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At least 91 records · Page 5Linked to original sources
PubMed2001

Role of the superior colliculus in analyses of space: superficial and intermediate layer contributions to visual orienting, auditory orienting, and visuospatial discriminations during unilateral and bilateral deactivations.

The superior colliculus (SC) has been implicated in spatial analyses of the environment, although few behavioral studies have explicitly tested this role. To test its imputed role in spatial analyses, we used a battery of four spatial tasks combined with unilateral and bilateral cooling deactivation of the upper and intermediate layers of the superior colliculus. We tested the abilities of cats to orient to three different stimuli: (1) moving visual, (2) stationary visual, (3) stationary white-noise aural. Furthermore, we tested the ability of the cats to discriminate the relative spatial position of a landmark. Unilateral cooling deactivation of the superficial layers of the SC induced a profound neglect of both moving and stationary visual stimuli presented in, and landmark objects located within, the contralateral hemifield. However, responses to auditory stimuli were unimpaired. Unilateral cooling deactivation of both the superficial and intermediate layers induced a profound contralateral neglect of the auditory stimulus. Additional and equivalent deactivation of the opposite SC largely restored orienting to either moving visual or auditory stimuli, and restored landmark position reporting to normal levels. However, during bilateral SC deactivation, orienting to the static visual stimulus was abolished throughout the entire visual field. Overall, unilateral SC deactivation results show that the upper and intermediate layers of the SC contribute in different ways to guiding behavioral responses to visual and auditory stimuli cues. Finally, bilateral superior colliculus deactivations reveal that other structures are sufficient to support spatial analyses and guide visual behaviors in the absence of neural operations in the superior colliculus, but only under certain circumstances.

Acoustic Stimulation↗
PubMed1991

Orientation in birds. Satellite tracking: a new method in orientation research.

The study of bird migration by satellite tracking began in the 1980s, after transmitters had become sufficiently small to allow the monitoring of larger migrating species. The initial studies in this direction were all successful with respect to establishing this method (Section 2) of elucidating new migration patterns and various aspects of orientation. These pilot studies are summarized in Section 3, Table 1, Figures 1-4. We believe that studies on avian orientation and navigation will, in general, greatly benefit from satellite tracking if some prerequisites are fulfilled and adequate experiments planned (Section 4). In future studies, smaller transmitters with increased life expectancies are needed, and possible effects of these transmitters on bird behaviour must be examined. Considerable improvement of satellite tracking in avian orientation research is to be expected, along with the development of a new generation of satellites allowing communication between satellites and transmitters (Sections 4, 5).

Animals↗
PubMed1998

Effective serial measurement of cognitive orientation in rehabilitation: the Orientation Log.

OBJECTIVE: To introduce a brief quantitative measure of cognitive orientation (to place, time, and situation) developed for daily use at bedside with rehabilitation inpatients. The Orientation Log (O-Log) is a 10-item scale that allows for partial credit based on responsiveness to logical, multiple-choice, or phonemic cueing. It is formatted for rapid visual analysis of orientation trends that can be used to evaluate pharmacologic and cognitive-behavioral interventions. DESIGN: Descriptive study of the O-Log's reliability (interrater and internal consistency). SETTING: Inpatient rehabilitation center affiliated with a large university medical school. PATIENTS: Fifteen neurorehabilitation inpatients. RESULTS: For individual items, Spearman rho interrater reliability coefficients ranged from .851 to 1.00. The interrater reliability of the total score was .993. O-Log internal consistency (coefficient alpha) was .922. CONCLUSIONS: The O-Log is a reliable and easily administered scale that promises to be a useful tool in monitoring cognitive recovery during rehabilitation.

Adolescent↗
PubMed2000

The neural correlates of orienting: an integration of fMRI and skin conductance orienting.

In fMRI studies, the averaging of neural activity across multiple trials might obscure important psychophysiological subprocesses. The orienting response (OR) is a distinctive subprocess signalling the active orientation of attention towards potentially significant events. We sought to elucidate fMRI activity associated with visual stimuli that did or did not evoke simultaneously recorded electrodermal ORs (using customised skin conductance recording). 'With-OR' stimuli were associated with significant activity in the hippocampus, anterior cingulate and ventromedial prefrontal cortex. Averaged analysis revealed activity only in the expected visual circuits. Our results suggest that potentially significant stimuli (with-OR) activate different functional networks to familiar (without-OR) stimuli, and that orienting may therefore be an informative subprocess to consider in cognitive fMRI studies.

Attention↗
PubMed1991

Reaction time to a word in different orientations with letters rotated separately in different orientations.

Six men and six women were timed as they made judgments about a word whose line of letters and individual letters were separately turned in different angular orientations. The subjects were asked to indicate by manual key-pressing responses whether the letters in the word were normal letters or reflected, mirror-image letters. Analysis showed that (1) reaction time (RT) was slower for reflected letters than for normal letters, and for subjects using the left (nondominant) hand rather than the right (dominant) hand for responding to normal letters. (2) RT generally increased in relation to the deviation of the individual letters from normal upright orientation but increased more reliably for normal than for reflected letters. (3) Although there were exceptions, RT for words composed of normal letters generally increased in relation to the deviation of the individual letters from normal upright, regardless of the orientation of the line of letters.

Adult↗
PubMed1976

The differential impact of work-oriented vs. communication-oriented juvenile correction programs upon recidivism rates in delinquent males.

This study examined recidivism rates in work-oriented (N = 30) and communication-oriented (N = 30) juvenile delinquency programs for males. Both groups were matched for age, ethnic origin, educational achievement, and reading scores. Chi-square analyses indicated significant differences in recidivism rates between groups in both residential (chi2 - 6.71, df = 1, p less than .01) and aftercare (chi2 = 3.89, df = 1, p less than .05) programs. In each phase of the treatment program, recidivism was highest in the work-oriented group. The results suggested that (a) facilitation of family interaction and communication is related closely to successful treatment of the delinquent and consequent recidivism; (b) group counseling that provides the youth and parents an opportunity to learn better communication skills appears to improve family cohesion and solidarity; and (c) newer therapeutic approaches in delinquency should concentrate on filial and family-type therapies.

Adolescent↗
PubMed1998

TM-AFM Threshold Analysis of Macromolecular Orientation: A Study of the Orientation of IgG and IgE on Mica Surfaces.

Adsorption and orientation properties of two different types of immunoglobulin molecules on derivatized and native mica surfaces were investigated using TM-AFM. The analyses included height measurements at two different pH values and a new technique, presented here as threshold analysis, which displays the outer mantle shape of an adsorbed protein. A major difference in preferential orientation is observed upon comparing the adsorption of the two proteins onto the different surfaces. The characteristics of both the adsorbed immunoglobulin and the surface are important for any preferential orientation of the adsorbed protein. Copyright 1998 Academic Press.

Journal Article↗
PubMed1994

The orientation of spin-probes attached to Cys374 on actin in oriented gels.

Changes in protein orientation are thought to be involved in the generation of force that occurs in active muscle. To address the possibility that such changes occur in the actin filament, a spin label was attached to Cys374 of actin and its orientation was measured for filaments that were aligned in capillaries. In the best aligned samples the label was found in two populations, one with a narrow distribution of angles centered at an average angle of 36 (+/- 4) degrees, and a second in a broad distribution centered at an average angle of 45(+/- 4) degrees. The birefringence of the samples was high and X-ray diffraction patterns showed that the actin filaments were well aligned with average angles similar to the population of the better aligned spin labels, suggesting that the more disordered population of probes arose from either disorder of the probe relative to the protein, or from disorder of a local portion of the protein. When myosin subfragment-1 (S-1) was also included with the actin, molar ratio 1 S-1 to 4 actins, there was little change in the angular distribution of either of the two probe populations. We conclude that the binding of the myosin head does not produce appreciable alterations in the orientation of this domain.

Actins↗
PubMed1978

Studies on the orientations of the mitochondrial redox carriers. I. Orientation of the hemes of cytochrome c oxidase with respect to the plane of a cytochrome oxidase-lipid model membrane.

The liganded derivatives of mitochondrial cytochrome c oxidase have been prepared in hydrated oriented multilayers of membranous cytochrome c oxidase. The optical spectra of the liganded derivatives recorded at an angle of 45 degrees between the incident light beam and the normal to the planes of the membranes in the multilayers show dichroic ratios of almost 2 in the visible region and 1.2-1.4 in the Soret region. The dichroic ratios were found to be similar for both cytochromes a and a3. Electron paramagnetic resonance spectra of the azide, sulfide, and formate complexes of cytochrome c oxidase obtained as a function of the orientation of the applied magnetic field relative to the planes of the membranes in the multilayer confirm the optical data and demonstrate that both hemes of cytochrome c oxidase are oriented such that the angle between the heme normal and the membrane normal is approximately 90 degrees.

Animals↗
PubMed2004

2D TRIPLE in orientationally disordered samples--a means to resolve and determine relative orientation of hyperfine tensors.

The two-dimensional (2D) TRIPLE experiment provides correlations between electron-nuclear double resonance (ENDOR) frequencies that belong to the same electron-spin manifold, M(S), and therefore allows to assign ENDOR lines to their specific paramagnetic centers and M(S) manifolds. This, in turn, also provides the relative signs of the hyperfine couplings. So far this experiment has been applied only to single crystals, where the cross-peaks in the 2D spectrum are well resolved with regular shapes. Here we introduce the application of the 2D TRIPLE experiment to orientationally disordered systems, where it can resolve overlapping powder patterns. Moreover, analysis of the shape of the cross-peaks shows that it is highly dependent on the relative orientation of the hyperfine tensors of the two nuclei contributing to this particular peak. This is done initially through a series of simulations and then demonstrated experimentally at a high field (W-band, 95 GHz). The first example concerned the (1)H hyperfine tensors of the stable radical alpha,gamma-bisdiphenylene-beta-phenylallyl (BDPA) immobilized in a polystyrene matrix. Then, the experiment was applied to a more complex system, a frozen solution of Cu(II)-bis(2,2':6',2'' terpyridine) complex. There, the 2D TRIPLE experiment was combined with the variable mixing time (VMT) ENDOR experiment, which determined the absolute sign of the hyperfine couplings involved, and orientation selective ENDOR experiments. Analysis of the three experiments gave the hyperfine tensors of a few coupled protons.

Journal Article↗
PubMed2000

Orientation of Phalerisida maculata Kulzer (Coleoptera, Tenebrionidae) in sandy beaches of the Chilean coast. Orientation of Phalerisida maculata in sandy beaches.

The orientation stimuli of adult individuals of the beetle Phalerisida maculata Kulzer (Coleoptera, Tenebrionidae) over the beach surface, were studied at two sandy beaches of the chilean coast approximately 1300 km apart, Apolillado (ca. 29 degrees S) and Playa Universitaria de Mehuín (ca. 39 degrees S). Phalerisida maculata did not orient by astronomic cues such as the sun and moon, nor by the terrestrial magnetic field. Both populations showed positive scototaxis, and oriented downward on slopes with dry sediments, and upwards on slopes with wet sediments.

Journal Article↗
PubMed2002

Teaching target-oriented and diversity-oriented organic synthesis at Harvard University.

Diversity-oriented synthesis presents many formidable challenges to the practitioners of synthetic organic chemistry. Those challenges include the effective teaching of this new and evolving discipline to ensure that students are well positioned to begin exploring its full potential. Fortunately, the teaching of synthetic organic chemistry has a rich history in the context of target-oriented synthesis, and this precedent can serve as a strong foundation for meeting the challenges of teaching diversity-oriented synthesis.

Alkylation↗
PubMed2001

Field- and phage-induced dipolar couplings in a homodimeric DNA quadruplex: relative orientation of G.(C-A) triad and G-tetrad motifs and direct determination of C2 symmetry axis orientation.

We present a new NMR procedure for determining the three-dimensional fold of C2-symmetric nucleic acid homodimers that relies on long-range orientational constraints derived from the measurement of two independent sets of residual dipolar couplings under two alignment conditions. The application is demonstrated on an (15)N/(13)C-enriched deoxyoligonucleotide sequence, d(G-G-G-T-T-C-A-G-G), shown previously to dimerize into a quadruplex in solution and form a pair of G.(C-A) triads and G-G-G-G tetrads (G-tetrad) motifs. One-bond (1)H-(15)N ((1)D(NH)) and (1)H-(13)C ((1)D(CH)) residual dipolar couplings have been measured between nuclei in the bases of these motifs using bacteriophage as an ordering medium, and under direct magnetic field alignment (800 MHz). By combining the two dipolar data sets in an order matrix analysis, the orientation of the G.(C-A) triad relative to the G-tetrad within a contiguous monomeric unit can directly be determined, even in the presence of interstrand/intrastrand NOE ambiguity. We further demonstrate that the orientation of the C2-axis of molecular symmetry in the homodimer relative to the G.(C-A) triad and G-tetrad motifs can unambiguously be determined using the two sets of independent dipolar coupling measurements. The three-dimensional fold of the homodimer determined using this procedure is very regular and in excellent agreement with a previously determined high-resolution NOE-based NMR structure, where interstrand/intrastrand NOEs were treated as ambiguous and where noncrystallographic symmetry constraints were implicitly imposed during the structure calculation.

Base Pairing↗
PubMed1995

Covert orienting biases in scene-based reference frames: orientation priming and visual field differences.

Performance advantages for stimuli presented in the right versus the left visual field have been found in a variety of attentional tasks. Such advantages were exploited in the present set of studies to examine orientation priming and directional biases in retinotopic and scene-based spatial coordinates. The results demonstrate that directional biases occur within spatial coordinates across orientation transformations that dissociate retinotopic from scene-based visual half fields. The results are discussed concerning the representation of spatial maps in higher visual analysis, the role of spatial coordinates in guiding covert orienting, and methods of presenting stimuli in the right or left visual field to test for functional hemispheric asymmetries.

Adult↗
PubMed1991

Trunk orientation as the determining factor of the 'contralateral' deficit in the neglect syndrome and as the physical anchor of the internal representation of body orientation in space.

The present study examines which egocentric coordinate system determines the border between the disturbed 'contralateral' and the normal 'ipsilateral' side in patients with hemineglect. Based on the observation of significantly longer reaction times for saccades towards stimuli presented in the left visual field (LVF) in right brain-damaged patients with hemineglect, stimuli were presented randomly to the LVF or RVF and the corresponding saccadic reaction times (SRTs) were compared. Beginning with the standard body position generally used for the investigation of neglect patients, where the midlines of head, trunk and visual field are parallel and oriented straight towards the middle of the projection screen, the spatial relation between orientation of head and trunk midlines and location of the target stimuli was systematically varied while holding the retinal projection of the stimuli constant. The deficit in SRTs towards the LVF in 4 right brain-damaged patients with left-sided hemineglect could be compensated for by turning the patients' trunk to the left, such that both LVF and RVF-stimuli were projected to the right, ipsilateral side of trunk space. The results suggest that the spatial orientation of the trunk midline divides our normal perception of space into an egocentric 'left' and an egocentric 'right' sector and seems to be the decisive factor for determining the neglected 'contralateral' part of space in patients with brain-damage. They indicate that the trunk midline constitutes the physical anchor for calculation of the internal egocentric coordinate frame for representing body position with respect to external objects. The hypothesis of Ventre et al. (1984) that deficient reactions to contralaterally located stimuli in neglect patients could be the result of a displacement of these egocentric coordinates towards the non-neglected, ipsilateral side is discussed.

Adult↗
PubMed1995

Spatial orientation in the lamprey. II. Visual influence on orientation during locomotion and in the attached state

The responses of attached lampreys to homogeneous visual stimulation and the role of visual stimuli in orientation during locomotion were investigated. Experiments were performed by video recording the responses of intact and lesioned animals to illumination. The following results were obtained. 1. In lampreys attached with their sucker mouth to the bottom of the aquarium, illumination of one eye evoked several possible motor responses (ordered after mean latency): (a) movement of the illuminated eye downwards, and the contralateral eye upwards; (b) rotation of the body around the longitudinal axis, with the illuminated side tilting downwards; (c) deviation of the caudal part of the anterior dorsal fin in the contralateral direction (away from the light); and (d) flexion of the neck and body towards the side of illumination. 2. Illumination of one eye in attached lampreys often resulted in detachment and subsequent movement in a direction away from the light source (negative phototaxis). This response was not related to the degree of roll tilt before detachment, so the negative phototaxis does not appear to be a consequence of the vestibular stimulation. 3. Negative phototaxis was also seen during locomotion: lampreys turned through 180 ° when they approached a brightly illuminated area. Photostimulation also affected their orientation in the transverse plane during swimming. Illumination of one eye from the side induced a roll movement, so that the illuminated side tilted downwards and the dorsum of the lamprey became turned towards the light. This is similar to the 'dorsal light response' of fish and shows that vision also plays a role in postural control in lampreys. 4. The behaviour of blinded animals differed strikingly from that of intact ones. Whereas intact animals preferentially swam close to the bottom, along horizontal trajectories, blinded animals showed episodes of continuous swimming upwards, near the water surface. During horizontal swimming, their orientation in the transverse plane remained normal, with the dorsal side up.

Journal Article↗
PubMed2004

Tilt angles of transmembrane model peptides in oriented and non-oriented lipid bilayers as determined by 2H solid-state NMR.

Solid-state NMR methods employing (2)H NMR and geometric analysis of labeled alanines (GALA) were used to study the structure and orientation of the transmembrane alpha-helical peptide acetyl-GWW(LA)(8)LWWA-amide (WALP23) in phosphatidylcholine (PC) bilayers of varying thickness. In all lipids the peptide was found to adopt a transmembrane alpha-helical conformation. A small tilt angle of 4.5 degrees was observed in di-18:1-PC, which has a hydrophobic bilayer thickness that approximately matches the hydrophobic length of the peptide. This tilt angle increased slightly but systematically with increasing positive mismatch to 8.2 degrees in di-C12:0-PC, the shortest lipid used. This small increase in tilt angle is insufficient to significantly change the effective hydrophobic length of the peptide and thereby to compensate for the increasing hydrophobic mismatch, suggesting that tilt of these peptides in a lipid bilayer is energetically unfavorable. The tilt and also the orientation around the peptide axis were found to be very similar to the values previously reported for a shorter WALP19 peptide (GWW(LA)(6)LWWA). As also observed in this previous study, the peptide rotates rapidly around the bilayer normal, but not around its helix axis. Here we show that these properties allow application of the GALA method not only to macroscopically aligned samples but also to randomly oriented samples, which has important practical advantages. A minimum of four labeled alanine residues in the hydrophobic transmembrane sequence was found to be required to obtain accurate tilt values using the GALA method.

Alanine↗
PubMed1992

Psychometric properties of the Learning-Orientation Grade-Orientation II Scale.

The Learning-Orientation Grade-Orientation Scale of Eison, Pollio, and Milton was administered to 85 college students and analyzed to study the psychometric properties of the instrument. Scale means were consistent with those usually reported. Cronbach coefficients alpha for 5 of the 6 scales ranged from .58 to .70; however, the coefficient alpha for learning-orientation attitude scale was questionably low (.29). Item analyses and factor analyses support the continued use of at least 5 of the 6 scales measured by the inventory.

Achievement↗