Tuesday, April 12, 2016

Former House Speaker Dennis Hastert abused 4 boys, prosecutors say, Scientists find evidence of 'anti-memories'

Former House Speaker Dennis Hastert abused 4 boys, prosecutors say
By Faith Karimi, CNN  Sun Apr 10, 2016

The revelation comes days before his April 27 sentencing in a financial violation case. He pleaded guilty last year to structuring money transactions to evade reporting where he took massive amounts of funds he was withdrawing.
Investigators said the transactions involved $3.5 million he paid in hush money to one of his accusers.

Prosecutors listed four boys Hastert allegedly abused at a high school in Yorkville, Illinois.
An additional one -- a fifth student -- died years later, according to the document.
Accuser allegedly paid off
The accusations came to light after investigators found out he was paying an ex-student to stay quiet about sexual abuse allegations, prosecutors allege.
The student was among four others who told investigators he abused them, including one who was 14 at the time, the documents allege.

The allegations date to the 1960s and 1970s, according to the prosecutors' court filing.
Hastert will not face sexual abuse charges because the statutes of limitation have expired....

Scientists find evidence of 'anti-memories', and it could change our understanding of neuroscience

Unmasking the process that silences dormant memories. PETER DOCKRILL 6 APR 2016

At one point or another, we've all experienced something that we'd rather forget, so it's a good thing our brains aren't designed to hold onto every single memory forever. If they did, we might never be able to store new, more important information, such as the names of new people you meet or where you parked your car.

But at the level of the neuron, what regulates our ability to store and recall information? New research suggests one of the processes involved is 'anti-memories' – connections between neurons that generate the exact opposite pattern of electrical activity to that of the original memory.

The 'anti-memories' hypothesis comes back to the idea that healthy brain function results from the interaction between two types of brain cells: excitatory and inhibitory neurons. Like the names suggest, the excitatory neurons excite electrical activity in our brains, while inhibitory neurons suppress it....

To examine this, the researchers used functional magnetic resonance imaging (fMRI) and other techniques to take a detailed look at the brain activity of volunteers. The participants were introduced to pairs of shapes, which helped them to form associative memories of the pairs.

"Over 24 hours, the shape associations in the brain became silent. That could have been because the brain was rebalanced or it could simply be that the associations were forgotten," said neuroscientist Helen Barron from the University of Oxford.

"So the following day, some of the volunteers undertook additional tests to confirm that the silencing was a consequence of rebalancing. If the memories were present but silenced by inhibitory replicas, we thought that it should be possible to re-express the memories by suppressing inhibitory activity."

Using transcranial direct current stimulation (tDCS) to apply a low current of electricity to the participants' brains, the team was able to suppress the concentration of certain neurochemicals in the brain, including GABA, which is linked to inhibition. By doing this, they reduced the activity of the anti-memory inhibitory neurons, which meant the memories of the shape associations were re-expressed and came back to the volunteers.

"'We have shown that reducing cortical inhibition can unmask silent memories," said Barron. "This result is consistent with a balancing mechanism – the increase in excitation seen in learning and memory formation, when excitatory connections are strengthened, appears to be balanced out by a strengthening of inhibitory connections. From this we can infer that memories are stored in balanced E/I cortical ensembles.".... 

Volume 90, Issue 1, p191–203, 6 April 2016

Unmasking Latent Inhibitory Connections in Human Cortex to Reveal Dormant Cortical Memories
H.C. Barron, T.P. Vogels, U.E. Emir, T.R. Makin, J. O’Shea, S. Clare, S. Jbabdi, R.J. Dolan, T.E.J. Behrens  DOI: http://dx.doi.org/10.1016/j.neuron.2016.02.031  

....We show that associated stimuli exhibit fMRI repetition suppression in cortex immediately after learning. The magnitude of this cross-stimulus suppression correlates with memory performance measured behaviorally, suggesting that it reflects expression of cortical memory. This cortical memory expression reduces over time and is absent the following day. Cortical memory can however be re-exposed by reduction in local GABA concentrations, induced using tDCS. The extent to which the memory is re-expressed occurs in proportion to the induced GABA reduction. By embedding memories in a spiking network model of memory formation (Vogels and Abbott, 2009, Vogels et al., 2011) and replicating each experimental step in silico, we show that these data are consistent with the balancing of memories via inhibitory synaptic plasticity in cortex.

Unmasking latent inhibitory connections in the human cortex to reveal dormant memories
University of Oxford  
Dr Helen Barron explains her research into how the brain balances excitation and inhibitionThe increase in excitation seen in learning and memory formation, when excitatory connections are strengthened, appears to be balanced out by a strengthening of inhibitory connections. From this we can infer that memories are stored in balanced E/I cortical ensembles.

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