Attending to salient sensory attributes of food, such as tastes that are new, displeasing, or unexpected, allows the procurement of nutrients without food poisoning. Exposure to new tastes is known to increase norepinephrine (NE) release in taste processing forebrain areas, yet the central source for this release is unknown. Locus ceruleus norepinephrine neurons (LC-NE) emerge as a candidate in signaling salient information about taste, as other salient sensory stimuli (e.g., visual, auditory, somatosensation) are known to activate LC neurons. To determine if LC neurons are sensitive to features of taste novelty, we used fiber photometry to record LC-NE activity in water-restricted mice that voluntarily licked either novel or familiar substances of differential palatability (saccharine, citric acid). We observed that LC-NE activity was suppressed during lick bursts and transiently activated upon the termination of licking and that these dynamics were independent of the familiarity of the substance consumed...

A sublethal ischemic episode [termed preconditioning (PC)] protects neurons in the brain against a subsequent severe ischemic injury. This phenomenon is known as brain ischemic tolerance and has received much attention from researchers because of its robust neuroprotective effects. We have previously reported that PC activates astrocytes and subsequently upregulates P2X7 receptors, thereby leading to ischemic tolerance. However, the downstream signals of P2X7 receptors that are responsible for PC-induced ischemic tolerance remain unknown. Here, we show that PC-induced P2X7 receptor-mediated lactate release from astrocytes has an indispensable role in this event. Using a transient focal cerebral ischemia model caused by middle cerebral artery occlusion, extracellular lactate levels during severe ischemia were significantly increased in mice who experienced PC; this increase was dependent on P2X7 receptors. In addition, the intracerebroventricular injection of lactate protected against cerebral ischemic inju...

Trace eyeblink conditioning (TEBC) has been widely used to study associative learning in both animals and humans. In this paradigm, conditioned responses (CRs) to conditioned stimuli (CS) serve as a measure for retrieving learned associations between the CS and the unconditioned stimuli (US) within a trial. Memory consolidation, that is, learning over time, can be quantified as an increase in the proportion of CRs across training sessions. However, how hippocampal oscillations differentiate between successful memory retrieval within a session and consolidation across TEBC training sessions remains unknown. To address this question, we recorded local field potentials (LFPs) from the rat dorsal hippocampus during TEBC and investigated hippocampal oscillation dynamics associated with these two functions. We show that transient broadband responses to the CS were correlated with memory consolidation, as indexed by an increase in CRs across TEBC sessions. In contrast, induced alpha (8–10 Hz) and beta (16–20 Hz) ...

In the article “Protein Nanoparticles Modified with PDGF-B as a Novel Therapy after Acute Cerebral Infarction,” by Soh Takagishi, Koichi Arimura, Masaharu Murata, Katsuma Iwaki, Tomohiro Okuda, Keisuke Ido, Ataru Nishimura, Sayoko Narahara, Takahito Kawano, and Koji Iihara which published online on August 30, 2021, Figure 3 and its legend appeared incorrectly. In Figure 3 B , an incorrect image was used for the lower-middle panel. Additionally, the legend for G and H were labeled incorrectly as D and E . The correct figure and legend appear below. This does not affect …

Long-term programmed rheostatic changes in physiology are essential for animal fitness. Hypothalamic nuclei and the pituitary gland govern key developmental and seasonal transitions in reproduction. The aim of this study was to identify the molecular substrates that are common, and unique to developmental and seasonal timing. Adult and juvenile quail were collected from reproductively mature and immature states and key molecular targets examined in the mediobasal hypothalamus (MBH) and pituitary gland. qPCR assays established deiodinase type-2 ( DIO2 ) and type-3 ( DIO3 ) expression in adults changed with photoperiod manipulations. However, DIO2 and DIO3 remain constitutively expressed in juveniles. Pituitary gland transcriptome analyses established 340 transcripts were differentially expressed across seasonal photoperiod programs; and 1189 transcripts displayed age-dependent variation in expression. Prolactin ( PRL ) and follicle-stimulating hormone subunit beta ( FSHβ ) are molecular markers of seasonal ...

Neuromodulation of the peripheral nervous system (PNS) by electrical stimulation may augment autonomic function after injury or in neurodegenerative disorders. Nerve fiber size, myelination, and distance between individual fibers and the stimulation electrode may influence response thresholds to electrical stimulation. However, information on the spatial distribution of nerve fibers within the PNS is sparse. We developed a new 2-dimensional (2D) morphological mapping tool to assess spatial heterogeneity and clustering of nerve fibers. The L6-S3 ventral roots (VRs) in rhesus macaques were used as a model system to map preganglionic parasympathetic, γ-motor, and α-motor fibers. Random and ground-truth distributions of nerve fiber centroids were determined for each VR by light microscopy. The proposed tool allows for non-binary determinations of fiber heterogeneity by defining the minimum distance between nerve fibers for cluster inclusion and comparisons with random fiber distributions for each VR. There was...

Long-term sensitization in Aplysia is accompanied by a persistent up-regulation of mRNA encoding the peptide neurotransmitter Phe-Met-Arg-Phe-amide (FMRFa), a neuromodulator that opposes the expression of sensitization through activation of the arachidonic-acid second-messenger pathway. We completed a pre-registered test of the hypothesis that FMRFa plays a critical role in the forgetting of sensitization. Aplysia received long-term sensitization training and were then given whole-body injections of vehicle ( N = 27), FMRFa ( N = 26), or 4-bromophenacylbromide (4-BPB; N = 31), a phospholipase inhibitor that prevents the release of arachidonic acid. FMRFa produced no changes in forgetting. 4-BPB decreased forgetting measured 6 days after training ( d s = 0.55 95% CI[0.01, 1.09]), though the estimated effect size is uncertain. Our results provide preliminary evidence that forgetting of sensitization may be a regulated, active process in Aplysia , but could also indicate a role for arachidonic acid in stabili...

Laboratory outreach programs for K-12 students in the United States from 2020-2022 were suspended or delayed due to COVID-19 restrictions. While Southern Nevada also observed similar closures for onsite programs, we and others hypothesized that in-person laboratory activities could be prioritized after increasing vaccine doses were available to the public and masking was encouraged. Here, we describe how the Laboratory of Neurogenetics and Precision Medicine at the University of Nevada Las Vegas (UNLV) collaborated with administrators from a local school district to conduct training activities for high school students during the COVID-19 pandemic. The Science Education for the Youth (SEFTY) program's curriculum was constructed to incorporate experiential learning, fostering collaboration and peer-to-peer knowledge exchange. Leveraging neuroscience tools from our UNLV laboratory, we engaged with 117 high school applicants from 2021-2022. Our recruitment efforts yielded a diverse cohort, with >41% Pacific Is...

As the global elderly population grows, age-related cognitive decline is becoming an increasingly significant healthcare issue, often leading to various neuropsychiatric disorders. Among the many molecular players involved in memory, AMPA-type glutamate receptors are known to regulate learning and memory, but how their dynamics change with age and affect memory decline is not well understood. Here, we examined the in vivo properties of the AMPA type glutamate receptor GLR-1 in the AVA interneuron of the C. elegans nervous system during physiological aging. We found that both total and membrane-bound GLR-1 receptor levels decrease with age in wild-type worms, regardless of their location along the axon. Using fluorescence recovery after photobleaching (FRAP), we also demonstrated that a reduction in GLR-1 abundance correlates with decreased local, synaptic GLR-1 receptor dynamics. Importantly, we found that reduced GLR-1 levels strongly correlate with the age-related decline in short-term associative memory...

The hippocampus is generally considered to have relatively late involvement in recognition memory, its main electrophysiological signature being between 400 and 800 ms after stimulus onset. However, most electrophysiological studies have analyzed the hippocampus as a single responsive area, selecting only a single-site signal exhibiting the strongest effect in terms of amplitude. These classical approaches may not capture all the dynamics of this structure, hindering the contribution of other hippocampal sources that are not located in the vicinity of the selected site. We combined intracerebral electroencephalogram recordings from epileptic patients with independent component analysis (ICA) during a recognition memory task involving the recognition of old and new images. We identified two sources with different responses emerging from the hippocampus: a fast one (maximal amplitude at ∼250 ms) that could not be directly identified from raw recordings, and a later one, peaking at ∼400 ms. The earliest compo...