If the reaction is exaggerated or absent, it may indicate a damage to the central nervous system Most reflexes go completely unnoticed because they don’t involve a visible and sudden movement Body functions such as digestion or blood pressure, for example, are all regulated by reflexes

Motor weakness often is accompanied by upper motor neuron signs, such as mild spasticity, hyperreflexia, and pathologic signs The most common initial presentation is paraparesis, but weakness can be also found in just one extremity (monoparesis) or all four extremities (quadriparesis)

An abnormal response is slower and consists of extension of the great toe with fanning of the other toes and often knee and hip flexion This reaction is of spinal reflex origin and indicates spinal disinhibition due to an upper motor neuron lesion

Westphal’s sign refers to a decreased or absent patellar tendon reflex, also known as the knee-jerk reflex, observed on physical exam The patellar tendon reflex refers to a kicking-like motion produced by the extension of the knee joint upon the ipsilateral stimulation of the patellar tendon

In adults or children over 2 years old, a positive Babinski sign happens when the big toe bends up and back to the top of the foot and the other toes fan out This can mean that you may have an underlying nervous system or brain condition that’s causing your reflexes to react abnormally

Reflexes There are many various reflexes that can occur simultaneously during a startle response The fastest reflex recorded in humans happens within the masseter muscle or jaw muscle The reflex was measured by electromyography which records the electrical activity during movement of the muscles

All reflex actions are involuntary in nature but all involutary actions are not reflexes For example – The beating of heart and peristalsis are involuntary actions, but not reflex action

Some functions are involuntarily performed, such as breathing, digestion, heart beating, eye reflexes, etc, but some involuntary actions have voluntary control to a certain extent – examples are breathing, salivation, deglutition (swallowing), defecation, micturition (urination) and others

Involuntary action is the set of muscle movement which do not require thinking But it is controlled by brain for example beating of heart beat While on the other hand, the reflex action is rapid and spontaneous action in response to any stimulus which doesn’t involve brain

medulla oblongata

This is controlled by the part of the brain called cerebellum Involuntary actions happen automatically in our body without our control They are usually important actions, like breathing, heart pumping, digestion A part in the back of the brain called medulla oblongata controls most of these actions

In children, some of the most common causes of involuntary movements are: hypoxia, or insufficient oxygen at the time of birth kernicterus, which is caused by an excess pigment produced by the liver called bilirubin cerebral palsy, which is a neurological disorder that affects the body’s movement and muscle function

The cerebellum is located behind the brain stem While the frontal lobe controls movement, the cerebellum “fine-tunes” this movement This area of the brain is responsible for fine motor movement, balance, and the brain’s ability to determine limb position

Imaging studies suggest that the happiness response originates partly in the limbic cortex Another area called the precuneus also plays a role The precuneus is involved in retrieving memories, maintaining your sense of self, and focusing your attention as you move about your environment

The cerebellum is at the back of the brain, below the cerebrum It’s a lot smaller than the cerebrum But it’s a very important part of the brain It controls balance, movement, and coordination (how your muscles work together)

Cerebrum

READING CAN IMPROVE OUR MEMORY When you read, you’re engaging more than a few brain functions, such as phonemic awareness, visual and auditory processes, comprehension, fluency, and more Reading jolts your brain into action, maintains concentration, and allows your mind to process the events happening before you

Recognition of smell usually involves parts of the frontal lobe Parietal lobe The middle part of the brain, the parietal lobe helps a person to identify objects and understand spatial relationships (where one’s body is compared to objects around the person)

Scientists have found that dozens of illnesses have a particular smell: Diabetes can make your urine smell like rotten apples, and typhoid turns body odor into the smell of baked bread Worse, yellow fever apparently makes your skin smell like a butcher’s shop, if you can imagine that

Brief episodes of phantom smells or phantosmia — smelling something that’s not there — can be triggered by temporal lobe seizures, epilepsy, or head trauma Phantosmia is also associated with Alzheimer’s and occasionally with the onset of a migraine

Phantosmia is a medical condition sometimes known as olfactory hallucinations Individuals with this condition believe they can smell certain odors such as smoke, natural gas, dirt, and flowers even when the smell does not exist