Navigation skills-another example of use it or lose it brain theory

A cat’s 200 mile trek home leaves scientists guessing

Recently the above titled article was published in The New York Times dated January 20th 2013. Holly, a domestic cat after getting lost on a family excursion was able to trek back to about a mile away from her family home, a distance of nearly 200 miles. Just how was this domestic animal able to achieve this remarkable feat of navigation ignited some healthy discussion among cat biologists. Wild animals navigate using visual, smell and magnetic cues. Domestic animals such as cats and dogs on the other hand are able to navigate successfully only in the immediate vicinity of their homes. It seems domestication and evolution resulted in loss of navigation qualities which their still wild ancestors (feral cats, big cats and wolves) possess. Take your dog and drop him off in a suburb of Washington DC and it is highly unlikely he shall show up at your apartment door in New York. This got me thinking on how the current generation of homo sapiens navigate. Take any self respecting New Yorker (no self respecting New Yorker will ask another New Yorker for directions) and ask him to find his way to Greenwich Street from say Charles Street and I bet you that only a few shall find their way in a timely fashion. Heck we even use GPS technology to navigate our way in the city we live in. Gone are the days when we navigated using the stars in the sky. We risk losing whatever remaining navigation skills we still possess thanks to the Google maps app on our smart phones. Maybe Holly the cat is a dying breed among cat explorers not just yet willing to let go of the traits of her ancestors.


Nitin K. Sethi, MD

New York-Presbyterian Hospital


525 East, 68th Street

New York, NY10065



Brain diseases blog: it is up and running again

To the readers of my blog and my website ( thank you for your continued support and positive feedback as well as constructive criticism.  I apologize for my delay in replying to your questions. No good excuse apart from that I was really busy the last few months. The blog though is now up and running and I shall be answering all your questions as well writing a few new posts.

Personal Regards,

Nitin Sethi, MD

I had a stroke like episode—what do I do?

I had a stroke like episode—what do I do?


Nitin K Sethi, MD

Assistant Professor of Neurology

New York-Presbyterian Hospital

Weill Cornell Medical Center

New York, NY 10065




I frequently see patients admitted to the hospital for evaluation of a suspected stroke like episode. Most of these patients are “normal” with no neurological signs and symptoms (the presenting symptom has invariably resolved by the time of their admission to an acute care facility).

So what are these stroke like episodes which scare patients and doctors alike leading to admission to a hospital and invariably a battery of tests including but not limited to MRI scans of the brain? Well some may be as vague as an episode of sudden dizziness, difficulty walking or weakness in the arms and legs, others are more restricted-an episode of difficulty speaking (I could speak but my words did not come out right or my speech was slurred as if I was drunk), loss of vision in an eye and so on.

When patients present to the ER or a doctor’s office with a history of such symptoms, they are frequently advised admission to rule out a possible stroke. When people think of stroke, they usually think of someone with weakness of the arm and leg but stroke signs and symptoms can be more subtle. Many patients have what we refer to as transient ischemic attacks (TIAs) prior to the stroke. As the name suggests, TIAs are transient (short lived) episodes of ischemia to the brain. Let me try to explain a TIA with the aid of an example. Let us assume a clot (entangled platelets and cholesterol crystals) breaks from the heart and goes up to the brain via the carotid artery (the carotid artery is one of the main arteries carrying blood to the brain). As it goes up further and further, it may get lodged in the ophthalmic artery (the ophthalmic artery is a branch of the carotid artery and supplies the retina of the eye). Now if the ophthalmic artery gets blocked by the clot there is no blood supply to the retina with resulting loss of vision in that eye (patients frequently complain of a black curtain descending in front of their eye). If the clot breaks by itself and dissolves the vision comes back (we call this transient monocular blindess—transient blindness in one eye). There you have suffered a transient ischemic episode.

There can be other types of TIAs which can involve different blood vessels in the brain and present with a myriad of signs and symptoms such as dizziness, double vision and difficulty speaking. So what is so important about TIAs?

Well put in simple language a TIA may be a warning sign of a future stroke (and by future, I mean in the NEAR future). It is a sign that all is NOT well with the blood vessels of the brain or the heart (either the vessels are slowing getting narrowed or the heart is not functioning well and throwing up small blood clots into the brain). TIAs thus should be aggressively and thoroughly investigated.


What are the stroke risk factors?

How can they be modified?

Does the patient need to be on any blood thinners?


As I frequently explain to my patients and their families









A confused mass of “protoplasm”

The human mind continues to fascinate me. Recently I met a close friend after a long time.  Over dinner and drinks he filled me up on his life. He now had a successful business employing well over 20 people. As we were chatting he said Nitin, I feel I have a problem. I asked what, to which he replied “I think my brain is a confused mass of protoplasm”. Intrigued I asked what did he meant by that.

He answered ” my brain is always working. It never stops thinking. All the time I have thoughts going through my head. What I have to do today, what needs to be done tomorrow. How I wish for just a short while my brain would stop thinking. I am doing one thing but my brain is already thinking about what next has to be done. In the morning I get up to take a shower and as the cold water strikes my face, thoughts race through my mind. Needless and endless thoughts. Do you have any drug which I can take to control my mind?”

I guess the pressures and distractions of modern life has made all our minds (some more than others) confused masses of protoplasm. Our minds are constantly getting bombarded by external images, sense objects, pressures of modern life, all causing a sensory overload which our minds are unable to compensate for. More and more people are burning out at a young age, some willingly and others been forced to opt out of the rat race. Turning to meditation, yoga and solitude to bring this incessant brain chatter under their control. Unfortunately we still do not have any magic drug to switch on and off these thoughts and ramblings of the brain.

Till that happens we continue to suffer the price of modern existence.

Nitin Sethi, MD

The healthy brain


As a neurologist, I see the diseased brain everyday. Patients suffering from acute and chronic debilitating neurological conditions like strokes, uncontrolled seizures, brain tumors, Parkinson disease and ALS. The devastating toll of neurodegenerative conditions like Alzhemiers dementia is enormous. They affect not just the immediate patient but also family and friends.

It seems to me that as doctors we talk a lot about the brain in disease (the diseased brain) but precious little about the brain in health (the healthy brain). Why this fascination with the brain in disease? Why do we not invest more in keeping the brain healthy.

There is so much literature out there about how to keep the heart healthy. Take a low cholesterol diet, exercise regularly, keep your blood pressure under control, eat fish and keep your stress low to keep your heart healthy. What about the brain’s health?  Can we extrapolate data obtained from studies done on the heart and apply it to the brain? Are the heart and brain alike? Is their physiology the same? What is good for the heart, is it also good for the brain?

At the expense of making cardiologists really angry I would like to point out here what was once told to me by my friend. The only function of the heart is to keep the brain alive!!! To pump blood to the brain so that the supercomputer, the masterboard of the human body can work smoothly. The heart and brain are not alike and what is good for the heart need not be good for the brain. The blood vessels of the heart and brain do not work in the same way. The human brain is far more intricate and complex and there is still precious little we know about it.

The decade of the brain came and went. True there has been an explosion of knowledge in the field of neurosciences but we still have miles and miles to go. I think we have reached the stage when we pretty much know everything about the heart, we can open blocked blood vessels, bypass coronary vessels and hey even transplant the heart. A few nicks here and there and out pops the old heart and in goes a new one. But what about the brain? Can we even dream of transplanting a human brain? One can imagine a neurosurgeon trying to connect billions of synaptic connections, so that the new brain works just like th old one. It is the brain which defines us, makes us what we are, the seat of our emotions, memory and intelligence. How would we make sure that the new brain still houses all the old information?

As you can see there are more questions than answers at least with our current degree of understanding of the human brain. So till we learn more, we should as doctors and patient advocates talk more about the brain in health. How do we keep this supercomputer healthy? For every one lecture a neurologist gives about treatment of stroke, he should give ten about stroke prevention. We need good quality research to figure out what foods does our supercomputer like (what are these brain foods, how much is good and how much is bad). How much sleep and down time this supercomputer needs? Does it like complementary therapies like yoga, meditation and tai-chi? Does neurobics help in keeping it hale and hearty.


Emotions that define us as human beings such as love come from the brain. The rush one feels as he sees his beloved, the longing, the pain all come from the brain. Hmm I even propose that instead of having a arrow through the heart to display cupid, we should have an arrow through the brain, after all that is where the love center is.

So lets take a pledge to keep our brains healthy. There is no better gift we can give ourselves than a healthy brain and mind.


Nitin Sethi, MD

The human brain: the world’s foremost supercomputer

Read a fascinating post in the Wall Street Journal by By ROBERT LEE HOTZ titled ” Get out of your own way”. The author reports on studies and ongoing research into how our brain makes a “conscious” decision.

Let me take an example to explain the above. Suppose you are in a market place looking for apples. You are standing by the basket which is full of red apples. You look at the apples and are trying to pick just the “right” juicy ones. Then you make a choice and reach in and pick up the apple you wanted. Now you may think this is a conscious act, conscious decision making went into picking the apple. Research though shows that the human brain is far more superior and faster.

Even before you make the choice, the brain has already made its choice and knows which apple it wants from the lot. And that is the apple you finally pick up.

Functional MRI scans show that parts of brain are activated 10 seconds before the decision reaches the consciousness. This research sheds new light into the functioning of the human brain and the speed of its computation power. When the human brain is presented with choices, it is able to analyze countless permuations and combinations. How does our brain do this? How could the human brain defeat the worlds most advanced supercomputer in a game of chess. Surely the supercomputer would have been better with numbers and analyzing various possible chest moves. Like I said before, we still do not know how the brain actually works. But one thing which differentiates us from a machine is we think but we can think with emotions too. I can “cheat” in a game of poker or chess to throw you off. A computer once you understand how it works  or “thinks” you know it shall not work or “think” in any other way. A computer shall not cheat you.

A human brain on the other hand is never stationary. It has the unique ability to form new thinking processes. So now lets get back to our apple story. If the brain in few seconds has already made the choice it thinks is the right one (in this case the right apple) and that is the apple you finally pick up, then there may be some truth to the old saying of “going with your gut feeling”.

Overthinking a decision may not always be great. You go into a car dealership and are flip flopping over which car to buy. Thinking and rethinking your decision. Hmmm now you may say, it is a big buy and one must think through it well. True but the brain it seems has already decided and from what we know it has probably made the right choice as soon as you entered the dealership. If the first thing which crossed your mind was ” I want that red ford” well then probably that is what is right for you.

Now you may rethink and change your decision but it may not be the best one.  I find this concept fascinating and it just amazes me how the brain works. It is truly the world’s foremost supercomputer powered by God not intel!!!

Personal Regards,

Nitin Sethi, MD

MRI white matter lesions: does it represent MS?

MRI white matter lesions

Many times I get consulted by patients or their relatives when their MRI brain report reads multiple scattered white matter lesions seen. The radiologist’s report usually further reads that these can be seen in primary demyelinating conditions like multiple sclerosis or in vascular disorders. Patient’s and caregivers are naturally worried when they get this MRI report and do not know what to do and how to proceed further. So I thought that here I shall talk about these white matter abnormalities seen on the MRI. What is their significance? Do they represent evidence of multiple sclerosis?

White matter signal changes on the MRI essentially means that on the MRI, the white matter  showed some scattered bright spots. White matter in the brain refers to the fiber tracts that carry information to and fro from the brain.

My first question when somebody asks me what next and what does this mean is to ask them why was the MRI done in the first place. If the MRI was done because there was a clinical suspicion of multiple sclerosis then these white matter lesions may indeed have significance and may represent radiological evidence of MS plaques. Let me explain this with an example. You go to your doctor, you have signs and symptoms that suggest MS (example you may have had an attack of optic neuritis), when the doctor examines you he is able to elict signs in the examination compatible with a diagnosis of MS, then he orders an MRI to see if you do have evidence of white matter lesions in the brain. In a case like this the presence of white matter lesions/ signal changes in the MRI is obviously important. Here it likely does suggest the presence of MS. That said and done I again want to re-emphasize that the diagnosis of MS is made on the basis of clinical history of previous attacks, CSF (spinal fluid) examination and MRI, not just on the basis of the MRI alone. Also there are certain criteria which have to be satisfied on MRI to make a definite diagnosis of MS. These radiological criteria for MS include the number of lesions on  the MRI, their location and their size.

Thus it is important to remember that a person who is noted to have white matter lesions on a brain MRI does not necessarily have MS. White matter lesions can be seen in numerous other conditions and they are more commonly seen as we grow older. The thinking behind this is that they represent microvascular ischemic changes in the brain (the smaller caliber blood vessels in the brain showing signs of ischemia or decreased blood flow). Hence these white matter abnormalities on MRI are more commonly seen in patients who have microvascular and macrovascular risk factors such as a history of hypertension, diabetes and high cholesterol (dyslipidemia/ bad lipid profile).

White matter signal changes on MRI may also be seen in patients who have infectious and other inflammatory conditions. They have been reported in the MRI of patients with a history of migraine headaches (migraine too is a vascular disorder and that may explain the connection).

So I want to end by saying that the presence of these white matter signal changes on brain MRI has to be correlated to the history, clinical examination and other ancillary investigations. Your doctor shall help you in going about this in a methodical manner. I repeat these white matter lesions do not suggest MS in each and every case they are found.

 Dr. Sethi

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Your brain on religion

Just some random thoughts on the neuroscience behind religion. What is religion ? How are our religious beliefs generated? Do we have a center in the brain dedicated to religion (is there a religion center in the brain?) Role of temporal lobe and limbic structures in religion. Some patients with temporal lobe epilepsy are hyperreligious. Does the temporal lobe house the religion center of the brain?

I shall be musing about these thoughts further.

Dr. S