types of pictorial representation and that many of these effects are incompatible with traditional explanations involving a perceptual bias for overhead illumination. When this bias was neutralized by placing the light source at the point of observation, the effects of image orientation were just as large as with overhead illumination. Similar results were also obtained for surfaces depicted with texture or motion in which all relevant shading information was eliminated. These results can be explained by a perceptual bias for backward slanting surfaces, but additional evidence suggests that this bias can be attenuated by the presence of smooth occlusion contours. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The organization of human abilities.

There are "two unfortunate tendencies in recent work on human abilities: the proliferation of factors and the tendency to think of only the first-order factors as the primary ones. An alternative model is to place factors in hierarchical order as advocated by the British psychometricians, especially Vernon. The application of the hierarchical model to a logical hierarchy of possible tests of mechanical information is presented, some hypothetical correlations are factored in several orders, and the Schmid-Leiman transformation is used to convert the factors back into a single orthogonal matrix manifesting the hierarchical principle. Facet analysis would enable one to define a population of tests… [and] helps restate the need for homogeneity in a test." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of contextual organization on spatial memory of middle-aged and older women.

Examined the memory performance of 20 women aged 31–59 yrs and 20 aged 65–85. Ss reconstructed spatial arrays, replacing miniature objects in either a contextually organized panorama or a noncontextually organized bank of cubicles. Performance of the middle-aged Ss did not differ between the 2 tasks. Older Ss performed as well as middle-aged Ss in the panorama task, but in the cubicles task their scores were lower than in the panorama task and lower than those of the younger Ss in the cubicles task. Results support the conclusion that in a task that allows the use of existing contextual organization as a memory aid, age differences in memory performance disappear. Age differences may be limited to tasks that remove previously learned relationships between items (as in recall of lists of unrelated words), requiring Ss to invent an organizational structure to facilitate recall. Though such tasks predominate in research, they probably do not represent the memory problems met in everyday life, especially by older adults. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional organization of spatial and nonspatial working memory processing within the human lateral frontal cortex

The present study used functional magnetic resonance imaging to demonstrate that performance of visual spatial and visual nonspatial working memory tasks involve the same regions of the lateral prefrontal cortex when all factors unrelated to the type of stimulus material are appropriately controlled. These results provide evidence that spatial and nonspatial working memory may not be mediated, respectively, by mid-dorsolateral and mid-ventrolateral regions of the frontal lobe, as widely assumed, and support the alternative notion that specific regions of the lateral prefrontal cortex make identical executive functional contributions to both spatial and nonspatial working memory.     

Dissociation of muscular and spatial constraints on patterns of interlimb coordination.

Interlimb coordination is subject to constraints. One major constraint has been described as a tendency for homologous muscle groups to be activated simultaneously. Another has been described as a biasing of limb segments to movement in the same direction. In 2 experiments, the 2 constraints were placed in opposition: In-phase or antiphase contraction of homologous muscles of contralateral limbs produced movement that was spatially antiphase or in-phase, respectively. Probability distributions of relative phase were obtained under manipulations of phase detuning and movement speed. They revealed that the equilibrium and stability of coordination were related, respectively, to spatial relative phase and muscular relative phase. Previously observed spatial and muscular constraints reflect a (possibly very general) factorization of attractor location and attractor strength in the dynamics of interlimb coordination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)