Orthodromic tetanization produces in the turtle visual cortex two types of reversible plastic changes of electrical responses: facilitation and depression. Posttetanic facilitation is attended with reversible enhancement of evoked postsynaptic potentials and APs; the excitability of the electroexcitable membrane increases: the critical level of depolarization of the evoked spike shifts in the negative direction and its threshold potential decreases. Posttetanic depression is accompanied by a reversible decrease of the amplitude of evoked postsynaptic and spike potentials; the excitability of the electroexcitable membrane decreases: the critical level of depolarization of the evoked spike shifts in the positive direction, and its threshold potential increases. Reversible changes of excitability of the spike generating membrane following tetanization testify to the existence of an active mechanism of spike discharge change.
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Nat Neurosci
January 2025
Brain Research Institute, University of Zurich, Zurich, Switzerland.
Appropriate risk evaluation is essential for survival in complex, uncertain environments. Confronted with choosing between certain (safe) and uncertain (risky) options, animals show strong preference for either option consistently across extended time periods. How such risk preference is encoded in the brain remains elusive.
View Article and Find Full Text PDFJ Neurodev Disord
January 2025
Graduate Neuroscience Program, University of California, Riverside, CA, USA.
Background: Fragile X syndrome (FXS) is a leading known genetic cause of intellectual disability and autism spectrum disorders (ASD)-associated behaviors. A consistent and debilitating phenotype of FXS is auditory hypersensitivity that may lead to delayed language and high anxiety. Consistent with findings in FXS human studies, the mouse model of FXS, the Fmr1 knock out (KO) mouse, shows auditory hypersensitivity and temporal processing deficits.
View Article and Find Full Text PDFNeuroscience
December 2024
Department of Psychology, Concordia University, Montreal, Canada. Electronic address:
Estrogens and progesterone can have rapid effects on neuronal function and can modify the use of spatial navigation strategies dependent upon the prefrontal cortex, striatum, and hippocampus. Here, we assessed the effects of 17β-estradiol (E2), progesterone, and its metabolite allopregnanolone, on evoked excitatory postsynaptic potentials in the infralimbic region of the female rat prefrontal cortex. Field excitatory postsynaptic potentials (fEPSPs) evoked by stimulation of layer I were first characterized by recording responses at multiple depths between the cortical surface and the underlying white matter.
View Article and Find Full Text PDFElife
December 2024
Auditory Neuroscience and Synaptic Nanophysiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
Neural diversity can expand the encoding capacity of a circuitry. A striking example of diverse structure and function is presented by the afferent synapses between inner hair cells (IHCs) and spiral ganglion neurons (SGNs) in the cochlea. Presynaptic active zones at the pillar IHC side activate at lower IHC potentials than those of the modiolar side that have more presynaptic Ca channels.
View Article and Find Full Text PDFHippocampus
January 2025
Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada.
The hypothesis that the hippocampal theta rhythm consists of inhibitory postsynaptic potentials (IPSPs) was critical for understanding the theta rhythm. The dominant views in the early 1980s were that intracellularly recorded theta consisted of excitatory postsynaptic potentials (EPSPs) with little participation by IPSPs, and that IPSPs generated a closed monopolar field in the hippocampus. I (Leung) conceived of a new model for generation of the hippocampal theta rhythm, with theta-rhythmic IPSPs as an essential component, and thus sought to reinvestigate the relation between theta and IPSPs quantitatively with intracellular and extracellular recordings.
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