The human brain works in quietly astonishing ways – many of which were never covered in school textbooks. From moments when your vision briefly switches off, to why emotional pain can feel physically real, neuroscience reveals just how complex and clever our brains truly are. These lesser-known mechanisms shape how we see, feel, and sleep every single day, often without us realising it.
Dr Sermed Mezher, a family medicine physician and health content creator based in England with over 15 years of experience, has shared three fascinating neuroscience facts that shed light on how the brain works in ways you may not have realised. In an Instagram video shared on February 9, the physician breaks down how the brain processes eye movements, why emotional pain feels physical, and what actually happens in the body when you’re asleep.
1. Humans are motion blind for hours every day
According to Dr Mezher, humans are effectively motion-blind for nearly 40 minutes to two hours every day. When your eyes jump rapidly from one point to another, the brain briefly switches off visual processing to prevent the world from appearing blurry or disorienting. During these rapid eye movements, the brain receives signals that tell it to ignore retinal information for a few milliseconds, helping maintain visual stability. To fill in this gap, the brain often stretches the perception of the moment immediately after the eye movement – which is why, when you glance at a clock, the first second can seem noticeably longer than the ones that follow.
The physician explains, “During rapid eye movements known as saccades, the brain employs a sophisticated neurological ‘editing’ process called saccadic suppression to maintain visual clarity. When your eyes jump quickly from one point to another, the image across the retina moves at a velocity that would normally result in a disorienting, motion-blurred smear. To prevent this, the brain momentarily shuts down the processing of visual information during the duration of the “jump.” This brief window of functional blindness ensures that your internal perception of the world remains stable and sharp, rather than a shaky mess of streaks.”
2. Heartache can hurt physically
Dr Mezher explains that the brain uses overlapping processing centres for both emotional and physical pain. Because of this shared neural circuitry, emotional distress is experienced by the body in much the same way as physical injury – which is why heartache and emotional pain can genuinely hurt on a physical level.
He highlights, “Your brain has shared processing centers for emotional and physical pain. These include the anterior insula and anterior cingulate cortex. So heartache can genuinely hurt.”
3. REM sleep functionally paralyses you
Dr Mezher explains that during REM sleep, the brain deliberately switches off the body’s ability to move, effectively paralysing the muscles so you don’t physically act out your dreams. This same mechanism is at play during sleep paralysis, when you wake up mentally aware but your brain still believes you’re in REM sleep – leaving your body temporarily unable to move.
He states, “Your brain functionally paralyses you when you enter REM sleep. Could have a few different functions like stopping you from acting out your dreams of becoming a bedroom base jumper. It also would be particularly useful if we or our ancestors slept in compromising positions like high up in a tree. It’s also thought to be a central mechanism during the pretty frightening experience of sleep paralysis where you wake up, are fully conscious but cannot move.”
