A leading cause of disability, OA affects more than 30 million men and women in the United States. Here’s everything you need to know about OA, from treatment to prevention and more. OA is caused by joint damage. This damage can accumulate over time, which is why age is one of the main causes of the joint damage leading to osteoarthritis. The older you are, the more wear and tear you’ve had on your joints. Other causes of joint damage include past injury, such as:

• torn cartilage
• dislocated joints
• ligament injuries

Cartilage is a tough, rubbery substance that’s flexible and softer than bone. Its job is to protect the ends of bones within a joint and allow them to move easily against each other. When cartilage breaks down, these bone surfaces become pitted and rough. This can cause pain within the joint, and irritation in surrounding tissues. Damaged cartilage can’t repair itself. This is because cartilage doesn’t contain any blood vessels.

People with RA have immune systems that mistake the soft lining around joints to be a threat to the body, causing it to attack that area. This soft lining, which includes the synovial fluid, is called the synovium. As the immune system launches its assault, fluid buildup within the joint occurs, causing stiffness, pain, swelling, and inflammation.

If you’re not sure which form of arthritis you have, your best bet is to talk to your doctor. But you can also do your own research

Habits drive our lives — so much so that sometimes we might want to break the habit, as the saying goes, and experience something new. But habits are a useful tool; when we do something enough times, we become effortlessly good at it, which is perhaps why Aristotle reportedly believed that “excellence […] is not an act but a habit.” So, what does habit formation look like in the brain? How do our neural networks behave as we learn something and consolidate it into an effortless behavior through repetition? These are the questions that Ann Graybiel and her colleagues — from the Massachusetts Institute of Technology in Chestnut Hill — set out to answer in a recent study, the findings of which are published in the journal Current Biology.

Although a habitual action seems so simple and effortless, it actually typically involves a string of small necessary movements — such as unlocking the car, getting into it, adjusting the mirrors, securing the seatbelt, and so on. This complex set of movements that amount to one routine action that we perform unconsciously is called “chunking,” and although we know that it exists, exactly how “chunks” form and stabilize has remained mysterious so far. The new study now suggests that some brain cells are tasked with “bookending” the chunks that correspond to habitual actions.

To ensure that there would be no doubt regarding the solidity of the experiment’s results — and that they would be able to identify brain activity patterns related to habit formation rather than anything else — the scientists taught the rats different sequences.