The researchers used functional magnetic resonance imaging scans to record subtle brain-circuitry changes in the patients as they performed Web searches and read book passages. fMRI scans track the intensity of cell responses in the brain by measuring the level of blood flow through the brain

But Internet searches revealed differences between the two groups. While all the participants showed the same activity as during the book-reading, the Web-savvy group also registered activity in the frontal, temporal and cingulate areas of the brain, whereas those new to the net did not. (These areas of the brain control decision-making and complex reasoning.)

Compared with reading, the wealth of choices on the Internet requires that people make decisions about what to click on, which engages important cognitive circuits in the brain

Neurons exist in a number of different shapes and sizes and can be classified by their morphology and function. The anatomist Camillo Golgi grouped neurons into two types; type I with long axons used to move signals over long distances and type II without axons. type I cells can be further divided by where the cell body or soma is located. The basic morphology of type I neurons, represented by spinal motor neurons, consists of a cell body called the soma and a long thin axon which is covered by the myelin sheath. Around the cell body is a branching dendritic tree that receives signals from other neurons. The end of the axon has branching terminals (axon terminal) that release transmitter substances into a gap called the synaptic cleft between the terminals and the dendrites of the next neuron.