The Look of Eye Contact
Michael van Manen in Phenomenology of the Newborn, 2018
While literature on the development of premature newborns is still in its infancy, we recognize that the phenomenon of looking and eye contact continues to change in the months following birth of the term infant. Does the response to visual stimuli constitute a visual experience? It is apparent that infants rely on visual stimuli for development. For example, term infants’ vision is monochromatic to red, seemingly a function of light transilluminating hemoglobin within the womb (Clark-Gambelunghe & Clark, 2015); and the development of stereoscopic vision appears to be more dependent on how long it is that a child has been outside of the womb, rather than the child’s age in relation to conception (Jandó et al., 2012). For the development of later vision, it seems that infants are resilient in their visual development. Even if their eyes are deprived of vision because of congenital cataract or other obstruction to vision, visual development can still occur if the obstruction is relieved in the first months of life (Lambert & Drack, 1996). Nonetheless, lack of visual input can affect other sensory modalities.
Discussions (D)
Terence R. Anthoney in Neuroanatomy and the Neurologic Exam, 2017
♦ 2. To test for the “groping response,” is the examiner’s hand simply placed near the patient’s hand, or does it instead touch the patient’s hand? In other words, is the stimulus visual, tactile, or both?is the hand touched only once or repeatedly?is the hand touched only between the thumb and index finger, or can it be touched elsewhere?are the patient’s eyes open or closed when the hand is touched?must the object presented visually (non-tactilely) be a hand, or will any graspable object do?must the object presented visually (non-tactilely) be near the patient’s hand?
Laterality Effects for Higher Cognitive Processes
Robert Miller in Axonal Conduction Time and Human Cerebral Laterality, 2019
Perception of emotion may be influenced by two quite different sorts of stimuli: Neutral stimuli may secondarily acquire emotional meaning because of what they are used to signify. Examples of this include the auditory stimuli used to represent emotion (e.g. by means of prosody in speech, or of melodic line or harmony in music), or the perception of visual stimuli used to convey emotion (e.g. body gesture). Similarly, emotion may be conveyed in the visual or auditory sense by explicit word meanings; or it may be merely inferred without ever using a word of direct emotional meaning. Quite apart from neutral stimuli which acquire secondary emotional meaning, emotional experience may be affected by primary emotional stimuli, in other words stimuli used as rewards or punishments. The primary and secondary emotional attributes of stimuli are not sharply separate in practice, and sometimes, it is not clear whether the emotional attributes of a stimulus are primary or secondary. For instance with facial expressions conveying emotion, it is difficult to say whether the stimulus is a primary emotional one, or one which has secondarily acquired emotional value.
Attentional capture by physically salient stimuli in the gamma frequency is associated with schizophrenia symptoms
Published in The World Journal of Biological Psychiatry, 2018
Laura Kornmayer, Gregor Leicht, Christoph Mulert
The paradigm was displayed using Presentation® software (Version 15.0, Neurobehavioral Systems). Two sets of basic visual stimuli were applied. In the target-only (TO) condition, a bright or dark-grey target cross was displayed at central position on the screen against a homogenous medium grey background. Participants were asked to respond to the targets by pressing a button (left for bright targets, right for dark targets). Stimuli were presented for 250 ms at a visual angle of 4°. The inter-stimulus interval (ISI) between trials varied in the range of 2500–7500 ms. The 270 trials (75% of total trials) of the TO condition were pseudo-randomly intermixed by 90 further trials (25% of total trials), additionally containing physically salient distracter (PSD) stimuli, irrelevant for the ongoing target-detection task. Distracter stimuli were coloured discs around the targets: either red (RGB: 225 0 0), green (RGB: 0 255 0) or blue (RGB: 0 0 255) (Figure 1). Direct succession of distracter trials was avoided during pseudo-randomization. The total of 360 trials was presented in four blocks to allow eye relaxation during breaks. Before the beginning of the measurement a short test run including instructions, which button to press for bright and dark-grey targets, respectively, was carried out. The instructions were shown again before the beginning of every new block. Reaction times were registered from stimulus onset to button press for all correct trials. Any button presses beyond 1500 ms post-stimulus onset and wrong button presses were counted as errors.
Post-sauna recovery enhances brain neural network relaxation and improves cognitive economy in oddball tasks
Published in International Journal of Hyperthermia, 2018
Margarita Cernych, Andrius Satas, Marius Brazaitis
Two oddball tasks in randomized order with 175 stimuli in each task were used in this study. In one task, visual stimuli and in the other task, auditory stimuli were presented. Two types of stimuli in each task were used: requiring a response (press the left mouse button) to the target stimuli (20% probability, ‘X’ for the visual task, 2000 Hz tone for the auditory task) or no response to the standard stimuli (80% probability, ‘O’ for the visual task, 1000 Hz for the auditory task). Stimulus duration for the visual task was 0.5 s, and for the auditory task it was 0.05 s; interstimuli intervals were 1.5 s for both tasks. The auditory stimuli were presented via headphones at 60 dB sound pressure level. Stimuli were presented in random order. Reaction times (RTs, in ms) and accuracy of response to the target stimulus (%) were measured.
Literature overview on P3 measurement as an objective measure of auditory performance in post-lingually deaf adults with a cochlear implant
Published in International Journal of Audiology, 2019
Laure Jacquemin, Griet Mertens, Winfried Schlee, Paul Van de Heyning, Annick Gilles
ERPs in CI users can be evoked by a wide range of stimuli and the choice of the stimulus mainly depends on the research question. Most studies use auditory stimuli and/or visual stimuli in their experiments. Nonsense syllables are often chosen as auditory stimuli, but pure tones, complex tones, noise or words are also used. The use of speech stimuli may be optimal for assessing central processing during speech perception (Beynon et al. 2002). General recommendations for P3 recording in clinical research are published by Duncan et al. (2009). The recommended frequencies are 1.0 kHz (target) and 0.5 kHz (standard) with a duration between 50 ms and 150 ms, a 5 ms rise- and fall time and an intensity of 70 dB SPL. The interstimulus interval should be approximately 1–2 s and even longer if the task is difficult. The probability of the target is preferred to be between 10 and 20% with a minimum of 36 artefact-free trials (Duncan et al. 2009). However, it is important to bear in mind that these recommendations are not specific for CI studies. The parts of the cochlea stimulated by these recommended stimuli will differ between CI users. Hence, CI-related factors need to be taken into account, such as implant model, number of active electrodes and insertion angle. In CI studies, stimuli with a short duration can be used in order to minimise the overlap between the CI artefact and the ERPs.
Related Knowledge Centers
- Central Nervous System
- Chemoreceptor
- Mechanoreceptor
- Physiology
- Reflex
- Sensory Neuron
- Transduction
- Homeostasis
- Fight-Or-Flight Response
- Absolute Threshold