Adolescent-like Processing of Behaviorally Salient Cues in Sensory and Prefrontal Cortices of Adult Preterm-Born Mice.

Preterm birth is a leading risk factor for atypicalities in cognitive and sensory processing, but it is unclear how prematurity impacts circuits that support these functions. To address this, we trained adult mice born a day early (preterm mice) on a visual discrimination task and found that they commit more errors and fail to achieve high levels of performance. Using , we found that the neurons in the primary visual cortex (V1) and the V1-projecting prefrontal anterior cingulate cortex (ACC) are hyper-responsive to the reward, reminiscent of cue processing in adolescence.

Preterm birth accelerates the maturation of spontaneous and resting activity in the visual cortex.

Prematurity is among the leading risks for poor neurocognitive outcomes. The brains of preterm infants show alterations in structure and electrical activity, but the underlying circuit mechanisms are unclear. To address this, we performed a cross-species study of the electrophysiological activity in the visual cortices of prematurely born infants and mice.

Preterm birth accelerates the maturation of spontaneous and resting activity in the visual cortex.

Prematurity is among the leading risks for poor neurocognitive outcomes. The brains of preterm infants show alterations in structure and electrical activity, but the underlying circuit mechanisms are unclear. To address this, we performed a cross-species study of the electrophysiological activity in the visual cortices of prematurely born infants and mice.

Concerted roles of LRRTM1 and SynCAM 1 in organizing prefrontal cortex synapses and cognitive functions.

Multiple trans-synaptic complexes organize synapse development, yet their roles in the mature brain and cooperation remain unclear. We analyzed the postsynaptic adhesion protein LRRTM1 in the prefrontal cortex (PFC), a region relevant to cognition and disorders. LRRTM1 knockout (KO) mice had fewer synapses, and we asked whether other synapse organizers counteract further loss.

Emerging Roles of Synapse Organizers in the Regulation of Critical Periods.

Experience remodels cortical connectivity during developmental windows called critical periods. Experience-dependent regulation of synaptic strength during these periods establishes circuit functions that are stabilized as critical period plasticity wanes. These processes have been extensively studied in the developing visual cortex, where critical period opening and closure are orchestrated by the assembly, maturation, and strengthening of distinct synapse types.

Synaptic Connectivity and Cortical Maturation Are Promoted by the ω-3 Fatty Acid Docosahexaenoic Acid.

Brain development is likely impacted by micronutrients. This is supported by the effects of the ω-3 fatty acid docosahexaenoic acid (DHA) during early neuronal differentiation, when it increases neurite growth. Aiming to delineate DHA roles in postnatal stages, we selected the visual cortex due to its stereotypic maturation.

Synapse-Selective Control of Cortical Maturation and Plasticity by Parvalbumin-Autonomous Action of SynCAM 1.

Cortical plasticity peaks early in life and tapers in adulthood, as exemplified in the primary visual cortex (V1), wherein brief loss of vision in one eye reduces cortical responses to inputs from that eye during the critical period but not in adulthood. The synaptic locus of cortical plasticity and the cell-autonomous synaptic factors determining critical periods remain unclear. We here demonstrate that the immunoglobulin protein Synaptic Cell Adhesion Molecule 1 (SynCAM 1/Cadm1) is regulated by visual experience and limits V1 plasticity.

Analyzing Structural Plasticity of Dendritic Spines in Organotypic Slice Culture.

Understanding the rules of synapse dynamics in the context of development, learning, and nervous system disorders is an important part of several fields of neuroscience. Despite significant methodological advances, observations of structural dynamics of synapses still present a significant experimental challenge. In this chapter we describe a set of techniques that allow repetitive observations of synaptic structures in vitro in organotypic cultures of rodent hippocampus.

Excitatory Synaptic Drive and Feedforward Inhibition in the Hippocampal CA3 Circuit Are Regulated by SynCAM 1.

Unlabelled: Select adhesion proteins control the development of synapses and modulate their structural and functional properties. Despite these important roles, the extent to which different synapse-organizing mechanisms act across brain regions to establish connectivity and regulate network properties is incompletely understood. Further, their functional roles in different neuronal populations remain to be defined.

A short N-terminal domain of HDAC4 preserves photoreceptors and restores visual function in retinitis pigmentosa.

Retinitis pigmentosa is a leading cause of inherited blindness, with no effective treatment currently available. Mutations primarily in genes expressed in rod photoreceptors lead to early rod death, followed by a slower phase of cone photoreceptor death. Rd1 mice provide an invaluable animal model to evaluate therapies for the disease.

Structural organization and function of mouse photoreceptor ribbon synapses involve the immunoglobulin protein synaptic cell adhesion molecule 1.

Adhesive interactions in the retina instruct the developmental specification of inner retinal layers. However, potential roles of adhesion in the development and function of photoreceptor synapses remain incompletely understood. This contrasts with our understanding of synapse development in the CNS, which can be guided by select adhesion molecules such as the Synaptic Cell Adhesion Molecule 1 (SynCAM 1/CADM1/nectin-like 2 protein).

Differential effects of maternal immune activation and juvenile stress on anxiety-like behaviour and physiology in adult rats: no evidence for the "double-hit hypothesis".

Environmental disruptions can influence neurodevelopment during pre- and postnatal periods. Given such a large time window of opportunity for insult, the "double-hit hypothesis" proposes that exposure to an environmental challenge may impact development such that an individual becomes vulnerable to developing a psychopathology, which then manifests upon exposure to a second challenge later in life. The present study in male rats utilized the framework of the "double-hit hypothesis" to investigate potential compounding effects of maternal immune activation (MIA) during pregnancy and exposure of offspring to stress during juvenility on physiological and behavioural indications of anxiety in adulthood.

Activity-dependent regulation of MHC class I expression in the developing primary visual cortex of the common marmoset monkey.

Background: Several recent studies have highlighted the important role of immunity-related molecules in synaptic plasticity processes in the developing and adult mammalian brains. It has been suggested that neuronal MHCI (major histocompatibility complex class I) genes play a role in the refinement and pruning of synapses in the developing visual system. As a fast evolutionary rate may generate distinct properties of molecules in different mammalian species, we studied the expression of MHCI molecules in a nonhuman primate, the common marmoset monkey (Callithrix jacchus).

Neuronal MHC class I molecules are involved in excitatory synaptic transmission at the hippocampal mossy fiber synapses of marmoset monkeys.

Several recent studies suggested a role for neuronal major histocompatibility complex class I (MHCI) molecules in certain forms of synaptic plasticity in the hippocampus of rodents. Here, we report for the first time on the expression pattern and functional properties of MHCI molecules in the hippocampus of a nonhuman primate, the common marmoset monkey (Callithrix jacchus). We detected a presynaptic, mossy fiber-specific localization of MHCI proteins within the marmoset hippocampus.

Stress upregulates TPH1 but not TPH2 mRNA in the rat dorsal raphe nucleus: identification of two TPH2 mRNA splice variants.

Serotonin is implicated in stress-related psychopathologies. Two isoforms of the rate-limiting enzyme of serotonin biosynthesis, tryptophan hydroxylase, TPH1 and TPH2, are known. We show here that in the rat dorsal raphe nucleus (DRN), the nucleus that contains the highest number of 5-HT neurons in the brain, TPH1 mRNA reveals a low level of expression but is detectable both by quantitative real-time PCR and in situ hybridization whereas in the pineal gland (PiG), TPH1 mRNA is strongly expressed.