Monika Jansen, 85, gazes at a hippo during a visit to the Berlin Zoo. Photo: Markus Schreiber.

Christel Krueger pressed his eyes against his thick glasses, gazing through the murky water at the Berlin Zoo, where a mother hippo and her calf lay asleep on a sandbar. At 86, the moment was more than just a sightseeing experience; it was a rare stimulus to his memory and emotions, functions that are gradually declining due to dementia .

She joined a tour specifically designed for people with this condition, along with her daughter and other seniors. Ingrid Barkow observed elephants from her wheelchair, while Monika Jansen had to stand on tiptoe to get a better look at a rhinoceros. “When I get home, I’ll still be thinking about it,” Jansen said, picturing the daydreams continuing the experience.

These seemingly simple moments are actually part of an approach being widely adopted in neuroscience: using the environment, senses, and memory to help people with dementia maintain connections with the world. Dementia is a group of disorders in which the brain gradually loses its ability to process information. Nerve cells are damaged or degenerate, causing signal transmission between brain regions to decline.

As a result, memory, language, reasoning ability, and spatial awareness are affected. Patients may experience personality changes, loss of emotional control, and difficulty understanding what they see.

Not all memories disappear. Long-lasting memories, especially childhood memories, are often stored deeper within neural networks. They are reinforced over the years by repetition, making neural connections more robust. So, when someone with dementia returns to familiar spaces like the zoo, places they visited as a child, these memories may be reactivated.

Seemingly simple stimuli such as the smell of air, environmental sounds, or images of animals act as "keys" to unlock forgotten areas of memory.

This phenomenon is related to the context-dependent recall mechanism, where the brain retrieves information more easily if the current environment is similar to the environment in which the memory was formed. In the case of tours, visual, auditory, and olfactory elements simultaneously affect the brain, creating a form of multisensory stimulation.

Vision helps in image recognition, hearing processes sounds, and the sense of smell is directly linked to the limbic system—the brain region associated with emotions and memory. This combination enhances recall and retention of attention.

Conventional tours are often fast-paced, crowded, and full of distractions, easily leading to cognitive overload. Patients may become confused, unfocused, or anxious. By reducing the number of attractions, extending observation time, and creating a quieter environment, these programs allow the brain sufficient time to process information.

These experiences not only impact cognition but also affect emotional state and social relationships. People with dementia often become increasingly isolated from community activities, partly due to difficulties in communication.

However, the human brain retains the ability to respond to social cues, even as language declines. Engaging with others in similar situations creates a sense of belonging, reducing stress and improving mental well-being. For family members and caregivers, this is also a rare opportunity to connect in a more positive context.

In many cases, communication ceases to take place through words. Manuela Grudda, Mrs. Barkow's daughter, says she can't converse with her mother in the usual way, but when she points to the animals, her mother still looks and pays attention.

This reflects a biological fact. Brain regions that process emotions and visual responses are often affected later than those that process language. Eye contact, gestures, and attention therefore become crucial communication channels, helping to maintain a connection between the patient and their surroundings.

Trips like those to the Berlin Zoo aren't exactly traditional treatments, but they've shown the potential to maintain a quality of life for patients. When the brain is properly stimulated, neural networks can still function, albeit at a limited level.

Old memories are resurfaced, emotions are activated, and attention is maintained, all contributing to helping patients continue to engage with the world instead of becoming isolated from it.