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

Circadian system and it's changes in Lurcher mutant mice

The main topic of this thesis are changes in Circadian rhythms caused by cerebellar disorders. Mice with Lurcher mutation, which have specifically degenerated Purkinje cells layer, were choosen as animal model. Our results show that mutation of the glutamate receptor GluRδ2, which causes gradual degeneration of Purkinje cells, leads to damage of Circadian system. Mice with this mutation have reduced capability to adapt to external conditions in different light modes. They are also showing increased variability in endogenous cycle. The mice are also unable to show anticipatory behavior in time-restricted feeding. Compared to control group, affected mice do not show significant rhythm in levels of protein of Bmal1 gene in suprachiasmatic nuclei, paraventricular nuclei nor in habenula. Phosphorylated kinases ERK1/2 and GSK3ß also had distorted rhythms in suprachiasmatic nuclei. Because Circadian oscillations in locomotor activity are partly preserved, Circadian system is likely not damaged on molecular level. Cerebellar mutation hampers synchronization between suprachiasmatic nuclei of neurons and can also affect processes in the ventromedial hypothalamus regulating food intake. Our findings are the first to suggest functional interactions between cerebellum and Circadian pacemaker in suprachiasmatic...Tématem této diplomové práce jsou změny v cirkadiánních rytmech způsobené poruchou cerebella. Jako animální model byly vybrány myši s mutací Lurcher, které mají specificky degenerovanou vrstvu Purkyňových buněk. Z našich výsledků vyplývá, že mutace glutamátového receptoru GluRδ2, která podmiňuje postupnou degeneraci Purkyňových buněk, vede k poškození cirkadiánního systému. Myši s touto mutací mají sníženou schopnost synchronizace s vnějšími světelnými podmínkami, vykazují zvýšenou variabilitu v délce endogenní periody a nejsou schopny generovat anticipační chování v režimu časově omezeného přístupu k potravě. Na rozdíl od kontrolních myší, u postižených myší jsme nedetekovali významný rytmus v hladině proteinu hodinového genu Bmal1 v suprachiasmatických jádrech, paraventrikulárních jádrech ani v habenule. Hladiny fosforylovaných kináz ERK1/2 a GSK3ß měly také narušený rytmus v suprachiasmatických jádrech. Vzhledem k částečně zachovaným cirkadiánním oscilacím v lokomoční aktivitě patrně nedochází k narušení cirkadiánního systému na molekulární úrovni. Cerebelární mutace spíše narušuje vzájemnou synchronizaci neuronů suprachiasmatických jader a může také ovlivňovat procesy ve ventromediálním hypotalamu regulujícím příjem potravy. Naše poznatky jsou první, které naznačují funkční interakci cerebella...Department of PhysiologyKatedra fyziologieFaculty of SciencePřírodovědecká fakult

Molecular dissection of the retinal projectome

The retina transforms visual sensation into perception. Extracted visual features are encoded by retinal ganglion cells (RGCs), the output neurons of the eye, and sent to the brain in parallel processing channels. Morphologically, RGCs fall into more than fifty diverse types, which innervate distinct brain areas. Such visual pathways differentially regulate various behaviors. However, the genetic determinants of RGC type diversity are unknown and thus we lack genetic access to study visual pathways. A generation of a more comprehensive RGC type atlas integrating molecular, morphological and functional properties is essential to dissect the functional architecture of the visual system. In a collaborative effort, I used single cell transcriptomics to molecularly classify RGCs during larval and adult stages. RGC types segregate into many discrete transcriptional clusters each with a unique molecular composition. Relatedness of clusters revealed a molecular taxonomy, in which RGC types are arranged into major RGC groups that comprise subclasses and diversify into individual types. This organization of RGC type diversification underlies a code of gene expression patterns, composed primarily of transcription factors. Differential gene expression analysis identified dozens of novel cluster-specific genetic markers for RGC types. Comparison of transcriptional signatures revealed that larval RGCs exhibit higher molecular diversity, which facilitates segregation of similar types, while adult RGCs maintain a core molecular identity suggesting a tight correspondence between larval and adult RGC types. Next, I mapped transcriptional clusters to RGC morphotypes. Select candidate markers were exploited as genetic entry points in a CRISPR-Cas9 transgenesis approach. To restrict labeling specifically to cluster-specific RGC types, I established a genetic intersection with a broad RGC marker. This intersectional transgenic approach allowed to correspond various clusters to distinct morphologically classified RGC types. I generated two transgenic lines using RGC subclass markers, one of which is based on the transcription factor eomesa expressed by RGC types routing to visual areas in hypothalamus, pretectum and tectum. Based on homologies to RGC types characterized in other species, I hypothesized that eomesa+ RGCs constitute intrinsically photosensitive RGCs and have non-image forming functions. I tested this hypothesis by characterizing their response profiles to a battery of visual stimuli and found that they are not tuned to canonical pattern stimuli. Rather eomesa+ RGCs encode ambient luminance levels corroborating my hypothesis. I further tested their necessity in non-image forming behavior, specifically visual background adaptation, which by initial investigation appears to not be affected by chemogenetic ablation of eomesa+ RGCs. In conclusion, this thesis presents a strong foundation for a RGC type atlas and reconciles molecular, morphological and functional features of discrete cell types. This comprehensive molecular classification of RGC types, together with the identified markers and newly established transgenic tools, provides a rich resource towards a better understanding of visual pathway function