scholarly journals Fluidic microactuation of flexible electrodes for neural recording

2017 ◽  
Author(s):  
Flavia Vitale ◽  
Daniel G. Vercosa ◽  
Alexander V. Rodriguez ◽  
Sushma Sri Pamulapati ◽  
Frederik Seibt ◽  
...  
Keyword(s):  
Action Potentials ◽  
Brain Slices ◽  
Model Organism ◽  
Cell Loss ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Electrode Position ◽  
Flexible Electrodes ◽  
Carbon Nanotube Fiber ◽  
The Brain

Ultra-flexible microelectrodes that can bend and flex with the natural movement of the brain reduce the inflammatory response and improve the stability of long-term neural recordings.1-5However, current methods to implant these highly flexible electrodes rely on temporary stiffening agents that increase the electrode size6-10thus aggravating neural damage during implantation, which leads to cell loss and glial activation that persists even after the stiffening agents are removed or dissolve.11-13A method to deliver thin, ultra-flexible electrodes deep into neural tissue without increasing the stiffness or size of the electrodes will enable minimally invasive electrical recordings from within the brain. Here we show that specially designed microfluidic devices can apply a tension force to ultra-flexible electrodes that prevents buckling without increasing the thickness or stiffness of the electrode during implantation. Additionally, these “fluidic microdrives” allow us to precisely actuate the electrode position with micron-scale accuracy. To demonstrate the efficacy of our fluidic microdrives, we used them to actuate highly flexible carbon nanotube fiber (CNTf) microelectrodes11,14for electrophysiology. We used this approach in three proof-of-concept experiments. First, we recorded compound action potentials in a soft model organism, the small cnidarianHydra. Second, we targeted electrodes precisely to the thalamic reticular nucleus in brain slices and recorded spontaneous and optogenetically-evoked extracellular action potentials. Finally, we inserted electrodes more than 4 mm deep into the brain of rats and detected spontaneous individual unit activity in both cortical and subcortical regions. Compared to syringe injection, fluidic microdrives do not penetrate the brain and prevent changes in intracranial pressure by diverting fluid away from the injection site during insertion and actuation. Overall, the fluidic microdrive technology provides a robust new method to implant and actuate ultra-flexible neural electrodes.

Asymmetry and modulation of spike timing in electrically coupled neurons

2015 ◽  
Vol 113 (6) ◽  
pp. 1743-1751 ◽  
Author(s):  
Jessica Sevetson ◽  
Julie S. Haas
Keyword(s):  
Critical Role ◽  
Electrical Coupling ◽  
Brain Slices ◽  
Spike Timing ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Electrical Synapses ◽  
Thalamic Relay ◽  
Coupled Networks ◽  
The Brain

Electrical coupling mediates interactions between neurons of the thalamic reticular nucleus (TRN), which play a critical role in regulating thalamocortical and corticothalamic communication by inhibiting thalamic relay cells. Accumulating evidence has shown that asymmetry of electrical synapses is a fundamental and dynamic property, but the effect of asymmetry on coupled networks is unexplored. Recording from patched pairs in rat brain slices, we investigate asymmetry in the subthreshold regime and show that electrical synapses can exert powerful effects on the spike times of coupled neighbors. Electrical synaptic signaling modulates spike timing by 10–20 ms, in an effect that also exhibits asymmetry. Furthermore, we show through modeling that coupling asymmetry expands the set of outputs for pairs of coupled neurons through enhanced regions of synchrony and reversals of spike order. These results highlight the power and specificity of signaling exerted by electrical synapses, which contribute to information flow across the brain.

scholarly journals Significance of the Thalamic Reticular Nucleus GABAergic Neurons in Normal and Pathological Activity of the Brain

2012 ◽  
Vol 02 (04) ◽  
pp. 436-444 ◽  
Author(s):  
Zakaria I. Nanobashvili ◽  
Arkadi G. Surmava ◽  
Irine G. Bilanishvili ◽  
Maia G. Barbaqadze ◽  
Magda D. Mariamidze ◽  
...  
Keyword(s):  
Gabaergic Neurons ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
The Brain

Anatomic, Intrinsic, and Synaptic Properties of Dorsal and Ventral Division Neurons in Rat Medial Geniculate Body

1999 ◽  
Vol 81 (5) ◽  
pp. 1999-2016 ◽  
Author(s):  
Edward L. Bartlett ◽  
Philip H. Smith
Keyword(s):  
Membrane Potential ◽  
Nmda Receptors ◽  
Brain Slices ◽  
Medial Geniculate Body ◽  
Dendritic Tree ◽  
Dendritic Morphology ◽  
Thalamic Reticular Nucleus ◽  
Membrane Properties ◽  
Reticular Nucleus ◽  
Medial Geniculate

Anatomic, intrinsic, and synaptic properties of dorsal and ventral division neurons in rat medial geniculate body. Presently little is known about what basic synaptic and cellular mechanisms are employed by thalamocortical neurons in the two main divisions of the auditory thalamus to elicit their distinct responses to sound. Using intracellular recording and labeling methods, we characterized anatomic features, membrane properties, and synaptic inputs of thalamocortical neurons in the dorsal (MGD) and ventral (MGV) divisions in brain slices of rat medial geniculate body. Quantitative analysis of dendritic morphology demonstrated that tufted neurons in both divisions had shorter dendrites, smaller dendritic tree areas, more profuse branching, and a greater dendritic polarization compared with stellate neurons, which were only found in MGD. Tufted neuron dendritic polarization was not as strong or consistent as earlier Golgi studies suggested. MGV and MGD cells had similar intrinsic properties except for an increased prevalence of a depolarizing sag potential in MGV neurons. The sag was the only intrinsic property correlated with cell morphology, seen only in tufted neurons in either division. Many MGV and MGD neurons received excitatory and inhibitory inferior colliculus (IC) inputs (designated IN/EX or EX/IN depending on excitation/inhibition sequence). However, a significant number only received excitatory inputs (EX/O) and a few only inhibitory (IN/O). Both MGV and MGD cells displayed similar proportions of response combinations, but suprathreshold EX/O responses only were observed in tufted neurons. Excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) had multiple distinguishable amplitude levels implying convergence. Excitatory inputs activated α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-d-aspartate (NMDA) receptors the relative contributions of which were variable. For IN/EX cells with suprathreshold inputs, first-spike timing was independent of membrane potential unlike that of EX/O cells. Stimulation of corticothalamic (CT) and thalamic reticular nucleus (TRN) axons evoked a GABAA IPSP, EPSP, GABAB IPSP sequence in most neurons with both morphologies in both divisions. TRN IPSPs and CT EPSPs were graded in amplitude, again suggesting convergence. CT inputs activated AMPA and NMDA receptors. The NMDA component of both IC and CT inputs had an unusual voltage dependence with a detectable dl-2-amino-5-phosphonovaleric acid-sensitive component even below −70 mV. First-spike latencies of CT evoked action potentials were sensitive to membrane potential regardless of whether the TRN IPSP was present. Overall, our in vitro data indicate that reported regional differences in the in vivo responses of MGV and MGD cells to auditory stimuli are not well correlated with major differences in intrinsic membrane features or synaptic responses between cell types.

scholarly journals Differential inputs to striatal cholinergic and parvalbumin interneurons imply functional distinctions

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Jason R Klug ◽  
Max D Engelhardt ◽  
Cara N Cadman ◽  
Hao Li ◽  
Jared B Smith ◽  
...  
Keyword(s):  
Pedunculopontine Nucleus ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Cortical Input ◽  
Parvalbumin Interneurons ◽  
Controlling Behavior ◽  
Health And Disease ◽  
Striatal Interneurons ◽  
Striatal Function ◽  
The Brain

Striatal cholinergic (ChAT) and parvalbumin (PV) interneurons exert powerful influences on striatal function in health and disease, yet little is known about the organization of their inputs. Here using rabies tracing, electrophysiology and genetic tools, we compare the whole-brain inputs to these two types of striatal interneurons and dissect their functional connectivity in mice. ChAT interneurons receive a substantial cortical input from associative regions of cortex, such as the orbitofrontal cortex. Amongst subcortical inputs, a previously unknown inhibitory thalamic reticular nucleus input to striatal PV interneurons is identified. Additionally, the external segment of the globus pallidus targets striatal ChAT interneurons, which is sufficient to inhibit tonic ChAT interneuron firing. Finally, we describe a novel excitatory pathway from the pedunculopontine nucleus that innervates ChAT interneurons. These results establish the brain-wide direct inputs of two major types of striatal interneurons and allude to distinct roles in regulating striatal activity and controlling behavior.

scholarly journals Identification of Retinal Ganglion Cell Types and Brain Nuclei expressing the transcription factor Brn3c/Pou4f3 using a Cre recombinase knock-in allele

2020 ◽  
Author(s):  
Nadia Parmhans ◽  
Anne Drury Fuller ◽  
Eileen Nguyen ◽  
Katherine Chuang ◽  
David Swygart ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Ganglion Cell ◽  
Retinal Ganglion Cell ◽  
Visual Information ◽  
Cell Types ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Retinal Ganglion ◽  
Brain Nuclei ◽  
The Brain

AbstractMembers of the POU4F/Brn3 transcription factor family have an established role in the development of retinal ganglion cell types (RGCs), the projection sensory neuron conveying visual information from the mammalian eye to the brain. Our previous work using sparse random recombination of a conditional knock-in reporter allele expressing Alkaline Phosphatase (AP) and intersectional genetics had identified three types of Pou4f3/Brn3c positive (Brn3c+) RGCs. Here, we describe a novel Brn3cCre mouse allele generated by serial Dre to Cre recombination. We use this allele to explore the expression overlap of Brn3c with Brn3a and Brn3b and the dendritic arbor morphologies and visual stimulus properties of Brn3c+ RGC types. Furthermore, we explore Brn3c-expressing brain nuclei. Our analysis reveals a much larger number of Brn3c+ RGCs and more diverse set of RGC types than previously reported. The majority of RGCs having expressed Brn3c during development are still Brn3c positive in the adult, and all of them express Brn3a while only about half express Brn3b. Intersection of Brn3b and Brn3c expression highlights an area of increased RGC density, similar to an area centralis, corresponding to part of the binocular field of view of the mouse. Brn3c+ neurons and projections are present in multiple brain nuclei. Brn3c+ RGC projections can be detected in the Lateral Geniculate Nucleus (LGN), Pretectal Area (PTA) and Superior Colliculus (SC) but also in the thalamic reticular nucleus (TRN), a visual circuit station that was not previously described to receive retinal input. Most Brn3c+ neurons of the brain are confined to the pretectum and the dorsal midbrain. Amongst theses we identify a previously unknown Brn3c+ subdivision of the deep mesencephalic nucleus (DpMe). Thus, our newly generated allele provides novel biological insights into RGC type classification, brain connectivity and midbrain cytoarchitectonic, and opens the avenue for specific characterization and manipulation of these structures.

scholarly journals Synergistic Roles of GABAA Receptors and SK Channels in Regulating Thalamocortical Oscillations

2009 ◽  
Vol 102 (1) ◽  
pp. 203-213 ◽  
Author(s):  
Max Kleiman-Weiner ◽  
Mark P. Beenhakker ◽  
William A. Segal ◽  
John R. Huguenard
Keyword(s):  
Brain Slices ◽  
Absence Epilepsy ◽  
Cellular Level ◽  
Reticular Nucleus ◽  
Sk Channels ◽  
Sk Channel ◽  
Spike Wave Discharges ◽  
Thalamocortical Oscillations ◽  
The Brain

Rhythmic oscillations throughout the cortex are observed during physiological and pathological states of the brain. The thalamus generates sleep spindle oscillations and spike-wave discharges characteristic of absence epilepsy. Much has been learned regarding the mechanisms underlying these oscillations from in vitro brain slice preparations. One widely used model to understand the epileptiform oscillations underlying absence epilepsy involves application of bicuculline methiodide (BMI) to brain slices containing the thalamus. BMI is a well-known GABAA receptor blocker that has previously been discovered to also block small-conductance, calcium-activated potassium (SK) channels. Here we report that the robust epileptiform oscillations observed during BMI application rely synergistically on both GABAA receptor and SK channel antagonism. Neither application of picrotoxin, a selective GABAA receptor antagonist, nor application of apamin, a selective SK channel antagonist, alone yielded the highly synchronized, long-lasting oscillations comparable to those observed during BMI application. However, partial blockade of SK channels by subnanomolar concentrations of apamin combined with picrotoxin sufficiently replicated BMI oscillations. We found that, at the cellular level, apamin enhanced the intrinsic excitability of reticular nucleus (RT) neurons but had no effect on relay neurons. This work suggests that regulation of RT excitability by SK channels can influence the excitability of thalamocortical networks and may illuminate possible pharmacological treatments for absence epilepsy. Finally, our results suggest that changes in the intrinsic properties of individual neurons and changes at the circuit level can robustly modulate these oscillations.

scholarly journals Microglia modulate stable wakefulness via the thalamic reticular nucleus in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hanxiao Liu ◽  
Xinxing Wang ◽  
Lu Chen ◽  
Liang Chen ◽  
Stella E. Tsirka ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Eye Movement ◽  
Nrem Sleep ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Rapid Eye Movement ◽  
Metabolomic Analysis ◽  
The Brain ◽  
Ceramide Production ◽  
Brain Homeostasis

AbstractMicroglia are important for brain homeostasis and immunity, but their role in regulating vigilance remains unclear. We employed genetic, physiological, and metabolomic methods to examine microglial involvement in the regulation of wakefulness and sleep. Microglial depletion decreased stable nighttime wakefulness in mice by increasing transitions between wakefulness and non-rapid eye movement (NREM) sleep. Metabolomic analysis revealed that the sleep-wake behavior closely correlated with diurnal variation of the brain ceramide, which disappeared in microglia-depleted mice. Ceramide preferentially influenced microglia in the thalamic reticular nucleus (TRN), and local depletion of TRN microglia produced similar impaired wakefulness. Chemogenetic manipulations of anterior TRN neurons showed that they regulated transitions between wakefulness and NREM sleep. Their firing capacity was suppressed by both microglial depletion and added ceramide. In microglia-depleted mice, activating anterior TRN neurons or inhibiting ceramide production both restored stable wakefulness. These findings demonstrate that microglia can modulate stable wakefulness through anterior TRN neurons via ceramide signaling.

scholarly journals L-type calcium channel-dependent inhibitory plasticity in the thalamus

2014 ◽  
Vol 112 (9) ◽  
pp. 2037-2039 ◽  
Author(s):  
Sarah R. Hulme ◽  
William M. Connelly
Keyword(s):  
Ion Channels ◽  
Action Potentials ◽  
Dendritic Tree ◽  
Calcium Transients ◽  
Inhibitory Neurons ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Inhibitory Input ◽  
Inhibitory Plasticity ◽  
Channel Dependent

Thalamocortical neurons integrate sensory and cortical activity and are regulated by input from inhibitory neurons in the thalamic reticular nucleus. Evidence suggests that during bursts of action potentials, dendritic calcium transients are seen throughout the dendritic tree of thalamocortical cells. Here, we review a recent study that suggests these calcium transients regulate inhibitory input, and we attempt to reconcile studies that differ on which ion channels are the source of the calcium.

scholarly journals GABAergic Synaptic Transmission Triggers Action Potentials in Thalamic Reticular Nucleus Neurons

2012 ◽  
Vol 32 (23) ◽  
pp. 7782-7790 ◽  
Author(s):  
Y.-G. Sun ◽  
C.-S. Wu ◽  
J. J. Renger ◽  
V. N. Uebele ◽  
H.-C. Lu ◽  
...  
Keyword(s):  
Synaptic Transmission ◽  
Action Potentials ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Gabaergic Synaptic Transmission
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