Playful exercises to activate both sides of your baby’s brain

“Crossing the midline” is a skill that child development experts talk about a lot—but why does it matter? Whenever you buckle your seat belt or read from left to right, you’re crossing the midline. These actions involve the corpus callosum, a thick bundle of nerves that coordinates communication between the two hemispheres of your brain. 

Your baby activates their corpus callosum when they bring one or both hands across their body or follow a moving object side-to-side with their eyes. Getting the two sides of their brain working together prepares  your baby to crawl, talk, read, and even regulate their emotions 🙂

Each brain hemisphere has specializations. For example, most emotions are processed in the right hemisphere, but speaking is controlled by the left—talking about emotions requires communication between both.  

Try these activities to help your baby practice crossing the midline:

1. Track a rattle. Part of crossing the midline is coordinating visual input from the right and left eyes. When your baby focuses on an object moving across their line of sight, it activates the corpus callosum. Try moving the Wooden Rattle or another noise-making object from the left to the right side of their visual field and back again to help your baby practice visual tracking.

2. Pass hand to hand. Place the Hand to Hand Discs in one of your baby’s hands. They may bring it to their mouth with one hand, bring it to their mouth with both hands, or even start passing it from hand to hand.

3. Go big. If your baby can hold up their head independently, try placing them in a seated position in front of you, supported by your body or pillows. Hold a larger object, like the Soft Book from The Charmer, right in front of your baby. If they grab it with both hands, place it a little to one side so they have to cross the midline using both hands to grasp it next time. 

4. Roll across the midline. With your baby lying on their back, hold a plaything, like the Crinkle Bag, on one side of their body. Then, slowly move the toy across their body to the opposite side. Your baby will get practice crossing the midline, and they may reach all the way over to roll from their back to their belly.

5. Reach for the toes. Put one of the Play Socks from The Senser Play Kit partially on your baby’s foot as they lie on their back. Your baby may use one or both hands to grab the sock and try to pull it off. To help them see, lift their feet toward their face. They may not succeed in crossing the midline quite yet, but they will in time.

The Charmer Play Kit (Months 3-4)

Delight and engage your baby with toys from The Charmer Play Kit.

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The Senser Play Kit (Months 5-6)

Enhance your baby’s sensory development with toys from The Senser Play Kit

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Learn more about the research

Scharoun, S. M., & Bryden, P. J. (2014). Hand preference, performance abilities, and hand selection in children. Frontiers in Psychology, 5, 82.

Sgandurra, G., Cecchi, F., Serio, S. M., Del Maestro, M., Laschi, C., Dario, P., & Cioni, G. (2012). Longitudinal study of unimanual actions and grasping forces during infancy. Infant Behavior and Development, 35(2), 205-214.