Related Experiment Video
Updated: Jul 10, 2026
08:29
Symmetric Bihemispheric Postmortem Brain Cutting to Study Healthy and Pathological Brain Conditions in Humans
Published on: December 18, 2016
Semantic dementia: a unique clinicopathological syndrome
John R Hodges1, Karalyn Patterson
1Prince of Wales Medical Research Institute, University of New South Wales, Sydney, Australia. john.hodges@mrc-cbu.cam.ac.uk
The Lancet. Neurology
|October 20, 2007
Summary
Semantic dementia (SD), a frontotemporal dementia variant, shows distinct cognitive and imaging features. Research highlights its impact on semantic memory, implicating specific brain regions and characteristic neuropathology.
Area of Science:
- Neurology
- Neuroscience
- Cognitive Science
Background:
- Semantic dementia (SD) is a clinical variant of frontotemporal dementia.
- It presents unique clinical and neuroimaging abnormalities.
- SD significantly impacts understanding of semantic memory organization.
Purpose of the Study:
- To describe the epidemiological, cognitive, and radiological features of Semantic Dementia.
- To elucidate the role of specific brain regions in SD.
- To outline the typical neuropathological findings in SD.
Main Methods:
- Review of epidemiological data.
- Neuropsychological assessments to identify cognitive deficits.
- Structural MRI and functional fluorodeoxyglucose-PET imaging.
- Analysis of neuropathological findings.
Main Results:
- Consistent neuropsychological deficits affecting semantic memory, language, and perception.
- Imaging studies emphasize the involvement of temporopolar and perirhinal cortices.
- Neuropathology typically reveals ubiquitin-positive, tau-negative neuronal inclusions.
Conclusions:
- Semantic dementia has predictable neuropathological features distinct from other frontotemporal dementia syndromes.
- The study reinforces the critical role of temporopolar and perirhinal cortices in semantic memory.
- Findings advance the understanding of semantic memory's neural basis and its relationship with other cognitive functions.
Related Concept Videos
01:22Dementia l: Introduction
Dementia is an acquired, progressive syndrome characterized by a decline in multiple cognitive domains severe enough to impair daily functioning and reduce independence. Although memory loss is a central feature, the diagnosis requires additional deficits involving language, executive function, visuospatial skills, judgment, calculation, or abstract reasoning. These cognitive impairments reflect underlying neurodegenerative or vascular processes that gradually disrupt neuronal networks...
01:30Dementia
Dementia is a collective term for cognitive disorders primarily affecting memory, thinking, and reasoning. It is not a specific disease but a syndrome, with Alzheimer's disease being the most common cause, accounting for approximately 60-80% of cases. Other types include vascular dementia, Lewy body dementia, and frontotemporal dementia. Dementia affects millions worldwide, particularly older adults, though it is not a normal part of aging.
The progression of dementia is generally gradual.
The progression of dementia is generally gradual.
01:27Psychosis: Pathophysiology of Schizophrenia and Other Psychotic Disorders
Schizophrenia is a neurodevelopmental disorder whose origins are rooted in complex genetic components. Despite our burgeoning understanding, the pathophysiology of this disorder remains incompletely deciphered.
Researchers have identified genetic factors that increase susceptibility to schizophrenia, underscoring the intricate interplay between genetics and environment in disease development. At the core of schizophrenia's pathophysiology is excessive dopaminergic neurotransmission within the...
Researchers have identified genetic factors that increase susceptibility to schizophrenia, underscoring the intricate interplay between genetics and environment in disease development. At the core of schizophrenia's pathophysiology is excessive dopaminergic neurotransmission within the...
01:29Alzheimer Disease l: Introduction
Alzheimer disease is a chronic, progressive, and irreversible neurodegenerative disorder and the most common cause of dementia in older adults. It leads to gradual neuronal loss, causing cognitive decline, behavioral changes, and loss of functional independence.Risk Factors and EtiologyThe disease is multifactorial. Age is the strongest risk factor, with prevalence doubling every 5 years after age 65. Genetic factors include mutations in genes such as APP, PSEN1, and PSEN2, which are associated...
01:26Encephalitis ll: Pathophysiology
Encephalitis is inflammation of the brain parenchyma caused by direct viral invasion or immune-mediated mechanisms triggered by infections or tumors. Both processes lead to neuronal injury, disrupted neurotransmission, and diverse neurological symptoms, often with overlapping clinical and pathological features.Autoimmune EncephalitisIn autoimmune encephalitis, antibodies target neuronal antigens on cell surfaces, synapses, or within neurons. A key example is anti-NMDAR encephalitis, which can...
01:22Lysosomal Hydrolases
Lysosomes are the site for the degradation of macromolecules and biological polymers released during membrane trafficking events such as secretory, endocytic, autophagic, and phagocytic pathways. The membrane-enclosed area of the lysosome, called the lumen, contains hydrolytic enzymes active in an acidic environment. These acid hydrolases are functional at a pH between 4.5 and 5 and are involved in cellular processes such as cell signaling, energy metabolism, restoration of the plasma membrane,...