Browsing by Subject "RETINAL GANGLION-CELLS"

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  • Donner, Kristian; Yovanovich, Carola (2020)
    From the mid-19th century until the 1980's, frogs and toads provided important research models for many fundamental questions in visual neuroscience. In the present century, they have been largely neglected. Yet they are animals with highly developed vision, a complex retina built on the basic vertebrate plan, an accessible brain, and an experimentally useful behavioural repertoire. They also offer a rich diversity of species and life histories on a reasonably restricted physiological and evolutionary background. We suggest that important insights may be gained from revisiting classical questions in anurans with state-of-the-art methods. At the input to the system, this especially concerns the molecular evolution of visual pigments and photoreceptors, at the output, the relation between retinal signals, brain processing and behavioural decision-making.
  • Bauer, Michael; Glenn, Tasha; Alda, Martin; Andreassen, Ole A.; Angelopoulos, Elias; Ardau, Raffaella; Ayhan, Yavuz; Baethge, Christopher; Bauer, Rita; Baune, Bernhard T.; Becerra-Palars, Claudia; Bellivier, Frank; Belmaker, Robert H.; Berk, Michael; Bersudsky, Yuly; Bicakci, Sule; Birabwa-Oketcho, Harriet; Bjella, Thomas D.; Cabrera, Jorge; Cheung, Eric Y. Wo; Del Zompo, Maria; Dodd, Seetal; Donix, Markus; Etain, Bruno; Fagiolini, Andrea; Fountoulakis, Kostas N.; Frye, Mark A.; Gonzalez-Pinto, Ana; Gottlieb, John F.; Grof, Paul; Harima, Hirohiko; Henry, Chantal; Isometsä, Erkki T.; Janno, Sven; Kapczinski, Flavio; Kardell, Mathias; Khaldi, Slim; Kliwicki, Sebastian; Konig, Barbara; Kot, Timur L.; Krogh, Rikke; Kunz, Mauricio; Lafer, Beny; Landen, Mikael; Larsen, Erik R.; Lewitzka, Ute; Licht, Rasmus W.; Lopez-Jaramillo, Carlos; MacQueen, Glenda; Manchia, Mirko; Marsh, Wendy; Martinez-Cengotitabengoa, Monica; Melle, Ingrid; Meza-Urzua, Fatima; Ming, Mok Yee; Monteith, Scott; Morken, Gunnar; Mosca, Enrica; Mozzhegorova, Anton A.; Munoz, Rodrigo; Mythri, Starlin V.; Nacef, Fethi; Nadella, Ravi K.; Nery, Fabiano G.; Nielsen, Rene E.; O'Donovan, Claire; Omrani, Adel; Osher, Yamima; Sorensen, Helle Ostermark; Ouali, Uta; Ruiz, Yolanda Pica; Pilhatsch, Maximilian; Pinna, Marco; da Ponte, Francisco D. R.; Quiroz, Danilo; Ramesar, Raj; Rasgon, Natalie; Reddy, M. S.; Reif, Andreas; Ritter, Philipp; Rybakowski, Janusz K.; Sagduyu, Kemal; Raghuraman, Bharathram Sathur; Scippa, Angela M.; Severus, Emanuel; Simhandl, Christian; Stackhouse, Paul W.; Stein, Dan J.; Strejilevich, Sergio; Subramaniam, Mythily; Sulaiman, Ahmad Hatim; Suominen, Kirsi; Tagata, Hiromi; Tatebayashi, Yoshitaka; Tondo, Leonardo; Torrent, Carla; Vaaler, Arne E.; Vares, Edgar; Veeh, Julia; Vieta, Eduard; Viswanath, Biju; Yoldi-Negrete, Maria; Zetina, Mark; Zgueb, Yosra; Whybrow, Peter C. (2019)
    In many international studies, rates of completed suicide and suicide attempts have a seasonal pattern that peaks in spring or summer. This exploratory study investigated the association between solar insolation and a history of suicide attempt in patients with bipolar I disorder. Solar insolation is the amount of electromagnetic energy from the Sun striking a surface area on Earth. Data were collected previously from 5536 patients with bipolar I disorder at 50 collection sites in 32 countries at a wide range of latitudes in both hemispheres. Suicide related data were available for 3365 patients from 310 onset locations in 51 countries. 1047 (31.1%) had a history of suicide attempt. There was a significant inverse association between a history of suicide attempt and the ratio of mean winter solar insolation/mean summer solar insolation. This ratio is smallest near the poles where the winter insolation is very small compared to the summer insolation. This ratio is largest near the equator where there is relatively little variation in the insolation over the year. Other variables in the model that were positively associated with suicide attempt were being female, a history of alcohol or substance abuse, and being in a younger birth cohort. Living in a country with a state-sponsored religion decreased the association. (All estimated coefficients p <0.01). In summary, living in locations with large changes in solar insolation between winter and summer may be associated with increased suicide attempts in patients with bipolar disorder. Further investigation of the impacts of solar insolation on the course of bipolar disorder is needed.
  • Koskela, Sanna; Turunen, Tuomas; Ala-Laurila, Petri (2020)
    Circadian clocks predictively adjust the physiology of organisms to the day/night cycle. The retina has its own clock, and many diurnal changes in its physiology have been reported. However, their implications for retinal functions and visually guided behavior are largely unresolved. Here, we study the impact of diurnal rhythm on the sensitivity limit of mouse vision. A simple photon detection task allowed us to link well-defined retinal output signals directly to visually guided behavior. We show that visually guided behavior at its sensitivity limit is strongly under diurnal control, reaching the highest sensitivity and stability at night. The diurnal differences in visual sensitivity did not arise in the retina, as assessed by spike recordings from the most sensitive retinal ganglion cell types: ON sustained, OFF sustained, and OFF transient alpha ganglion cells. Instead, we found that mice, as nocturnal animals, use a more efficient search strategy for visual cues at night. Intriguingly, they can switch to the more efficient night strategy even at their subjective day after first having performed the task at night. Our results exemplify that the shape of visual psychometric functions depends robustly on the diurnal state of the animal, its search strategy, and even its diurnal history of performing the task. The results highlight the impact of the day/night cycle on high-level sensory processing, demonstrating a direct diurnal impact on the behavioral strategy of the animal.
  • Smeds, Lina; Takeshita, Daisuke; Turunen, Tuomas; Tiihonen, Jussi Samuli; Westö, Johan; Martyniuk, Nataliia; Seppänen, Aarni Juhani; Ala-Laurila, Petri (2019)
    All sensory information is encoded in neural spike trains. It is unknown how the brain utilizes this neural code to drive behavior. Here, we unravel the decoding rules of the brain at the most elementary level by linking behavioral decisions to retinal output signals in a single-photon detection task. A transgenic mouse line allowed us to separate the two primary retinal outputs, ON and OFF pathways, carrying information about photon absorptions as increases and decreases in spiking, respectively. Wemeasured the sensitivity limit of rods and the most sensitive ON and OFF ganglion cells and correlated these results with visually guided behavior using markerless head and eye tracking. We show that behavior relies only on the ON pathway even when the OFF pathway would allow higher sensitivity. Paradoxically, behavior does not rely on the spike code with maximal information but instead relies on a decoding strategy based on increases in spiking.
  • Smedowski, Adrian; Liu, Xiaonan; Pietrucha-Dutczak, Marita; Matuszek, Iwona; Varjosalo, Markku; Lewin-Kowalik, Joanna (2016)
    Glaucoma is an optic neuropathy that leads to irreversible blindness. Because the current therapies are not sufficient to protect against glaucoma-induced visual impairment, new treatment approaches are necessary to prevent disease progression. Cell transplantation techniques are currently considered to be among the most promising opportunities for nervous system damage treatment. The beneficial effects of undifferentiated cells have been investigated in experimental models of glaucoma, however experiments were accompanied by various barriers, which would make putative treatment difficult or even impossible to apply in a clinical setting. The novel therapy proposed in our study creates conditions to eliminate some of the identified barriers described for precursor cells transplantation and allows us to observe direct neuroprotective and pro-regenerative effects in ongoing optic neuropathy without additional modifications to the transplanted cells. We demonstrated that the proposed novel Schwann cell therapy might be promising, effective and easy to apply, and is safer than the alternative cell therapies for the treatment of glaucoma.
  • Donner, Kristian (2021)
    Time is largely a hidden variable in vision. It is the condition for seeing interesting things such as spatial forms and patterns, colours and movements in the external world, and yet is not meant to be noticed in itself. Temporal aspects of visual processing have received comparatively little attention in research. Temporal properties have been made explicit mainly in measurements of resolution and integration in simple tasks such as detection of spatially homogeneous flicker or light pulses of varying duration. Only through a mechanistic understanding of their basis in retinal photoreceptors and circuits can such measures guide modelling of natural vision in different species and illuminate functional and evolutionary trade-offs. Temporal vision research would benefit from bridging traditions that speak different languages. Towards that goal, I here review studies from the fields of human psychophysics, retinal physiology and neuroethology, with a focus on fundamental constraints set by early vision.
  • Yovanovich, Carola A. M.; Koskela, Sanna M.; Nevala, Noora; Kondrashev, Sergei L.; Kelber, Almut; Donner, Kristian (2017)
    The presence of two spectrally different kinds of rod photoreceptors in amphibians has been hypothesized to enable purely rod-based colour vision at very low light levels. The hypothesis has never been properly tested, so we performed three behavioural experiments at different light intensities with toads (Bufo) and frogs (Rana) to determine the thresholds for colour discrimination. The thresholds of toads were different in mate choice and prey-catching tasks, suggesting that the differential sensitivities of different spectral cone types as well as task-specific factors set limits for the use of colour in these behavioural contexts. In neither task was there any indication of rod-based colour discrimination. By contrast, frogs performing phototactic jumping were able to distinguish blue from green light down to the absolute visual threshold, where vision relies only on rod signals. The remarkable sensitivity of this mechanism comparing signals from the two spectrally different rod types approaches theoretical limits set by photon fluctuations and intrinsic noise. Together, the results indicate that different pathways are involved in processing colour cues depending on the ecological relevance of this information for each task. This article is part of the themed issue 'Vision in dim light'.
  • Yovanovich, Carola A. M.; Koskela, Sanna M.; Nevala, Noora; Kondrashev, Sergei L.; Kelber, Almut; Donner, Kristian (The Royal Society of Chemistry, 2017)
    The presence of two spectrally different kinds of rod photoreceptors in amphibians has been hypothesized to enable purely rod-based colour vision at very low light levels. The hypothesis has never been properly tested, so we performed three behavioural experiments at different light intensities with toads (Bufo) and frogs (Rana) to determine the thresholds for colour discrimination. The thresholds of toads were different in mate choice and prey-catching tasks, suggesting that the differential sensitivities of different spectral cone types as well as task-specific factors set limits for the use of colour in these behavioural contexts. In neither task was there any indication of rod-based colour discrimination. By contrast, frogs performing phototactic jumping were able to distinguish blue from green light down to the absolute visual threshold, where vision relies only on rod signals. The remarkable sensitivity of this mechanism comparing signals from the two spectrally different rod types approaches theoretical limits set by photon fluctuations and intrinsic noise. Together, the results indicate that different pathways are involved in processing colour cues depending on the ecological relevance of this information for each task. This article is part of the themed issue 'Vision in dim light'.