Explaining EMDR to Clients: Bilateral Stimulation in EMDR Therapy
Unlocking the Brain with Bilateral Stimulation (BLS)
One of the unique and powerful aspects of EMDR therapy is bilateral stimulation (BLS). This can take the form of side-to-side eye movements, gentle tapping on alternate sides of the body, or sounds alternating between your ears. BLS helps your brain work in a way that’s similar to what happens during REM (rapid eye movement) sleep — when your brain naturally processes emotions, thoughts, and memories.
Think of your brain like a file cabinet. When we experience something distressing, those memories sometimes get "misfiled" or don’t even make it to the cabinet — staying raw and stuck instead of being stored in a way that allows us to learn and be present without carrying the incredible weight of those adverse experiences on our shoulders. BLS works like a librarian, helping the brain locate those misfiled memories, process them, and move them to the right place where they no longer cause distress.
What Does BLS Do in Your Brain?
Research using brain imaging shows that BLS activates both sides of the brain, helping them work together in a balanced way. Here's what happens:
Accessing the Stuck Memory:
BLS activates parts of the brain, like the amygdala (responsible for emotions) and hippocampus (involved in memory processing), that hold onto the "stuck" memory.
It also reduces the over activation of the amygdala, calming your nervous system so you can revisit the memory without being as overwhelmed.
Processing and Unsticking the Memory:
As BLS sets continue (we do 20 - 30 seconds of BLS at a time), your brain begins to access its natural ability to process information. This involves connecting the "stuck" memory to adaptive information stored in other parts of the brain.
For example, a memory tied to "I’m not good enough" might shift as your brain integrates a healthier perspective, like "I did my best" or "That wasn’t my fault."
Creating New Connections:
Brain scans show that BLS enhances communication between the emotional and logical parts of the brain. This helps the memory shift from being emotionally charged and "frozen in time" to being stored as a more neutral, manageable experience.
You might feel a sense of relief or even insight — like a puzzle piece finally clicking into place.
I often think of memories as being snapsots or photos. Each ‘snapshot’ holds onto the information from the negative experience — what we thought about ourselves, others, or the world, our emotions, our body sensations, and our sensory experiences (what we saw, heard, smelled, tasted, or touched). The snapshot is cut into puzzle pieces and scattered on the surface (like the leaves and foliage on tree branches, if we go back to our tree metaphor). We sort the pieces into groups (e.g., a branch holding leaves that go together). As we do sets of BLS while remembering a memory, our brain is sorting the puzzle pieces and putting them together. At the same time, the brain makes the image less vivid and more distant — so we don’t fee like we are in the snapshot right now. When the puzzle is assembled into a whole, or all the branches on the tree have been processed, the ‘gut punch’ has been taken out of the memory, the distress has dimmed, and there is adaptive, positive information stored on the snapshot (e.g., “I am good enough”, my body feels calm).
The Science Behind It
Researchers have found that:
Eye Movements Reduce Emotional Intensity: Studies show that bilateral eye movements can decrease the vividness and emotional charge of distressing memories. This helps you feel more like an observer of the memory, rather than being stuck in it.
Enhanced Neural Integration: Brain imaging studies suggest that BLS may improve connectivity between different brain regions, promoting the reorganization and adaptive processing of traumatic memories.
Activation of Adaptive Networks: BLS helps your brain access positive, adaptive networks — parts of your brain that know how to heal and grow — so you can replace distressing feelings or beliefs with healthier, more balanced ones.
What This Means for You
As you heal those roots through EMDR therapy, you might notice changes ripple through your thoughts, emotions, and even physical sensations. The memory doesn’t disappear, but it no longer feels like it’s running your life. Current triggers will feel less intense because the foundation they were tied to has been resolved — the roots have been processed and are healing.
BLS is a simple yet powerful way to help your brain do what it naturally wants to do: heal, adapt, and grow. Together with your therapist, you can safely untangle those roots and build a healthier, more grounded present and future.
Healing is possible — and you don’t have to do it alone. An EMDR Trained or Certified Therapist can walk with you on your journey.