How exactly are memories stored in brain cells? After years of study, much evidence supports the idea that memory involves a persistent change in synapses, the connections between neurons.

Studies of the body’s own pain-control system demonstrated the existence of naturally occurring opioids — the endorphins.

Once the neurons reach their final location, they must make the proper connections so that a particular function, such as vision or hearing, can emerge.

Processing information from the sensory systems is one of many functions of the brain. Such information is often the first step in other brain activities, including learning and retaining knowledge.

Genes and the environment converge powerfully during early sensitive windows of brain development to form the neural circuits underlying behavior. Although most neuronal cell death occurs in the embryo, the paring down of connections occurs in large part during critical periods in early postnatal life.

A major breakthrough in understanding how the brain accomplishes learning and memory began with the study of a person known by his initials, H.M.

Cells within the nervous system, called neurons, communicate with each other in unique ways. The neuron is the basic working unit of the brain.

Brain injury is all too common, but treatments are being improved constantly. Those who survive a brain injury face a lifetime of disability, with economic costs approaching $60 billion annually.

Currently approved treatments for Alzheimer’s disease do not modify the course of the disease and offer only temporary mitigation of some symptoms, such as agitation, anxiety, unpredictable behavior, sleep disturbances, and depression.

The ability to react quickly in response to threatening events has been with us since the time of our earliest ancestors.