Asymmetries of representation in the visual system of pigeons

Although functional asymmetries in the course of visual information processing have been known for a long time in humans as well as in non-human species, the structural basis of these asymmetries is largely unknown. We now report that due to an asymmetry of commissural projections in the pigeon the left nucleus rotundus of the ascending tectofugal visual system predominantly represents inputs from both eyes while the right nucleus rotundus mainly represents the contralateral left eye. We suggest that a comparable organization exists for several asymmetries in humans. A representation of both hemifields can provide the dominant hemisphere with direct access to all stimulus features when objects cross the vertical meridian.     

Electrophysiologic analysis of the representation of the somatosensory system in the dogfish midbrain tectum

Evoked responses in the dogfish tectum opticum were studied during electrical stimulation of the spinal cord, its dorsal roots and ramus ophthalmicus of the facial nerve. Recordings were obtained from different depth as well as from different points on the tectum surface. Evoked responses could be detected mainly on the contralateral side of the tectum opticum either as slow positive (spinal cord stimulation) or negative-positive (facial stimulation) waves which were preceeded by one or two fast, probably, presynaptic deflections and followed by a very slow low-amplitude negative wave. The evoked responses possessed the properties of tectal postsynaptic responses, being somatotopically distributed on the surface and reversely represented in the inner part of the tectal lamina. Projections of different inputs were widely overlapped, but specific areas of maximal activity were presented. These findings evidence that the tectum opticum performs a double function: a primary projecting and an integrative centre.     

Morphological studies on the human heart conduction system

An attempt has been made to demonstrate morphological equivalents of electrocardiographically determined conduction disturbances in the human heart. In 50% of our cases an authentic morphological change was found. In 25% the correlation remained doubtful, and in another 25% there was no connection. The highest coincidence was found in chronic left bundle branch block and in dissecting aneurysms causing hemopericardium. The correlation between function and morphology is very loose in patients who have undergone cardiac surgery. Etiology is discussed only marginally; ischemia is the predominant feature.     

Morphological organization of the globus pallidus-subthalamic nucleus system studied in organotypic cultures

The morphological organization of the globus pallidus (GP), the subthalamic nucleus (STN), and the pallidosubthalamic projection was studied in organotypic cultures. Coronal slices from the GP, the STN, the striatum (CPu), and the cortex (Cx) were taken from the rat after postnatal days 0-2 and grown for 2 or 5-6 weeks. For analysis, immunocytochemistry against glutamate (GLU), parvalbumin (PV), and calretinin (CR) was combined with confocal microscopy. After 2 weeks in vitro, the STN showed a densely packed, homogeneous GLU-immunoreactive (ir) cell population. Pallidal GLU-ir neurons were heterogeneous, consisting of large-sized weakly GLU-ir neurons and small-sized intensively GLU-ir neurons. After 5-6 weeks in vitro, pallidal axons had radiated from numerous large-sized PV-ir cells and selectively innervated the STN, where they heavily ramified. Cultured STN neurons were not stained for PV; however, multipolar intensely PV-ir neurons were located at the border of the STN with their dendrites oriented towards the STN. Double labeling for PV and CR in both mature cultures and in the adult rat revealed that the culture CR-ir neurons from the GP, the Cpu, and from areas adjacent to the STN were different from cultured PV-ir neurons and their morphologies and distribution corresponded to that in vivo. These results demonstrate that 1) cultured CP and STN neurons display similar morphologies found in in vivo, 2) PV-ir pallidal neurons heavily and selectively innervate the STN; 3) there is a specific class of STN border neurons; and 4) in contrast to the in vivo situation, most cultured STN neurons are PV-negative.     

What can we learn from the morphology of Hebrew? A masked-priming investigation of morphological representation.

[Correction Notice: An erratum for this article was reported in Vol 23(5) of Journal of Experimental Psychology: Learning, Memory, and Cognition (see record 2008-09898-001). On page 854, two Hebrew words are missing from Appendix F. The corrected Appendix appears with the erratum.] All Hebrew words are composed of 2 interwoven morphemes: a triconsonantal root and a phonological word pattern. The lexical representations of these morphemic units were examined using masked priming. When primes and targets shared an identical word pattern, neither lexical decision nor naming of targets was facilitated. In contrast, root primes facilitated both lexical decisions and naming of target words that were derived from these roots. This priming effect proved to be independent of meaning similarity because no priming effects were found when primes and targets were semantically but not morphologically related. These results suggest that Hebrew roots are lexical units whereas word patterns are not. A working model of lexical organization in Hebrew is offered on the basis of these results. (A correction concerning this article appears in Journal of Experimental Psychology: Learning, Memory, and Cognition, 1997, Vol 23(5), 1189–1191. On page 854 of the current issue, two Hebrew words are missing from Appendix F. The corrected Appendix appears in this correction.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Morphological correlates of neural regeneration in the feeding system of Aplysia californica after central nervous system lesions

Specific direct bradykinin (BK) binding and competitive inhibition was detected in human neutrophil and peripheral blood mononuclear cell (PBMC) detergent solubilized extracts and purified plasma membranes using in vitro radioreceptor ligand binding. Scatchard analyses of [125I]-BK binding revealed an equilibrium dissociation constant (Kd) of 2.9 x 10(-11) M for neutrophils and 5.6 x 10(-11) M for PBMC using [des-arg9]-BK a B1 agonist; 2.6 x 10(-11) M for neutrophils, 6.2 x 10(-11) M for PBMC with BK a B2 agonist; 5.4 x 10(-11) M for PBMC using Lys-BK a B2 agonist. The number of binding sites (Bmax) was calculated to be 0.113 fM/microgram protein (720 receptors per cell) for neutrophils and 0.200 fM/microgram protein (1289 receptors per cell) for PBMC with the B1 agonist while with the B2 agonists the values were 0.128 fM/microgram protein (818 receptors per cell) for neutrophils and 0.157 fM/microgram protein (1005 receptors per cell) for PBMC with BK, and 0.293 fM/microgram protein (1870 receptors per cell) with Lys-BK for PBMC. In a competitive binding inhibition assay using neutrophil and PBMC glycerol purified plasma membranes, high affinity binding in the nanomolar range was detected to Lys-BK and BK but with [des-arg9]-BK a 10-100 fold lower order affinity was observed this being indicative of pharmacologically defined B2 characteristics.     

A deficit in the short-term retention of lexical-semantic information: Forgetting words but remembering a story.

This article examines the long-term memory of a 73-yr-old brain-damaged patient, AB, who had previously been reported to have problems in the short-term retention of word meanings. The authors found that AB had a problem not only in the short-term but also in the long-term retention of lexical-semantic information. AB, however, had no problem in the long-term retention of other kinds of information (pictures, shapes, propositional information). This pattern of results was interpreted as evidence that lexical-semantic representations have their own specific memory resources that are involved in the retention of the corresponding representations across different time intervals (e.g., they are involved in short-term as well as long-term retention). Implications for models of memory are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The morphology and thermal stability of the Cu−Cu2S eutectic system

A study has been made of the morphology of unidirectionally solidified and as-cast Cu?Cu₂S eutectic alloys. The growth morphology of the eutectic is rod-like, consisting of rods of Cu₂S which are circular in cross-section in a copper matrix. Following solidification, the Cu₂S rods neck down, pinch off, and spheroidize in a sequence which has previously been termed “ovulation”. The spheroids subsequently coarsen rapidly by a process which is controlled by the volume diffusion of sulfur in copper.     

国内外钢铁及合金牌号统一数字代号表示方法综述

对国内外钢铁及合金牌号统一数字代号表示方法进行介绍.     

Spatial representation in body coordinates: Evidence from errors in remembering positions of visual and auditory targets after active eye, head, and body movements.

Eight participants were presented with auditory or visual targets and then indicated the target's remembered positions relative to their head eight seconds after actively moving their eyes, head or body to pull apart head, retinal, body, and external space reference frames. Remembered target position was indicated by repositioning sounds or lights. Localization errors were found related to head-on-body position but not of eye-in-head or body-in-space for both auditory (0.023 dB/deg in the direction of head displacement) and visual targets (0.068 deg/deg in the direction opposite to head displacement). The results indicate that both auditory and visual localization use head-on-body each information, suggesting a common coding into body coordinates--the only conversion that requires this information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Handedness and the cerebral representation of speech

Hand preferences vary not discretely but continuously and the continuum of preference is closely and reliably linked with a continuous roughly Normal distribution of differences between the hands in skill. Questions about handedness can be usefully formulated in terms of the distribution of differences in skill and in terms of the theshold or criterion which divided those likely to be classified as right handers from those likely to be classified as left handers. A theory of the origin of hand preferences suggests that three factors are involved. The first in non-genetic accidental variation in the development of the two sides of the body in all bilaterally symmetrical species showing limb preferences. The second in a systematic bias to the right hand in man, probably linked with the tendency for the left hemisphere to serve speech. The third is socio-cultural factors affecting the expression of sinistrality. An explanation of the relation between hand preference and cerebral speech laterality requires the assumption that in some individuals the factor biasing speech to the left hemisphere is absent. This would imply that the bias is not a universal species character but that it is subject to genetic variation. Making the simplest possible further assumptions that in the absence of bias, the laterality of handedness and of cerebral speech are independent and each governed by chance, it is possible to account for the distribution of right and left handers with dysphasias following right and left unilateral cerebral lesions.