Of mice and mental models: Neuroscientific implications of risk-optimized behavior in the mouse

(Medical Xpress) — Regardless of an organism’s biological complexity, every encephalized animal continuously makes under-informed behavioral choices that can have serious consequences. Despite its ubiquity, however, there’s a long-standing question about its neurological basis – namely, whether these choices are made through probabilistic world models constructed by the brain, or by reinforcement of learned associations. Recently, however, scientists in the Department of Psychology at Rutgers University found that reinforcement cannot account for the rapidity with which mice modify their behavior when the chance of a given phenomenon changes. The researchers say this indicates that mice may have primordially-evolved neural capabilities to represent likelihood and perform calculations that optimize their resulting behavior – and therefore that such genetic mechanisms can be investigated and manipulated by genetic and other procedures.

No new neurons in the human olfactory bulb

(Medical Xpress) — Research from Karolinska Institutet shows that the human olfactory bulb – a structure in the brain that processes sensory input from the nose – differs from that of other mammals in that no new neurons are formed in this area after birth. The discovery, which is published in the scientific journal Neuron, is based on the age-determination of the cells using the carbon-14 method, and might explain why the human sense of smell is normally much worse than that of other animals.