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 →

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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 →

Periventricular Leukomalacia (PVL)

Periventricular Leukomalacia (PVL) is a type of brain damage that affects fetuses and premature babies. At this stage of brain  development, the white matter surrounding the ventricles is particularly vulnerable to hypoxic (lack of oxygen) or ischemic (lack of blood flow) injury for a variety of reasons, including high metabolic demand in a location that... Continue Reading →

Dura Metastasis: Hepatocellular Carcinoma

The most common tumors found in the central nervous system and dura (i.e. the dense fibrous covering that envelops the brain) are those that have traveled from other body sites in a process called metastasis.  Depicted here is hepatocellular carcinoma (HCC), a cancer of liver cells, that has metastasized to the dura overlying the anterior pole of the right frontal lobe. Microscopically, the neoplastic liver... Continue Reading →

Globose Neurofibrillary Tangle

Neurodegenerative diseases commonly have abnormal protein inclusions that ultimately contribute to neuron death.  One such example is abnormally hyperphosphorylated tau protein, the major component of neurofibrillary tangles (NFTs), which are a key microscopic feature of Alzheimer Disease and lesser known neurodegenerative diseases, such as Frontotemporal Lobar Degeneration (FTLD).  Like water in a vase, an NFT will assume the shape of the cell in which it arises.  For example, the classic... Continue Reading →

Cortical Atrophy in an Elderly Person (90 years old)

A normal adult loses about 0.2% of brain volume every year after middle age.  Compared to young and middle-aged adults, the brains of the elderly have comparatively widened sulci, narrowed gyri, a thin cortical ribbon, and enlarged ventricles due to progressive brain volume loss, which, clinically, may contribute slower processing speed for cognitive tasks and other changes.  Microglia-mediated synaptic pruning and other etiologies for decreasing cortical volume in the... Continue Reading →

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