• Attention
• Hormones
• Lobes
• Long-Term Memory
• Memory
• Nervous System
• Neuroplasticity
• Neurotransmitters
• Procedural Memory
• Senses
• Synaptic Pruning
• Working Memory

There’s a burst of activity as the neurons in a newborn’s brain sprout dendrites and axons, forming millions of new connections. In fact, from the time you were born until your toddler years, the number of connections from each neuron in your cerebral cortex increased to 15,000, from about 2,500. Your brain doesn’t actually need all of these connections, so in the following years, millions disappeared, in a process called synaptic pruning. At the same time, many connections became stronger. Neuroscientists often describe the “use it or lose it” principle to explain why some connections are strengthened while others are pruned. The most active connections—those you use most often—become stronger. In fact, you make new connections every time you experience or learn something new (sprouting). But the connections that aren’t used become weaker and eventually wither away (pruning).