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Injection of HYase reduced the frequency of spontaneous columnar events and increased cross-columnar activity spread aTop, Recordings of spontaneous activity showed the occurrence of spontaneous events of translaminar synaptic information flow mimicking evoked columnar feedforward activation profiles called spontaneous columnar events. SCE’s in untreated cortex showed information flow starting from pacemaker activity in layer Vb (see inset right). Bottom, After Injection of HYase SCE’s were shorter in duration, showed no infragranular pacemaker structure and did not expand through all cortical layers (see inlay right). Frequency of SCE’s was quantified by peak detection of the AVREC trace based on crossings of 3 SD above baseline (blue traces). b Mean RMS amplitudes (±SEM) within separate cortical layers were all significantly reduced after HYase treatment. c Frequency of SCE’s per second was significantly reduced after HYase treatment. d Decreased RMS amplitude of the AVREC ( ± SEM) was paralleled with a significant increase of the RMS amplitude (±SEM) of the RelResCSD. Box plots represent the median (circle) and the interquartile range (25% and 75% percentile). The whiskers represent the full range of data. Plotted single data represent outliers. Asterisks mark significant differences between groups (paired Student’s t-test, **p < 0.01; ***p < 0.001).
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In the adult vertebrate brain, enzymatic removal of the extracellular matrix (ECM) is increasingly recognized to promote learning, memory recall, and restorative plasticity. The impact of the ECM on translaminar dynamics during cortical circuit processing is still not understood. Here, we removed the ECM in the primary auditory cortex (ACx) of adul...
Citations
... In addition, the LGN is considered as a transfer station for visual information. On the one hand, it receives information from retinal ganglion cells and transmits it to the visual cortex and, on the other hand, receives feedback information from the visual cortex and regulates the electrical activity of visual neurons through neurotransmitters to achieve a balanced (101,102). An imbalance between excitatory/inhibitory neurotransmission has been posited as a central characteristic of the neurobiology of autism (103). ...
Autism spectrum disorder (ASD) is associated with severe impairment in social functioning. Visual information processing provides nonverbal cues that support social interactions. ASD children exhibit abnormalities in visual orientation, continuous visual exploration, and visual–spatial perception, causing social dysfunction, and mechanisms underlying these abnormalities remain unclear. Transmission of visual information depends on the retina-lateral geniculate nucleus–visual cortex pathway. In ASD, developmental abnormalities occur in rapid expansion of the visual cortex surface area with constant thickness during early life, causing abnormal transmission of the peak of the visual evoked potential (P100). We hypothesized that abnormal visual perception in ASD are related to the abnormal visual information transmission and abnormal development of visual cortex in early life, what’s more, explored the mechanisms of abnormal visual symptoms to provide suggestions for future research.
... Spatial dimensions would impact on the concentrations of potassium and other activity related ions (Rasmussen et al. 2019). The extracellular matrix influences translaminar cortical network dynamics (El-Tabbal et al. 2021), and, as aggregations of perineuronal nets (PNN), influences high-speed, energetic activity of parvalbumin + inhibitory neurons (Bucher et al. 2021). PNN can be visualized by immunohistochemistry in postmortem tissues, and provide yet another assay of area-specific specializations that might be explored under different conditions. ...
... The extracellular matrix influences translaminar cortical network dynamics (El-Tabbal et al. 2021), and, as aggregations of perineuronal nets (PNN), influences high-speed, energetic activity of parvalbumin + inhibitory neurons (Bucher et al. 2021). PNN can be visualized by immunohistochemistry in postmortem tissues, and provide yet another assay of area-specific specializations that might be explored under different conditions. ...
The angular gyrus is associated with a spectrum of higher order cognitive functions. This mini-review undertakes a broad survey of putative neuroanatomical substrates, guided by the premise that area-specific specializations derive from a combination of extrinsic connections and intrinsic area properties. Three levels of spatial resolution are discussed: cellular, supracellular connectivity, and synaptic micro-scale, with examples necessarily drawn mainly from experimental work with nonhuman primates. A significant factor in the functional specialization of the human parietal cortex is the pronounced enlargement. In addition to "more" cells, synapses, and connections, however, the heterogeneity itself can be considered an important property. Multiple anatomical features support the idea of overlapping and temporally dynamic membership in several brain wide subnetworks, but how these features operate in the context of higher cognitive functions remains for continued investigations.
Most scientist agree that subjective tinnitus is the pathological result of an interaction of damage to the peripheral auditory system and central neuroplastic adaptations. Here we investigate such tinnitus related adaptations in the primary auditory cortex (AC) 13 days after noise trauma induction of tinnitus by quantifying the density of the extracellular matrix (ECM) in the AC of Mongolian gerbils (Meriones unguiculatus). The ECM density has been shown to be relevant for neuroplastic processes and synaptic stability within the cortex. We utilized a mild monaural acoustic noise trauma in 9 gerbils to induce tinnitus and a sham exposure in 3 control animals. Tinnitus was assessed by a behavioral response paradigm. Four of the trauma animals did show tinnitus 13 days after trauma (T), the remaining 5 trauma (NT) and the 3 control animals (C) did not show the percept. The ECM density 13 days after trauma was quantified using immunofluorescence luminance of Wisteria floribunda lectin-fluoresceine-5-isothiocyanate (WFA-FITC) on histological slices of the primary AC, relative to the non-auditory brainstem as a reference area. We found that the WFA-FITC luminance of the AC of NT animals was not significantly different from that of C animals. However, we found a significant increase of luminance in T animals’ ACs compared to NT or C animals’ cortices. This effect was found exclusively on the AC side contralateral to the trauma ear. These results point to a process of stabilization of synaptic connections in primary AC, which may be involved in the chronic manifestation of tinnitus.
Learning can induce neurophysiological plasticity in the auditory cortex at multiple timescales. Lasting changes to auditory cortical function that persist over days, weeks, or even a lifetime, require learning to induce de novo gene expression. Indeed, transcription is the molecular determinant for long-term memories to form with a lasting impact on sound-related behavior. However, auditory cortical genes that support auditory learning, memory, and acquired sound-specific behavior are largely unknown. Using an animal model of adult, male Sprague-Dawley rats, this report is the first to identify genome-wide changes in learning-induced gene expression within the auditory cortex that may underlie long-lasting discriminative memory formation of acoustic frequency cues. Auditory cortical samples were collected from animals in the initial learning phase of a two-tone discrimination sound-reward task known to induce sound-specific neurophysiological and behavioral effects. Bioinformatic analyses on gene enrichment profiles from bulk RNA sequencing identified cholinergic synapse (KEGG rno04725), extra-cellular matrix receptor interaction (KEGG rno04512), and neuroactive receptor interaction (KEGG rno04080) among the top biological pathways are likely to be important for auditory discrimination learning. The findings characterize candidate effectors underlying the early stages of changes in cortical and behavioral function to ultimately support the formation of long-term discriminative auditory memory in the adult brain. The molecules and mechanisms identified are potential therapeutic targets to facilitate experiences that induce long-lasting changes to sound-specific auditory function in adulthood and prime for future gene-targeted investigations.
