Paresis in the context of Developmental neuroscience

Palsy is a medical term which refers to various types of paralysis or paresis, often accompanied by weakness and the loss of feeling and uncontrolled body movements such as shaking. The word originates from the Anglo-Norman paralisie, parleisie et al., from the accusative form of Latin paralysis, from Ancient Greek παράλυσις (parálusis), from παραλύειν (paralúein, "to disable on one side"), from παρά (pará, "beside") + λύειν (lúein, "loosen"). The word is longstanding in the English language, having appeared in the play Grim the Collier of Croydon, reported to have been written as early as 1599:

In some editions, the Bible passage of Luke 5:18 is translated to refer to "a man which was taken with a palsy". More modern editions simply refer to a man who is paralysed. Although the term has historically been associated with paralysis generally, it "is now almost always used in connection to the word cerebral—meaning the brain".

The development of the nervous system, or neural development (neurodevelopment), refers to the processes that generate, shape, and reshape the nervous system of animals, from the earliest stages of embryonic development to adulthood. The field of neural development draws on both neuroscience and developmental biology to describe and provide insight into the cellular and molecular mechanisms by which complex nervous systems develop, from nematodes and fruit flies to mammals.

Defects in neural development can lead to malformations such as holoprosencephaly, and a wide variety of neurological disorders including limb paresis and paralysis, balance and vision disorders, and seizures, and in humans other disorders such as Rett syndrome, Down syndrome and intellectual disability.

Central facial palsy (colloquially referred to as central seven) is a symptom or finding characterized by paralysis or paresis of the lower half of one side of the face. It usually results from damage to upper motor neurons of the facial nerve.

The facial motor nucleus has dorsal and ventral divisions that contain lower motor neurons supplying the muscles of the upper and lower face, respectively. The dorsal division receives bilateral upper motor neuron input (i.e. from both sides of the brain) while the ventral division receives only contralateral input (i.e. from the opposite side of the brain).

Cerebral palsy (CP) is a group of movement disorders that appear in early childhood. Signs and symptoms vary among people and over time, but include poor coordination, stiff muscles, weak muscles, and tremors. There may be problems with sensation, vision, hearing, and speech. Often, babies with cerebral palsy do not roll over, sit, crawl or walk as early as other children. Other symptoms may include seizures and problems with thinking or reasoning. While symptoms may get more noticeable over the first years of life, underlying problems do not worsen over time.

Cerebral palsy is caused by abnormal development or damage to the parts of the brain that control movement, balance, and posture. Most often, the problems occur during pregnancy, but may occur during childbirth or shortly afterwards. Often, the cause is unknown. Risk factors include preterm birth, being a twin, certain infections or exposure to methylmercury during pregnancy, a difficult delivery, and head trauma during the first few years of life. A study published in 2024 suggests that inherited genetic causes play a role in 25% of cases, where formerly it was believed that 2% of cases were genetically determined.