Tuesday, 15 December 2015

Neuroscience news of the week

Just thought I'd do a little round up of some of the more interesting Neuroscience news stories that have been published in the past few weeks! I've been really busy with my Literature Review and final year project aaaand applying for a MSc course so haven't had much time to write a new blog post! 

This post is based on a radio show I hosted last week with one of my fellow Neuroscience students, Georgie. If you'd like to hear more on any of these topics, please click here

1. Lab-grown dopamine neurons could help treat Parkinson’s disease (PD)
Scientists at the University of Buffalo may have discovered a new method for reprogramming human cells to produce ‘designer dopamine neurons’, which could be potentially life-saving for those with PD. 

PD is a progressive disease of the NS. Those with the disease often exhibit symptoms such as tremor, muscular rigidity and slow, imprecise movement. It is associated with degeneration of the basal ganglia and a deficiency of the neurotransmitter dopamine.

A loss of dopamine neurons in the Substantia Nigra (another area of the brain) is also associated with PD. These neurons degenerate due to inflammation and oxidative stressBecause of this, scientists have been trying to generate an effective way to produce these dopamine neuron cells in the lab, but so far with little success.

Some areas of the brain affected by PD, including the Substantia Nigra
@Wikimedia Commons

This new discovery from the scientists at UoB, however, has identified a protein called p53 as an instrumental factor in the degeneration of dopamine neurons. The role of p53 usually is to read the genetic information of a cell and prevent it from being converted to something else.By acting on p53, the team was able to supress its activity. This has opened up the potential to reprogram cells, such as the team’s conversion of human fibroblasts into dopaminergic neurons.

To do this, the team inhibited p53, and then added many other molecules that are important for the development and expression of dopaminergic neurons. The neurons the team produced were of the same type as found in the ventral midbrain area, which is where the Substantia Nigra is located.The difference in this study and others of a similar kind is that this team was able to produce the neurons at an extremely high pace – converting 60% of the fibroblasts into neurons in 10 days. Previously other teams had taken 2 weeks to convert just 5%!

More info on this story here.

2. Scientists have enabled a woman to feel pain again

Pain is unpleasant, but extremely important so that we know when external stimuli is harming us. Analgesia is the inability to feel pain – people with this condition face unfathomable amounts of dangers in their everyday lives (i.e. have to check themselves every time they sit down, get out the shower etc. for any cuts/scratches they would not have felt happen).
Before, the woman could not detect any pain, including paper cuts.
@Wikimedia Commons

Analgesia is caused by a mutation in the gene SCN9A which encodes a type of sodium channels in the brain, Nav1.7. These normally facilitate the transmission of pain signals. 

By inhibiting the expression of SCN9A in mice, researchers noted that they could prevent the formation of Nav1.7 channels AND stimulate an increase in endogenous opioid peptides - which ‘dull’ feelings of pain. Endogenous is a term that means something that is intrinsic to the body, that we don't get it from our environment or surroundings.

The researchers administered naloxone, an opioid antagonist, inhibiting this reduced pain feeling. They then applied both heat and pressure to test withdrawal of the patient's limbs – found “a dramatic reversal of analgesia and restoration of thermal and mechanical pain thresholds”.

When they tested this on a woman with analgesia (who was completely unaware of heat under normal conditions) the administration of naloxone allowed her to recognise this heat 80 per cent of the time. However, this is not a long-term solution as effects wear off after an hour, but the study did reveal new information about pain relievers. This information is thought to be adopted for new clinical trials in 2017.

More info here.

3. How our brains overrule our senses

A complex new study published in Nature Neuroscience has identified processes in the brains of mice that may explain why we can look at images and see two different ones (like the duck and rabbit illusion image). Scientists have known for a long time that when stimuli are weak, such as an object seen through fog in the distance or a faint sound, repetition of these stimuli can result in different perceptions in the brain.

The duck-rabbit illusion that confuses our brain
@Wikimedia Commons

A senior researcher from the study, Dr Daniel O’Connor, said that "in everyday life, we experience weak stimuli all the time… when the brain receives [this], it can interpret that information in multiple ways". The study investigated this phenomenon in mice by gently tickling a single mouse whisker, a sensory organ of mice. The researchers trained the mice to indicate when it felt tickled, by training the mice to lick a water spout in their cage when they perceived a tickle.

The researchers then paired this indication of tickle sensation with the activity of neurons that they monitored. When the mice perceived a tickle and indicated so, there was a higher level of activity in the cortex (specifically in the primary sensory area, also known as S1) as compared to when the mouse was tickled but did not perceive it – i.e. the mice themselves responded differently to the same stimulus.

The researchers investigated further and then looked at specific neurons that connected to individual neurons in the whiskers. They found that these neurons responded equally to all tickles, whether the mice perceived it or not. They then looked back to the cortex to find an explanation for the variability in perception.

Deeper in the brain, in an area called S2 (or the secondary sensory area of the cortex), they found neurons that mirrored exactly the neurons with direct connections to the whiskers.
This tells us that something is going on the S1. O’Connor says it implies that "activity in S1 is being shaped by S2… and that what we perceive is not a fixed thing based only on sensory input but is influenced by our prior experiences and the current state of our brain".

More info here

1 comment:

  1. Thank you so much for your post as it provides useful medical information for people who are not related to medical field and next easy for them to understand such diseases in a very easy way