Internal representations and operations in the visual comparison of transformed patterns: Effects of pattern point-inversion,positional symmetry,and separation

A scheme for visual pattern recognition is described. It is supposed, amongst other things, that patterns are internally represented by the visual system in terms of local features, spatial-order relations between local features, and global spatial relations specifying approximate pattern position with respect to the point of fixation. It is further supposed that there are two distinct types of internal operation that may be applied to the components of internal representations in the process of pattern comparison: typically a discrete spatial-order-reversal operation and a continuous position-shift operation. Some general predictions of the scheme are tested against data obtained in an experiment using random-dot patterns that were subjected to rigid transormations and presented at various locations along the horizontal meridian. Patterns were presented sequentially, in pairs, to subjects in a same-different comparison task. Pattern pairs were to be responded to as same if they were identical or related by point-inversion (planar rotation through 180°) or responded to as different. Extending earlier findings, the present results showed that same-detection performance for identical and point-inverted patterns depended differentially on the distance between the patterns and the symmetry of the pattern positions about the point of fixation in a manner consistent with the predictions of the scheme.Part of the work reported in this study was carried out while DHF was on leave from the University of Keele in 1983 as Visiting Professor in the Department of Psychology, Queen's University at Kingston, Ontario. Support by grants from Professor P.C. Dodwell and the Department of Psychology, Queen's University, is gratefully acknowledged. Support by an award from the Science and Engineering Research Council (SERC) to JIK is also gratefully acknowledged     

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.     

Auditory filters, features, and redundant representations

Responses in auditory cortex tend to be weaker, more phasic, and noisier than those of auditory brainstem and midbrain nuclei. Is the activity in cortex therefore merely a "degraded echo" of lower-level neural representations? In this issue of Neuron, Chechik and colleagues show that, while cortical responses indeed convey less sensory information than auditory midbrain neurons, their responses are also much less redundant.     

Spirits in Culture, History, and Mind

Spirits in Culture, History, and Mind. Jeannette Marie Mageo and Alan Howard. eds. New York: Routledge, 1996. 282 pp.     

Orchids,bilateral symmetry and insect perception

The basic characteristics of orchids, possessing the greatest number of complex floral images of any Angiosperm family, are reviewed. Bilateral symmetry (zygomorphy) is shown by use of information theory techniques to give much greater possibilities for the transmission of visually mediated information than radial symmetry. The difference in information content is further enhanced by motion. The analysis is offered as evidence that the evolution of diversity in complex images, if effected by the unique behavioral specificity of pollinators known as “flower constancy”, is most economically explained by hypothesizing recognition and storage of the total image (“gestalt”) in the agents of natural selection.     

Kinematics,material symmetry,and energy densities for lipid bilayers with spontaneous curvature

Continuum mechanical tools are used to describe the deformation, energy density, and material symmetry of a lipid bilayer with spontaneous curvature. In contrast to conventional approaches in which lipid bilayers are modeled by material surfaces, here we rely on a three-dimensional approach in which a lipid bilayer is modeling by a shell-like body with finite thickness. In this setting, the interface between the leaflets of a lipid bilayer is assumed to coincide with the mid-surface of the corresponding shell-like body. The three-dimensional deformation gradient is found to involve the curvature tensors of the mid-surface in the spontaneous and the deformed states, the deformation gradient of the mid-surface, and the transverse deformation. Attention is also given to the coherency of the leaflets and to the area compatibility of the closed lipid bilayers (i.e., vesicles). A hyperelastic constitutive theory for lipid bilayers in the liquid phase is developed. In combination, the requirements of frame indifference and material symmetry yield a representation for the energy density of a lipid bilayer. This representation shows that three scalar invariants suffice to describe the constitutive response of a lipid bilayer exhibiting in-plane fluidity and transverse isotropy. In addition to exploring the geometrical and physical properties of these invariants, fundamental constitutively associated kinematical quantities are emphasized. On this basis, the effect on the energy density of assuming that the lipid bilayer is incompressible is considered. Lastly, a dimension reduction argument is used to extract an areal energy density per unit area from the three-dimensional energy density. This step explains the origin of spontaneous curvature in the areal energy density. Importantly, along with a standard contribution associated with the natural curvature of the lipid bilayer, our analysis indicates that constitutive asymmetry between the leaflets of the lipid bilayer gives rise to a secondary contribution to the spontaneous curvature.     

Resting-State fMRI Functional Connectivity Is Associated with Sleepiness,Imagery, and Discontinuity of Mind

Resting-state functional magnetic resonance imaging (rs-fMRI) is widely used to investigate the functional architecture of the healthy human brain and how it is affected by learning, lifelong development, brain disorders or pharmacological intervention. Non-sensory experiences are prevalent during rest and must arise from ongoing brain activity, yet little is known about this relationship. Here, we used two runs of rs-fMRI both immediately followed by the Amsterdam Resting-State Questionnaire (ARSQ) to investigate the relationship between functional connectivity within ten large-scale functional brain networks and ten dimensions of thoughts and feelings experienced during the scan in 106 healthy participants. We identified 11 positive associations between brain-network functional connectivity and ARSQ dimensions. ‘Sleepiness’ exhibited significant associations with functional connectivity within Visual, Sensorimotor and Default Mode networks. Similar associations were observed for ‘Visual Thought’ and ‘Discontinuity of Mind’, which may relate to variation in imagery and thought control mediated by arousal fluctuations. Our findings show that self-reports of thoughts and feelings experienced during a rs-fMRI scan help understand the functional significance of variations in functional connectivity, which should be of special relevance to clinical studies.     

Snx5, as a Mind bomb-binding protein, is expressed in hematopoietic and endothelial precursor cells in zebrafish

Notch signaling has an evolutionarily conserved function for cell fate determination and stem cell maintenance. Previously, we identified a novel component of the Notch signaling pathway in zebrafish, mind bomb, which encodes an E3 ubiquitin ligase essential for Notch signal activation. Further studies showed that Mind bomb(-/-) mouse embryos exhibited pan-Notch phenotypes in various tissues, suggesting that Mind bomb function is conserved in mammals. Therefore we sought to understand the various molecular partners of Mind bomb using yeast two-hybrid screening. In this search we identified Sorting nexin 5 (Snx5) as a novel interacting partner of Mind bomb. Furthermore we demonstrated that Snx5 colocalizes with Mind bomb in early endosomal compartments, suggesting that Snx5 is important for Mind bomb trafficking. In addition, we identified zebrafish orthologue of Snx5 and showed that snx5 is predominantly expressed in hematopoietic and endothelial precursor cells in zebrafish. We also found defects in hematopoiesis and blood vessel development in snx5 morpholino-injected embryos. Taken together, we show that Snx5, a novel interacting partner of Mind bomb, may have an essential role for cell fate determination in early development.     

The living cell as an ecosystem: Hierarchical analog and symmetry

Biology has benefited from a number of analogies and metaphors, in its attempt to rationalize the hierarchical structure of life's manifestations. Oft-cited is the comparison of a living organism to a society. Phenomenological similitude between the two extremes of the biological spectrum - the microscale of the cell and the macroscale of socioecosystems - has become strikingly evident, with the recent accumulation of empirical information on the metabolic infrastructure of the living cell. From the universal perspective of 'physiological determinism' reciprocal (or symmetric) relations are apparent at both levels of complexity. Unification of the biological hierarchy may follow a similar epistemological course to that in contemporary physics.     

Dryland residue and soil organic matter as influenced by tillage, crop rotation, and cultural practice

Novel management practices are needed to increase dryland soil organic matter and crop yields that have been declining due to long-term conventional tillage with spring wheat (Triticum aestivum L.)-fallow system in the northern Great Plains, USA. The effects of tillage, crop rotation, and cultural practice were evaluated on dryland crop biomass (stems + leaves) yield, surface residue, and soil organic C (SOC) and total N (STN) at the 0?C20?cm depth in a Williams loam (fine-loamy, mixed, superactive, frigid, Typic Argiustolls) from 2004 to 2007 in eastern Montana, USA. Treatments were two tillage practices [no-tillage (NT) and conventional tillage (CT)], four crop rotations [continuous spring wheat (CW), spring wheat-pea (Pisum sativum L.) (W-P), spring wheat-barley (Hordeum vulgaris L.) hay-pea (W-B-P), and spring wheat-barley hay-corn (Zea mays L.)-pea (W-B-C-P)], and two cultural practices [regular (conventional seed rates and plant spacing, conventional planting date, broadcast N fertilization, and reduced stubble height) and ecological (variable seed rates and plant spacing, delayed planting, banded N fertilization, and increased stubble height)]. Crop biomass and N content were 4 to 44% greater in W-B-C-P than in CW in 2004 and 2005 and greater in ecological than in regular cultural practice in CT. Soil surface residue amount and C and N contents were greater in NT than in CT, greater in CW, W-P, and W-B-C-P than in W-B-P, and greater in 2006 and 2007 than in 2004 and 2005. The SOC and STN concentrations at 0?C5?cm were 4 to 6% greater in CW than in W-P or W-B-P in NT and CT from 2005 and 2007. In 2007, SOC content at 10?C20?cm was greater in W-P and W-B-P than in W-B-C-P in CT but STN was greater in W-B-P and W-B-C-P than in CW in NT. From 2004 to 2007, SOC and STN concentrations varied at 0?C5?cm but increased at 5?C20?cm. Diversified crop rotation and delayed planting with higher seed rates and banded N fertilization increased the amount of crop biomass returned to the soil and surface residue C and N. Although no-tillage increased surface residue C and N, continuous nonlegume cropping increased soil C and N levels at the surface layer compared with other crop rotations. Continued return of crop residue from 2004 to 2007 may increase soil C and N levels but long-term studies are needed to better evaluate the effect of management practices on soil C and N levels under dryland cropping systems in the northern Great Plains.     

Human body odour, symmetry and attractiveness.

Several studies have found body and facial symmetry as well as attractiveness to be human mate choice criteria. These characteristics are presumed to signal developmental stability. Human body odour has been shown to influence female mate choice depending on the immune system, but the question of whether smell could signal general mate quality, as do other cues, was not addressed in previous studies. We compared ratings of body odour, attractiveness, and measurements of facial and body asymmetry of 16 male and 19 female subjects. Subjects wore a T-shirt for three consecutive nights under controlled conditions. Opposite-sex raters judged the odour of the T-shirts and another group evaluated portraits of the subjects for attractiveness. We measured seven bilateral traits of the subject's body to assess body asymmetry. Facial asymmetry was examined by distance measurements of portrait photographs. The results showed a significant positive correlation between facial attractiveness and sexiness of body odour for female subjects. We found positive relationships between body odour and attractiveness and negative ones between smell and body asymmetry for males only if female odour raters were in the most fertile phase of their menstrual cycle. The outcomes are discussed in the light of different male and female reproductive strategies.     

Chemoreception, symmetry and mate choice in lizards

Research on fluctuating asymmetry (FA)-mediated sexual selection has focused almost exclusively on visual signals and ignored chemical communication despite the fact that many species rely on chemical signals for attracting mates. Female mate choice based on visual traits appears to be rare in lizards. However, the femoral glands of male lizards produce pheromones which might transmit chemical information about an individual's developmental stability. Therefore, we hypothesized that mate choice may be based on chemical cues. We analysed the effect of the developmental stability levels of males on the attractiveness of males' scents to females in a laboratory experiment with the lizard Lacerta monticola. When we offered two males of similar body size, females preferentially associated with the scents of males with low FA in their femoral pores and also with the scents of males with a higher number of femoral pores. This suggested that the females were able to discriminate the FA of the males by chemical signals alone and that the females preferred to be in areas marked by males of high quality, thus increasing their opportunities of mating with males of high quality. We suggest that the quality and/or amount of male pheromones could communicate the heritable genetic quality of a male to the female and thereby serve as the basis for adaptive female choice in lizards.