Investigating the Unexpected Effect of Bulkheads in a Dementia Model of Mice Through Molecular Analysis of the Hippocampus.

Aim: This study aimed to evaluate the impact of long-term exposure to physical barriers used as preventive measures during the coronavirus disease 2019 (COVID-19) pandemic on cognitive function and behavior in an apolipoprotein E (ApoE) mouse dementia model.

Methods: ApoE mice were divided into co-housed, partitioned by a transparent bulkhead (partitioned), and isolated groups. To assess anxiety, cognitive recognition, and spatial learning, behavioral tests, including the open-field test, novel object recognition test, and Morris water maze test, were conducted at three and six months after the start of the 33-week rearing period.

Hearing loss-related altered neuronal activity in the inferior colliculus.

Hearing loss is well known to cause plastic changes in the central auditory system and pathological changes such as tinnitus and hyperacusis. Impairment of inner ear functions is the main cause of hearing loss. In aged individuals, not only inner ear dysfunction but also senescence of the central nervous system is the cause of malfunction of the auditory system.

Erratum: Modified Fear Conditioning for Inducing Flight Behaviors in Mice.

This corrects the article 10.3791/66266.

Disruption of sphingomyelin synthase 2 gene alleviates cognitive impairment in a mouse model of Alzheimer's disease.

The membrane raft accommodates the key enzymes synthesizing amyloid β (Aβ). One of the two characteristic components of the membrane raft, cholesterol, is well known to promote the key enzymes that produce amyloid-β (Aβ) and exacerbate Alzheimer's disease (AD) pathogenesis. Given that the raft is a physicochemical platform for the sound functioning of embedded bioactive proteins, the other major lipid component sphingomyelin may also be involved in AD.

Spatiotemporal development of the neuronal accumulation of amyloid precursor protein and the amyloid plaque formation in the brain of 3xTg-AD mice.

The amyloid plaque is a hallmark of Alzheimer's disease. The accumulation of the amyloid precursor protein (APP) in the neuronal structure is assumed to lead to amyloid plaque formation through the excessive production of β-amyloid protein. To study the relationship between the neuronal accumulation of APP and amyloid plaque formation, we histologically analyzed their development in the different brain regions in 3xTg-AD mice, which express Swedish mutated APP (APP) in the neurons.

Modified Fear Conditioning for Inducing Flight Behaviors in Mice.

The appropriate manifestation of defensive behavior in a threatening situation is critical for survival. The prevailing theory suggests that an active defensive behavior, such as jumping or rapid darting, is expressed under high threat imminence or actual threat, whereas passive defensive behavior, such as freezing, is expressed when the threat is predicted, but the threat imminence is relatively low. In classical fear conditioning, subjects typically exhibit freezing as a conditioned defensive response, with little expression of active defensive behavior in most cases.

Pain-related neuronal ensembles in the primary somatosensory cortex contribute to hyperalgesia and anxiety.

The mechanism by which acute pain or itch information at the periphery is processed in the primary somatosensory cortex (S1) remains unclear. To elucidate this, we used a viral-mediated targeted-recombination-in-active population system to target S1 neuronal ensembles that are active during pain or itch sensations. We induced the expression of excitatory or inhibitory designer receptors exclusively activated by designer drugs in pain- or itch-related S1 neurons.

[Characterization of the dorsal raphe-periaqueductal grey DAT neurons innervating onto the extended amygdala].

It has been known that a number of tyrosine hydroxylase (TH)-positive neurons, which are regarded as dopaminergic (DA) neurons, exist in the dorsal raphe (DR). These DA neurons in the DR and periaqueductal gray (PAG) region (DA neurons) are thought to belong to the A10 cluster, which is known to be heterogeneous. This DA population projects to the central nucleus of the amygdala (CeA) and the bed nucleus of the stria terminalis (BNST) and has been reported to modulate various affective behaviors.

Convergence of bilateral auditory midbrain inputs on neurons in the auditory thalamus of chicken.

In the avian ascending auditory pathway, the nucleus mesencephalicus lateralis pars dorsalis (MLd; the auditory midbrain center) receives inputs from virtually all lower brainstem auditory nuclei and sends outputs bilaterally to the nucleus ovoidalis (Ov; the auditory thalamic nucleus). Axons from part of the MLd terminate in a particular domain of Ov, thereby suggesting a formation of segregated pathways point-to-point from lower brainstem nuclei via MLd to the thalamus. However, it has not yet been demonstrated whether any spatial clustering of thalamic neurons that receive inputs from specific domains of MLd exists.

5-HT and α-m-5-HT attenuate excitatory synaptic transmissions onto the lateral amygdala principal neurons via presynaptic 5-HT receptors.

Accumulating evidence suggests that the serotonergic (5-HT) system in the amygdala has significant effects on affective states. Dysregulation of the 5-HT system in the basolateral amygdaloid complex causes affective disorders. To search for therapeutic targets, subtype specification of 5-HT receptors is crucial.

Vocalization during agonistic encounter in Mongolian gerbils: Impact of sexual experience.

Behaviors and vocalizations associated with aggression are essential for animals to survive, reproduce, and organize social hierarchy. Mongolian gerbils (Meriones unguiculatus) are highly aggressive and frequently emit calls. We took advantage of these features to study the relationship between vocalizations and aggressive behaviors in virgin and sexually experienced male and female Mongolian gerbils through the same-sex resident-intruder test.

Histochemical Characterization of the Dorsal Raphe-Periaqueductal Grey Dopamine Transporter Neurons Projecting to the Extended Amygdala.

The dorsal raphe (DR) nucleus contains many tyrosine hydroxylase (TH)-positive neurons which are regarded as dopaminergic (DA) neurons. These DA neurons in the DR and periaqueductal gray (PAG) region (DA neurons) are a subgroup of the A10 cluster, which is known to be heterogeneous. This DA population projects to the central nucleus of the amygdala (CeA) and the bed nucleus of the stria terminalis (BNST) and has been reported to modulate various affective behaviors.

Kv4.2-Positive Domains on Dendrites in the Mouse Medial Geniculate Body Receive Ascending Excitatory and Inhibitory Inputs Preferentially From the Inferior Colliculus.

The medial geniculate body (MGB) is the thalamic center of the auditory lemniscal pathway. The ventral division of MGB (MGV) receives excitatory and inhibitory inputs from the inferior colliculus (IC). MGV is involved in auditory attention by processing descending excitatory and inhibitory inputs from the auditory cortex (AC) and reticular thalamic nucleus (RTN), respectively.

Remodeling of projections from ventral hippocampus to prefrontal cortex in Alzheimer's mice.

Emotional dysregulation often accompanies cognitive deficits in Alzheimer's disease (AD). The hippocampus, most notably damaged by AD pathology, is classified into the cognition-bound posterior and emotion-bound anterior hippocampi. Since the anterior hippocampus or its rodent counterpart, the ventral hippocampus (VH), sends dense afferents to the prefrontal cortex (PFC) and the basolateral amygdala (BLA), the two structures implicated in fear responses, we investigated whether these afferents are modified in 3xTg AD model mice.

Combinational Approach of Genetic SHP-1 Suppression and Voluntary Exercise Promotes Corticospinal Tract Sprouting and Motor Recovery Following Brain Injury.

. Brain injury often causes severe motor dysfunction, leading to difficulties with living a self-reliant social life. Injured neural circuits must be reconstructed to restore functions, but the adult brain is limited in its ability to restore neuronal connections.

Acoustic trauma induced the alteration of the activity balance of excitatory and inhibitory neurons in the inferior colliculus of mice.

We examined the effect of acoustic trauma on the spontaneous activities of the glutamatergic and GABAergic neurons in the inferior colliculus (IC) of mice. Optogenetics was used to identify the neuron type. In control animals, the spontaneous firing rate was higher in GABAergic neurons than in glutamatergic neurons.

Serotonergic control of GABAergic inhibition in the lateral amygdala.

Much evidence implicates the serotonergic regulation of the amygdala in anxiety. Thus the present study was undertaken to characterize the influence of serotonin (5-HT) on principal neurons (PNs) of the rat lateral amygdala (LA), using whole cell recordings in vitro. Because inhibition is a major determinant of PN activity, we focused on the control of GABAergic transmission by 5-HT.

Neuronal sensitivity to the interaural time difference of the sound envelope in the mouse inferior colliculus.

We examined the sensitivity of the neurons in the mouse inferior colliculus (IC) to the interaural time differences (ITD) conveyed in the sound envelope. Utilizing optogenetic methods, we compared the responses to the ITD in the envelope of identified glutamatergic and GABAergic neurons. More than half of both cell types were sensitive to the envelope ITD, and the ITD curves were aligned at their troughs.

Inhibitory Neural Circuits in the Mammalian Auditory Midbrain.

The auditory midbrain is the critical integration center in the auditory pathway of vertebrates. Synaptic inhibition plays a key role during information processing in the auditory midbrain, and these inhibitory neural circuits are seen in all vertebrates and are likely essential for hearing. Here, we review the structure and function of the inhibitory neural circuits of the auditory midbrain.

Optogenetics Identification of a Neuronal Type with a Glass Optrode in Awake Mice.

It is a major concern in neuroscience how different types of neurons work in neural circuits. Recent advances in optogenetics have enabled the identification of the neuronal type in in vivo electrophysiological experiments in broad brain regions. In optogenetics experiments, it is critical to deliver the light to the recording site.

Long-Lasting Sound-Evoked Afterdischarge in the Auditory Midbrain.

Different forms of plasticity are known to play a critical role in the processing of information about sound. Here, we report a novel neural plastic response in the inferior colliculus, an auditory center in the midbrain of the auditory pathway. A vigorous, long-lasting sound-evoked afterdischarge (LSA) is seen in a subpopulation of both glutamatergic and GABAergic neurons in the central nucleus of the inferior colliculus of normal hearing mice.