Neuropixels

…The role uses Neuropixels electrophysiology, optogenetics, optical physiology, rodent behavior, histology, and data-quality analysis within a collaborative brain-wide-circuit programme.

…project combines systems neuroscience, Neuropixels recordings, imaging, circuit manipulation and transcriptomics in the SciLifeLab and Department of Neuroscience research environment.

…To address this question, we used Neuropixels electrodes to record layer 5 excitatory populations in mouse V1, then transcriptomically identified the recorded cell types. To do so, we performed a subsequent recording of the same cells using 2-photon (2p) calcium imaging, identifying neurons b

The genome governs the developmental trajectory of neural circuits [1, 2], guiding processes like neurogenesis and synaptogenesis to ultimately shape the structure of the brain. Here, we study the impact of genetic variation during development on the dynamics and geometry of neural population activity in the motor cortex (MOp) of adult mice during natural feeding behavior. We focus on autism spectrum disorder (ASD) models, many cases of which are characterized by stereotypical motor impairments [3]. Specifically, we compare neural activity during a dexterous cued self-feeding task in two trans

To understand the neural basis of many cognitive processes, such as learning and memory, we need to track the millisecond, single-spike activity of neurons across days. However, compared to calcium imaging methods, tracking neurons in chronic electrophysiological recordings remains challenging. Recent studies have designed algorithms to do so, but mostly rely on engineered parameters that may not take advantages of the full complexity of the neuron’s electrophysiological waveform and miss or falsely match neurons. To go beyond these limitations, we developed DeepMatch, a deep neural network fr

Understanding how the brain encodes movements is vital for motor control. Research suggests that this involves comparing proprioceptive inputs from the body with an internal model of expected movement. When these signals match, vestibular signals---which would otherwise stabilize the head against movements---are suppressed, allowing voluntary movement to occur. This mechanism implies that integrating proprioceptive and vestibular inputs is crucial for effective coordination. While previous studies indicate the involvement of multiple brain areas, with the PIVC at the forefront, the mechanisms

…across cortical depth with human Neuropixels probes. The studies ask which representations and operations connect speech sounds to meaning, and how information at different timescales is nested across time and cortical space. Comparing biological recordings with artificial models reveals candidate mechanisms for exchangin

Psychedelics (5-HT2AR agonists) show great promise in treating mental disorders but their effects on neuronal population activity are not clear. Latent dimensions identified by Principal Component Analysis (PCA) capture the dynamics of this interrelated neuronal population activity. We asked whether latent dimensions emerge or disappear as a result of psychedelic administration (acute), and across other naturally occurring brain state transitions (sleep, arousal). Contrastive PCA (cPCA) [Abid et al. (2018), Nature Comm.] was applied to spontaneous brain activity recordings in rodents before

Perception is inherently variable; the same external stimulus might be detected or missed in different instances. Neuronal signals governing this variability remain elusive. Past studies have shown that mice can be trained to report optogenetic stimulation of primary somatosensory cortex (S1), bypassing the trial-by-trial perceptual variability associated with external stimuli. These studies, however, stimulated different populations of S1 neurons on different trials which may also contribute to perceptual variability. Our aim is to use spatial light modulation (SLM) to stimulate the same S1 n

Sixty years after the discovery of a slow monotonic drift in electroencephalographic recordings preceding voluntary self-paced actions ("the readiness potential"), its physiological underpinnings remain elusive. A classical interpretation holds that readiness potential onset reflects the decision to act, with the drift thereafter proceeding deterministically to movement onset. However, more recent analyses suggest that the readiness potential's monotonicity may be an artifact of trial averaging; rather than a slow, deterministic process, fast stochastic processes underlie self-paced decisions.

The ability to detect, represent and exploit statistical regularities in the environment is a key feature of animal cognition. The brain holds internal models of the world to optimally interpret incoming sensory inputs and guide the appropriate responses. Previously, we have shown that humans and rodents are sensitive to the underlying sensory statistics in a 2-alternative-forced-choice auditory categorisation task. In this work, we investigate the neural signatures of behavioural adaptation to changes in sensory statistics, where the sampling distribution of sounds within each category is mod

Most brain functions involve interactions among multiple, distinct areas or nuclei. Yet our understanding of how populations of neurons in interconnected brain areas communicate is in its infancy. Using a population approach, we found that interactions between early visual cortical areas (V1 and V2) occur through a low-dimensional bottleneck, termed a communication subspace. In this talk, I will focus on the statistical methods we have developed for studying interactions between brain areas. First, I will describe Delayed Latents Across Groups (DLAG), designed to disentangle concurrent, bi-

…in high-channel-count probes like Neuropixels (NP) and extracellular analysis pipelines allow for extracting a rich set of spike features to direc

…We recorded brain-wide activity via Neuropixels in mice performing a delay-varying olfactory WM task, to reveal animal’s capacity in maintaining both olfaction and duration information simultaneously. Neurons encoded WM information predominantly in transient patterns and generated cross-region activity waves, reflecting distinct cell assemblies that encoded olfaction-only, duration-only, or both information. The regional proportion of neurons and wave timing within cell ass

It has been commonly reported across species and brain regions that neural population dynamics are low-dimensional, leading to a broad range of theories on the significance of this structure [1, 2]. However, several recent studies have reported that spontaneous activity in rodent sensory regions is high-dimensional [3], presenting a challenge to explanations which posit low-dimensional dynamics as integral to neural computations. Here we hypothesized that the observation of high-dimensional population dynamics in these datasets results from neural activity progressing through a series of low-d

During navigation, animals estimate their position using path integration and landmarks. In a series of two studies, we used virtual reality and electrophysiology to dissect how these inputs combine to generate the brain’s spatial representations. In the first study (Campbell et al., 2018), we focused on the medial entorhinal cortex (MEC) and its set of navigationally-relevant cell types, including grid cells, border cells, and speed cells. We discovered that attractor dynamics could explain an array of initially puzzling MEC responses to virtual reality manipulations. This theoretical framewo

It was recently shown that glutamatergic neurons in the lateral hypothalamus (LHA) projecting to the lateral habenula (LH) encode negative value. However, it is still unclear how such aversive neuronal pathways located in subcortical neuronal populations affect the activity of the rest of the brain. We report here how the neuronal activity in an integrative cortical area previously reported to be involved in aversion, the medial prefrontal cortex (mPFC), is modulated when an internal aversive signal is emitted in the hypothalamic-habenula (LHA-LH) pathway. We have used a transgenic mouse line

…Here, using electrodes and Neuropixels in the motor cortices of macaques engaged in a reaching task, we probed how local population dynamics are affected by two perturbation modalities: optogenetic excitation and electrical intracortical microstimulation (ICMS). Both st

Sharp-wave ripples (SWR) are high frequency events recorded in the local field potential (LFP) of the hippocampus of rodents and humans. During SWR, the sequential firing of ensembles of neurons act to reactivate memory traces of previously encoded experience. SWR-related interventions can influence hippocampal-dependent cognitive function, making their real-time detection crucial to understand underlying mechanisms. However, existing SWR identification tools mostly rely on using spectral methods, which remain suboptimal. Here, we introduce a 1D convolutional neural network (CNN) operating o

Performing two skills, such as swinging a tennis racquet or axe, requires both differences in typical motor output and different feedback-driven adjustments. The motor cortex (M1) is clearly involved in specifying motor output. Less-well understood is the extent and nature of its role in performing computations underlying skill-specific feedback control. In addressing this question, a technical hurdle is that it can be difficult to discern when skill-specific aspects of neural activity reflect different motor outputs versus skill-specific feedback control. To overcome this hurdle, we employed

…Here, we used Neuropixels probes to record from large populations of neurons in prefrontal cortex of mice given the psychedelic drug TCB-2. The primary effect of drug ingestion was stretching of the distribution of log firing rates of the recorded population. This phenomenon was previously observed across transitions between sleep and wakefulness,

…from these distributed circuits - Neuropixels probes for large-scale electrophysiology - and our findings from studies deploying these tools to study visual detection and discrimination in mice.

…of technologies, with a main focus on Neuropixels probes. Dr Kris Schoepfer, US Product Specialist at Scientifica, will provide an overview of multielectrode technologies available to record from one or more brain areas simultaneously, including: DIY multielectrode probes; Tetrodes / Hyperdrives; Silicon probes; Neuropixels. Dr Sylvia Schröd