Normal Pineal Gland with Calcifications

The pineal gland is a midline structure involved in the regulation of circadian rhythm. The "internal clock" that allows for coordination of sleep and wake cycles with changes in night and day is largely regulated by the actions of melatonin, a neurotransmitter that is produced by the constituent cell of the pineal gland: the pinealocyte. Pinealocytes give rise to a rare group of tumors... Continue Reading →

Dorsal Root Ganglion

The dorsal root ganglia consist of the cell bodies of sensory afferent neurons and are located along either side of the spinal cord. These unipolar neurons characteristically have large cell bodies, which are needed to support the very long axons that carry sensory information from the distal extremities to the cord. Normal ganglia (such as the one... Continue Reading →

Tripolar Atypical Mitosis in Glioblastoma

Cell division occurs in four major stages (prophase, metaphase, anaphase, and telophase) during which DNA duplicates itself and condenses, chromosomes centrally align and are pulled apart by two centrosomes on either side of the cell, and the cytoplasm separates to form two separate daughter cells. Cancer cells are able to enter into cell division by bypassing the usual complex ballet of cell... Continue Reading →

Vestibular Schwannomas

Intracranial schwannomas most commonly arise from the vestibular portion of the Vestibulocochlear nerve (cranial nerve VIII). The central/proximal aspect of the nerve is myelinated by oligodendroglial cells whereas the distal/peripheral aspect is myelinated by Schwann cells. These distally located Schwann cells give rise to vestibular schwannomas that originate in the distal aspect of the nerve, usually within the internal auditory canal where it... Continue Reading →

Resorption of Embolic Material in Arteriovenous Malformation (AVM)

Vascular brain lesions have increased risk of intracranial bleeding and, therefore, present a challenge to neurosurgeons attempting surgical resection.  Such tumors may first be embolized prior to surgical excision in order to reduce the risk of bleeding.  Onyx, an ethylene vinyl alcohol copolymer, is one of many embolic agents available to accomplish this task.  Onyx has... Continue Reading →

Fetal Gyral Development

During the first half of gestation, the human fetal brain has a smooth surface.  At about 20 weeks gestation, the brain begins to form the bumps (gyri) and grooves (sulci) that are typical of the adult brain, averaging about 1 sulcus per week of gestation after 20 weeks.  The brain of this 25 week gestation... Continue Reading →

Hippocampal Atrophy

The hippocampus is critical to learning and memory.  Patients with hippocampal atrophy often have difficulty with declarative memory (i.e. remembering facts, names, events, etc.) and making new memories. Hippocampal atrophy can be seen a variety of disease processes, including epilepsy and neurodegenerative disease. Note how atrophy in this elderly patient, who had memory difficulties prior to... Continue Reading →

Cerebral Vascular Territories

The cerebral hemispheres are supplied with blood via three major arteries: the anterior, middle, and posterior cerebral arteries.  This coronal section through the frontal lobes shows hemorrhage involving the vascular territory of which of these three major cerebral arteries? Answer:  The cerebral hemispheres are supplied with blood via three major arteries: the anterior, middle, and posterior... Continue Reading →

Substantia Nigra decreased pigmentation in Parkinson Disease

The substantia nigra (literal translation: “black substance”) is a portion of the midbrain that contains pigmented dopamine-producing neurons.  Degeneration of these cells causes relative depigmentation the substantia nigra, representing a finding that is typical of Parkinson Disease, but may also be present in other neurodegenerative disorders such as Alzheimer Disease. Shown here is the basal... Continue Reading →

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