Hippocampal and cortical function in a maze devoid of left and right turns

1979 ◽  
Vol 23 (3) ◽  
pp. 601-603 ◽  
Author(s):  
Robert Thompson
Keyword(s):  
Cortical Function ◽  
Left And Right ◽  
Right Turns

The Effect of Driving Environments on Simulator Sickness

2007 ◽  
Vol 51 (18) ◽  
pp. 1232-1236 ◽  
Author(s):  
Ronald R. Mourant ◽  
Prasanna Rengarajan ◽  
Daniel Cox ◽  
Yingzi Lin ◽  
Beverly K. Jaeger
Keyword(s):  
Optic Flow ◽  
Substantial Contribution ◽  
Simulator Sickness ◽  
Driving Simulators ◽  
City Environment ◽  
Rate Of Increase ◽  
Left And Right ◽  
The City ◽  
Right Turns

In order to be an effective tool for driver evaluation and education, driving simulators need to be better designed to reduce simulator sickness. This study investigated driving in four environments (country, suburban, city, and curves) using a simulator. When driving on straight roads (city and suburban environments) subjects reported less simulator sickness then driving in the city environment (which included left and right turns) and on curves. A mini-SSQ was used to measure the accumulation of simulator sickness over trials. From trial 1 to trial 5, reported simulator sickness increased linearly. From trial 5 through 8, the rate of increase in simulator sickness decreased. We suggest that the rapid and distorted optic flow experienced while executing turns and driving on curves in driving simulators makes a substantial contribution to simulator sickness.

scholarly journals Asymmetries in Ground Reaction Forces During Turns by Elite Slalom Alpine Skiers Are Not Related to Asymmetries in Muscular Strength

2021 ◽  
Vol 12 ◽  
Author(s):  
Jan Ogrin ◽  
Nejc Šarabon ◽  
Mads Kjær Madsen ◽  
Uwe Kersting ◽  
Hans-Christer Holmberg ◽  
...  
Keyword(s):  
Muscular Strength ◽  
Satellite System ◽  
The Body ◽  
Ground Reaction Forces ◽  
Alpine Skiing ◽  
Reaction Forces ◽  
Left And Right ◽  
Alpine Skiers ◽  
Global Navigation Satellite ◽  
Right Turns

The ground reaction forces (GRF) associated with competitive alpine skiing, which are relatively large, might be asymmetric during left and right turns due to asymmetries in the strength of the legs and torso and the present investigation was designed to evaluate this possibility. While skiing a symmetrical, 20-gate slalom course, the asymmetries of 9 elite alpine skiers were calculated on the basis of measurements provided by inertial motion units (IMU), a Global Navigation Satellite System and pressure insoles. In addition, specialized dynamometers were utilized to assess potential asymmetry in the strength of their legs and torso in the laboratory. In total, seven variables related to GRF were assessed on-snow and eight related to strength of the legs and torso in the laboratory. The asymmetries in these parameters between left and right turns on snow were expressed in terms of the symmetry (SI) and Jaccard indices (JI), while the asymmetries between the left and right sides of the body in the case of the laboratory measurements were expressed as the SIs. The three hypotheses to be tested were examined using multivariable regression models. Our findings resulted in rejection of all three hypotheses: The asymmetries in total GRF (H1), as well as in the GRF acting on the inside and outside legs (H2) and on the rear- and forefeet GRF (H3) during left and right turns were not associated with asymmetries in parameters related to muscular strength. Nevertheless, this group of elite slalom skiers exhibited significant asymmetry between their right and left legs with respect to MVC during ankle flexion (0.53 ± 0.06 versus 0.60 ± 0.07 Nm/kg, respectively) and hip extension (2.68 ± 0.39 versus 2.17 ± 0.26 Nm/kg), as well as with respect to the GRFs on the inside leg while skiing (66.8 ± 7.39 versus 76.0 ± 10.0 %BW). As indicated by the JI values, there were also large asymmetries related to GRF as measured by pressure insoles (range: 42.7–56.0%). In conclusion, inter-limb asymmetries in GRFs during elite alpine skiing are not related to corresponding asymmetries in muscular strength. Although our elite athletes exhibited relatively small inter-limb asymmetries in strength, their asymmetries in GRF on-snow were relatively large.

Response Learning versus Place Learning

1956 ◽  
Vol 2 (3) ◽  
pp. 401-406 ◽  
Author(s):  
Anthony Davids
Keyword(s):  
Test Trial ◽  
Place Learning ◽  
Albino Rats ◽  
Preliminary Training ◽  
Response Learning ◽  
Starting Point ◽  
Left And Right ◽  
The Right ◽  
Right Turns

The purpose of this study, modified from an earlier experiment by Tolman, Ritchie, and Kalish, was to test Hull's theory of response learning and Tolman's theory of place learning. 10 female albino rats were trained to run an elevated T-maze. Preliminary training consisted of 6 trials per day for 4 days, emphasizing the alternation of left and right turns on successive trials. The experiment proper commenced on the fifth day and continued until each rat had reached the criterion of 11 out of 12 successive errorless trials of turning to the right, with food serving as the reinforcement. After reaching the criterion, each rat was given a test trial which consisted of a run from a new starting point, located exactly 180° from the original starting point, to either the previously rewarded goal box now located to the animal's left or to the previously unrewarded goal box now located to the animal's right. It was found that on the test trials 8 of the rats ran to the previously rewarded place and only 2 made the previously rewarded response of turning to the right. This proportion is different from chance at the .055 level. It was concluded that in situations in which there are marked intra-maze cues and marked extra-maze cues there is some evidence that place learning is probably simpler than response learning. The evidence points consistently, however, to the interpretation that the animals learned something more than merely the place where the food was to be found.

LEAVING AN UNKNOWN MAZE USING AN ERROR-PRONE COMPASS

2010 ◽  
Vol 20 (03) ◽  
pp. 307-325 ◽  
Author(s):  
TOM KAMPHANS ◽  
ELMAR LANGETEPE
Keyword(s):  
Limited Resources ◽  
Left And Right ◽  
Right Turns

Imagine you are trapped in a maze of caves. All you have is an old rusty compass and barely enough light to read it. How much inaccuracy can you allow to ensure that you can leave the maze? Or you are walking in a maze of hedgerows that are on the whole orthogonal. Can you find the exit by counting left and right turns? We consider the problem of escaping from an unknown polygonal maze under limited resources and errors in inputs and motion. It is well known that the Pledge algorithm always finds a path out of an unknown maze without any means of orientation—provided that such a path exists—but it relies on fact that inputs and motions are correct.

Bicycle accidents and drivers' visual search at left and right turns

1996 ◽  
Vol 28 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Heikki Summala ◽  
Eero Pasanen ◽  
Mikko Räsänen ◽  
Jukka Sievänen
Keyword(s):  
Visual Search ◽  
Left And Right ◽  
Right Turns

Abstract W P130: Recovery of "Cortical Deficits" after Thalamic Stroke Related to Changes in Functional Connectivity in Cortex

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Argye E Hillis ◽  
Andreia Faria
Keyword(s):  
Functional Connectivity ◽  
Normal Values ◽  
Motor Impairment ◽  
Cognitive Testing ◽  
Precentral Gyrus ◽  
Z Score ◽  
Resting State Functional Connectivity ◽  
Cortical Function ◽  
Thalamic Stroke ◽  
Left And Right

Background: Thalamic stroke can cause various “higher cortical” deficits, including impaired naming after left thalamic stroke and impaired emotional empathy after right thalamic stroke. Impaired naming is also associated with left inferior temporal gyrus (ITG) lesions, and impaired empathy with right ITG lesions. Deficits after thalamic stroke may be due to diaschisis, or dysfunction of cortex due to impaired input from thalamus. Changes in cortical function can be explored using resting state functional connectivity MRI (rsfcMRI). We tested the hypotheses that in patients with acute ischemic stroke restricted to left or right thalamus with naming/empathy impairment but no motor impairment, connectivity between left and right ITG (but not between left and right precentral gyrus; PrG) is (1) significantly different from that of controls within 3 days of stroke, and (2) normalizes over time with recovery of the naming/empathy impairment. Methods: We evaluated 7 patients with ischemic strokes restricted to the thalamus within 3 days of onset and 7 age-matched controls with rsfcMRI, structural and perfusion MRI, and testing of naming and empathy. Three patients had repeat imaging and cognitive testing. Results: Stroke patients showed significantly higher connectivity between left and right ITG at onset compared to controls (z score= 2.21 vs. 1.42; p=0.04), but showed no difference in connectivity between left and right PrG (z score= 1.87 vs. 1.70; p=0.53). Three patients who showed recovery of naming/empathy showed change in homologous connectivity toward more normal values in ITG, but less change (or change toward less normal values) in PrG from Time 1 to Time 2 (see Figure). Conclusion: In patients with thalamic infarcts, recovery of naming or empathy is associated with “normalization” of homologous connectivity in cortical regions thought to be critical for those cortical functions (e.g. ITG), consistent with recovery from diaschisis.

Upward direction, mental rotation, and discrimination of left and right turns in maps

Cognition ◽  
1984 ◽  
Vol 18 (1-3) ◽  
pp. 161-193 ◽  
Author(s):  
Roger N. Shepard ◽  
Shelley Hurwitz
Keyword(s):  
Mental Rotation ◽  
Upward Direction ◽  
Left And Right ◽  
Right Turns

The three-dimensional structure of frozen-hydrated left- and right-handed forms of bacterial flagellar filaments from an identical serotype

1986 ◽  
Vol 44 ◽  
pp. 298-299
Author(s):  
S. Trachtenberg ◽  
D. J. DeRosier
Keyword(s):  
Ionic Strength ◽  
Basal Body ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Protein Species ◽  
Liquid Environment ◽  
Bacterial Flagellum ◽  
Left And Right ◽  
Rotary Motor ◽  
Helical Parameters

The bacterial cell is propelled through the liquid environment by means of one or more rotating flagella. The bacterial flagellum is composed of a basal body (rotary motor), hook (universal coupler), and filament (propellor). The filament is a rigid helical assembly of only one protein species — flagellin. The filament can adopt different morphologies and change, reversibly, its helical parameters (pitch and hand) as a function of mechanical stress and chemical changes (pH, ionic strength) in the environment.

Advantages of Complementary Stereo Images as Viewed with the Low-Temperature Field-Emission SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1314-1315
Author(s):  
William P. Wergin ◽  
Eric F. Erbe
Keyword(s):  
Fold Increase ◽  
Horizontal Displacement ◽  
Three Dimensions ◽  
Stereo Image ◽  
Stereo Pair ◽  
Sem Micrograph ◽  
Left And Right ◽  
The Common ◽  
The Brain ◽  
Pair Analysis

The eye-brain complex allows those of us with normal vision to perceive and evaluate our surroundings in three-dimensions (3-D). The principle factor that makes this possible is parallax - the horizontal displacement of objects that results from the independent views that the left and right eyes detect and simultaneously transmit to the brain for superimposition. The common SEM micrograph is a 2-D representation of a 3-D specimen. Depriving the brain of the 3-D view can lead to erroneous conclusions about the relative sizes, positions and convergence of structures within a specimen. In addition, Walter has suggested that the stereo image contains information equivalent to a two-fold increase in magnification over that found in a 2-D image. Because of these factors, stereo pair analysis should be routinely employed when studying specimens.Imaging complementary faces of a fractured specimen is a second method by which the topography of a specimen can be more accurately evaluated.

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