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1. Glossary

Phantom limb pain

Phantom pains are called phantom pains because they occur in phantom limbs – limbs that have been amputated.

1. Glossary

Plaques

Senile plaques accumulate in the gray matter of the brain when a protein – known as amyloid precursor protein – is not broken down correctly. Inflammation and disorders of fat or sugar metabolism can promote plaque formation. On average, the deposits reach a diameter of 50 micrometers. The appearance of plaques is one of several anatomical changes in the brain that pathologists can use to diagnose Alzheimer's disease after death.

1. Glossary

Plasticity

The term neuroplasticity describes the ability of synapses, nerve cells, and entire areas of the brain to change structurally and functionally depending on the degree to which they are used. Synaptic plasticity refers to the adaptation of the signal transmission strength of synapses to the frequency and intensity of incoming stimuli, for example in the form of long-term potentiation or depression. In addition, the size, interconnection, and activity patterns of different areas of the brain also change depending on their use. This phenomenon is referred to as cortical plasticity when it specifically affects the cortex.

1. Glossary

Pons

Area in the brain stem between the medulla oblongata and the mesencephalon. It acts as a switching station for many nerve pathways between the brain and spinal cord and contains numerous nuclei, including cranial nerves and those involved in controlling motor function in cooperation with the cerebellum.

1. Glossary

Positron emission tomography

An imaging technique that helps doctors visualize metabolic processes in the body. The patient is injected with a weakly radioactive substance that emits positrons, i.e., beta radiation. When the positrons encounter electrons in the body, energy is released in the form of two photons. These photons travel in opposite directions. Detectors are arranged around the patient in the PET scanner to register the photons that strike them. This makes it possible to track whether the radioactive substance accumulates in certain areas of the body, which can indicate the presence of a tumor, for example. Positron emission tomography is also used in the early diagnosis of dementia. The radiation exposure is low and acceptable in a medical context.

1. Glossary

posterior

A positional term – posterior means "towards the back, located at the rear." In relation to the nervous system, it refers to a direction towards the tail.

1. Glossary

Posterior parietal cortex

The posterior parietal lobe receives inputs from numerous visual, auditory, somatosensory, and proprioceptive cortical areas. It integrates this information into an overall spatial picture that enables orientation, spatial attention, and the planning and execution of goal-directed movements.

1. Glossary

Postcentral gyrus

The postcentral gyrus is the fold on the surface of the cerebrum located immediately behind the central sulcus. It contains the primary somatosensory cortex, where touch, pressure, temperature, and proprioceptive stimuli are processed.

1. Glossary

Pre-dementia

Alzheimer's disease typically progresses through several clinical stages, preceded by an early phase with initial cognitive impairments. This phase, formerly known as pre-dementia, is now usually referred to as mild cognitive impairment (MCI) due to Alzheimer's disease. It can manifest itself through symptoms such as declining short-term memory. With modern imaging techniques, especially amyloid PET, characteristic amyloid deposits in the brain can already be detected in this early phase. Laboratory chemical analyses of blood or cerebrospinal fluid can also provide indications of changes in protein concentrations typical of Alzheimer's disease. Although the clinical diagnosis of dementia is only made in later stages, the underlying Alzheimer's pathology can often be detected in advance today.

1. Glossary

Prefrontal cortex

The prefrontal cortex (PFC) forms the front part of the frontal lobe and is one of the brain's most important integration and control centers. It receives highly processed information from many other areas of the cortex and is responsible for planning, controlling, and flexibly adapting one's own behavior. Its central tasks include executive functions, working memory, emotion regulation, and decision-making. In addition, the PFC plays an important role in the cognitive evaluation and modulation of pain.