Press releases
Please quote Nature Neuroscience as the source of these items.
The June 2007 issue of Nature Neuroscience is available online.
June 2007
Recovering from amblyopia
Nature Neuroscience pp 679 - 681
Environmental enrichment in adulthood promotes recovery from amblyopia, according to a study in the June issue of Nature Neuroscience. These results suggest that the loss of visual acuity caused by abnormal visual experience early in life may be treatable in adults.
Alessandro Sale and colleagues deprived rats of visual input in one eye during development, a manipulation known to cause permanent changes in visual acuity (amblyopia). Later, during adulthood, animals were deprived of input to the other eye, and placed in an enriched environment, which led to increased exploratory behaviour and sensory-motor stimulation. After two to three weeks in the new environment, the animals fully recovered from amblyopia, despite being well beyond the traditional critical period for neural plasticity.
Physiological recordings suggested that the change in environmental conditions re-activated neural plasticity that had ended before adulthood. Pharmacological experiments indicated that the crucial factor in increasing this plasticity was a decrease in inhibition within the visual cortex. These findings raise the possibility that environmental enrichment may have therapeutic potential to promote recovery of normal visual functions in adults with amblyopia caused by childhood conditions such as strabismus - in which the eyes do not align properly with each other.
Environmental enrichment in adulthood promotes amblyopia recovery through a reduction of intracortical inhibition pp 679 - 681
Alessandro Sale, José Fernando Maya Vetencourt, Paolo Medini, Maria Cristina Cenni, Laura Baroncelli, Roberto De Pasquale & Lamberto Maffei
Published online: 29 April 2007 | doi10.1038/nn1899
The wisdom of youth
Nature Neuroscience pp 787 - 791
Older adults have an asymmetric neural response to monetary gains and losses, finds a new study in the June issue of Nature Neuroscience. Compared to a younger group, older adults have a lower response to losses but not gains.
Gregory Samanez-Larkin and colleagues compared adults aged 19-27 years with another group who were over 65 years old. While being scanned by functional magnetic resonance imaging (fMRI), both groups completed a task in which they had to respond to a cue either to get a monetary reward or to avoid a loss. On each trial, both groups also rated their positive or negative arousal at the prospect of the potential gain or loss.
The authors found that while both the young and older adults had similar positive arousal at the prospect of an impending gain, the older group had less negative arousal to anticipated losses. The neural response mirrored this behavior - activity in a part of brain called the striatum was similarly changed by the amount of gain in both the young and old adults, but only the young adults showed a change in activity paralleling the amount of anticipated loss. Previous work has identified the striatum in reward processing, and this study shows that the functioning of this area depends on age as well. These findings suggest that older and younger adults could weigh gains and losses differently when making decisions.
Anticipation of monetary gain but not loss in healthy older adults pp 787 - 791
Gregory R Samanez Larkin, Sasha E B Gibbs, Kabir Khanna, Lisbeth Nielsen, Laura L Carstensen & Brian Knutson
Published online: 29 April 2007 | doi10.1038/nn1894
A red-letter day for brain connectivity
Nature Neuroscience pp 792 - 797
Insights into grapheme-colour synesthesia are presented in a paper in the June issue of Nature Neuroscience. People with this condition - who see a cascade of colours associated with individual letters when looking at a page of text - appear to have more neural connections at several locations in the brain.
Romke Rouw and Steven Scholte used a technique called diffusion tensor imaging (DTI) to look at brain differences between grapheme-colour synesthetes and healthy controls without this condition. DTI allows non-invasive visualisation of the white matter tracts, or axons, connecting neural cell bodies. The researchers found that synesthetes had increased connectivity at three locations in the brain: the right fusiform gyrus, near regions involved in word and color processing, and the left intraparietal sulcus and frontal cortex, both part of a network of regions involved in binding and consciousness.
The study also found differences among the synesthetes, according to how they perceived the association between words and colors. Some synesthetes, known as projectors, report experiences that are projected into the external world, while others, known as associators, report experiences that appear in their 'mind's eye'. The degree of structural connectivity in a region known as the right temporal cortex was correlated with the subjective location of the synesthetic experience.
Increased structural connectivity in grapheme-color synesthesia pp 792 - 797
Romke Rouw & H Steven Scholte
Published online: 21 May 2007 | doi10.1038/nn1906
