Extrageniculate Contributions to Reflex Visual Orienting in Normal Humans: A Temporal Hemifield Advantage

1991 ◽  
Vol 3 (4) ◽  
pp. 322-328 ◽  
Author(s):  
Robert Rafal ◽  
Avishai Henik ◽  
Jean Smith
Keyword(s):  
Reaction Time ◽  
Visual Attention ◽  
Choice Reaction Time ◽  
Human Subjects ◽  
Visually Guided ◽  
Manual Responses ◽  
Visual Orienting ◽  
Normal Humans ◽  
Normal Human ◽  
Benefits And Costs

Evidence is presented that the phylogenetically older retin-otectal pathway contributes to reflex orienting of visual attention in normal human subjects. The study exploited a lateralized neuroanatomic arrangement of retinotectal pathways that distinguishes them from those of the geniculostriate system; namely, more direct projections to the colliculus from the temporal hemifield. Subjects were tested under monocular viewing conditions and responded to the detection of a peripheral signal by making either a saccade to it or a choice reaction time manual keypress. Attention was summoned by noninformative peripheral precues, and the benefits and costs of attention were calculated relative to a central precue condition. Both the benefits and costs of orienting attention were greater when attention was summoned by signals in the temporal hemifield. This temporal hemifield advantage was present for both saccade and manual responses. These findings converge with observations in patients with occipital and midbrain lesions to show that the phylogenetically older retinotectal pathway retains an important role in controlling visually guided behavior; and they demonstrate the usefulness of temporal-nasal hemifield asymmetries as a marker for investigating extrageniculate vision in humans.

scholarly journals The Ability to Orient Attention in Gilles de la Tourette Syndrome

1999 ◽  
Vol 11 (4) ◽  
pp. 205-209 ◽  
Author(s):  
Debra Howells ◽  
Nellie Georgiou-Karistianis ◽  
John Bradshaw
Keyword(s):  
Reaction Time ◽  
Tourette Syndrome ◽  
Choice Reaction Time ◽  
Index Finger ◽  
Reaction Time Task ◽  
Choice Reaction Time Task ◽  
Directed Attention ◽  
Time Task ◽  
Tactile Modality ◽  
Benefits And Costs

Gilles de la Tourette syndrome is characterised by tics, although patients also commonly present with attentional problems. This experiment aimed to ascertain whether TS patients have problems in orienting attention, via the use of a vibrotactile choice reaction time task. Participants were required to push a button in response to a faint vibration delivered to the index finger. Prior to each stimulus vibration, a pre-cue (valid, neutral or invalid) was administered to the finger. The performance benefits and costs participants gained from valid and invalid precues were calculated. Contrary to our prediction TS patients did not show significantly different costs or benefits. Furthermore, both patients and controls showed an equal and increased benefit in the crossed arm posture, compared to the uncrossed. These results suggest TS patients do not generally have problems in orienting attention. In addition, in the tactile modality, both patients and controls may benefit from directed attention when difficulty levels are maximal.

Reaction time and acoustic startle in normal human subjects

1995 ◽  
Vol 195 (2) ◽  
pp. 97-100 ◽  
Author(s):  
J. Valls-Solé ◽  
A. Solé ◽  
F. Valldeoriola ◽  
E. Muñoz ◽  
L.E. Gonzalez ◽  
...  
Keyword(s):  
Reaction Time ◽  
Human Subjects ◽  
Acoustic Startle ◽  
Normal Human

scholarly journals Endogenous hyperthermia in normal human subjects: I. Experimental study of evoked potentials and reaction time

1985 ◽  
Vol 13 (4) ◽  
pp. 258-267 ◽  
Author(s):  
Dennis L. Reeves ◽  
Don R. Justesen ◽  
Daniel M. Levinson ◽  
Donald W. Riffle ◽  
Edward L. Wike
Keyword(s):  
Experimental Study ◽  
Reaction Time ◽  
Evoked Potentials ◽  
Human Subjects ◽  
Normal Human

Developmental changes in orienting towards faces: A behavioral and eye-tracking study

2019 ◽  
Vol 44 (2) ◽  
pp. 157-165
Author(s):  
Masahiro Hirai ◽  
Yukako Muramatsu ◽  
Miho Nakamura
Keyword(s):  
Reaction Time ◽  
Visual Attention ◽  
Newborn Infants ◽  
Relative Strength ◽  
Developmental Changes ◽  
Manual Responses ◽  
The Face ◽  
Face Stimuli ◽  
Fixation Proportion ◽  
Human Faces

Previous studies show that newborn infants and adults orient their attention preferentially toward human faces. However, the developmental changes of visual attention captured by face stimuli remain unclear, especially when an explicit top-down process is involved. We capitalized on a visual search paradigm to assess how the relative strength of visual attention captured by a non-target face stimulus and explicit attentional control on a target stimulus evolve as search progresses and how this process changes during development. Ninety children aged 5–14 years searched for a target within an array of distractors, which occasionally contained an upright face. To assess the precise picture of developmental changes, we measured: (1) manual responses, such as reaction time and accuracy; and (2) eye movements such as the location of the first fixation, which reflect the attentional profile at the initial stage, and looking times, which reflect the attentional profile at the later period of searching. Both reaction time and accuracy were affected by the presence of the target-unrelated face, though the interference effect was observed consistently across ages. However, developmental changes were captured by the first fixation proportion, suggesting that initial attention was preferentially directed towards the target-unrelated face before 6.9 years of age. Furthermore, prior to 12.8 years of age, the first fixation towards face stimuli was significantly more frequent than for object stimuli. In contrast, the looking time proportion for the face stimuli was significantly higher than that for the objects across all ages. These findings suggest that developmental changes do not influence the later search periods during a trial, but that they influence the initial orienting indexed by the first fixation. Moreover, the manual responses are tightly linked to eye movement behaviors.

Hemispheric differences in normal human subjects: further evidence from study of reaction time to lateralized visual stimuli

1973 ◽  
Vol 49 (2) ◽  
pp. 499 ◽  
Author(s):  
C. Umiltà ◽  
G. Rizzolatti ◽  
C.A. Marzi ◽  
G. Zamboni ◽  
C. Franzini ◽  
...  
Keyword(s):  
Reaction Time ◽  
Human Subjects ◽  
Visual Stimuli ◽  
Hemispheric Differences ◽  
Normal Human

Hyperoxia and moderate hypoxia fail to affect inspiratory muscle fatigue in humans

1989 ◽  
Vol 66 (2) ◽  
pp. 894-900 ◽  
Author(s):  
B. T. Ameredes ◽  
T. L. Clanton
Keyword(s):  
Human Subjects ◽  
Initial Pressure ◽  
Inspiratory Muscles ◽  
Mouth Pressure ◽  
Rate Of Decay ◽  
Normal Humans ◽  
Normal Human ◽  
End Tidal ◽  
Arterial O2 Saturation ◽  
Inspiratory Muscle Fatigue

Normal human subjects (n = 7) breathing 21% O2 (normoxia), 13% O2 (hypoxia), or 100% O2 (hyperoxia) performed repeated maximal inspiratory maneuvers (inspiratory duration = 1.5 s, total breath duration = 3.5 s) on an “isoflow” system, which delivered a constant mouth flow (1.25 or 1 l/s) while maintaining normocapnia (5.5% end-tidal CO2). Respective mean arterial O2 saturation values (ear lobe oximetry) were 98 +/- 1, 91 +/- 4 (P less than or equal to 0.01), and 99 +/- 1% (NS). Maximal mouth pressure (Pm) was measured during inspirations at rest and during a 10-min fatigue trial, and the Pm measurements obtained during the fatigue trials were fit to an exponential equation. The parameters of the equation included the time constant (tau), which describes the rate of decay of Pm from the initial pressure (Pi) to the asymptote, or “sustainable” pressure (Ps). The mean fraction of Pm remaining at the end of the fatigue trials (Ps/Pi) was 63 +/- 5%. No significant differences in Pi, Ps, or tau were observed between O2 treatments. This suggests that fatigue of the inspiratory muscles in normal humans occurs by a mechanism that is insensitive to changes in blood O2 content that occur during inspiration of O2 in the range of 13–100%.

Observations on a Relationship between Steroid Metabolism and the Concentration of Plasma Fibrinogen

1963 ◽  
Vol 10 (02) ◽  
pp. 400-405 ◽  
Author(s):  
B. A Amundson ◽  
L. O Pilgeram
Keyword(s):  
Blood Coagulation ◽  
Methyl Ether ◽  
Broad Spectrum ◽  
Human Subjects ◽  
Plasma Fibrinogen ◽  
Steroid Metabolism ◽  
Specific Site ◽  
Chain Reaction ◽  
Normal Human ◽  
A Chain

SummaryEnovid (5 mg norethynodrel and 0.075 mg ethynylestradiol-3-methyl ether) therapy in young normal human subjects causes an increase in plasma fibrinogen of 32.4% (P >C 0.001). Consideration of this effect together with other effects of Enovid on the activity of specific blood coagulatory factors suggests that the steroids are exerting their effect at a specific site of the blood coagulation and/or fibrinolytic system. The broad spectrum of changes which are induced by the steroids may be attributed to a combination of a chain reaction and feed-back control.

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