An imaging study reveals why older adults are better at remembering positive events. The study, involving young adults (ages 19-31) and older adults (ages 61-80) being shown a series of photographs with positive and negative themes, found that while there was no difference in brain activity patterns between the age groups for the negative photos, there were age differences for the positive photos. In older adult brains, but not the younger, two emotion-processing regions (the ventromedial prefrontal cortex and the amygdala) strongly influenced the memory-encoding hippocampus.
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It is well known that the onset of puberty marks the end of the optimal period for learning language and certain spatial skills, such as computer/video game operation. A mouse study has now revealed that this is connected to an increase in a specific brain receptor (named Alpha4-Beta-Delta GABA-A). However, the learning deficit could be reversed by application of a stress steroid (THP). Although this natural hormone acts on adults like a tranquilizer, in adolescents it has a stimulation effect. The findings suggest that mild stress may be useful to improve learning in adolescents.
A new study provides more support for the idea that cognitive decline in older adults is a product of a growing inability to ignore distractions. Moreover, the study, involving 21 older adults (60-80) shown random sequences of pictures containing faces and scenes and asked to remember only the scene or the face, reveals that being given forewarning about which specific pictures would be relevant (say the second, or the fourth) did not help.
Supporting the idea that repeated anaesthesia in children can lead to memory impairment, a rodent study has revealed that repeated anaesthesia wiped out a large portion of the stem cells in the hippocampus. This was associated with impaired memory in young animals, which worsened as they got older. The effect did not occur in adult animals. A similar effect has also been found with radiotherapy, and animal studies have found physical activity after radiotherapy results in a greater number of new stem cells that partly replace those that have been lost.
A computerized self test (CST) has been developed that is 96% accurate in diagnosing Alzheimer’s and MCI-A (compared to 71% for the MMSE and 69% for the Mini-Cognitive — tests currently in use). Moreover, the test accurately classified 91% of the six experimental groups (control, MCI, early Alzheimer's, mild to moderate, moderate to severe, and severe) as compared to 54% for the MMSE and 48% for the Mini-Cog. The brief, interactive online test is designed to be used in the primary care setting, where physicians may not have detailed training in recognizing cognitive impairments.
It’s well established that we are better at recognizing faces of our own racial group, but a new study shows that this ability disappears when we’re mildly intoxicated. The study tested about 140 university students of Western European and east-Asian descent and found that recognition of different-race faces was unaffected by alcohol, yet both groups showed impaired recognition of own-race faces, bringing it down to about the same level of accuracy as for different-race faces. Those given a placebo drink were unaffected.
Several reports have come out in recent years on how recent events replay in the hippocampus, a process thought to be crucial for creating long-term memories. Now a rat study suggests that these replays are not merely echoes of past events, but a dynamic process aimed at improving decision-making. Rather than being solely replays of recent or frequent paths through the maze, the replays were often paths that the rats had rarely taken or, in some cases, had never taken, as if the rats were trying to build maps to help them make better navigation decisions.
A study in which 60 young adult mice were trained on a series of maze exercises designed to challenge and improve their working memory ability (in terms of retaining and using current spatial information), has found that the mice improved their proficiency on a wide range of cognitive tests, and moreover better retained their cognitive abilities into old age.
Like human faces, infants are predisposed to pay attention to words. Now a new study shows that they learn concepts from them from a very early age. In the study, in which 46 three-month-old infants were shown a series of pictures of fish that were paired either with words (e.g., "Look at the toma!") or beeps (carefully matched to the words for tone and duration), those who heard the words subsequently showed signs of having formed the category “fish”, while those who heard the tones did not.
A new test has been developed that measures amyloid-beta oligomers in the cerebrospinal fluid, promising a reliable means of early diagnosis. In a comparison of patients with Alzheimer’s, patients with MCI that later developed into Alzheimer’s, and controls, levels of these protein fragments directly correlated with Alzheimer’s, and was more accurate than levels of the more usual amyloid plaques.