Balancing Act: New research reveals how the brain keeps you on your feet
The ability to maintain balance and coordinate movement is a central challenge for the brain and one that allows us to navigate our daily lives. Much of this happens in the cerebellum region, a region in the back of the brain, where disruptions to this complex process can cause anything from dizzy spells to more serious balance issues like ataxia.
In a study published in the journal Current Biology, Johns Hopkins researchers discovered that individual neurons in the cerebellum’s nodulus/uvula region combine proprioception (body position) and vestibular (balance) input to help us stay steady and upright relative to gravity even as we move around.
Senior author Kathleen Cullen, the Raj and Neera Singh Professor of Biomedical Engineering, noted these findings could pave the way for new therapeutics and neuroprosthetics for people with balance and movement disorders.
“Our work provides new insight into the neural computations that stabilize gaze and maintain balance and posture relative to gravity, processes that are vital for our mobility and independence,” said Cullen, who conducted the study with postdoctoral fellows Robyn L. Mildren and Lex J. Gómez.
To better understand the processing performed by the cerebellum, Cullen’s team, working with rhesus monkeys, zeroed in on Purkinje cells, the major output neuron of the cerebellum in primates. In the lab, researchers recorded the cells’ activity when exposed to vestibular and proprioceptive stimulation, such as turning the head
They discovered that Purkinje cells integrate both types of sensory information, retuning to ensure accurate postural neural commands are sent to control our muscles whenever the head and/or body moves. Overall, the researchers demonstrated that groups of Purkinje cells “work together” to send more precise signals to other brain regions about the body’s overall position and movement relative to Earth’s gravity.
The researchers say this discovery provides a clearer picture of why the brain is so good at quickly adjusting to keep bodies balanced and upright in everyday life.
“Unlike earlier studies that focused on one sensory modality and single channel recordings, our approach demonstrates, for the first time, the real-time synergy between two streams of sensory input, and how together they stabilize posture and maintain accurate spatial orientation relative to gravity,” said Cullen.
Cullen and colleagues aim to further uncover details about the cellular processes in the brain that maintain balance, with the ultimate goal of advancing therapies to restore normal balance function for those with balance disorders.
The team’s next experiments will involve applying their techniques to see how the Purkinje cells process balance information during dynamic active movements, when our bodies are running or otherwise in motion.