In Episode 6 of Across STEM with YSI Season 2, our conversation begins with something deceptively simple: the realization that your brain is always guessing.

Uzra Abid Ali joins Amirali Banani to talk about dreams, illusions, and the moments when perception quietly slips without us noticing. Drawing from her recent talk at STEM Quest 3.0, Inside Your Limit: The Neuroscience of Dreams & Illusions, Uzra explains how the brain isn’t a camera capturing reality as it is. It is a fierce prediction machine, constantly filling in gaps based on experiences and expectations.

She talks about dreams as one of the clearest examples of this. When external sensory input shuts off, the brain does not go quiet.

It becomes more creative.

Entire scenes, emotions, and narratives emerge out of nothing, without any real-world data feeding them. For Uzra, this isn’t just fascinating, it’s revealing. Dreams show what happens when perception is driven almost entirely from the inside out, which can unravel essential cues about consciousness.

She then discussed illusions, and not as tricks or party curiosities. Uzra describes illusions as moments where the brain’s shortcuts become visible. When an illusion fools us, which happens very often, it isn’t because our brain is broken—it’s because it’s trying to work efficiently, prioritizing speed and coherence over perfection or accuracy. This idea reshapes how we think about error and distortion in neuroscience.

Following this, Uzra reflects on how learning about the neuroscience of dreams and illusions has affected her personally. She admits that once you understand predictive processing, it becomes harder to take your own perceptions at face value. You begin to notice how easily the mind fills in details and how confidently it tells stories that feel real in the moment. It is a testament to how easily our brain at times can be tricked by the laws of physics, and thus how easily we can get tricked by our own brain into thinking that something it has made up is actually real.

A key takeaway from Uzra’s episode worth noting down: the focus is not to be placed on finding firm answers. It is on learning to pay attention to the moments when reality feels slightly unstable.

These are the moments that often reveal the most about how the mind actually works.

Watch Uzra’s STEM Quest 3.0 talk