Temporal Cortex Neurons in Frontotemporal Dementia
Introduction <table class="infobox infobox-cell">Pick bodies </td>CBD tau </td>PSP tau </td>Type A </td>Type B </td>Type C </td>Type D </td>Tau (3R/4R) </td>TDP-43 </td>FUS </td>VCP </td>Serotonergic </td>
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Temporal Cortex Neurons in Frontotemporal Dementia
Introduction <table class="infobox infobox-cell">Pick bodies </td>CBD tau </td>PSP tau </td>Type A </td>Type B </td>Type C </td>Type D </td>Tau (3R/4R) </td>TDP-43 </td>FUS </td>VCP </td>Serotonergic </td>Glutamatergic </td>Cholinergic </td>Dopaminergic </td>
Frontotemporal dementia (FTD) encompasses a group of neurodegenerative disorders characterized by progressive deficits in behavior, language, and executive function. The temporal cortex—particularly the anterior and lateral regions—is prominently affected in multiple FTD subtypes, with distinct patterns of neuronal loss, protein pathology, and clinical manifestations.
Temporal cortex involvement in FTD provides insight into disease mechanisms and distinguishes FTD from Alzheimer's disease, which typically shows later temporal lobe involvement (mesial temporal structures). Understanding temporal cortex pathology is essential for accurate diagnosis, prognostication, and therapeutic development.
FTD Pathological Subtypes
Semantic Variant Primary Progressive Aphasia (svPPA) The semantic variant of PPA shows the most selective temporal cortex involvement[@gornoTempini2018]:
Anatomical distribution:
Anterior temporal lobe : Most severely affected, often asymmetric (left > right)Bottom of superior temporal sulcus : Early involvementTemporal pole : Progressive atrophyAmygdala and hippocampus : Variable involvementPathology:
TDP-43 Type C inclusions (neuronal cytoplasmic and intranuclear)
Spherical tau-negative inclusions
Relative preservation of posterior temporal and parietal regions
"Knife-edge" appearance of atrophic cortex
Clinical features:
Loss of word meaning (semantic knowledge)
Object recognition deficits
Surface dyslexia (reading errors)
Spared speech production
Logopenic Variant PPA Anatomical distribution:
Posterior superior temporal gyrus : Left hemisphere predominantAngular gyrus : Language-related network disruptionPosterior temporal-parietal junction : VariablePathology:
Often AD-type pathology (tau)
May have TDP-43 in some cases
Less selective than svPPA
Clinical features:
Anomia (word-finding difficulty)
Phonological errors
Sentence repetition impairment
Spared comprehension (initially)
Behavioral Variant FTD (bvFTD) Anatomical distribution:
Anterior temporal lobes : Often bilateralOrbitofrontal cortex : Early involvementAnterior cingulate : VariableInsula : VariablePathology:
TDP-43 Type B (most common)
Less commonly tau (Pick disease, CBD, PSP)
Heterogeneous subtypes
Clinical features:
Disinhibition and inappropriate behavior
Apathy and loss of initiative
Loss of empathy
Dietary changes (hyperphagia)
Cellular Pathology
Tau Pathology Tau inclusions in temporal cortex[@seeley2021]:
Neurofibrillary tangles:
Prefrontal and anterior temporal predominance
Correlation with neuronal loss
Progressive spread pattern
Neuronal loss:
30-60% reduction in severely affected regions
Layer-specific vulnerability (layers II, III)
Associated with gliosis
TDP-43 Pathology TDP-43 inclusions in temporal cortex[@rascovsky2011]:
Neuronal inclusions:
Cytoplasmic and nuclear TDP-43
Ubiquitin-positive
Correlate with neuronal loss
FUS Pathology
Less common than tau/TDP-43
FUS-positive inclusions
Usually in young-onset FTD
Associated with ALS
Molecular Mechanisms
Protein Aggregation
Synaptic Dysfunction Dendritic spine loss:
Correlation with cognitive decline
Early manifestation (pre-neuronal loss)
Targets excitatory synapses
Neurotransmitter deficits:
Glutamate: Excitotoxicity
Acetylcholine: Basal forebrain involvement
Serotonin: Raphe nuclei involvement
Network disruption:
Default mode network impairment
Salience network alterations
Language network disruption
Clinical Correlates
Language Deficits Anomia:
Word-finding difficulties
Tip-of-the-tongue phenomenon
Circumlocution strategies
Progresses to complete loss
Comprehension deficits:
Semantic memory loss
Impaired word comprehension
Object recognition failure
Reading comprehension decline
Repetition deficits:
Phonological errors
Sentence repetition impairment
Agraphia (writing difficulty)
Behavioral Changes Anterior temporal involvement:
Loss of empathy
Social cognition deficits
Theory of mind impairment
Orbitofrontal involvement:
Disinhibition
Inappropriate social behavior
Loss of manners
Dietary changes:
Hyperphagia (especially sweet foods)
Food preference changes
Weight gain
Therapeutic Approaches
Symptomatic Treatments
Disease-Modifying Approaches Anti-aggregation therapies:
Tau aggregation inhibitors
TDP-43 targeting strategies
RNA-based approaches:
Antisense oligonucleotides
RNA splicing modifiers
Neuroprotection:
Neurotrophic factors
Antioxidants
Anti-inflammatory approaches
Circuit Model
Mermaid diagram (expand to render)
Cross-References
[Frontotemporal Dementia](/diseases/frontotemporal-dementia)
[Tau Pathology](/mechanisms/tau-pathology)
[TDP-43 Pathology](/mechanisms/tdp-43-pathology)
[Language Networks](/mechanisms/language-networks)
[Cell Types Index](/cell-types)
Pathway Diagram The following diagram shows the key molecular relationships involving Temporal Cortex Neurons in Frontotemporal Dementia discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)
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