ABSTRACT
Perivascular epithelioid cell neoplasms (PEComas) are a group of mesenchymal tumours with concurrent melanocytic and myogenic differentiation. Although many cases are sporadic, PEComas can be associated with tuberous sclerosis. A distinct subset of deep-seated PEComas has been shown to carry TFE3 fusions. To our knowledge, this is the first reported case of primary subcutaneous malignant PEComa with molecular confirmation of TFE3 gene rearrangement.
Subject(s)
Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/genetics , Muscle Neoplasms/genetics , Perivascular Epithelioid Cell Neoplasms/genetics , Adult , Buttocks , Female , Gene Rearrangement/genetics , Humans , Muscle Neoplasms/diagnosis , Perivascular Epithelioid Cell Neoplasms/diagnosis , ThighABSTRACT
The purpose of this study was to clarify the neurogenesis of thalamically evoked gamma frequency (approximately 40 Hz) oscillations in auditory cortex by comparing simultaneously recorded extracellular and intracellular responses elicited with electrical stimulation of the posterior intralaminar nucleus of the thalamus (PIL). The focus of evoked gamma activity was located between primary and secondary auditory cortex using a 64-channel epipial electrode array, and all subsequent intracellular recordings and single-electrode field potential recordings were made at this location. These data indicate that PIL stimulation evokes gamma oscillations in auditory cortex by tonically depolarizing pyramidal cells in the supra- and infragranular layers. No cells revealed endogenous membrane properties capable of producing activity in the gamma frequency band when depolarized individually with injected current, but all displayed both sub- and supra-threshold responses time-locked to extracellular fast oscillations when the population was depolarized by PIL stimulation. We propose that cortical gamma oscillations may be produced and propagated intracortically by network interactions among large groups of neurons when mutually excited by modulatory input from the intralaminar thalamus and that these oscillations do not require specialized pacemaker cells for their neurogenesis.
Subject(s)
Auditory Cortex/physiology , Biological Clocks/physiology , Thalamus/physiology , Acoustic Stimulation , Action Potentials/physiology , Animals , Arousal/physiology , Auditory Cortex/cytology , Electric Stimulation , Electrodes, Implanted , Electroencephalography , Evoked Potentials, Auditory , Intralaminar Thalamic Nuclei/physiology , Male , Nerve Net/physiology , Neurons/physiology , Pyramidal Cells/physiology , Rats , Rats, Sprague-Dawley , Signal Processing, Computer-AssistedABSTRACT
The purpose of this study was to investigate interactions among laminar cell populations producing spontaneous and evoked high-frequency (approximately 40 Hz) gamma oscillations in auditory cortex. Electrocortical oscillations were recorded using a 64-channel epipial electrode array and a 16-channel linear laminar electrode array while electrical stimulation was delivered to the posterior intralaminar (PIL) nucleus. Spontaneous gamma oscillations, and those evoked by PIL stimulation, are confined to a location overlapping primary and secondary auditory cortex. Current source-density and principal components analysis of laminar recordings at this site indicate that the auditory evoked potential (AEP) complex is characterized by a stereotyped asynchronous activation of supra- and infragranular cell populations. Similar analysis of spontaneous and evoked gamma waves reveals a close spatiotemporal similarity to the laminar AEP, indicating rhythmic interactions between supra- and infragranular cell groups during these oscillatory phenomena. We conclude that neural circuit interactions producing the laminar AEP onset in auditory cortex are the same as those generating evoked and spontaneous gamma oscillations.
