The Life of the Brain

Ever wondered how exactly you’re able to wonder? Shail Bhatt explores the development of the brain throughout our lives.

It’s needless to say that the brain and nervous system are vital: they govern our life and our death, and help us to experience and understand the events in between. Both clearly undergo significant changes during our lives. This process ⁠— how our brain actually becomes conscious, how it starts to tick when we’re born, how it fades out towards the end of our lives⁠ — is truly intriguing, and almost defies comprehension. 

The Beginning

We begin forming our first nerves whilst in the womb. Six weeks into the pregnancy, the first connections between these start to be formed. These connections, or ‘synapses’, start to transmit information to create our first minute muscle contractions and movements. In the next few weeks, these contractions become more prominent and are accompanied by other involuntary actions that stay with us throughout the rest of our lives, such as yawning, hiccupping, swallowing, and stretching. All of this happens in the first trimester of pregnancy, most of it without the mother’s knowledge. 

The second trimester is when things get really interesting, as foetuses begin more complicated processes including breathing movements, sucking, and swallowing reflexes. The cerebral cortex also begins to develop, which is the part of our brain responsible for most of our thinking and feeling. In the final trimester, foetuses start growing more aware, and begin to understand and learn. They have even been shown to respond to certain noises and smells. The cerebral cortex, responsible for our ability to think, remember, and feel, is the last part of the brain to fully mature. 

It would be ridiculously difficult, if not impossible, to remember life as a one month old baby. The truth is, babies only start to display signs of consciousness at the age of five months. This was confirmed through observing how babies process information. Our brain normally registers objects when we see them, even if they’re moving quite quickly, and signals are transmitted from the visual part of our brain to the prefrontal cortex, where we process that image.  This processing only happens quickly from around eighteen months old, and is much weaker and slower before then. In fact, this phenomenon was barely registered in those below five months old. All of this has led us to believe that we actually become conscious within months of our birth. 

The Middle

From our teenage years onwards, however, we find it hard to think back to our childhood memories: we seem to remember very specific events but not the rest of the picture. This ‘childhood amnesia’ occurs because our brain reshuffles the way we think and what we remember. Around the age of seven, some memories are lost as the brain gets rid of useless and ineffective synapses. This process, known as pruning, reduces the overall number of synapses and is highly dependent on the way a child learns and their surrounding  environment. 

The End

So, fast forward to the end. When we die, our body shuts down all of its processes, much like how you shut a computer down before closing it. Neurons stop firing and you stop responding altogether. The process through which this happens is contested, but in general, the last thirty seconds of human life are intense. The brain dies from the top, and our identities, our ability to think, and our ‘human’ characteristics disappear in the first twenty seconds. In the final ten seconds, our neurons spread out, and our memories drift away last. However, that’s not all: research has shown that once our heart stops beating, our brain still functions for a very short period of time. Many survivors of cardiac arrest and individuals who have been resuscitated claim that they were able to understand that they were dying and were aware of what was going on around them. This claim was further bolstered when it was seen in rats that brain activity spiked right after death occurred, due to conscious processing. 

The way we perceive life is thanks to our brain, and the way in which we transition from a foetus to a conscious human is nothing short of a miracle. Even the way we are able to experience our own consciousness and mortality before dying is nothing short of poetic.