Brain’s Face Processing Ability does Reduce with Age

GLASGOW A British study suggests that the ability to identify a face, when it is shown for only a fraction of a second, reduces as people age.

Lead researcher Guillaume Rousselet, from the University of Glasgow, came to this conclusion after analysing electric activity from the brains of young and old people as they watched pictures of faces with cloud-like noise.

He said: “Very few studies have attempted to measure the effect of ageing on the time-course of visual processing in response to complex stimuli like faces. We found that, as well as a general reduction in speed in the elderly, one particular component of the response to a face, the N170, is less sensitive to faces in the elderly.”

The N170 occurs 170 milliseconds after a stimulus is presented.

The researchers revealed that it was more closely associated with the appearance of a face among the young subjects.

However, in older subjects, the researcher said that it occurred also in response to noise, perhaps implying reduced ability to differentiate faces from noise.

Revealing the findings of the study, Rousselet said: “Our data support the common belief that as we get older we get slower. Beyond this general conclusion, our research provides new tools to quantify by how much the brain slows down in the particular context of face perception. Now, we need to identify the reasons for the speed reduction and for the heterogeneity of the effects – indeed, why the brains of some older subjects seem to tick as fast as the brains of some young subjects is, at this point, a complete mystery.”

The study has been published in the journal BMC Neuroscience.

How Addictive Drugs Influence Learning and Memory

HOUSTON – In a new study on mice, researchers have found why and how the use of addictive drugs take control of reward signals and influence neural processes associated with learning and memory.

The study could help explain how drug-associated memories, such as the place of drug use, drive and perpetuate the addiction.

It is known that the neurochemical dopamine, a key player in the brain’s reward system, is involved in the process of addiction.

Research has indicated that dopamine participates in neural processes associated with learning, such as the strengthening of neuronal connections, called synaptic potentiation.

Evidence has also implicated the hippocampus, a deep-brain structure that is critical for formation of new memories, in the development of drug addiction.

“Although addictive drugs like nicotine have been shown to influence the induction of synaptic potentiation, there has been little or no research in freely moving animals that monitors ongoing induction of synaptic potentiation by a biologically relevant drug dose,” explains senior author Dr. John Dani from the Department of Neuroscience at the Baylor College of Medicine in Houston, Texas.

The researchers recorded from the brains of freely moving mice while applying physiologically relevant concentrations of nicotine, the addictive component in tobacco.

The researchers found that nicotine induced synaptic potentiation correlated with the mice learning to prefer a place associated with the nicotine dose.

Importantly, these effects required a local dopamine signal within the hippocampus.

The finding reinforces the view that dopamine enables memory for specific events.

Overall, the results point to some intriguing possibilities about how drug-associated memories might contribute to behaviors associated with addiction.

“An animal’s memories or feelings about the environment are updated when the dopamine signal labels a particular event as important, new, and salient. Normally these memories help us to perform successful behaviors, but in our study, those memories were linked to the addictive drug.

When specific environmental events occur, such as the place or people associated with drug use, they are capable of cuing drug-associated memories or feelings that motivate continued drug use or relapse,” concluded Dani.

The study has been published in the latest issue of the journal Neuron.