substantia nigra

Examples of substantia nigra in the following topics:

• Basal Ganglia

  • the substantia nigra (composed of both substantia nigra pars compacta (SNc) and substantia nigra pars reticulata (SNr)).
  • One part of substantia nigra, the reticulata (SNr), functions similarly to the pallidum, and another part (compacta or SNc) provides the source of the neurotransmitter dopamine's input to the striatum.
  • The most notable are Parkinson's disease, which involves degeneration of the melanin-pigmented dopamine-producing cells in the substantia nigra pars compacta (SNc), and Huntington's disease, which primarily involves damage to the striatum.
  • Blue=striatum, green=globus pallidus (external and internal segments), yellow=subthalamic nucleus, red=substantia nigra (pars reticulata and pars compacta).

• Midbrain

  • It extends from the substantia nigra to the cerebral aqueduct (also called the ventricular mesocoeli).
  • The substantia nigra is closely associated with motor system pathways of the basal ganglia.
  • Dopamine produced in the substantia nigra plays a role in motivation and habituation of species from humans to the most elementary animals such as insects.

• The Role of the Basal Ganglia in Movement

  • Parkinson's disease involves the major loss of dopaminergic cells in the substantia nigra.
  • The inputs from the cortex and thalamus to the striatum and subthalamic nucleus are glutamatergic, but the outputs from the striatum, pallidum, and substantia nigra pars reticulata all use GABA.
  • Dopamine is used by the projection from the substantia nigra pars compacta to the dorsal striatum and also in the analogous projection from the ventral tegmental area to the ventral striatum (nucleus accumbens).

• Motor Areas

  • The basal nuclei receive input from the substantia nigra of the midbrain and motor areas of the cerebral cortex and send signals back to both of these locations.

• Neurodegenerative Disorders

  • Parkinson's disease causes the loss of dopamine neurons in the substantia nigra, a midbrain structure that regulates movement.
  • This conversion increases the overall level of dopamine neurotransmission and can help compensate for the loss of dopaminergic neurons in the substantia nigra.

• Functions of the Diencephalon

  • It receives afferent connections from the substantia nigra and striatum and regulates skeletal muscle movements.

• Lower-Level Structures

  • The substantia nigra, a part of the brain that plays a role in reward, addiction, and movement (due to its high levels of dopaminergic neurons) is located in the midbrain.
  • In Parkinson's disease, which is characterized by a deficit of dopamine, death of the substantia nigra is evident.

• Disorders of the Basal Ganglia

  • These include the striatum, (composed of the putamen and caudate nucleus), globus pallidus, substantia nigra, and the subthalamic nucleus.

• Overview of the Cerebrum

  • The olfactory bulb also receives "top-down" information from such brain areas as the amygdala, neocortex, hippocampus, locus coeruleus, and substantia nigra.

• Anatomical Changes

  • These signs include the presence of human chorionic gonadotropin (hCG) in the blood and urine, missed menstrual period, implantation bleeding (occurs at implantation of the embryo in the uterus during the third or fourth week after last menstrual period), increased basal body temperature sustained for over 2 weeks after ovulation, Chadwick's sign (darkening of the cervix, vagina, and vulva), Goodell's sign (softening of the vaginal portion of the cervix), Hegar's sign (softening of the uterus isthmus), and pigmentation of the linea alba (called linea nigra), which is darkening of the skin in a midline of the abdomen.