Saturday, June 24, 2017

What happens in the brain of those with bipolar disorder

What happens in the brain of those with bipolar disorder
By Claudia Mosby

A person in the manic phase of bipolar disorder (BPD) may appear full of energy, hedonistic and grandiose. During the depressed state of the illness, that same individual may lack energy, exhibit slower thinking and movement and profound depression.

What happens in the brain of a bipolar individual to produce such extreme swings in states of being?

“It is difficult to think of any illnesses in medicine that present with symptoms that can almost be diametrically opposite in one state (e.g., mania) compared to another state (e.g., depression),” says Husseini K. Manji, MD, FRCPC, a pre-eminent researcher of bipolar disorder and the global therapeutic head for neuroscience at Janssen Research & Development, Pharmaceutical Companies of Johnson & Johnson. Manji also serves on the Scientific Council of the Brain & Behavior Research Foundation, which awards grants to scientists seeking new treatments and cures for psychiatric disorders.

“These observations were among the first clues to suggest that BPD wasn’t about ‘too much’ or ‘too little’ serotonin or dopamine but rather about synaptic and neural plasticity,” adds Manji. He describes plasticity as the attribute that enables billions of nerve cells in the brain to change and adapt on a millisecond-by-millisecond basis in response to the many inputs continually being received and processed.

“What we’ve learned in the last 10 years is that whether we’re talking about memory, mood or movement, all advanced brain functions involve changes in the ability of synapses to convey information in different brain circuits.

“For a mood disorder like bipolar, the problem resides in the intracellular machinery of signal transmission, machinery that is engaged in both information processing but also in helping nerve cells survive and grow.”

These observations may explain, says Manji, why MRI scans on patients with BPD often reveal “shrinkage” of neurons in specific brain areas. “It‘s very important to emphasize that while there appears to be shrinkage,” he adds, “the neurons themselves are not dead; they are sick.”

He describes healthy neurons as having a profusion of treelike branches that communicate with one another by forming a multitude of synapses, tiny transmission gaps or “communication channels” that join the message-sending and message-receiving neurons between the branches.

“If that branch shrivels up, you lose synaptic contacts,” says Manji. “And how can you expect to have normal nerve-to-nerve communication when that happens?”

Date and Article

No comments:

Post a Comment