BRAIN DISCONNECT
Where Brain Parts Can't Communicate with Each Other Well
CONTENTS — FIND IN PAGE
DIVIDED BRAIN
It is possible for someone to have a disconnected corpus callosum. This can occur in two main ways:
1. Congenital Absence (Agenesis of the Corpus Callosum):
Some people are born without all or part of their corpus callosum, a condition called agenesis of the corpus callosum (ACC)1,2,6. In these cases, the thick bundle of nerve fibers that connects the right and left hemispheres of the brain is partially or completely missing from birth.
The effects of ACC vary widely. Some individuals may experience developmental delays, cognitive impairment, or difficulties with motor skills, while others may have only mild symptoms or even lead relatively typical lives1,5,6.
Interestingly, people born without a corpus callosum often do not exhibit the classic "disconnection syndrome" seen in those who acquire the disconnection later in life. This is because their brains can sometimes form alternative neural pathways to compensate for the missing structure5.
2. Surgical Disconnection (Corpus Callosotomy):
In some cases, the corpus callosum is intentionally severed through a surgical procedure called corpus callosotomy, usually as a last-resort treatment for severe epilepsy that does not respond to medication3,7. This operation disconnects the two hemispheres to prevent seizures from spreading.
After such surgery, patients can develop "split-brain" or callosal syndrome, a type of disconnection syndrome characterized by unusual neurological symptoms. For example, each hemisphere can act independently, leading to phenomena like alien hand syndrome or difficulties in coordinating tasks that require both sides of the brain3,4,7.
The severity and type of symptoms depend on whether the disconnection is partial or complete3,7.
Summary Table: Disconnected Corpus Callosum
Cause; Description; Possible Effects
Congenital (ACC); Born without all/part of corpus callosum; Variable: from mild to severe developmental issues; often some compensation by alternative brain pathways1,5,6
Surgical (Callosotomy); Corpus callosum cut to treat epilepsy; Split-brain syndrome; disconnection symptoms; less compensation, especially in adults3,4,7
In conclusion, a disconnected corpus callosum can occur both from birth or as a result of surgery, and the outcomes are highly variable depending on the cause and the individual1,3,5.
LEFT BRAIN RATIONALIZATION
When the brain hemispheres are unable to communicate—such as in split-brain patients whose corpus callosum has been severed—the left hemisphere often generates explanations or rationalizations for actions or perceptions it cannot directly access {It makes GUESSES, which it wrongly labels as FACTS}. This phenomenon is well-documented in neuroscience.
Key Findings:
In classic split-brain experiments, when information is presented only to the right hemisphere (for example, via the left visual field), the left hemisphere—which typically controls speech—cannot access this information directly. When asked to explain actions initiated by the right hemisphere (like picking up an object with the left hand), the left hemisphere often invents a plausible but incorrect explanation, a process known as "confabulation" or the "interpreter" function1,2,3.
For instance, in a famous experiment, a split-brain patient was shown a picture of a chicken foot to the left hemisphere and a snowy scene to the right hemisphere. When asked to explain why they chose a shovel (selected by the right hemisphere), the patient’s left hemisphere responded, "the shovel is for cleaning out the chicken coop"—an explanation that fit the information available to the left hemisphere, even though the real reason was only accessible to the right hemisphere1.
Research shows the left hemisphere has a tendency to create explanations or hypotheses even when it does not have access to all the relevant information, sometimes resulting in false or illogical rationalizations3.
This left hemisphere "interpreter" effect highlights the brain's drive to create coherent narratives, even if those narratives are not based on the full picture1,2,3.
Summary Table: Left Hemisphere Explanation in Split-Brain
Scenario; What Happens; Example
Right hemisphere acts, left hemisphere unaware; Left hemisphere invents explanation; Choosing a shovel and saying it's for the chicken coop1
Random events needing explanation; Left hemisphere seeks patterns, even if none exist; Trying to find a pattern in random dot flashes3
In summary, the video’s claim is accurate: when the hemispheres cannot communicate, the left hemisphere frequently constructs explanations for perceptions or actions, even if those explanations are not grounded in the actual cause1,2,3.
IN/ABILITY TO UNDERSTAND
It is possible to explain to someone with a disconnected corpus callosum (such as a split-brain patient) that their hemispheres cannot fully communicate and that the left hemisphere may invent explanations for actions or perceptions it cannot access. However, there are important limitations and challenges:
Language Access: In most people, the left hemisphere controls language. This means that if you explain the phenomenon verbally, the explanation will be processed by the left hemisphere. The left hemisphere can understand the concept that it sometimes makes up explanations, but it may not have direct awareness of the specific instances when this happens, especially if the triggering information was only available to the right hemisphere2,4,6.
Awareness of the Deficit: Split-brain patients often do not realize when their left hemisphere is confabulating. They may accept the explanations they generate as accurate, since the left hemisphere lacks access to the information held by the right hemisphere4,6.
Compensation and Adaptation: Over time, some split-brain patients develop strategies to compensate for their disconnection, sometimes using subtle cues or cross-cueing to share information between hemispheres3. This means they might be able to reflect on their own experiences to some extent if prompted carefully.
Clinical Practice: Neuropsychologists and neurologists do explain these phenomena to split-brain patients, often using demonstrations or tailored experiments to help patients observe the effects directly. For example, a clinician might show how the patient can draw an object with one hand but not name it, and then explain why this happens2,6.
In summary, you can explain the phenomenon to a split-brain patient, but their ability to fully grasp or internalize it depends on the nature of their disconnection and which hemisphere is receiving the explanation. The left hemisphere can understand the general concept, but may not recognize its own confabulations in real time2,4,6.
RIGHT HEMISPHERE LANGUAGE
The right hemisphere is capable of certain language functions, but its abilities differ significantly from those of the left hemisphere.
The left hemisphere is generally dominant for core language skills such as grammar, syntax, and most aspects of speech production and comprehension3,4,8.
The right hemisphere contributes to language in several important ways:
It processes the emotional tone of speech (prosody), humor, sarcasm, metaphors, and indirect requests2,3,4,9.
It helps interpret the broader context of conversations and understands social concepts and intentions behind language1,2,3,4.
It is involved in early stages of language learning, such as distinguishing new speech sounds5.
In children, the right hemisphere is more actively involved in language processing, and can compensate for language functions if the left hemisphere is damaged early in life6,8.
However, the right hemisphere's capacity for language is limited:
It struggles with complex syntax and grammar, and its ability to generate or understand detailed, structured language is much weaker than the left hemisphere7.
In split-brain or brain-bisected patients, the right hemisphere may recognize simple words or objects, but has trouble with verbs, commands, and constructing sentences7.
In summary, the right hemisphere is not "nonverbal"—it plays a vital role in the emotional, contextual, and pragmatic aspects of language, and can compensate to some extent if the left hemisphere is damaged, especially in children. But for most adults, it cannot fully support complex language on its own3,4,7,8.
CAUSE BY MEDS?
Certain medications—especially some antiepileptic drugs (AEDs)—can indeed harm the corpus callosum in specific circumstances. Clinical studies and case reports have documented the following:
Antiepileptic Drugs (AEDs): Drugs such as phenytoin (Dilantin) and vigabatrin have been linked to the development of discrete, focal, reversible lesions in the splenium (posterior part) of the corpus callosum. These lesions, seen on MRI, are believed to result from reversible demyelination or toxicity related to high doses or drug sensitivity. In some cases, these lesions resolved after discontinuing the offending medication2,5.
Long-term AED Therapy: Research also suggests that chronic use of AEDs may contribute to microstructural changes and secondary degeneration in the corpus callosum, particularly in the splenium. These changes are more pronounced with longer medication duration and may affect white matter integrity9.
Other Medications: There is no strong evidence that commonly used medications outside of certain AEDs routinely harm the corpus callosum in otherwise healthy individuals. In fact, some medications used in Alzheimer's disease (like donepezil and rivastigmine) have been associated with improvements in corpus callosum size in affected patients7.
Summary Table: Medication Effects on the Corpus Callosum
Medication/Class; Potential Effect on Corpus Callosum; Reversibility
Phenytoin (Dilantin)Focal, reversible lesions (demyelination) in the splenium; Often reversible
Vigabatrin; Similar focal lesions, especially with high doses or sensitivity; Often reversible
Chronic AED therapy; Microstructural changes, possible secondary degeneration; May persist
Donepezil, Rivastigmine; May improve corpus callosum size in Alzheimer's patients; Beneficial effect
In summary, while most medications do not harm the corpus callosum, certain antiepileptic drugs can cause reversible lesions or contribute to long-term microstructural changes, especially with prolonged use or high doses2,5,9.
KEPPRA
There is limited evidence that Keppra (levetiracetam) directly causes harm to the corpus callosum. Most reports of antiepileptic drug-induced corpus callosum lesions involve other medications, such as phenytoin, phenobarbital, or carbamazepine6,9. However, there is a notable case report describing transient lesions of the splenium of the corpus callosum following rapid withdrawal of levetiracetam, not its use1. This suggests that abrupt changes in Keppra dosing, rather than the drug itself, could be associated with reversible corpus callosum abnormalities.
Overall, levetiracetam is generally considered safe and well-tolerated with respect to white matter structures like the corpus callosum4. There is no strong evidence from clinical studies or case series that Keppra, when used as prescribed, causes direct or permanent damage to the corpus callosum4,7.
In summary:
Keppra is not known to directly harm the corpus callosum.
Rapid withdrawal may be associated with transient, reversible lesions in rare cases1.
Keppra (levetiracetam) can cause paranoia, anger, and other significant mood or behavioral changes in some people. These side effects are well-documented and sometimes referred to as "Keppra rage." Reported symptoms include:
Mood swings, irritability, and rapidly changing emotions3,6,7,10
Anxiety, agitation, and depression, including suicidal thoughts in rare cases1,2,3,9,10
While these psychiatric and behavioral side effects do not affect everyone, they can be severe for some patients and may appear soon after starting the medication or after a dosage increase6,8,9. If you or someone you know experiences these symptoms while taking Keppra, it is important to contact a healthcare provider promptly, as adjusting the dose or switching medications may be necessary3,9,10.
ZOLOFT
Current research does not show that Zoloft (sertraline) causes direct harm or permanent damage to the corpus callosum. However, some studies suggest that SSRI antidepressants, including sertraline, can affect white matter in the brain, including regions in and around the corpus callosum.
Short-term effects: One study found that acute SSRI administration led to decreased diffusivity in white matter, particularly in frontal brain regions and areas in and around the corpus callosum. This indicates a reduction in water movement within these brain areas, but the clinical significance and permanence of these changes are unclear2.
Long-term effects: Animal studies and research in non-depressed individuals suggest that sertraline may cause subtle changes in brain structure, but these changes are generally described as region-specific and not clearly linked to harm or loss of function in the corpus callosum1,6.
Clinical context: In patients with depression, effective SSRI treatment has sometimes been associated with preservation or even enlargement of certain brain structures, including frontal regions, rather than degeneration8. No clinical studies or drug safety reports specifically link Zoloft to corpus callosum injury or dysfunction in humans5.
In summary, while Zoloft may influence white matter microstructure—including areas near the corpus callosum—there is no evidence it causes direct harm or lasting damage to the corpus callosum itself when used as prescribed1,2,8.
Zoloft can raise prolactin levels, which theoretically could lead to pituitary changes if hyperprolactinemia is severe and prolonged, but this is rare. Regular monitoring and consultation with a healthcare provider are recommended if symptoms of hormonal imbalance or pituitary dysfunction occur.
“The Dangerous Psychiatrist” Who is Dr. Peter R. Breggin?
Long-term Effects of Antipsychotics on the Brain
PSYCHOSIS
Psychosis can be caused by disconnects between parts of the brain.
The brain works by having different areas communicate with each other.
In psychosis, these connections—like the brain’s “wiring”—often don’t work properly.
This can be because the physical links (called white matter) are damaged or weaker.
Or, the brain areas might not “talk” to each other in the right way, even if the wiring is there.
These disconnects can affect how people think, feel, and understand reality, leading to symptoms of psychosis.
In short:
Problems with how brain parts connect and communicate can help cause psychosis.
PTSD & AUTISM
CONTRADICTORY STATEMENTS. A person with both PTSD and autism can say contradictory things out of subconscious fear or distress without knowingly lying.
Overlapping Symptoms and Communication Challenges
Both PTSD and autism can cause significant difficulties in emotional regulation, sensory processing, and social communication1,4,5.
PTSD is associated with heightened fear responses, dissociation, and avoidance, while autism can involve literal thinking, difficulty interpreting social cues, and sensory overload1,4.
When these conditions co-occur, the complexity increases: emotional distress or fear can disrupt memory, attention, and self-awareness, making communication less consistent1,4.
Contradictory Statements and Subconscious Fear
People with PTSD may experience dissociation or memory fragmentation, leading to inconsistencies in their accounts of events or feelings. This is not intentional deception but a result of trauma-related changes in how memories are stored and retrieved4.
Autistic individuals, especially under stress, may struggle to express themselves accurately or may mask their true feelings to avoid conflict or distress, sometimes resulting in statements that appear contradictory6.
Both conditions can heighten anxiety and fear of negative consequences, which may subconsciously influence what is said in the moment. For example, someone might say what they think is safest or most acceptable, even if it conflicts with previous statements, without conscious intent to deceive4,6.
Honesty and Intent
Autistic people are often described as being very honest, sometimes to a fault, and may find lying uncomfortable or cognitively taxing6.
When contradictions occur, it is more likely due to confusion, stress, or subconscious processes (such as masking or trauma responses) rather than deliberate lying6.