Rethinking the network determinants of motor disability in Parkinson’s disease
By Emma Sherrell onWhile the basal ganglia circuit model underpinning the notion that striatal dopamine (DA) depletion was the critical determinant of network pathophysiology underlying the motor symptoms of Parkinson’s disease, the hypothesis itself has never been directly tested. It is time for a new model of the network determinants of motor disability in PD.
RectiPy software package
By Emma Sherrell onRecurrent neural network training in Python (RectiPy) is a software package developed by Richard Gast that allows for lightweight implementations of recurrent neural networks (RNNs) based on ordinary or delayed differential equations. Here, the team provides a tool that allows for the implementation of biologically informed spiking neural networks and optimizes the parameters of these networks via gradient descent.
α-Synuclein pathology disrupts mitochondrial function in dopaminergic and cholinergic neurons at-risk in Parkinson’s disease
By Emma Sherrell onThe mechanisms by which intracellular aSYN pathology contributes to dysfunction and degeneration of neurons in the brain are still unclear. Genetic and physiological methods were used to monitor mitochondrial function in substantia nigra pars compacta (SNc) dopaminergic and pedunculopontine nucleus (PPN) cholinergic neurons after stereotaxic injection of aSYN pre-formed fibrils (PFFs) into the mouse brain.
Motor learning selectively strengthens cortical and striatal synapses of motor engram neurons Dataset
By Emma Sherrell onThis upload includes 1) ImageJ macros / scripts for minor automated cell counting for brain slides with immunostaining and 2) MATLAB functions / scripts for minor automated spine location cluster analysis (nearest neighbor distance / index).
surmeierlab/EZT2022SA: EZTNotebooks
By Emma Sherrell onThis repository contains five Jupyter Notebooks (Python 3.0) created or modified for specific use with action potential analysis for the Zampese, et.al. 2022 Science Advances paper.
Source data for “Ca2+ channels couple spiking to mitochondrial metabolism in substantia nigra dopaminergic neurons”
By Emma Sherrell onSource data for publication: "Ca2+ channels couple spiking to mitochondrial metabolism in substantia nigra dopaminergic neurons."
Dynamic behaviour restructuring mediates dopamine-dependent credit assignment
By Emma Sherrell onPublished: Reinforcement mechanism promotes not only reinforcement, but gradual refinement of the entire behavioral repertoire to assign credit to specific actions and action sequences that lead to dopamine release.
Day2023 dataset
By Emma Sherrell onDatasets for all figures 1-8 in: GABAergic regulation of striatal spiny projection neuron excitability depends upon their activity state Image is taken from Fig 1B inset and illustrates RiboTag-eGFP in SPNs of the striatum.
Day2023 supplementary dataset
By Emma Sherrell onDatasets for all supplementary figures S1-4 in GABAergic regulation of striatal spiny projection neuron excitability depends upon their activity state (2023).
Day2023 R code and analysis
By Emma Sherrell onDatasets for all figures 1-8 in: GABAergic regulation of striatal spiny projection neuron excitability depends upon their activity state. Image is taken from Fig 1B inset and illustrates RiboTag-eGFP in SPNs of the striatum.
Scalable, flexible carbon fiber electrode thread arrays for three-dimensional probing of neurochemical activity in deep brain structures of rodents
By Emma Sherrell onThe authors' CFET array has the potential to unlock a wide range of applications, from uncovering the role of neuromodulators in synaptic plasticity, to addressing critical safety barriers in clinical translation towards diagnostic and adaptive treatment in Parkinson’s disease and major mood disorders.
Standard operating procedure (SOP) for combined ICA and systemic administration of MPTP: The overlesioned (Bilateral Asymmetric) non-human primate model
By Emma Sherrell onThis SOP describes the procedures for the combined internal carotid artery (ICA) and systemic (intravenous or intramuscular) administration of MPTP in non-human primates. This model produces an overlesioned or bilateral asymmetric model, induced by unilateral ICA plus systemic administration. This protocol has been adapted from Bankiewicz et al. (1999).
Electrophysiological recording from a chronic chamber-implanted non-human primate
By Emma Sherrell onThis protocol describes the preparation and insertion of extracellular recording electrodes into intracranial targets of a non-human primate implanted with a chronic recording chamber. A piercing guide cannula is used to penetrate the dura and to guide the electrode. Practices related to targeting, electrode cleaning, and electrode movement and settling relative to brain tissue are discussed.
Essential surgeries for the electrophysiological recording from a behaving non-human primate brain 2 (Craniotomy)
By Emma Sherrell onOutlined are the steps to complete a craniotomy in an existing recording chamber placed on a cranial implant. This procedure can be done concurrently with the implant surgery (not recommended), or can take place upon recovery from the implant surgery.
Essential surgeries for the electrophysiological recording from a behaving non-human primate brain 1 (Head fixation post and recording chamber implantation)
By Emma Sherrell onThe performing surgical procedures under strictly sterile conditions is the key to the successful progress of the project.
Maintenance of the recording chamber for non-human primate (Chamber cleaning and dura scraping)
By Emma Sherrell onOnce a craniotomy has been done in the chamber, the inside of the chamber must be cleaned regularly (2-3 times per week) to prevent infection. This protocol explains two procedures to maintain the recording chamber in a healthy condition:(1) chamber cleaning and (2) dura scraping.
Evaluation of a novel method for spectral analysis of neurophysiology data
By Emma Sherrell onThis code implements a novel method for correcting a distortion effect that is present in the power spectra of neuronal spike trains. This method is compared to an alternative, inter-spike interval shuffling procedure that has been conventionally employed for this purpose in the past.
Synchronous measurements of extracellular action potentials and neurochemical activity with carbon fiber electrodes in nonhuman primates
By Emma Sherrell onSynchronous measures of spike and dopamine signals displayed contrasting relations to the behavioral task parameters, as taken from the small set of representative data, suggesting a complex relationship between these two modes of neural signaling.
Neuropathological assessment of the olfactory bulb and tract in individuals with COVID-19
By Emma Sherrell onThe team concluded from their autopsy series that after a fatal course of COVID-19, microscopic changes, when present, in the rostral, intracranial portion of the olfactory circuitry generally reflected neurodegenerative processes seen elsewhere in the brain. In general, inflammation correlated best with the degree of Alzheimer's-linked tauopathy and declined with progression of age in COVID19+ patients.
Persistent hyposmia as surrogate for α-Synuclein-Linked brain pathology
By Emma Sherrell onPreprint: The team identified significant age- and posit that simple-to-administer, quantitative smell tests could serve as inexpensive screening tools in future population studies for the identification of α-synuclein-related brain disorders, including Parkinson's during its premotor phase.