This Week in Neuroscience News – 4/16/17


More brain stimulation news came this week when researchers at the University of Zurich pinpointee the brain mechanism that regulates decisions between honesty and self-interest. Using transcranial direct current stimulation, they could even increase honest behavior.

The work highlights a deliberation process between honesty and self-interest in the right dorsolateral prefrontal cortex (rDLPFC).

Christian Ruff, UZH Professor of Neuroeconomics, said:

“This finding suggests that the stimulation mainly reduced cheating in participants who actually experienced a moral conflict, but did not influence the decision making process in those not in those who were committed to maximizing their earnings. These brain processes could lie at the heart of individual differences and possibly pathologies of honest behavior”

When researchers applied transcranial direct current stimulation over a region in the right dorsolateral prefrontal cortex, during a dice rolling task, participants were less likely to cheat. However, the number of consistent cheaters remained the same. (Michel André Maréchal, et al. Increasing honesty in humans with noninvasive brain stimulation)

Another story featuring the prefrontal cortex showed that it’s neurons helped teach the hippocampus to process memories. The research looked at memory flexibility and interference, the mechanisms by which the brain interprets events and anticipates their likely outcomes.

The study was by Matthew Shapiro, PhD, from Icahn School of Medicine at Mount Sinai. The results suggest that neurons in the medial prefrontal cortex instruct hippocampal neurons to learn rules which differentiate memory-based predictions in otherwise identical situations. The mechanisms revealed could improve understanding of psychiatric conditions, such as schizophrenia, that involve hippocampal and prefrontal cortex interactions.

Epilepsy, Parkinsons And Alzheimer’s

NIH-funded research involving 446 children reported that insight into differences in treatment response in patients with childhood absence epilepsy could come from precision medicine. Childhood absence epilepsy (CAE) is the most common form of pediatric epilepsy.

The results suggest knowledge of specific gene variants in children with CAE may help predict what drugs would work best for them. For example, two specific forms of the calcium channel genes appeared more often in children for whom ethosuximide did not work.

Two other variants of the calcium channel genes were found in children for whom lamotrigine did work, but one form of the drug transporter gene was associated with a continuation of seizures. (Glauser TA et al. Pharmacogenetics of Antiepileptic Drug Efficacy in Childhood Absence Epilepsy. Annals of Neurology. March 25, 2017)

A new study published this week in the Proceedings of the National Academy of Sciences hones our understanding of a uniquely human skill; the ability to instantaneously assess a new environment and get oriented thanks to visual cues.

Whereas humans can look at a complex landscape like a mountain vista and almost immediately orient themselves to navigate its multiple regions over long distances, other mammals such as rodents orient relative to physical cues — like approaching and sniffing a wall — that build up over time.

The way humans navigate their surroundings and understand their relative position includes an environment-dependent scaling mechanism, an adaptive coordinate system with differences from other mammals, according to the study led by researchers at The University of Texas at Austin.

“Our research, based on human data, redefines the fundamental properties of the internal coordinate system,"

said Zoltan Nadasdy, lead author of the study and an adjunct assistant professor in the university’s Department of Psychology.

“Dysfunction in this system causes memory problems and disorientation, such as we see in Alzheimer’s disease and age-related decline. So, it’s vital that we continue to further our understanding of this part of the brain,” he said.

By measuring brain activity in the entorhinal cortex, researchers identified three previously unknown traits of the system:

  • Humans rescale their internal coordinate system according to the size of each new environment. This flexibility differs from rodents’ rigid map that has a constant grid scale and empowers humans to navigate diverse places.

  • When seeking navigational cues in any given location, humans automatically align their internal compass with the corners and shape of the space. In contrast, rodents do so relative to the walls of the environment through physical exploration.

  • The nature of the coordinate system differs between humans and rodents—Cartesian and hexagonal respectively.

(Zoltan Nadasdy et al. Context-dependent spatially periodic activity in the human entorhinal cortex)

A pair of preclinical studies suggest that silencing the SCA2 gene, using antisense oligonucleotide therapy, may help prevent neurological symptoms associated with spinocerebellar ataxia type 2 and amyotrophic lateral sclerosis.

Finally, in Sweden, Karolinska Institute researchers report a method to force astrocytes to transmute into dopamine neurons, that work like normal midbrain dopamininergic neurons. The finding, could be the first step in an alternate therapeutic approach for Parkinson’s disease.