| |
Wagenaar, D. A. (2012). An optically stabilized fast-switching light emitting diode as a light source for functional neuroimaging. PLoS One, 7(1), e29822.
Zusammenfassung: Neuroscience research increasingly relies on optical methods for evoking neuronal activity as well as for measuring it, making bright and stable light sources critical building blocks of modern experimental setups. This paper presents a method to control the brightness of a high-power light emitting diode (LED) light source to an unprecedented level of stability. By continuously monitoring the actual light output of the LED with a photodiode and feeding the result back to the LED's driver by way of a proportional-integral controller, drift was reduced to as little as 0.007% per hour over a 12-h period, and short-term fluctuations to 0.005% root-mean-square over 10 seconds. The LED can be switched on and off completely within 100 mus, a feature that is crucial when visual stimuli and light for optical recording need to be interleaved to obtain artifact-free recordings. The utility of the system is demonstrated by recording visual responses in the central nervous system of the medicinal leech Hirudo verbana using voltage-sensitive dyes.
Schlüsselwörter: Animals; Cells, Cultured; Diagnostic Techniques, Neurological/instrumentation; Functional Neuroimaging/*instrumentation/*methods; Leeches/cytology; Light; Lighting/instrumentation/*methods; Models, Biological; Optics and Photonics/instrumentation; Vision, Ocular/*physiology; Visual Pathways/metabolism/physiology
|
|
Valkova, T., & Vacha, M. (2012). How do honeybees use their magnetic compass? Can they see the North? Bull Entomol Res, , 1–7.
Zusammenfassung: While seeking food sources and routes back to their hive, bees make use of their advanced nervous and sensory capacities, which underlie a diverse behavioral repertoire. One of several honeybee senses that is both exceptional and intriguing is magnetoreception – the ability to perceive the omnipresent magnetic field (MF) of the Earth. The mechanism by which animals sense MFs has remained fascinating as well as elusive because of the intricacies involved, which makes it one of the grand challenges for neural and sensory biology. However, investigations in recent years have brought substantial progress to our understanding of how such magneto-receptor(s) may work. Some terrestrial animals (birds) are reported to be equipped even with a dual perception system: one based on diminutive magnetic particles – in line with the original model which has also always been hypothesized for bees – and the other one, as the more recent model describes, based on a sensitivity of some photochemical reactions to MF (radical-pair or chemical mechanism). The latter model postulates a close link to vision and supposes that the animals can see the position of the geomagnetic North as a visible pattern superimposed on the picture of the environment. In recent years, a growing body of evidence has shown that radical-pair magnetoreception might also be used by insects. It is realistic to expect that such evidence will inspire a re-examination and extension or confirmation of established views on the honeybee magnetic-compass mechanism. However, the problem of bee magnetoreception will not be solved at the moment that a receptor is discovered. On the contrary, the meaning of magnetoreception in insect life and its involvement in the orchestration of other senses is yet to be fully understood. The crucial question to be addressed in the near future is whether the compass abilities of the honeybee could suffer from radio frequency (RF) smog accompanying modern civilization and whether the fitness of this dominant pollinator might be affected by RF fields. The goal of this review is to provide an overview of the path that the behavioral research on honeybee magnetoreception has taken and to discuss it in the context of contemporary data obtained on other insects.
|
|
Wu, L. Q., & Dickman, J. D. (2012). Neural Correlates of a Magnetic Sense. Science, .
Zusammenfassung: Many animals rely on the Earth's magnetic field for spatial orientation and navigation. However, how the brain receives and interprets magnetic field information is unknown. Support for the existence of magnetic receptors in the vertebrate retina, beak, nose, and inner ear has been proposed and immediate gene expression markers have identified several brain regions activated by magnetic stimulation, but the central neural mechanisms underlying magnetoreception remain unknown. Here, we describe neuronal responses in the pigeon's brainstem that show how single cells encode magnetic field direction, intensity, and polarity-qualities that are necessary to derive an internal model representing directional heading and geosurface location. Our findings demonstrate a neural substrate for a vertebrate magnetic sense.
|
| |
Diese Datenbank wird gepflegt von Institute of Neurobiology (Neurobio). Bitte senden Sie Fragen und Vorschläge an unsere Feedback-Adresse. Die technische Implementierung dieser Datenbank basiert auf refbase, einer freien Datenbank-Schnittstelle zur Verwaltung wissenschaftlicher Literatur und Artikel. |
 |
|
