A rat study has revealed that as the rats slowly learned a new rule, groups of neurons in the medial frontal cortex switched quite abruptly to a new pattern corresponding directly to the shift in behavior, rather than showing signs of gradual transition. Such sudden neural and behavioral transitions may correspond to so- called "a-ha" moments, and support the idea that rule learning is an evidence-based decision process, perhaps accompanied by moments of sudden insight.
Latest Research News
For a long time, it has been assumed that mammals have different (better!) brains than other animals — partly because of the highly convoluted neocortex. Specifically, the mammalian neocortex features layers of cells (lamination) connected by radially arrayed columns of other cells, forming functional modules characterized by neuronal types and specific connections. Early studies of homologous regions in nonmammalian brains found no similar arrangement.
A rhesus monkey study has revealed which dendritic spines are lost with age, providing a new target for therapies to help prevent age-association cognitive impairment. It appears that it is the thin, dynamic spines in the dorsolateral prefrontal cortex, which are key to learning new things, establishing rules, and planning, that are lost. Learning of a new task was correlated with both synapse density and average spine size, but was most strongly predicted by the head volume of thin spines.
Why do women tend to be better than men at recognizing faces? Two recent studies give a clue, and also explain inconsistencies in previous research, some of which has found that face recognition mainly happens in the right hemisphere part of the face fusiform area, and some that face recognition occurs bilaterally. One study found that, while men tended to process face recognition in the right hemisphere only, women tended to process the information in both hemispheres.
A comprehensive study reveals how the ‘Alzheimer's gene’ (APOE ε4) affects the nature of the disease. It is not simply that those with the gene variant tend to be more impaired (in terms of both memory loss and brain damage) than those without. Different parts of the brain (and thus different functions) tend to be differentially affected, depending on whether the individual is a carrier of the gene or not. Carriers displayed significantly greater impairment on tests of memory retention, while noncarriers were more impaired on tests of working memory, executive control, and lexical access.
A study involving 163 overweight children and adolescents aged 10 to 17 has revealed that moderate to severe obstructive sleep apnea was linked to both lower academic grades and behavioral concerns. None of the students with moderate to severe OSA had an "A" average, and 30% had a "C" average or lower. In contrast, roughly 15% of those without sleep-disordered breathing had an "A" average, and only about 15% had a "C" average or lower. The results remained significant after adjustment for sex, race, socioeconomic status and sleep duration on school nights.
Another study showing the cognitive benefits of meditation has revealed benefits to perception and attention. The study involved 30 participants attending a three-month meditation retreat, during which they attended group sessions twice a day and engaging in individual practice for about six hours a day. The meditation practice involved sustained selective attention on a chosen stimulus (e.g., the participant’s breath).
We know that lead damages the brain, and that it does so by somehow affecting the release of neurotransmitters at synapses (the process by which neurons pass messages on). Now a new study explains exactly what lead does. Apparently, during the formation of synapses, lead lowers the levels of key proteins involved in neurotransmitter release (synaptophysin and synaptobrevin), and reduces the number of fast-releasing sites. These effects may occur through the inhibition of the NMDA receptor (which produced similar effects), disrupting the release of BDNF.
A study involving 54 older adults (66-76) and 58 younger adults (18-35) challenges the idea that age itself causes people to become more risk-averse and to make poorer decisions. Analysis revealed that it is individual differences in processing speed and memory that affect decision quality, not age. The stereotype has arisen no doubt because more older people process slowly and have poorer memory.
As I get older, the question of how we perceive speech becomes more interesting (people don’t talk as clearly as they used to!). So I was intrigued by this latest research that reveals that it is not so much a question of whether consonants or vowels are more important (although consonants do appear to be less important than vowels — the opposite of what is true for written language), but a matter of transitions.