Successful behavior depends on the attentional state and other factors related to decision-making, which may modulate neuronal activity differently. Here, we investigated whether attentional state and behavioral outcome (i.e., whether a target is detected or missed) are distinguishable using the power and phase of local field potential recorded bilaterally from area V4 of two male rhesus monkeys performing a cued visual attention task. To link each trial’s outcome to pairwise measures of attention that are typically averaged across trials, we used several methods to obtain single-trial estimates of spike count correlation and phase consistency. Surprisingly, while attentional location was best discriminated using gamma and high-gamma power, behavioral outcome was best discriminated by alpha power and steady-state visually evoked potential. Power outperformed absolute phase in attentional/behavioral discriminability, although single-trial gamma phase consistency provided reasonably high

The neural network, including the interstitial nucleus of Cajal (INC), functions as an oculomotor neural integrator involved in the control of vertical gaze holding. Impairment of the vestibulocerebellum (VC), including the flocculus (FL), has been shown to affect vertical gaze holding, indicating that the INC cooperates with the VC in controlling this function. However, a network between the INC and VC has not been identified. In this study, we aimed to obtain anatomical evidence of a neural pathway from the INC to the VC (the INC-VC pathway) in rats. Injection of dextran-conjugated Alexa Fluor 488 or adeno-associated virus 2-retro (AAV2retro) expressing GFP into the FL or another VC region (uvula/nodulus) did not reveal any retrogradely labeled neurons in the INC, suggesting that INC neurons do not project directly to the VC. Rabies virus-based transsynaptic tracing experiments revealed that the INC-VC pathway is mediated via synaptic connections with the prepositus hypoglossi nucleu

Each olfactory cortical hemisphere receives ipsilateral odor information directly from the olfactory bulb and contralateral information indirectly from the other cortical hemisphere. Since neural projections to the olfactory cortex (OC) are disordered and nontopographic, spatial information cannot be used to align projections from the two sides like in the visual cortex. Therefore, how bilateral information is integrated in individual cortical neurons is unknown. We have found, in mice, that the odor responses of individual neurons to selective stimulation of each of the two nostrils are significantly correlated, such that odor identity decoding optimized with information arriving from one nostril transfers very well to the other side. Nevertheless, these aligned responses are asymmetric enough to allow decoding of stimulus laterality. Computational analysis shows that such matched odor tuning is incompatible with purely random connections but is explained readily by Hebbian plasticity

Age-related brain changes affect sleep and are reflected in properties of sleep slow-waves, however, the precise mechanisms behind these changes are still not completely understood. Here, we adapt a previously established whole-brain model relating structural connectivity changes to resting state dynamics, and extend it to a slow-wave sleep brain state. In particular, starting from a representative connectome at the beginning of the aging trajectory, we have gradually reduced the inter-hemispheric connections, and simulated sleep-like slow-wave activity. We show that the main empirically observed trends, namely a decrease in duration and increase in variability of the slow waves are captured by the model. Furthermore, comparing the simulated EEG activity to the source signals, we suggest that the empirically observed decrease in amplitude of the slow waves is caused by the decrease in synchrony between brain regions.

Adeno-associated viral vector (AAV) serotypes vary in how effectively they express genes across different cell types and brain regions. Here we report a systematic comparison of the AAV serotypes 1, 2, 5, 8, 9, and the directed evolution derived AAVrg, in the inferior colliculus (IC) and cerebellum. The AAVs were identical apart from their different serotypes, each having a synapsin promotor and expressing GFP (AAV-hSyn-GFP). Identical titers and volumes were injected into the IC and cerebellum of adult male and female mice, and brains were sectioned and imaged 2 weeks later. Transduction efficacy, anterograde labeling of axonal projections, and retrograde labeling of somata were characterized and compared across serotypes. Cell-type tropism was assessed by analyzing the morphology of the GFP-labeled neurons in the cerebellar cortex. In both the cerebellum and IC, AAV1 expressed GFP in more cells, labeled a larger volume, and produced significantly brighter labeling than all other sero

Experimental evidence showed that an increase in intracellular chloride concentration ([Cl−]i) caused by gamma-aminobutyric acid (GABA) input can promote epileptic firing activity, but the actual mechanisms remain elusive. Here in this theoretical work, we show that influx of chloride and concomitant bicarbonate ion (HCO3−) efflux upon GABA receptor activation can induce epileptic firing activity by transition of GABA from inhibition to excitation. We analyzed the intrinsic property of neuron firing states as a function of [Cl−]i . We found that as [Cl−]i increases, the system exhibits a saddle–node bifurcation, above which the neuron exhibits a spectrum of intensive firing, periodic bursting interrupted by depolarization block (DB) state, and eventually a stable DB through a Hopf bifurcation. We demonstrate that only GABA stimuli together with HCO3− efflux can switch GABA’s effect to excitation which leads to a series of seizure-like events (SLEs). Exposure to a low [K+]bath can drive

Illusionism is a general philosophical framework in which specific theories of consciousness can be constructed without having to invoke a magical mind essence. The advantages of illusionism are not widely recognized, perhaps because scholars tend to think only of the most extreme forms and miss the range of possibilities. The brain’s internal models are never fully accurate, nothing is exactly as the brain represents it, and therefore some element of illusionism is almost certainly necessary for any working theory of consciousness or of any other property that is accessed through introspection. Here I describe the illusionist framework and propose six specific theories. One purpose of this article is to demonstrate the range of possibilities in a domain that is not yet sufficiently explored. The second purpose is to argue that even existing, popular theories, such as the integrated information theory or the global workspace theory, can be transformed and greatly strengthened by adding

The rat dorsomedial (DMS) and dorsolateral striatum (DLS), equivalent to caudate nucleus and putamen in primates, are required for goal-directed and habit behaviour, respectively. However, it is still unclear whether and how this functional dichotomy emerges in the course of learning. In this study, we investigated this issue by recording DMS and DLS single neuron activity in rats performing a continuous spatial alternation task, from the acquisition to optimized performance. We first applied a classical analytical approach to identify task-related activity based on the modifications of single neuron firing rate in relation to specific task events or maze trajectories. We then used an innovative approach based on Hawkes process to reconstruct a directed connectivity graph of simultaneously recorded neurons, that was used to decode animal behavior. This approach enabled us to better unravel the role of DMS and DLS neural networks across learning stages. We showed that DMS and DLS displa

Deficits in social behavior are found in neurodevelopmental disorders, including autism spectrum disorders (ASDs). Since abnormalities in cerebellar morphology and function are observed in ASD patients, the cerebellum is thought to play a role in social behavior. However, it remains unknown whether the cerebellum is involved in social behavior in other animals and how cerebellar circuits control social behavior. To address this issue, we employed zebrafish stereotyped orienting behavior as a model of social behaviors, in which a pair of adult zebrafish in two separate tanks approach each other, with one swimming at synchronized angles (orienting angles) with the other. We harnessed transgenic zebrafish that express botulinum toxin, which inhibits the release of neurotransmitters, in either granule cells or Purkinje cells (PCs), and zebrafish mutants of reelin , which is involved in the positioning of cerebellar neurons, including PCs. These zebrafish, deficient in the function or forma

Pyroptosis, an inflammatory programmed cell death, has recently been found to play an important role in spinal cord injury (SCI). C-type lectin domain family 5 member A (CLEC5A), triggering receptor expressed on myeloid cells 1 (TREM1), and NLR-family CARD-containing protein 4 (NLRC4) have been reported to be associated with neuronal pyroptosis, but few studies have clarified their functions and regulatory mechanisms in SCI. In this study, CLEC5A, TREM1, and NLRC4 were highly expressed in lidocaine-induced SCI rat models, and their knockdown alleviated lidocaine-induced SCI. The elevation of pyroptosis-related indicators LDH, ASC, GSDMD-N, IL-18, caspase-1, and IL-1β levels in SCI rats was attenuated after silencing of CLEC5A, TREM1, or NLRC4. Lidocaine-induced decrease in cell viability and the elevation in cell death were partly reversed after CLEC5A, TREM1, or NLRC4 silencing. Lidocaine-mediated effects on the levels of LDH, ASC, GSDMD-N, IL-18, caspase-1, and IL-1β in lidocaine-ind