CADENCE is an open Python 3-written neuroinformatics tool with Qt6 graphic user interface for supervised calcium events detection. In neuronal ensembles recording during calcium imaging experiments, the output of instruments such as Celena X, Zeiss LSM 5 Live confocal microscope and Miniscope is a movie showing flashing cells somata. There are few pipelines to convert video to relative fluorescence ΔF/F, from simplest ImageJ plugins to sophisticated tools like MiniAn (Dong et al. in Elife 11, https://doi.org/10.7554/eLife.70661 , 2022). Minian, an open-source miniscope analysis pipeline. Elife, 11.). While in some areas of study relative fluorescence ΔF/F may be the desired result in itself, researchers of neuronal ensembles are typically interested in a more detailed analysis of calcium events as indirect proxy of neuronal electrical activity. For such analyses, researchers need a tool to infer calcium events from the continuous ΔF/F curve in order to create a raster representation of calcium events for later use in analysis software, such as Elephant (Denker, M., Yegenoglu, A., Grün, S. (2018). Collaborative HPC-enabled workflows on the HBP Collaboratory using the Elephant framework. Neuroinformatics, 19.). Here we present such an open tool with supervised calcium events detection.

Organic semiconductor materials with a unique set of properties are very attractive for interfacing biological objects and can be used for noninvasive therapy or detection of biological signals. Here, we describe the synthesis and investigation of a novel series of organic push-pull conjugated molecules with the star-shaped architecture, consisting of triphenylamine as a branching electron donor core linked through the thiophene π-spacer to electron-withdrawing alkyl-dicyanovinyl groups. The molecules could form stable aqueous dispersions of nanoparticles (NPs) without the addition of any surfactants or amphiphilic polymer matrixes with the average size distribution varying from 40 to 120 nm and absorption spectra very similar to those of human eye retina pigments such as rods and green cones. Variation of the terminal alkyl chain length of the molecules forming NPs from 1 to 12 carbon atoms was found to be an efficient tool to modulate their lipophilic and biological properties. Possibilities of using the NPs as light nanoactuators in biological systems or as artificial pigments for therapy of degenerative retinal diseases were studied both on the model planar bilayer lipid membranes and on the rat cortical neurons. In the planar bilayer system, the photodynamic activity of these NPs led to photoinactivation of ion channels formed by pentadecapeptide gramicidin A. Treatment of rat cortical neurons with the NPs caused depolarization of cell membranes upon light irradiation, which could also be due to the photodynamic activity of the NPs. The results of the work gave more insight into the mechanisms of light-controlled stimulation of neuronal activity and for the first time showed that fine-tuning of the lipophilic affinity of NPs based on organic conjugated molecules is of high importance for creating a bioelectronic interface for biomedical applications.

Precise control of cellular temperature at the microscale is crucial for developing novel neurostimulation techniques. Here, the effect of local heat on the electrophysiological properties of primary neuronal cultures and HEK293 cells at the subcellular level using a cutting-edge micrometer-scale thermal probe, the diamond heater-thermometer (DHT), is studied. A new mode of local heat action on a living cell, thermal-capture mode (TCM), is discovered using the DHT probe. In TCM, the application of a 50 degrees C temperature step induces a great increase in cellular response, allowing the cell to be thermally captured and depolarized by up to 20 mV. This thermal effect is attributed to local phase changes in the phospholipid membrane, enabling precise and reproducible modulation of cell activity. The TCM is shown to open up new opportunities for thermal cell stimulation. DHT reliably triggers action potentials (APs) in neurons at rates up to 30 Hz, demonstrating the ability to control cell excitability with millisecond and sub-millisecond resolution. AP shape is modulated by local heat as well. The ability to precisely control the AP shape and rate via thermal-capture mode opens new avenues for non-invasive, localized neurostimulation techniques, particularly in controlling neuron excitability.

The perception of color by humans and other primates is a complex task which is addressed not only by neurophysiology, but also by other related sciences such as psychophysiology, psycholinguistics, and even philosophy. This review takes the neurophysiology of vision as a starting point to examine the contributions of all related disciplines to understanding how color perception is encoded in primates. The currently known neurophysiological mechanisms of color perception in primates are considered and a hypothetical scheme for processing color stimuli in the primate cortex is proposed in which color coding is carried out by conceptual neurons at the highest stage of stimulus processing, these cells being responsible only for reflecting the color parameter of the visual stimulus.

Perception of color by human and nonhuman primates is a complex problem, which is studied not only by neurophysiology, but also by neighboring fields of science such as psychophysiology, psycholinguistics, and even philosophy. With neurophysiology as a starting point, I review contributions of adjacent fields in understanding of the primates' color space encoding. All known at the moment neurophysiologic mechanisms of color perception by primates are reviewed and a hypothetical way of color stimuli processing is proposed, suggesting at a final stage involvement of conceptual (gnostic) neurons encoding only colors of visual stimuli.

Italian is sexy, German is rough-but how about Páez or Tamil? Are there universal phonesthetic judgments based purely on the sound of a language, or are preferences attributable to language-external factors such as familiarity and cultural stereotypes? We collected 2,125 recordings of 228 languages from 43 language families, including 5 to 11 speakers of each language to control for personal vocal attractiveness, and asked 820 native speakers of English, Chinese, or Semitic languages to indicate how much they liked these languages. We found a strong preference for languages perceived as familiar, even when they were misidentified, a variety of cultural-geographical biases, and a preference for breathy female voices. The scores by English, Chinese, and Semitic speakers were weakly correlated, indicating some cross-cultural concordance in phonesthetic judgments, but overall there was little consensus between raters about which languages sounded more beautiful, and average scores per language remained within ±2% after accounting for confounds related to familiarity and voice quality of individual speakers. None of the tested phonetic features-the presence of specific phonemic classes, the overall size of phonetic repertoire, its typicality and similarity to the listener's first language-were robust predictors of pleasantness ratings, apart from a possible slight preference for nontonal languages. While population-level phonesthetic preferences may exist, their contribution to perceptual judgments of short speech recordings appears to be minor compared to purely personal preferences, the speaker's voice quality, and perceived resemblance to other languages culturally branded as beautiful or ugly.

The optical imaging of neuronal activity with potentiometric probes has been credited with being able to address key questions in neuroscience via the simultaneous recording of many neurons. This technique, which was pioneered 50 years ago, has allowed researchers to study the dynamics of neural activity, from tiny subthreshold synaptic events in the axon and dendrites at the subcellular level to the fluctuation of field potentials and how they spread across large areas of the brain. Initially, synthetic voltage-sensitive dyes (VSDs) were applied directly to brain tissue via staining, but recent advances in transgenic methods now allow the expression of genetically encoded voltage indicators (GEVIs), specifically in selected neuron types. However, voltage imaging is technically difficult and limited by several methodological constraints that determine its applicability in a given type of experiment. The prevalence of this method is far from being comparable to patch clamp voltage recording or similar routine methods in neuroscience research. There are more than twice as many studies on VSDs as there are on GEVIs. As can be seen from the majority of the papers, most of them are either methodological ones or reviews. However, potentiometric imaging is able to address key questions in neuroscience by recording most or many neurons simultaneously, thus providing unique information that cannot be obtained via other methods. Different types of optical voltage indicators have their advantages and limitations, which we focus on in detail. Here, we summarize the experience of the scientific community in the application of voltage imaging and try to evaluate the contribution of this method to neuroscience research.

Perception of color by humans and other primates is a complex problem, studied by neurophysiology, psychophysiology, psycholinguistics, and even philosophy. Being mostly trichromats, simian primates have three types of opsin proteins, expressed in cone neurons in the eye, which allow for the sensing of color as the physical wavelength of light. Further, in neural networks of the retina, the coding principle changes from three types of sensor proteins to two opponent channels: activity of one type of neuron encode the evolutionarily ancient blue-yellow axis of color stimuli, and another more recent evolutionary channel, encoding the axis of red-green color stimuli. Both color channels are distinctive in neural organization at all levels from the eye to the neocortex, where it is thought that the perception of color (as philosophical qualia) emerges from the activity of some neuron ensembles. Here, using data from neurophysiology as a starting point, we propose a hypothesis on how the perception of color can be encoded in the activity of certain neurons in the neocortex. These conceptual neurons, herein referred to as ‘color neurons’, code only the hue of the color of visual stimulus, similar to place cells and number neurons, already described in primate brains. A case study with preliminary, but direct, evidence for existing conceptual color neurons in the human brain was published in 2008. We predict that the upcoming studies in non-human primates will be more extensive and provide a more detailed description of conceptual color neurons.

According to modern concepts, the dorsal hippocampus, specifically the CA1 field, plays a crucial role in the formation and reactivation of contextual fear conditioning (CFC) memory [1–5]. However, the extent to which the neurons of the dorsal hippocampus participate in CFC learning or memory reactivation remains poorly understood. The aim of this study was to examine the in vivo activity of neurons in the hippocampal CA1 field during CFC memory training and testing. The study conducted experimentations on male mice of the C57Bl/6 line (N=4). Miniature fluorescence microscopes, also known as miniscopes, were used to monitor neuronal activity in the CA1 field. The CA1 field in the hippocampus was injected with an AAV vector carrying the GCaMP6s calcium sensor, and implanted with a GRIN lens in the same area as the miniscope lens. The mice underwent CFC task training and the duration of freezing was then measured. After the training session, the mice exhibited a notable increase in freezing duration, suggesting the formation of context aversive memory. Throughout the training, a total of 591 active neurons were recorded (147.8±74.9 neurons per mouse), while 512 (128.0±40.6 neurons per mouse) neurons were recorded. The average frequency of calcium events per second during the complete duration of training session was 0.037±0.003, while for the testing, it was 0.042±0.015 events/second. Around 46% of the registered neurons remained active throughout the complete training procedure. The mean frequency of calcium events in these neurons surged considerably following the application of an electric shock (from 0.035±0.007 events/sec to 0.086±0.013 events/sec). Using k-means clustering, certain neurons showed increased activity after electric shock exposure, while others showed decreased activity. However, the type of activity change did not affect subsequent neuronal dynamics during memory retrieval. During memory retrieval, we observed that an average of 30–40% of neurons were reactivated. The number of active neurons notably decreased during episodes of freezing and almost all registered neurons were activated during episodes of movement. The average frequency of calcium events in the reactivating neurons did not change from the training to testing session. Thus, new data was obtained on the activation of neurons in the hippocampal CA1 area during memory formation and retrieval in CFC.

It is well known that the initiation of the reflex arcs of the vertebrate vestibular system occurs in the receptors of the labyrinthine organs which transmit the sensory signals via the ribbon synapses to the vestibular nerve afferents (an interneuron). In invertebrate species, and in particular, the statocyst of pulmonate mollusks, it is thought that the receptors send their axons out of the statocyst in the vestibular connective and establish the first synapse onto cerebral ganglia neurons, thereby bypassing the interneuron in the reflex arc. Morphological and electrophysiological techniques were used in this study to identify the first synapse in the vestibular arc of the mollusk Helix is actually within the vestibular connective on its way from the statocyst to cerebral ganglia. Cerebral interneurons were found that sent their neurites to the vestibular nerve, and thus have the potential to respond to the statocyst output or send efferent input to the statocyst.

This paper investigates the underlying cognitive processes of sound-color associations by connecting perceptual evidence from research on cross-modal correspondences to sound symbolic patterns in the words for colors in natural languages. Building upon earlier perceptual experiments, we hypothesized that sonorous and bright phonemes would be over-represented in the words for bright and saturated colors. This hypothesis was tested on eleven color words and related concepts (red-green, yellow-blue, black-white, gray, night-day, dark-light) from 245 language families. Textual data was transcribed into the International Phonetic Alphabet (IPA), and each phoneme was described acoustically using high-quality IPA recordings. These acoustic measurements were then correlated with the luminance and saturation of each color obtained from cross-linguistic color-naming data in the World Color Survey. As expected, vowels with high brightness and sonority ratings were over-represented in the words for colors with high luminance, while sonorous consonants were more common in the words for saturated colors. We discuss these results in relation to lexicalization patterns and the links between iconicity and perceptual cross-modal associations.

Immediate early genes (IEGs) are useful markers of neuronal activation and essential components of neuronal response. While studies of gastropods have provided many insights into the basic learning and memory mechanisms, the genome-wide assessment of IEGs has been mainly restricted to vertebrates. In this study, we identified IEGs in the terrestrial snail Helix lucorum In the absence of the genome, we conducted de novo transcriptome assembly using reads with short and intermediate lengths cumulatively covering more than 98 billion nucleotides. Based on this assembly, we identified 37 proteins corresponding to contigs differentially expressed (DE) in either the parietal ganglia (PaG) or two giant interneurons located within the PaG of the snail in response to the neuronal stimulation. These proteins included homologues of well-known mammalian IEGs, such as c-jun/jund, C/EBP, c-fos/fosl2, and Egr1, as well as homologues of genes not yet implicated in the neuronal response.

Protein kinase Mζ is considered important for memory formation and maintenance in different species, including invertebrates. PKMζ participates in multiple molecular pathways in neurons, regulating translation initiation rate, AMPA receptors turnover, synaptic scaffolding assembly, and other processes. Here, for the first time, we established the sequence of mRNA encoding PKMζ homolog in land snail Helix lucorum. We annotated important features of this mRNA: domains, putative capping sites, translation starts, and splicing sites. We discovered that this mRNA has at least two isoforms, and one of them lacks sequence encoding C1 domain. C1 deletion may be unique for snail because it has not been previously found in other species. We performed behavioral experiments with snails, measured expression levels of identified isoforms, and confirmed that their expression correlates with one type of learning.

The vestibular system receives a permanent influence from gravity and reflexively controls equilibrium. If we assume gravity has remained constant during the species' evolution, will its sensory system adapt to abrupt loss of that force? We address this question in the land snail Helix lucorum exposed to 30 days of near weightlessness aboard the Bion-M1 satellite, and studied geotactic behavior of postflight snails, differential gene expressions in statocyst transcriptome, and electrophysiological responses of mechanoreceptors to applied tilts. Each approach revealed plastic changes in the snail's vestibular system assumed in response to spaceflight. Absence of light during the mission also affected statocyst physiology, as revealed by comparison to dark-conditioned control groups. Readaptation to normal tilt responses occurred at ~20 h following return to Earth. Despite the permanence of gravity, the snail responded in a compensatory manner to its loss and readapted once gravity was restored.

It has been shown that a variety of long-term memories in different regions of the brain and in different species are quickly erased by local inhibition of protein kinase Mζ (PKMζ), a persistently active protein kinase. Using antibodies to mammalian PKMζ, we describe in the present study the localization of immunoreactive molecules in the nervous system of the terrestrial snail Helix lucorum. Presence of a homolog of PKMζ was confirmed with transcriptomics. We have demonstrated in behavioral experiments that contextual fear memory disappeared under a blockade of PKMζ with a selective peptide blocker of PKMζ zeta inhibitory peptide (ZIP), but not with scrambled ZIP. If ZIP was combined with a "reminder" (20 min in noxious context), no impairment of the long-term contextual memory was observed. In electrophysiological experiments we investigated whether PKMζ takes part in the maintenance of long-term facilitation (LTF) in the neural circuit mediating tentacle withdrawal. LTF of excitatory synaptic inputs to premotor interneurons was induced by high-frequency nerve stimulation combined with serotonin bath applications and lasted at least 4 h. We found that bath application of 2 × 10(-6) M ZIP at the 90th min after the tetanization reduced the EPSP amplitude to the non-tetanized EPSP values. Applications of the scrambled ZIP peptide at a similar time and concentration didn't affect the EPSP amplitudes. In order to test whether effects of ZIP are specific to the synapses, we performed experiments with LTF of somatic membrane responses to local glutamate applications. It was shown earlier that serotonin application in such an "artificial synapse" condition elicits LTF of responses to glutamate. It was found that ZIP had no effect on LTF in these conditions, which may be explained by the very low concentration of PKMζ molecules in somata of these identified neurons, as evidenced by immunochemistry. Obtained results suggest that the Helix homolog of PKMζ might be involved in post-induction maintenance of long-term changes in the nervous system of the terrestrial snail.

Neuron electrical activity was recorded using an optical method in which the probes were widely used monomolecular voltage-sensitive dyes. Current methods of loading voltage-sensitive dyes into nervous tissue have serious limitations, severely restricting their areas of use (insolubility in water, the need for toxic organic solvents, and the toxicity of the voltage-sensitive dyes themselves at high concentrations). We have developed a new method of loading voltage-sensitive dyes by “shooting” dye-coated gold microparticles into living brain slices. Three-dimensional reconstruction of nervous tissue fluorescence with a scanning confocal microscope showed that after loading with dye by this method, it propagated along the cell membrane, completely staining only one target cell with its processes, without spreading to surrounding cells via the intercellular fluid or through cell contacts. This method of staining neurons can be used for the optical recording of the electrical activity of individual neurons and to analyze the distribution of electric voltages across the compartments of excitable cells (axons and dendrites).

Currently, the studies of electrical activity and plasticity of neuronal networks are impossible without employing of imaging techniques to visualize functional signals that allowing revealing electrical events in multiple neurons, as well as in their tiny dendrites and axons placed on their morphological picture. Imaging with voltage-sensitive dyes (VSD) is one of unique available methods that providing both high spatial resolution and ultrafast sampling (< 0.1 ms) in realtime with perfect S-to-N ratio. During the last decade a significant progress in VSD application has been achieved due to major method improvements and new probe synthesis especially in the field of research of initiation and propagation of action potentials. There was evidence of the method efficiency and usability while the method was added to the toolbox of modern neuroscience for research in hottest topics.

Fast voltage-sensitive dyes (VSD) are widely used in modern neuroscience for optical recording of electrical potentials at many levels, from single cell compartment to brain areas, containing populations of many neural cells. The more lipophilic a VSD, the better signal-to-noise ratio of the optical signal, but there are no effective ways to deliver a water-insoluble dye into the membrane of live cell. Here we report a new protocol based on rapid biolistic delivery of VSDs, which is optimal for further recordings of optical signals from live neurons of rat brain slices. This protocol allows us to stain locally (150 mkm) neural somata of brain structures with a Golgi-like pattern, and a VSD propagates even to distant neurites of stained cells very quickly. This technique also can be used for rapid local delivery of any lipophilic and water-insoluble substances into live cells, further optical recording of neural activity, and analysis of potential propagation in a nerve cell.

Optical recording of membrane potential changes with fast voltage-sensitive dyes (VSDs) in neurons is one of the very few available methods for studying the generation and propagation of electrical signals to the distant compartments of excitable cells. The more lipophilic is the VSD, the better signal-to-noise ratio of the optical signal can be achieved. At present there are no effective ways to deliver water-insoluble dyes into the membranes of live cells. Here, we report a possibility to stain individual live neurons with highly lipophilic VSDs in acute brain slices using biolistic delivery. We tested four ANEP-based VSDs with different lipophilic properties and showed their ability to stain single neurons in a slice area of up to 150 μm in diameter after being delivered by a biolistic apparatus. In the slices of neocortex and hippocampus, the two most lipophilic dyes, di-8-ANEPPS and di-12-ANEPPQ, showed cell-specific loading and Golgi-like staining patterns with minimal background fluorescence. Simultaneous patch-clamp and optical recording of biolistically stained neurons demonstrated a good match of optical and electrical signals both for spontaneous APs (action potentials) and stimulus-evoked events. Our results demonstrate the high efficiency of a fast and targeted method of biolistic delivery of lipophilic VSDs for optical signals recording from mammalian neurons in vitro.