Mikko T. Vähäsöyrinki

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Shaker K(+)-channels are one of several voltage-activated K(+)-channels expressed in Drosophila photoreceptors. We have shown recently that Shaker channels act as selective amplifiers, attenuating some signals while boosting others. Loss of these channels reduces the photoreceptor information capacity (bits s(-1)) and induces compensatory changes in(More)
In dim light, scarcity of photons typically leads to poor vision. Nonetheless, many animals show visually guided behavior with dim environments. We investigated the signaling properties of photoreceptors of the dark active cockroach (Periplaneta americana) using intracellular and whole-cell patch-clamp recordings to determine whether they show selective(More)
An array of rapidly inactivating voltage-gated K+ channels is distributed throughout the nervous systems of vertebrates and invertebrates. Although these channels are thought to regulate the excitability of neurons by attenuating voltage signals, their specific functions are often poorly understood. We studied the role of the prototypical inactivating K+(More)
Optimization of sensory processing during development can be studied by using photoreceptors of hemimetabolous insects (with incomplete metamorphosis) as a research model. We have addressed this topic in the stick insect Carausius morosus, where retinal growth after hatching is accompanied by a diurnal-to-nocturnal shift in behavior, by recording from(More)
The common backswimmer, Notonecta glauca, uses vision by day and night for functions such as underwater prey animal capture and flight in search of new habitats. Although previous studies have identified some of the physiological mechanisms facilitating such flexibility in the animal's vision, neither the biophysics of Notonecta photoreceptors nor possible(More)
Determining the contribution of a single type of ion channel to information processing within a neuron requires not only knowledge of the properties of the channel but also understanding of its function within a complex system. We studied the contribution of slow delayed rectifier K+ channels to neural coding in Drosophila photoreceptors by combining(More)
The information transfer rate provides an objective and rigorous way to quantify how much information is being transmitted through a communications channel whose input and output consist of time-varying signals. However, current estimators of information content in continuous signals are typically based on assumptions about the system's linearity and signal(More)
In a microvillar photoreceptor, absorption of an incident photon initiates a phototransduction reaction that generates a depolarizing light-induced current (LIC) in the microvillus. Although in-depth knowledge about these processes in photoreceptors of the fruitfly Drosophila is available, not much is known about their nature in other insect species. Here,(More)
The importance of voltage-dependent conductances in sensory information processing is well-established in insect photoreceptors. Here we present the characterization of electrical properties in photoreceptors of the cockroach (Periplaneta americana), a nocturnal insect with a visual system adapted for dim light. Whole-cell patch-clamped photoreceptors had(More)
Ideally, neuronal functions would be studied by performing experiments with unconstrained animals whilst they behave in their natural environment. Although this is not feasible currently for most animal models, one can mimic the natural environment in the laboratory by using a virtual reality (VR) environment. Here we present a novel VR system based upon a(More)