Neuroscience Research最新文献

Most offspring are born helpless, requiring intense caregiving from parents especially during the first few days of neonatal life. For many species, infant cries are a primary signal used by parents to provide caregiving. Previously we and others documented how maternal left auditory cortex rapidly becomes sensitized to pup calls over hours of parental experience, enabled by oxytocin. The speed and robustness of this maternal plasticity suggests cortical pre-tuning or initial bias for pup call stimulus features. Here we examine the circuit basis of left-lateralized tuning to vocalization features with whole-cell recordings in brain slices. We found that layer 2/3 pyramidal cells of female left auditory cortex show selective suppression of inhibitory inputs with repeated stimulation at the fundamental pup call rate (inter-stimulus interval ~150 msec) in pup-naïve females and expanded with maternal experience. However, optogenetic stimulation of cortical inhibitory cells showed that inputs from somatostatin-positive and oxytocin-receptor-expressing interneurons were less suppressed at these rates. This suggested that disynaptic inhibition rather than monosynaptic depression was a major mechanism underlying pre-tuning of cortical excitatory neurons, confirmed with simulations. Thus cortical interneuron specializations can augment neuroplasticity mechanisms to ensure fast appropriate caregiving in response to infant cries.

Transcranial alternating current stimulation (tACS) can modulate endogenous brain oscillations in a frequency-specific manner. Previous studies have reported that beta tACS modulates the excitability of primary motor cortex and improves task performance. Tactile and proprioceptive stimuli also elicit event-related synchronization of the beta rhythm in contralateral sensorimotor cortex, termed beta rebound, and a strong correlation was reported between proprioception-induced rebound strength and clinical recovery in stroke patients. We investigated the effects of tACS matched to the dominant beta frequency on the strength of proprioception-induced beta rebound.We recorded the beta rebound from 14 healthy young adults in response to passive index finger movement by electroencephalography to determine individual peak beta frequency. Electroencephalograms (EEG) were recorded during passive movements before and after active or sham tACS. We recorded beta rebound of all participants to determine their individual peak frequency of beta rebound prior to this experiment. Active tACS at individually matched frequencies increased beta rebound strength during subsequent passive movement compared to sham tACS in the majority of participants, while the remaining participants demonstrated no significant change or a decrease. These findings on healthy participants provide an essential foundation for further studies on the effects of beta frequency-matched tACS for stroke patient rehabilitation.

Optineurin is a causative gene of amyotrophic lateral sclerosis (ALS) and has many roles in processes such as autophagy and inflammation. However, it is unclear how optineurin causes ALS. Optineurin knock-out (Optn-KO) mice, which have been generated by several researchers, exhibit motor neuron degeneration and TDP-43 aggregates, but no motor deficits. Motor dysfunction in ALS model mice is associated with TDP-43 in the spinal cord. We bred Optn-KO mice with TDP-43 overexpression transgenic mice and evaluated whether increased TDP-43 protein causes motor deficits and whether Optn-KO affects TDP-43 protein level. Optn-KO mice had spinal TDP-43 protein levels and motor function comparable to wild-type mice, and TDP-43-transgenic (TDP-43-tg) mice resulted in motor dysfunction and early death. However, double-mutant TDP-43-tg / Optn-KO mice had lower TDP-43 protein levels than TDP-43-tg mice at 18 months age, and showed inhibition of the TBK1-optinerurin autophagic pathway with aging. Furthermore, Optn-KO caused TDP-43-positive cytoplasmic aggregates. TDP-43 overexpression by itself induced spinal microgliosis, but Optn-KO suppressed that microgliosis. Finally, we showed that Optn-KO mice could not exhibit behavioral dysfunction because TDP-43 protein levels were not elevated despite autophagy inhibition. Thus, downregulation of Optn may suppress TDP-43 toxicity by regulating its abundance through aggregate formation.

Many types of voluntary movement depend on appropriate postural adjustments. In most situations, such postural adjustments are influenced by learning and are therefore subject to prediction strategies developed through learning. To address how these prediction strategies affect early postural adjustments (EPAs) that occur several hundred milliseconds before movement, we trained two cats in a reaching task where the location of the target was predictable through learning. At the beginning of each trial, the cat stood still with each paw on a force plate for several hundred milliseconds. A target then appeared on either side of a horizontal touch panel, prompting the cat to lift a forepaw. A food reward followed upon holding the target with the forepaw. Target location was alternated every three rewarded trials: one SWITCH followed by two STAY trials. In both cats, EPAs prior to target onset in STAY trials were significantly dependent on the predetermined target location, indicating that they anticipated the target location as a part of their strategy. In SWITCH trials, EPAs aligned with the subsequent STAY trials in both switch directions for one cat, but only in one direction for the other, suggesting that they developed different strategies to handle target location switches.

Studies of the parental brain have garnered significant attention, revealing neurobiological and psychological changes associated with caregiving. Here, we provide a comprehensive, data-driven overview of the scientific literature on the parental brain, analyzing a large dataset to map the field's knowledge structure. Our objectives include identifying influential authors, contributing countries, publication sources, and commonly used keywords as well as highlighting the most impactful documents and primary thematic areas of research. We analyzed 656 documents (and their 39,302 cited references) from Scopus using CiteSpace software for document co-citation analysis. Our analysis identified 17 key documents, of which the most influential focused on neural correlates of maternal and romantic love and maternal brain responses to infant cues in relation to attachment style. Our analysis additionally identified 10 major thematic domains in the parental brain literature. Qualitative analysis of research clusters revealed a trajectory in the study of the parental brain, progressing from foundational studies on dendritic spine density and maternal memory to the exploration of shared mammalian and human-specific brain networks underlying parental behaviors. Our study points to a growing interest in understanding neurobiological changes in fathers, with parental involvement and exposure to infant cues as moderating factors. The parental brain is a plastic, dynamic network, with bio-behavioral synchrony playing a central role as an interpersonal mechanism that enhances specificity of attachments.