Aerospace medicine and biology: A continuing bibliography with indexes (supplement 375)

This bibliography lists 212 reports, articles, and other documents recently introduced into the NASA Scientific and Technical Information System database. Subject coverage includes the following: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 361)

This bibliography lists 141 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during Mar. 1992. Subject coverage includes: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance

Impact of the pulvinar on the ventral pathway of the cat visual cortex

Signals from the retina are relayed to the lateral geniculate nucleus from which they are sent to the primary visual cortex. At the cortical level, the information is transferred across several visual areas in which the complexity of the processing increases progressively. Anatomical and functional evidence demonstrate the existence of two main pathways in visual cortex processing distinct features of the visual information: the dorsal and ventral streams. Cortical areas composing the dorsal stream are implicated mostly in motion processing while those comprising the ventral stream are involved in the processing of form and colour. This classic view of the cortical functional organization is challenged by the existence of reciprocal connections of visual cortical areas with the thalamic nucleus named pulvinar. These connections allow the creation of a trans-thalamic pathway that parallels the cortico-cortical communications across the visual hierarchy. The main goal of the present thesis is twofold: first, to obtain a better comprehension of the processing of light increments and decrements in an area of the cat ventral stream (area 21a); second, to characterize the nature of the thalamo-cortical inputs from the cat lateral posterior nucleus (LP) to area 21a. In study #1, we investigated the spatiotemporal response profile of neurons from area 21a to light increments (brights) and decrements (darks) using a reverse correlation analysis of a sparse noise stimulus. Our findings showed that 21a neurons exhibited stronger responses to darks with receptive fields exhibiting larger dark subfields. However, no differences were found between the temporal dynamics of brights and darks. In comparison with the primary visual cortex, the dark preference in area 21a was found to be strongly enhanced, supporting the notion that the asymmetries between brights and darks are transmitted and amplified along the ventral stream. In study #2, we investigated the impact of the reversible pharmacological inactivation of the LP nucleus on the contrast response function (CRF) of neurons from area 21a and the primary visual cortex (area 17). The thalamic inactivation yielded distinct effects on both cortical areas. While in area 17 the LP inactivation caused a slight decrease in the response gain, in area 21a a strong increase was observed. Thus, our findings suggest that the LP exerts a modulatory influence on the cortical processing along the ventral stream with stronger impact on higher order extrastriate areas. Taken together, our findings allowed a better comprehension of the functional properties of the cat ventral stream and contributed to the current knowledge on the role of the pulvinar on the cortico-thalamo-cortical processing of visual information.Les signaux provenant de la rétine sont relayés dans le corps géniculé latéral où ils sont envoyés au cortex visuel primaire. L’information passe ensuite à travers plusieurs aires visuelles où la complexité du traitement augmente progressivement. Des données tant anatomiques que fonctionnelles ont démontré l’existence de deux voies principales qui traitent différentes propriétés de l’information visuelle : les voies dorsale et ventrale. Les aires corticales composant la voie dorsale sont impliquées principalement dans le traitement du mouvement tandis que les aires de la voie ventrale sont impliquées dans le traitement de la forme et de la couleur. Cette vision classique de l’organisation fonctionnelle du cortex est toutefois remise en question par l’existence de connections réciproques entre les aires corticales visuelles et le pulvinar, un noyau thalamique. En effet, ces connections permettent la création d’une voie trans-thalamique parallèle aux connections cortico-corticales à travers la hiérarchie visuelle. Le but principal de la présente thèse consiste en deux volets : le premier est d’obtenir une meilleure compréhension du traitement des incréments et décréments de la lumière dans une aire de la voie ventrale du chat (aire 21a); le second est de caractériser la nature des inputs thalamo-corticaux du noyau latéral postérieur (LP) à l’aire 21a chez le chat. Dans l’étude #1, nous avons investigué le profil spatiotemporel des réponses des neurones de l’aire 21a aux incréments (blancs) et décréments (noirs) de lumière en utilisant l’analyse de corrélation inverse d’un stimulus de bruit épars. Les neurones de l’aire 21a ont répondu plus fortement aux stimuli noirs, en montrant des champs récepteurs avec des sous-champs noirs plus larges. Cependant, aucune différence n’a été trouvée en ce qui concerne les dynamiques temporelles des réponses aux blancs et aux noirs. En comparaison avec le cortex visuel primaire, la préférence aux stimuli noirs dans l’aire 21a s’est avérée fortement augmentée. Ces données indiquent que les asymétries entre les réponses aux blancs et aux noirs sont transmises et amplifiées à travers la voie ventrale. Dans l’étude #2, nous avons investigué l’impact de l’inactivation pharmacologique réversible du noyau LP sur la fonction de réponse au contraste (CRF) des neurones de l’aire 21a et du cortex visuel primaire (aire 17). L’inactivation a eu différents effets dans les deux aires corticales. Alors que, dans l’aire 17, l’inactivation du LP a causé une légère réduction du gain de la réponse, une forte augmentation a été observée dans l’aire 21a. Ainsi, nos résultats suggèrent que le LP exerce une influence modulatrice dans le traitement cortical à travers la voie ventrale avec un impact plus important dans des aires extrastriées de plus haut niveau. Nos résultats ont permis d’avoir une meilleure compréhension des propriétés fonctionnelles de la voie ventrale du chat et de contribuer à enrichir les connaissances actuelles sur le rôle du pulvinar dans le traitement cortico-thalamo-cortical de l’information visuelle

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 182, July 1978

This bibliography lists 165 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1978

Change blindness: eradication of gestalt strategies

Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task

Light, activity and sleep in my daily life: : Design of an online intervention targeting changes to routines and the home

Background: Older adults spend more time at home after retirement, and the home becomes a central place for activity. While research indicates that indoor lighting, exposure to daylight, physical activity and sleep interact to influence functioning, mood and daily rhythm, strategies are needed to promote behavioural changes to optimise these factors in daily life. The objective is to design an intervention delivered as a web-based course to encourage behaviour change related to outdoor physical activity, sleep patterns and changes to the home environment. The behaviour changes are intended to promote mental wellbeing and improve lighting and darkness conditions. The intervention strategy departs from the Information-Motivation-Behavioural Skills Model. Intervention components build on goal implementation theory. The Technology Acceptance Model is used as a framework to evaluate usability aspects of the course content and the learning management system. Method: Using a mixed-methods approach, qualitative and quantitative data were collected through video observations, semi-structured interviews and a 10-item Likert scale questionnaire (The System Usability Scale). Scores were averaged for each participant and converted into a usability score out of 100 (a score of 68 or above is considered above average). In a first round, three experts on pedagogy, design for older people and/or interaction design were invited to independently assess the usability of the course content on their laptops in a full-scale model of an apartment. The setting enabled manipulations of the lighting conditions (daylight mode and night mode, change of luminaires), contextual interviews and video observation to identify any problems when participants experimented with the test kit included in the course material. They participated on three occasions lasting 2 hours each. Six healthy adults (aged 70+) participated in a similar usability trial in a second round. Findings: Experts’ average usability score was 78.3, indicating “Good” usability. However, the interviews did reveal some issues (e.g. difficult or inconsistent terms, unclear instructions). Results were used to refine the course before the second usability trial with six participants. Based on the interviews and usability ratings, the participants were positive about the course, and the instructions were easy to follow. All six participants rated the overall user-friendliness of the course as 6 out of 7. The average usability score was 86.7, indicating “Excellent” usability. Based on the participants’ feedback and interactions in the apartment, changes to the course content included, e.g. clarifying terms, the different types of text links and instructions. Unexpected issues with online enrolment in the course appeared before the second trial because standard instructions developed by the university were not tailored to the participants.Conclusions: A two-step usability evaluation by experts in the first round and target users in the second proved valuable. It enabled refinement of the course content and significantly reduced the number of identified usability issues in the second trial. A learning management system seems promising for use in behaviour-change interventions. However, the time-limited lab trials restricted a complete evaluation. Therefore, the next step is to pilot the course and evaluate the feasibility in real-world homes

Aerospace medicine and biology: A cumulative index to a continuing bibliography (supplement 319)

This publication is a cumulative index to the abstracts contained in Supplements 307 through 318 of Aerospace Medicine and Biology: A Continuing Bibliography. Seven indexes are included -- subject, personal author, corporate source, foreign technology, contract number, report number and accession number