Neural Correlates of the Perception for Novel Objects

Perception of novel objects is of enormous importance in our lives. People have to perceive or understand novel objects when seeing an original painting, admiring an unconventional construction, and using an inventive device. However, very little is known about neural mechanisms underlying the perception for novel objects. Perception of novel objects relies on the integration of unusual features of novel objects in order to identify what such objects are. In the present study, functional Magnetic Resonance Imaging (MRI) was employed to investigate neural correlates of perception of novel objects. The neuroimaging data on participants engaged in novel object viewing versus ordinary object viewing revealed that perception of novel objects involves significant activation in the left precuneus (Brodmann area 7) and the right visual cortex. The results suggest that the left precuneus is associated with the integration of unusual features of novel objects, while the right visual cortex is sensitive to the detection of such features. Our findings highlight the left precuneus as a crucial component of the neural circuitry underlying perception of novel objects.     

Comparison of preferences for object properties in the rat using paired- and free-choice paradigms

A common method for testing preference for objects is to determine which of a pair of objects is approached first in a paired-choice paradigm. In comparison, many studies of preference for environmental enrichment (EE) devices have used paradigms in which total time spent with each of a pair of objects is used to determine preference. While each of these paradigms gives a specific measure of the preference for one object in comparison to another, neither method allows comparisons between multiple objects simultaneously. Since it is possible that several EE objects would be placed in a cage together to improve animal welfare, it is important to determine measures for rats’ preferences in conditions that mimic this potential home cage environment. While it would be predicted that each type of measure would produce similar rankings of objects, this has never been tested empirically. In this study, we compared two paradigms: EE objects were either presented in pairs (paired-choice comparison) or four objects were presented simultaneously (simultaneous presentation comparison). We used frequency of first interaction and time spent with each object to rank the objects in the paired-choice experiment, and time spent with each object to rank the objects in the simultaneous presentation experiment. We also considered the behaviours elicited by the objects to determine if these might be contributing to object preference. We demonstrated that object ranking based on time spent with objects from the paired-choice experiment predicted object ranking in the simultaneous presentation experiment. Additionally, we confirmed that behaviours elicited were an important determinant of time spent with an object. This provides convergent evidence that both paired choice and simultaneous comparisons provide valid measures of preference for EE objects in rats.     

Symbols, Meaning, and Origins of Mind

The mind maps symbols and the extra-symbolic relationships amongst them to specific meanings. When symbols of various levels are placed in a hierarchical ordering, one may look at such ordered classes as distinct worlds where one class represents objects and the other represents the objects’ corresponding meanings. However, such an explanation can only be partial because the number of potential levels in such an ordering is infinite and, therefore, it engenders problems of recursion and infinite regress. There are also logical problems in the form of paradoxes that emanate from the consideration of sets of sets. Given that most prior studies only consider symbols that are classical objects in associative relationships, we argue that there is a need to also consider objects with shifting boundaries and quantum objects. We believe that objects belonging to each of these three classes—that is classical objects, objects with shifting boundaries, and quantum objects—play a role in the workings of the mind.     

Application of Composite Small Calibration Objects in Traffic Accident Scene Photogrammetry

In order to address the difficulty of arranging large calibration objects and the low measurement accuracy of small calibration objects in traffic accident scene photogrammetry, a photogrammetric method based on a composite of small calibration objects is proposed. Several small calibration objects are placed around the traffic accident scene, and the coordinate system of the composite calibration object is given based on one of them. By maintaining the relative position and coplanar relationship of the small calibration objects, the local coordinate system of each small calibration object is transformed into the coordinate system of the composite calibration object. The two-dimensional direct linear transformation method is improved based on minimizing the reprojection error of the calibration points of all objects. A rectified image is obtained using the nonlinear optimization method. The increased accuracy of traffic accident scene photogrammetry using a composite small calibration object is demonstrated through the analysis of field experiments and case studies.     

Crowding-effect and attention

We studied the influence of additional objects on recognition of the test visual objects. The test objects were stylized low-contrast letters having size 1.1, 2.1 or 4.3 ang. deg. The additional objects after 30 ms were followed by the test objects which were presented in the middle of the screen. The additional objects were digits 1-9 having size 1.3 ang. deg. The digits were presented at various distances from the centre of the screen. The observers' task was to identify both the test objects and the digits. Recognition of the test objects deteriorated when the digits were at small distances to the tests (crowding-effect). Recognition of digits deteriorated with the increasing distances from the centre of the screen; the effect was more pronounced when the tests were large. The contribution of laterals masking and attention into crowding-effect is discussed.     

Automatic quantification of microvessels using unsupervised image analysis.

An automatic method for quantification of images of microvessels by computing area proportions and number of objects is presented. The objects are segmented from the background using dynamic thresholding of the average component size histogram. To be able to count the objects, fragmented objects are connected, all objects are filled, and touching objects are separated using a watershed segmentation algorithm. The method is fully automatic and robust with respect to illumination and focus settings. A test set consisting of images grabbed with different focus and illumination for each field of view, was used to test the method, and the proposed method showed less variation than the intraoperator variation using manual threshold. Further, the method showed good correlation to manual object counting (r = 0.80) on an other test set.     

Analysis of object clustering

Objects of a given type lie on a plane or in a thin layer. In the analysis of the arrangement of such objects, the question may arise as to whether these objects form clusters or whether they are randomly distributed. This question can be answered by the calculation of the coefficient of dispersion (CD) of the objects. Some statistical properties of this coefficient, i.e., its sensitivity and its chi-square approximation, are analyzed in this paper. The proposed approach for calculating sensitivity is a mathematical simulation that is not generally applicable but is valid in various biologic applications. Assuming that the objects are much smaller than the expected clusters and that no knowledge exists about interactions among the objects or between the objects and their surroundings, the objects can be assumed to be distributed randomly on the plane. Such situations may occur in various fields, i.e., biology, sociology, archaeology and ecology. The authors have applied this approach successfully in investigating the densities of T-cell lymphocytes in renal transplants treated with Cyclosporin A or conventional immunosuppressive therapy.     

Automated Correlation and Averaging of Three-Dimensional Reconstructions Obtained by Electron Tomography

We have developed a least-squares refinement procedure that in an automated way performs three-dimensional alignment and averaging of objects from multiple reconstructions. The computer implementation aligns the three-dimensional structures by a two-step procedure that maximizes the density overlap for all objects. First, an initial average density is built by successive incorporation of individual objects, after a global search for their optimal three-dimensional orientations. Second, the initial average is subsequently refined by excluding individual objects one at a time, realigning them with the reduced average containing all other objects and including them into the average again. The refinement is repeated until no further change of the average occurs. The resulting average model is therefore minimally biased by the order in which the individual reconstructions are incorporated into the average. The performance of the procedure was tested using a synthetic data set of randomly oriented objects with Poisson-distributed noise added. The program managed well to align and average the objects at the signal/noise ratio 1.0. The increase in signal/noise ratio was in all investigated cases almost equal to the expected square root of the number of objects. The program was also successfully tested on a set of authentic three-dimensional reconstructions from anin situspecimen containingEscherichia coli70S ribosomes, where the immediate environment of the reconstructed objects may also contain variable amounts of other structures.     

Marqueur d’identification à micro-échelle de l’ivoire de mammouth dans les objets préhistoriques

This paper illustrates the importance of the material identification in order to be able to answer archaeological questions and describes the definition of new markers based on the chemical analysis and the study of the inner micro-morphology of the objects. The challenge for the identification of mammoth ivory is highlighted amongst prehistoric objects, which were heavily worked and used. The applied analytical approach is non-invasive to preserve the integrity of the rare and precious prehistoric objects. The objects are studied by means of Proton Induced X-ray emission (PIXE) and micro X-ray tomography (microCT). Examples of the study of objects dating back to the Upper Palaeolithic nicely illustrate the informative potential of this kind of investigations.     

Developing classification in action: II. Young chimpanzees (Pan troglodytes)

The development of spontaneous object manipulation in 5 chimpanzees (Pan troglodytes) from ages 15 to 54 months was investigated, focusing on formal properties of subjects’ acts and the objects they manipulated. Young chimpanzees’ manipulation progress from serial one-at-a-time acts on one object to parallel two-at-a-time acts on two or more objects. With age, simultaneous acts become increasingly transformational and identical or reciprocal to each other. Moreover, the class properties of objects manipulated simultaneously change. When presented with objects belonging to two different classes, subjects shift, with age, from manipulating different objects to manipulating identical or similar objects. In all these respects young chimpanzee’ development is similar to human infants’. In others it differs. Most especially, the onset age is later and the development is slower as well as less structurally complex.     

Affect and Cognition in Attitude Formation toward Familiar and Unfamiliar Attitude Objects

At large attitudes are built on earlier experience with the attitude object. If earlier experiences are not available, as is the case for unfamiliar attitude objects such as new technologies, no stored evaluations exist. Yet, people are still somehow able to construct attitudes on the spot. Depending on the familiarity of the attitude object, attitudes may find their basis more in affect or cognition. The current paper investigates differences in reliance on affect or cognition in attitude formation toward familiar and unfamiliar realistic attitude objects. In addition, individual differences in reliance on affect (high faith in intuition) or cognition (high need for cognition) are taken into account. In an experimental survey among Dutch consumers (N = 1870), we show that, for unfamiliar realistic attitude objects, people rely more on affect than cognition. For familiar attitude objects where both affective and cognitive evaluations are available, high need for cognition leads to more reliance on cognition, and high faith in intuition leads to more reliance on affect, reflecting the influence of individually preferred thinking style. For people with high need for cognition, cognition has a higher influence on overall attitude for both familiar and unfamiliar realistic attitude objects. On the other hand, affect is important for people with high faith in intuition for both familiar and unfamiliar attitude objects and for people with low faith in intuition for unfamiliar attitude objects; this shows that preferred thinking style is less influential for unfamiliar objects. By comparing attitude formation for familiar and unfamiliar realistic attitude objects, this research contributes to understanding situations in which affect or cognition is the better predictor of overall attitudes.     

Old,socially housed rhesus monkeys manipulate objects

Recent research has indicated that old, individually housed monkeys show little interest in novel objects. Yet unanswered is whether this effect is caused primarily by age or housing condition. The purpose of this study was to assess the role of social living in promoting responsiveness to objects. We measured the rates of object manipulation in older animals, assessed responsiveness over time to particular objects as a measure of habituation, and examined social influences on object use. Several social groups of rhesus monkeys that contained older adults were studied. These groups were housed in indoor pens or in an outdoor enclosure, and all monkeys had continuous access to a variety of objects in their home environment. In contrast to previous studies of individually housed monkeys, our group-housed monkeys showed sustained interest in objects. Old monkeys manipulated objects extensively, and this response was all the more significant, given that the objects were not novel. Monkeys housed in an outdoor enclosure showed object manipulation patterns that were not different from monkeys housed in indoor pens. However, females exhibited much higher object-related responses than males. Social facilitation played a role in the reactions of some monkeys to objects. Patterns of social facilitation as well as avoidance were present in two of the three indoor groups that were observed. Failure to manipulate objects in rhesus macaques appears to be more a function of individual housing than of old age. Factors such as environmental complexity, social needs, and early experience should be considered in order to understand why individually housed rhesus monkeys are unresponsive to objects. © 1993 Wiley-Liss, Inc.     

Novel object exploration in mice: not all objects are created equal

Object exploration is an increasingly popular experimental paradigm in behavioral sciences. We have begun a series of studies with mice specifically looking at the parameters that influence behaviors in this test. The aim of the present study was to examine the effect of object type on performance in the object exploration test. More specifically, adult male C57BL/6J mice were trained and tested using objects that could be climbed (CLIMB) or with those that could only be touched (TOUCH). The results show that activity is affected by the presentation of objects, with object type interacting with some of these changes. C57 mice explored objects that can be climbed over significantly longer than objects that can only be touched and a more rapid habituation was observed using objects that could only be touched. Robust recognition memory was observed in both groups of mice, however mice in the CLIMB group exhibited a significantly greater discrimination index compared to mice in the TOUCH group. Taken together, these findings demonstrate that the selection of objects is of critical importance and it is recommended that special attention be given to the functional (affordant) properties of the objects to-be-used in future studies.     

The Optimal Human Ventral Stream from Estimates of the Complexity of Visual Objects

The part of the primate visual cortex responsible for the recognition of objects is parcelled into about a dozen areas organized somewhat hierarchically (the region is called the ventral stream). Why are there approximately this many hierarchical levels? Here I put forth a generic information-processing hierarchical model, and show how the total number of neurons required depends on the number of hierarchical levels and on the complexity of visual objects that must be recognized. Because the recognition of written words appears to occur in a similar part of inferotemporal cortex as other visual objects, the complexity of written words may be similar to that of other visual objects for humans; for this reason, I measure the complexity of written words, and use it as an approximate estimate of the complexity more generally of visual objects. I then show that the information-processing hierarchy that accommodates visual objects of that complexity possesses the minimum number of neurons when the number of hierarchical levels is approximately 15.     

Active manual control of object views facilitates visual recognition

Active exploration of large-scale environments leads to better learning of spatial layout than does passive observation [1] [2] [3]. But active exploration might also help us to remember the appearance of individual objects in a scene. In fact, when we encounter new objects, we often manipulate them so that they can be seen from a variety of perspectives. We present here the first evidence that active control of the visual input in this way facilitates later recognition of objects. Observers who actively rotated novel, three-dimensional objects on a computer screen later showed more efficient visual recognition than observers who passively viewed the exact same sequence of images of these virtual objects. During active exploration, the observers focused mainly on the 'side' or 'front' views of the objects (see also [4] [5] [6]). The results demonstrate that how an object is represented for later recognition is influenced by whether or not one controls the presentation of visual input during learning.     

Do Simultaneously Viewed Objects Influence Scene Recognition Individually or as Groups? Two Perceptual Studies

The ability to quickly categorize visual scenes is critical to daily life, allowing us to identify our whereabouts and to navigate from one place to another. Rapid scene categorization relies heavily on the kinds of objects scenes contain; for instance, studies have shown that recognition is less accurate for scenes to which incongruent objects have been added, an effect usually interpreted as evidence of objects'' general capacity to activate semantic networks for scene categories they are statistically associated with. Essentially all real-world scenes contain multiple objects, however, and it is unclear whether scene recognition draws on the scene associations of individual objects or of object groups. To test the hypothesis that scene recognition is steered, at least in part, by associations between object groups and scene categories, we asked observers to categorize briefly-viewed scenes appearing with object pairs that were semantically consistent or inconsistent with the scenes. In line with previous results, scenes were less accurately recognized when viewed with inconsistent versus consistent pairs. To understand whether this reflected individual or group-level object associations, we compared the impact of pairs composed of mutually related versus unrelated objects; i.e., pairs, which, as groups, had clear associations to particular scene categories versus those that did not. Although related and unrelated object pairs equally reduced scene recognition accuracy, unrelated pairs were consistently less capable of drawing erroneous scene judgments towards scene categories associated with their individual objects. This suggests that scene judgments were influenced by the scene associations of object groups, beyond the influence of individual objects. More generally, the fact that unrelated objects were as capable of degrading categorization accuracy as related objects, while less capable of generating specific alternative judgments, indicates that the process by which objects interfere with scene recognition is separate from the one through which they inform it.     

The effects of visual object priming on brain activation before and after recognition

BACKGROUND: Recognizing an object is improved by recent experience with that object even if one cannot recall seeing the object. This perceptual facilitation as a result of previous experience is called priming. In neuroimaging studies, priming is often associated with a decrease in activation in brain regions involved in object recognition. It is thought that this occurs because priming causes a sharpening of object representations which leads to more efficient processing and, consequently, a reduction in neural activity. Recent evidence has suggested, however, that the apparent effect of priming on brain activation may vary as a function of whether the neural activity is measured before or after recognition has taken place. RESULTS: Using a gradual 'unmasking' technique, we presented primed and non-primed objects to subjects, and measured activation time courses using high-field functional magnetic resonance imaging (fMRI). As the objects were slowly revealed, but before recognition had occurred, activation increased from baseline level to a peak that corresponded in time to the subjects' behavioural recognition responses. The activation peak for primed objects occurred sooner than the peak for non-primed objects, and subjects responded sooner when presented with a primed object than with a non-primed object. During this pre-recognition phase, primed objects produced more activation than non-primed objects. After recognition, activation declined rapidly for both primed and non-primed objects, but now activation was lower for the primed objects. CONCLUSIONS: Priming did not produce a general decrease in activation in the brain regions involved in object recognition but, instead, produced a shift in the time of peak activation that corresponded to the shift in time seen in the subjects' behavioural recognition performance.     

Materialising the king: The royal funeral of King Tāufa`āhau Tupou IV of Tonga

The arrival of the body of King Tāufa‘āhau Tupou IV, in Tonga on 12 September 2006, prompted complex funerary rites modelled on those of the previous monarch, Queen Sālote. Instead of looking at how funerals reinforce kinship ties or what the effective cost is of the objects exchanged, I concentrate on the presented objects, which formed the focal point of the funerary rites. In doing so, I engage with Keane (2005: 184) who asserts the relevance of semiotics in answering the question: ‘How can we both understand things and do full justice to their materiality?’ I argue that traditional prestigious objects (barkcloth, mats, baskets and coconut oil), ‘modern‐times’ valuables (flower garlands, flower baskets, and crocheted bed spreads), and contemporary objects (cakes wrapped in cling film, screens with chocolate, plastic baskets filled with bags of crisps, chocolate and sweets), materialise qualities the deceased king embodied as a descendant of a mythical ruler, as the fourth king in the modern Christian dynasty and as a contemporary ruler who reformed both education and economy. A consequence of materialising qualities is that they become contingently bound up with other qualities ( Keane 2005: 188 ). I thus concentrate on those objects where the bundling of qualities is realised visually, examining how barkcloth, fine mats, baskets and coconut oil embody female generative power, protecting, controlling and linking qualities. It is the qualities of the objects bundled in the matter of the objects themselves that make some objects matter more than others.     

Computer simulation of the directional displacement of rod-shaped,arc-shaped,and circular objects in an array of obstacles,representing a simple model for the gel electrophoresis of small DNA

The gel electrophoresis of DNA of identical length but various static conformations was simulated using a two-dimensional model of the movement of rod-shaped, arc-shaped, and circular objects through random arrays of disk-shaped obstacles. At low obstacle density, the displacement rate of these objects decreases from the rod-shaped to the circular to the arc-shaped objects. At high obstacle densities, the displacement rate of circular objects approaches zero. The alignment of the arc-shaped objects along the axis of the directional movement of the objects was less than that achieved by the rod-shaped objects. Rod-shaped and arc-shaped objects were retarded in their movement by collisions with the obstacles; the number of collisions of the former, in view of their greater ability to align, was less than that of the latter. Circular objects were exclusively retarded by collisions, while the arc-shaped objects exhibited an additional retarding mechanism, viz. the suspension (“hanging”) on the obstacles. When the rigid objects were made flexible, their displacement increased. The increase was most pronounced with the circular objects, allowing them to penetrate at obstacle densities from which the rigid objects were excluded. © 1995 John Wiley & Sons, Inc.