Is studying Neurosciences as easy as driving a car?

Warm wishes to all my dear teachers, colleagues and students who motivated me to an attempt to write this small piece of article for them.

-          Love, AS

One of the most interesting subjects that we as physiotherapists interact with is neurosciences. It is an extremely interesting subject wherein there are multiple challenges and equally interesting results seen. But somehow, many times the young budding Physios are scared or sceptical about this subject and majority have an aversion or a poor understanding for it.

I remember my own experiences as a young undergraduate student who was totally scared and aversive towards neurology as a clinical subject. But interaction with 5 Neuro stalwarts changed my perspectives towards neurology and made me realize that studying neurosciences is as easy as driving a 2 wheeler or a car.

My elder brother always used to tell me as a young lad learning to drive a 2 wheeler that the 1^st thing you have to know when you drive any vehicle is to know where the brakes are. Once you start, you won’t have the time to search for it later. So what happens if there is a problem with the brake of our vehicle? Obliviously it won’t stop and go out of control. So do we see such a thing in our body in any diseased condition? Do we see something like this when the patients cannot control their movements and tend to go out of control? This is what happens when we have a lesion in the cerebellum. Thus the cerebellum is the brake of the human body. Involvement of this system causes our break failure and we tend to see overshooting, inappropriate stepping, in coordination in walking and other activities. This is what we classically describe as ataxias.

But by itself the brakes cannot control the vehicle if we do not control the steering wheel or the handle. Thus it becomes very important to steer a vehicle properly in order to prevent accidents and reach our destination. This steering function is by our basal ganglia. Just like steering control loss would make the vehicle go out of control, similarly involvement of the basal ganglia can make us go out of control. Such is seen in conditions like hemiballismus where loss of steering control is seen.

So who drives us then? When we start a car, the engine starts but the vehicle cannot move. The engine is our wakefulness which is controlled by the Reticular system. If the reticular system is impaired, we won’t get ‘started’. Thus the driving force for us is in this system. But is the reticular system capable of driving us by itself? Even if the engine has started, it will just continue to be in idling unless we accelerate the vehicle. The accelerator is very important tool in this. So what happens when we keep the engine in idling without accelerating? It’s simple, we just won’t move anywhere. This function of generating stimulus for movement and accelerating our body is by the motor cortex of the cerebral system. The cortex ensures that we are accelerated adequately to move in an appropriate manner. So what happens if our accelerator gets damaged? We will have problems generating that amount of tone in order to move ahead. This is classically seen in injuries of the motor cortex like stroke patients. Their engines are at an idling situation but are unable to accelerate to move their body in a required manner and thus they generate spasticity.

Also, this engine, in order to move the vehicles, has to move the axle or the chain/ belt of the vehicle in a proper gear. What can happen if this axle or belt breaks? Results will be the same. The engine will keep on idling but will not be able to move the car. Thus axle or belt is the spinal cord. When it is injured, the brain generates an idling tone but the limbs cannot move as there is no transmission by the engine to the tyres. This is what can be seen in paraplegia or quadriplegia.

So then what happens to the car when the engine starts, we don’t put vehicle in gear but just accelerate? The car would not move. Instead, it would just create a lot of RPMs and start vigorously vibrating. The more we accelerate the more sound it would produce and create a static rigidity. This is classically what would happen when there is lesion of the extra pyramidal system. The body’s engine starts increasing a lot of tone, but the person cannot move anywhere. Thus the extra pyramidal system (Substantia Nigra) is the gear of the human body. We always have to drive our car in the proper gear or it can damage the engine due to excess RPMs. Even the extra pyramidal system puts our body in proper gears in order to drive ourselves in proper systems. So what if my gears don’t work properly? I would produce excess tone but not able to move properly. Just try driving your car in 1^st gear at speed of 40 or 50 and you will experience a festinating gait. (I didn’t advice to experiment such driving with the brakes cut). Thus an extra pyramidal system problem gives us excess tone but no movement. Incase we move, it will be like speeding in the 1^st gear. This is what we see in Parkinson’s patients, lot of resting movement but no motions as against Cerebellar Ataxias where there is no movement till vehicle moves, but once it does, there are movement tremors.

So if we look at things simply, the upper motor neuron, cerebellar system and extra pyramidal systems are much easy to understand. So what about the lower motor neuron system? Well, the vehicles have lots of wiring and cable systems. These connects the battery (heart) to the lights (visual), horn (auditory), brake cables (nerves), and the AutoCop security system (skin). Lesions in any of these cables will eventually cause inability to generate stimulus to that part and thus produce weakness. There may be a short circuit in the wires where the wire covering may be removed (neuropraxia) to the point where the entire wire is broken (neurotemesis) and thus cause problem in handling the car.

Well, there’s still a lot to go on. Recent technology allows us a lot of luxury while driving. We now have the GPS system which allows us to detect directions to reach our destination and identifies driving challenges. This is the role of the frontal cortex which helps in planning and mapping of tasks and systems and identifies objects. Also the high class vehicles have a climate (cruise) control system in order to automatically detect and maintain the temperature and internal atmosphere of the car. This is what the Hypothalamus does for us.

In spite of all the systems working ok, there would still be a problem if there is dust in the carburettor or the air filter. Also when the vehicle will run, the engine will get heated and the vehicle will start experiencing jerks. Such is the dyspnoea seen in disorders of the respiratory system. Also what can all these do when the chassis of the car breaks!!! Thus is the importance of the musculoskeletal system. But heyyy!!!, weren’t we just discussing neurosciences????

So easy or difficult is up to you all to decide. All I can say is thanks to my stalwarts of neurosciences and to many others who have been doing their best to generate interest in neurosciences amongst many young Physios for years apart. So who says studying neurology is really difficult. You always learn it when you just drive your car……

Apurv Shimpi