onsists of fiber tracts and two differentiated color areas:
- The red nucleus assists in movement and the coordination of sensorimotor information (where sensory information is synergized/integrated with motor responses and affects voluntary and reflexive actions).
Nerve fibers (crossed fibers) from the cerebellar peduncle surround and (some) terminate in the red nucleus. These fibers receive information from the motor cortex.
- Periaqueductal gray matter. Behavioral (like pain and stress) processing and responses occur in this midbrain region. This region receives its color from the lack of axons (i.e., the greater concentration of neuron bodies).
This region deals with pain suppression through endorphin production.
Although some sources view the substantia nigra as part of the tegmentum, others view it as a separate structure in the midbrain.
The tegmentum is essential for alertness, movement, and processing of pain.
Complications Of The Cerebral Peduncles
As with most brain regions, the cerebral peduncles are not exempt from experiencing injury and diseases. When negatively affected by these complications, the cerebral peduncles severely impact the organism’s ability to function correctly.
Some complications include:
- A lack of proprioception.
- Loss of balance.
- Unrefined motor skills.
- Various degrees of paralysis.
Trauma is a significant cause of complications of cerebral peduncles. When the cerebral peduncles are injured, the symptoms present in the corresponding body part (i.e., the part of the body that the damaged nerve cells connect to).
Diseases And Conditions Affecting The Cerebral Peduncles
Aside from trauma, diseases are the other significant reason for complications in the cerebral peduncles.
Some of these diseases include:
Bilateral Cerebral Peduncle Infarction
An infraction is when blood vessels leading to a particular organ (or part thereof) become blocked (often through swelling). This blockage leads to the “starvation” of cells in the affected area, which begin to die.
During a study in 2019, researchers discovered that the leading causes for these blockages in blood flow to the cerebral peduncles were due to pressure on the vertebrobasilar artery and its branches through stenosis or occlusion ( a full or partial blockage of a blood vessel).
Stenosis is narrowing spaces in the spine, applying pressure to the spinal cord and causing pain and discomfort, which could eventually lead to paralysis/loss of function.
An occlusion in the intracranial regions of the brain could cause ischemia (lack of oxygen). This ischemia leads to Wallenberg Syndrome, Locked-In Syndrome, and Top-of-the-basilar syndrome, depending on where the blockage occurs.
These diseases range in consequences/symptoms, from ataxia and disturbances in brain function to quadriplegia.
Developmental Disorders Affecting The Cerebral Peduncles
Although not limited to the cerebral peduncles, “cobblestone lissencephaly” is a developmental disorder affecting the midbrain (and, by extension, the cerebral peduncles).
Certain neurons fail to migrate during fetal development (especially during weeks 12 and 24). This failure results in the absence of grooves and folds developing on the brain’s surface.
Individuals affected by these disorders often suffer from:
- Cerebral ocular and muscle defects.
- Muscle-eye-brain and Fukuyama muscular dystrophy.
- Walker-Warburg syndrome.
Cerebral Peduncle Lesions And Tumors
The term “lesion” is a collective description of any damaged tissue in the brain. Although all tumors are lesions, not all lesions are tumors.
Unfortunately, tumors may develop in the midbrain and the cerebral peduncle. An example is gliomas. This type of tumor develops when glial cells grow out of control. While some patients may not show symptoms, these tumors are frequently cancerous (malignant).
These tumors are often fatal as they are challenging to treat/reach for surgery and may spread to other areas in the brain.
There are three types of gliomas:
- Astrocytomas. The tumors begin in astrocytes and vary in severity. Glioblastomas (a ty