Maybe I should return to the bus stop in case someone is meeting me there. I retrace my steps while rummaging through my handbag. I find a note saying “Bus stop, 3.30pm”. It’s 3.25pm. Good. I also discover a collection of articles on memory and start reading them to pass the time.

The first article is about the hippocampus, how it encodes people’s experiences as they pass through life. My brain still has a record of the time I ate a rotten watermelon while sunbathing on the beach, and spent a punishing night throwing up. I treasure the old memories of my mother holding my head over the toilet bowl, stroking my brow while I retched. I must have been eight or nine. But if you asked me where my mother lives today, I couldn’t tell you. Post-accident events can’t be stored in my brain. The older ones, from my childhood, must have crept out of my hippocampus before the accident.

I can't remember what happened in the accident or even a few years beforehand. These memories seem to have been knocked out. This, they say, is called retrograde amnesia – the loss of memories for events or facts that I learnt before the onset of my amnesia. Sometimes the loss can extend right back to childhood; thankfully in my case it’s only a few years. Most amnesics lose their memories for personally experienced events, and some can't remember factual information from before the accident, like their home address or what an old friend's name is.

The article says that another part of the brain, the amygdala, controls emotional memory. Maybe that’s what makes me feel scared whenever I walk barefoot on sand. Why do I react that way? I must have had quite a few bad experiences on sandy beaches. I think it’s called conditioning – my amygdala has linked sand with unpleasant events. I guess it’s a survival mechanism, to help me learn to avoid dangerous objects or places, but it’s annoying that I can’t enjoy the feel of sand on my bare feet.

I’ve found another article in my bag on a type of memory called priming. Hey! My name is mentioned. I must have been tested in one of the experiments. It says here that I’ve retained my unconscious ability to increase the speed with which I respond to things I’ve seen or heard recently. Although I don’t remember them showing me an animal and then showing it to me again the next day, the second time I see the animal I respond more quickly to it, though it feels like I’m seeing it for the first time. Well, that’s what it says in the article. I don’t remember any of this.

Some people are worse off than me. People with Korsakoff's amnesia are compelled to tell lies, to make things up about their past. Nobody understands why they do this. Maybe they’re desperate to fill in the blanks. Or maybe they've lost the ability to judge their own memories.

There’s something here about someone with semantic dementia. Poor bloke, he keeps pouring bleach into his cups of tea, because he doesn’t know it’s not milk. His semantic dementia means he fails to remember knowledge about objects, words and people. Though, unlike me, he can still remember day to day events well. This is because the disease affects parts of the temporal and frontal lobes of his brain but not so badly his hippocampus.

Some people lose their ability to remember words while still being able to recognise faces and other objects. For others it’s the reverse. It says here that the right side of the brain is involved in non-verbal memory while the left side does more with verbal memory. For me, I've lost a bit of both.