The activation of 5-HT(2A) receptors in medial prefrontal cortex (mPFC) by the hallucinogen DOI increases the firing activity of dorsal raphe (DR) 5-HT neurons and prefrontal 5-HT release. Here we show that the i.v. administration of DOI markedly affected the firing rate of identified pyramidal neurons recorded extracellularly. DOI excited (481%) 21/56 neurons, inhibited (11%) 17/56 neurons and left the rest unaffected (overall 2.4-fold increase in firing rate). Both effects were antagonized by 5-HT(2A) receptor blockade. 5-HT(2A)-mediated orthodromic excitations were recorded in pyramidal neurons projecting to DR after electrical stimulation of this nucleus. We also examined whether the effects of DOI in mPFC involve thalamic excitatory inputs. The disinhibition of the mediodorsal and centromedial nuclei of the thalamus by local bicuculline resembled the effects of DOI as it increased pyramidal cell firing and 5-HT release in mPFC. However, the selective activation of prefrontal micro -opioid and mGlu II receptors counteracted the effects of the thalamic disinhibition but not those of DOI. Moreover, extensive thalamic lesions did not alter the effect of DOI on pyramidal cell firing and 5-HT release. We conclude that DOI increases the activity of the mPFC-DR circuit by an action on postsynaptic 5-HT(2A) receptors unrelated to thalamocortical afferents.
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http://dx.doi.org/10.1093/cercor/13.8.870 | DOI Listing |
Electroencephalographic (EEG) recordings in individuals with Fragile X Syndrome (FXS) and the mouse model of FXS ( KO) display cortical hyperexcitability at rest, as well as deficits in sensory-driven cortical network synchrony. A form of circuit hyperexcitability is observed in cortical slices of KO mice as prolonged persistent activity, or Up, states. It is unknown if the circuit mechanisms that cause prolonged Up states contribute to FXS-relevant EEG phenotypes.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Key Laboratory of Mental Disorders, The Second Hospital of Shandong University, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, 250012, China.
Major depressive disorder (MDD) is usually considered associate with immune inflammation and synaptic injury within specific brain regions. However, the molecular mechanisms underlying the neural deterioration resulting in depression remain unclear. Here, it is found that miR-204-5p is markedly downregulated in the ventromedial prefrontal cortex (vmPFC) in a chronic unpredictable mild stress (CUMS) induce rat model of depression.
View Article and Find Full Text PDFJ Biophotonics
January 2025
Univ. Grenoble Alpes, CNRS, LIPhy, Grenoble, France.
A challenge in neuroimaging is acquiring frame sequences at high temporal resolution from the largest possible number of pixels. Measuring 1%-10% fluorescence changes normally requires 12-bit or higher bit depth, constraining the frame size allowing imaging in the kHz range. We resolved Ca or membrane potential signals from cell populations or single neurons in brain slices by acquiring fluorescence at 8-bit depth and by binning pixels offline, achieving unprecedented frame sizes at kHz rates.
View Article and Find Full Text PDFBiomed Pharmacother
January 2025
Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Italy. Electronic address:
Cannabis derivatives are among the most widely used psychoactive substances in the world, which leads to growing medical concerns regarding its chronic use and abuse especially among adolescents. Exposure to THC during formative years produces long-term behavioral alterations that share similarities with symptoms of psychiatric and neurodevelopmental disorders. In this study, we have analyzed the functional and molecular mechanisms that might underlie these alterations.
View Article and Find Full Text PDFCell Rep
January 2025
Department of Clinical Neurological Sciences, London Health Sciences Centre, Western University, London, ON, Canada; Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada; Western Institute for Neuroscience, Western University, London, ON, Canada.
Cortical neurons in brain slices display intrinsic spike frequency adaptation (I-SFA) to constant current inputs, while extracellular recordings show extrinsic SFA (E-SFA) during sustained visual stimulation. Inferring how I-SFA contributes to E-SFA during behavior is challenging due to the isolated nature of slice recordings. To address this, we recorded macaque lateral prefrontal cortex (LPFC) neurons in vivo during a visually guided saccade task and in vitro in brain slices.
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