The loss is in the eye of the beholder

RECENT ADVANCES IN RESTORATION OF SIGHT

 

John Freke, the first ophthalmic surgeon in Britain started practising at St Bart’s around the time when the Bristol Royal Infirmary opened its doors, but it was not until Baron de Wenzel’s appointment in 1772 that the specialty gained its true recognition. After becoming an oculist to King George III, de Wenzel perfected his skill in removing the cataracts, which was seen at a time as an almost miraculous deed of evangelical magnitude (1).

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Engineering Music to Sound Better With Cochlear Implants

 

When hearing loss becomes so severe that hearing aids no longer help, a cochlear implant not only amplifies sounds but also lets people hear speech clearly.

Music is a different story.

“I’ve pretty much given up listening to music and being able to enjoy it,” says Prudence Garcia-Renart, a musician who gave up playing the piano a few years ago.

“I’ve had the implant for 15 years now and it has done so much for me. Before I got the implant, I was working but I could not use a phone, I needed somebody to take notes for me at meetings, and I couldn’t have conversations with more than one person. I can now use a phone, I recognize people’s voices, I go to films, but music is awful.”

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Blind woman’s joy as she is able to read the time thanks to ‘bionic eye’

A patient who is the first in the UK to receive the world’s most advanced ‘bionic eye’ has been able to read the time for the first time in more than five years.

The moment Rhian Lewis, 49, realised she had correctly told the time is captured on BBC’s ‘Trust Me I’m A Doctor’, to be broadcast on Wednesday 6 January 2016.

Surgeons at the Oxford Eye Hospital at Oxford’s John Radcliffe Hospital implanted a tiny electronic chip at the back of Rhian’s retina in her right eye as part of ongoing NHS-funded research of the technology.

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Lamination Speeds the Functional Development of Visual Circuits

 

New research from the Department of Developmental Neurobiology at the Institute of Psychiatry, Psychology & Neuroscience, King’s College London, sheds light into the role of layers in the brain. The study, published in Neuron, shows that the formation of layers speeds the development of neuronal circuits although, surprisingly, it is not crucial for the establishment of functional and cell-type specific connections.

  • Robo2 directs lamination of direction-selective retinal axons and tectal dendrites
  • Tectal lamination is required for rapid assembly of direction-selective circuits
  • Functional direction-selective circuits eventually form when lamination is lost
  • Structural plasticity compensates for the loss of tectal lamination

Summary

A common feature of the brain is the arrangement of synapses in layers. To examine the significance of this organizational feature, we studied the functional development of direction-selective (DS) circuits in the tectum of astray mutant zebrafish in which lamination of retinal ganglion cell (RGC) axons is lost. We show that although never laminar, the tuning of DS-RGC axons targeting the mutant tectum is normal. Analysis of mutant tectal neurons at late developmental stages reveals that directional tuning is indistinguishable from wild-type larvae. Furthermore, we show that structural plasticity of tectal dendrites and RGC axons compensates for the loss of lamination, establishing connectivity between DS-RGCs and their normal tectal targets. However, tectal direction selectivity is severely perturbed at earlier developmental stages. Thus, the formation of synaptic laminae is ultimately dispensable for the correct wiring of direction-selective tectal circuits, but it is crucial for the rapid assembly of these networks.

Full article: http://www.cell.com/neuron/abstract/S0896-6273(15)00886-7

Nikolas Nikolaou and Martin P. Meyer

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