Age-Dependent Ocular Dominance Plasticity in Adult Mice

Background: Short monocular deprivation (4 days) induces a shift in the ocular dominance of binocular neurons in the juvenile mouse visual cortex but is ineffective in adults. Recently, it has been shown that an ocular dominance shift can still be elicited in young adults (around 90 days of age) by longer periods of deprivation (7 days). Whether the same is true also for fully mature animals is not yet known. Methodology/Principal Findings: We therefore studied the effects of different periods of monocular deprivation (4, 7, 14 days) on ocular dominance in C57Bl/6 mice of different ages (25 days, 90–100 days, 109–158 days, 208–230 days) using optical imaging of intrinsic signals. In addition, we used a virtual optomotor system to monitor visual acuity of the open eye in the same animals during deprivation. We observed that ocular dominance plasticity after 7 days of monocular deprivation was pronounced in young adult mice (90–100 days) but significantly weaker already in the next age group (109–158 days). In animals older than 208 days, ocular dominance plasticity was absent even after 14 days of monocular deprivation. Visual acuity of the open eye increased in all age groups, but this interocular plasticity also declined with age, although to a much lesser degree than the optically detected ocular dominance shift. Conclusions/Significance: These data indicate that there is an age-dependence of both ocular dominance plasticity and the enhancement of vision after monocular deprivation in mice: ocular dominance plasticity in binocular visual cortex is mos

Restoration of Contralateral Representation in the Mouse Somatosensory Cortex after Crossing Nerve Transfer

Avulsion of spinal nerve roots in the brachial plexus (BP) can be repaired by crossing nerve transfer via a nerve graft to connect injured nerve ends to the BP contralateral to the lesioned side. Sensory recovery in these patients suggests that the contralateral primary somatosensory cortex (S1) is activated by afferent inputs that bypassed to the contralateral BP. To confirm this hypothesis, the present study visualized cortical activity after crossing nerve transfer in mice through the use of transcranial flavoprotein fluorescence imaging. In naïve mice, vibratory stimuli applied to the forepaw elicited localized fluorescence responses in the S1 contralateral to the stimulated side, with almost no activity in the ipsilateral S1. Four weeks after crossing nerve transfer, forepaw stimulation in the injured and repaired side resulted in cortical responses only in the S1 ipsilateral to the stimulated side. At eight weeks after crossing nerve transfer, forepaw stimulation resulted in S1 cortical responses of both hemispheres. These cortical responses were abolished by cutting the nerve graft used for repair. Exposure of the ipsilateral S1 to blue laser light suppressed cortical responses in the ipsilateral S1, as well as in the contralateral S1, suggesting that ipsilateral responses propagated to the contralateral S1 via cortico-cortical pathways. Direct high-frequency stimulation of the ipsilateral S1 in combination with forepaw stimulation acutely induced S1 bilateral cortical representation of the forepaw area in naïve mice. Cortical responses in the contralateral S1 after crossing nerve transfer were reduced in cortex-restricted heterotypic GluN1 (NMDAR1) knockout mice. Functional bilateral cortical representation was not clearly observed in genetically manipulated mice with impaired cortico-cortical pathways between S1 of both hemispheres. Taken together, these findings strongly suggest that activity-dependent potentiation of cortico-cortical pathways has a critical role for sensory recovery in patients after crossing nerve transfer

Rapid development of motion-streak coding in the mouse visual cortex

Summary: Despite its importance, the development of higher visual areas (HVAs) at the cellular resolution remains largely unknown. Here, we conducted 2-photon calcium imaging of mouse HVAs lateromedial (LM) and anterolateral (AL) and V1 to observe developmental changes in visual response properties. HVA neurons showed selectivity for orientations and directions similar to V1 neurons at eye opening, which became sharper in the following weeks. Neurons in all areas over all developmental stages tended to respond selectively to dots moving along an axis perpendicular to their preferred orientation at slow speeds, suggesting a certain level of conventional motion coding already at eye opening. In contrast, at high speeds, many neurons responded to dots moving along the axis parallel to the preferred orientation in older animals but rarely after eye opening, indicating a lack of motion-streak coding in the earlier stage. Together, our results uncover the development of visual properties in HVAs

Livskunskap som ämne i skolan : En jämförelse mellan elevers och lärares syn på viktiga livskunskapsfrågor

Livskunskap som ämne kan vara en mötesplats där tid för diskussion och reflektion över viktiga livsfrågor finns. Syftet med den här studien är att undersöka vilka centrala livsfrågor som kan ligga till grund för samtal och reflektion i skolan inom ämnet Livskunskap. Genom enkäter undersökte vi vilka livsfrågor som är viktiga för elever och genom intervjuer vilka livsfrågor som skolpersonal anser/tror vara viktiga för elever. Resultatet av intervjuerna visade att skolpersonal anser att relationer, sex och samlevnad och elevernas personliga framtid är av störst intresse för dem. Enkäterna visade att följande teman rangordnades högst av flest elever: världens framtid, krig, trygghet, ensamhet/övergivenhet, sex och samlevnad, framtid, liv/död, miljö/natur, mänskliga rättigheter samt alla likas värde. Undersökningen visar att det finns intressanta likheter och skillnader i elevers syn på viktiga livsfrågor kontra skolpersonals syn på vad som är viktigt för elever

The Illocutionary Speech Acts of the Statistics for Language Research Course on Learning Management System

In the post-COVID-19 era, lecturers frequently employ internet tools to facilitate learning. However, the majority of speech act research to date has been conducted using data from online learning platforms such as Learning Management Systems (LMS) or Microsoft Teams. Therefore, this study aims to investigate the occurrence of illocutionary speech acts used by lecturers in the Statistics for Language Research course. Descriptive qualitative research was employed in this study to analyze data obtained from the speech characteristics in messages posted in the Statistics for Language Research (SLR) course on the LMS and conversations between the lecturer and students recorded on Microsoft Teams. Data analysis was conducted based on the speech acts theory from Searle (1969). The study's findings showed that the courses employed four different illocutionary speech patterns. The study's findings revealed that the courses utilized four distinct illocutionary speech patterns. The most frequent occurrences were noted in assertive, expressive, directive, and commissive speech acts. From the data, it is evident that assertive speech acts are the dominant type. Furthermore, commissive speech acts were involved in the LMS, primarily focusing on scheduling plans for class. To conclude, it is implied that the recordings highlighted assertive speech acts as the dominant type, which was mainly utilized for explaining materials to students

Schizophrenia Animal Modeling with Epidermal Growth Factor and Its Homologs: Their Connections to the Inflammatory Pathway and the Dopamine System

Epidermal growth factor (EGF) and its homologs, such as neuregulins, bind to ErbB (Her) receptor kinases and regulate glial differentiation and dopaminergic/GABAergic maturation in the brain and are therefore implicated in schizophrenia neuropathology involving these cell abnormalities. In this review, we summarize the biological activities of the EGF family and its neuropathologic association with schizophrenia, mainly overviewing our previous model studies and the related articles. Transgenic mice as well as the rat/monkey models established by perinatal challenges of EGF or its homologs consistently exhibit various behavioral endophenotypes relevant to schizophrenia. In particular, post-pubertal elevation in baseline dopaminergic activity may illustrate the abnormal behaviors relevant to positive and negative symptoms as well as to the timing of this behavioral onset. With the given molecular interaction and transactivation of ErbB receptor kinases with Toll-like receptors (TLRs), EGF/ErbB signals are recruited by viral infection and inflammatory diseases such as COVID-19-mediated pneumonia and poxvirus-mediated fibroma and implicated in the immune–inflammatory hypothesis of schizophrenia. Finally, we also discuss the interaction of clozapine with ErbB receptor kinases as well as new antipsychotic development targeting these receptors

In Vivo Functional Mapping of a Cortical Column at Single-Neuron Resolution

Summary: The cerebral cortex is organized in vertical columns that contain neurons with similar functions. The cellular micro-architecture of such columns is an essential determinant of brain dynamics and cortical information processing. However, a detailed understanding of columns is incomplete, even in the best studied cortical regions, and mostly restricted to the upper cortical layers. Here, we developed a two-photon Ca2+-imaging-based method for the serial functional mapping of all pyramidal layers of the mouse primary auditory cortex at single-neuron resolution in individual animals. We demonstrate that the best frequency-responsive neurons are organized in all-layers-crossing narrow columns, with fuzzy boundaries and a bandwidth of about one octave. This micro-architecture is, in many ways, different from what has been reported before, indicating the region and stimulus specificity of functional cortical columns in vivo. : Tischbirek et al. report a two-photon Ca2+-imaging-based approach to map sensory-evoked neuronal activity from L2/3 to L6 of mouse cortex. In the primary auditory cortex, the authors identify functional microcolumns at cellular resolution that bring together large-scale tonotopy and locally heterogeneous frequency responses throughout all cortical layers. Keywords: two-photon microscopy, calcium imaging, cortical column, cortical layers, cellular micro-architecture, mouse auditory cortex, tonotop