How much does your brain pay attention to the world while you ’re sleeping?

By guest blogger Daniel Bor When I was 13, I once dreamt that a beautiful woman was sensuously stroking the palm of my hand, as a family of fridges hummed in the background. In reality, a huge, buzzing wasp had landed on my right hand. It idly walked around for a bit, then stung me. After the shock had worn off, I was puzzled why my dreaming brain had stopped me from waking up to this potential danger. Contrast this with 6 years ago, when even my deepest sleep would be broken by the first sounds of my newborn baby daughter’s cries. How do our brains decide whether or not to wake us up, based on what’s going on in the world? And why does this policy change depending on whether we’re dreaming or in some other sleep state? In a recent paper in the Journal of Neuroscience, Thomas Andrillon and his colleagues have discovered intriguing clues that start to answer these questions. They used electroencephalography (EEG) to record their participants’ electrical brain activity while they completed a simple task: listening to a series of words and pressing a button with one hand if a given word was an animal, or the other hand if it was an object. Whenever the participants made an appropriate hand response, this was always preceded by a spike of brain activity – a well-known EEG marker, called the Lateral Readiness Potential (LRP), indicating extra activity over the motor cortex on the opposite side of the brain to the hand response. Crucially, the researchers had the partici...
Source: BPS RESEARCH DIGEST - Category: Psychiatry & Psychology Authors: Tags: Brain guest blogger Sleep and dreaming Source Type: blogs