Stress can become toxic when a child has frequent or prolonged experiences like abuse, neglect or poverty without adult support.
Basic motor skills start developing shortly after birth; fine motor ability begins developing in the second half of the first year. As a child grows, the number of neurons remains relatively stable, but each cell grows, becoming bigger and heavier. Brain functions. This electrical activity can be measured and displayed as a wave form called brain wave or brain rhythm.
A given neuron receives hundreds of inputs, almost exclusively on its dendrites and cell body. 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. The neural network expands exponentially. That depends on the language being spoken—or the identity of the neurotransmitter that is released.
The numbers of connections formed among neurons in an infant's brain are amazing:.
Connections that are used become permanent. They allow neurons to communicate with each other, computations to be performed, and information to be processed.
For instance, scientists have determined that the neurons for vision begin sending messages back and forth rapidly at 2 to 4 months of age, peaking in intensity at 8 months. Ask a neuroscientist your questions about the brain.
But regular eye exams, starting as early as two weeks of age, can detect problems that, if left uncorrected, can cause a weak or unused eye to lose its functional connections to the brain. Synaptic transmission Picture from Wikipedia http: This pulse travels rapidly along the cell's axon, and is transferred across a specialized connection known as a synapse to a neighbouring neuron, which receives it through its feathery dendrites.
The ongoing genetic revolution has made these questions more addressable than ever before, yet we still have a long way to go. Each axon terminal contains thousands of membrane-bound sacs called vesicles , which in turn contain thousands of neurotransmitter molecules each.
As the neurons mature, more and more synapses are made. The connections between neurons are not static, though, they change over time. Most neurons have a cell body, an axon, and dendrites.
In the case of motor neurons, the axon may travel from the spinal cord all the way down to a foot muscle. It used to be thought that the role of glial cells was limited to the physical support, nutrition and repair of the neurons of the central nervous system.
Each protein family is smaller in flies or worms than in mice or people, but its functions are quite similar. Unlike other cells, neurons never divide, and neither do they die off to be replaced by new ones. Dendrites extend from the neuron cell body and receive messages from other neurons.