Here are some really staggering numbers for your consideration.
There are around 100 billion neurons (brain cells) currently living in your cerebral cortex. These neurons communicate through electrochemical signals that are transported via synapses, which are structures that serve as the gateway to each neuron
If each of these 100 billion neurons only ever established one synaptic connection with one other neuron, the connections in your brain would easily equal the number of stars in the Milky Way galaxy.
However, our neurons make far more connections than that: an average of between 1,000 and 10,000 synapses exist for each cell. In total, this means that the number of connections in your brain is somewhere in the range of 1000 trillion. Researchers have estimated the number of stars in the universe to be between 10 sextillion and 1 septillion, so for the sake of simplicity, we will say that the number of actual connections in the human brain equals about half of the total stars in the universe.
But the truly astonishing part of this comparison is when we examine the total number of potential connections between neurons in the brain. The example used in this article factors only 1 billion, 1/100th of the actual number of neurons in the brain. According to these calculations, the possible connections total to 3 x 10^5,000,000,000, which is far greater a number than the estimated total mass of the entire universe. In short, there are more potential synaptic connections in your brain than the number of atoms in the universe.