scholarly journals Population imaging of neural activity in awake behaving mice in multiple brain regions

2019 ◽  
Author(s):  
Kiryl D. Piatkevich ◽  
Seth Bensussen ◽  
Hua-an Tseng ◽  
Sanaya N. Shroff ◽  
Violeta Gisselle Lopez-Huerta ◽  
...  
Keyword(s):  
Neural Activity ◽  
Hippocampal Neurons ◽  
High Performance ◽  
Response Times ◽  
Signal To Noise Ratio ◽  
Population Analysis ◽  
Brain Regions ◽  
Striatal Neurons ◽  
Temporal Precision ◽  
Highly Correlated

AbstractA longstanding goal in neuroscience has been to image membrane voltage, with high temporal precision and sensitivity, in awake behaving mammals. Here, we report a genetically encoded voltage indicator, SomArchon, which exhibits millisecond response times and compatibility with optogenetic control, and which increases the sensitivity, signal-to-noise ratio, and number of neurons observable, by manyfold over previous reagents. SomArchon only requires conventional one-photon microscopy to achieve these high performance characteristics. These improvements enable population analysis of neural activity, both at the subthreshold and spiking levels, in multiple brain regions – cortex, hippocampus, and striatum – of awake behaving mice. Using SomArchon, we detect both positive and negative responses of striatal neurons during movement, highlighting the power of voltage imaging to reveal bidirectional modulation. We also examine how the intracellular subthreshold theta oscillations of hippocampal neurons govern spike output, finding that nearby cells can exhibit highly correlated subthreshold activities, even as they generate highly divergent spiking patterns.

scholarly journals Perception and propagation of activity through the cortical hierarchy is determined by neural variability

2021 ◽  
Author(s):  
James M Rowland ◽  
Thijs L van der Plas ◽  
Matthias Loidolt ◽  
Robert Michael Lees ◽  
Joshua Keeling ◽  
...  
Keyword(s):  
Neural Activity ◽  
Signal To Noise Ratio ◽  
Brain Regions ◽  
Cortical Function ◽  
Population Activity ◽  
Two Photon ◽  
Secondary Somatosensory Cortex ◽  
Cortical Hierarchy ◽  
Robust Transmission ◽  
Neural Variability

The brains of higher organisms are composed of anatomically and functionally distinct regions performing specialised tasks; but regions do not operate in isolation. Orchestration of complex behaviours requires communication between brain regions, but how neural activity dynamics are organised to facilitate reliable transmission is not well understood. We studied this process directly by generating neural activity that propagates between brain regions and drives behaviour, allowing us to assess how populations of neurons in sensory cortex cooperate to transmit information. We achieved this by imaging two hierarchically organised and densely interconnected regions, the primary and secondary somatosensory cortex (S1 and S2) in mice while performing two-photon photostimulation of S1 neurons and assigning behavioural salience to the photostimulation. We found that the probability of perception is determined not only by the strength of the photostimulation signal, but also by the variability of S1 neural activity. Therefore, maximising the signal-to-noise ratio of the stimulus representation in cortex is critical to its continued propagation downstream. Further, we show that propagated, behaviourally salient activity elicits balanced, persistent, and generalised activation of the downstream region. Hence, our work adds to existing understanding of cortical function by identifying how population activity is formatted to ensure robust transmission of information, allowing specialised brain regions to communicate and coordinate behaviour.

scholarly journals Neural basis of functional ultrasound signals

2021 ◽  
Author(s):  
Anwar O. Nunez-Elizalde ◽  
Michael Krumin ◽  
Charu Bai Reddy ◽  
Gabriel Montaldo ◽  
Alan Urban ◽  
...  
Keyword(s):  
Firing Rate ◽  
Neural Activity ◽  
Brain Regions ◽  
Neuronal Firing ◽  
Linear Filter ◽  
Neural Firing ◽  
Hemodynamic Response Function ◽  
Neural Basis ◽  
Neural Recordings ◽  
Highly Correlated

SummaryFunctional ultrasound imaging (fUSI) is a popular method for studying brain function, but it remains unclear to what degree its signals reflect neural activity on a trial-by-trial basis. Here, we answer this question with simultaneous fUSI and neural recordings with Neuropixels probes in awake mice. fUSI signals strongly correlated with the slow (<0.3 Hz) fluctuations in firing rate measured in the same location and were closely predicted by convolving the firing rate with a 2.9 s wide linear filter. This filter matched the hemodynamic response function of awake mouse and was invariant across mice, stimulus conditions, and brain regions. fUSI signals matched neural firing also spatially: recordings with two probes revealed that firing rates were as highly correlated across hemispheres as fUSI signals. We conclude that fUSI signals bear a simple linear relationship to neuronal firing and accurately reflect neural activity both in time and in space.

scholarly journals Concussion-related Alterations in Neural Activity During Emotion Recognition: Case Studies of Short-term and Residual Effects

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Joshua Ricker ◽  
Kylee Smith ◽  
Aexandra Schmidt ◽  
Andrea Cripps ◽  
Palguna Thalla ◽  
...  
Keyword(s):  
Case Studies ◽  
Neural Activity ◽  
Response Times ◽  
Recognition Task ◽  
Collegiate Athletes ◽  
Occipital Lobe ◽  
Brain Regions ◽  
Residual Effects ◽  
Clear Understanding ◽  
Neural Activation

Concussions have recently become an area of concern among the general public, but a clear understanding of their total consequence is still being developed. Symptoms of concussions are wide-ranging, encapsulating a plethora of cognitive and emotional abilities that could be affected. Concussions transiently disrupt neural activation as well as behavioral responses across multiple categories. Skills pertaining to various aspects of emotions are often affected yet have rarely been studied after concussions. We present two case studies of collegiate athletes with a history of multiple concussions. This paper highlights the case of a collegiate athlete who had obtained two previous concussions with the most recent being sustained sixteen days prior to neuroimaging. A second athlete with two lifetime concussions was tested one year after the most recent injury. The current study utilized a novel emotional recognition task to assess the behavioral and neural effects of this injury. A group of five controls responded with high accuracy rates and quick response times to the task. They showed activation in regions of the frontal lobe as well as facial recognition areas of the occipital lobe. The 16-day case subject was impaired in recognizing emotions relative to controls and showed little to no overlap in brain activity for regions involved in emotional face processing. The athlete with a longer post-concussion period also showed residual effects of neural activity alteration when compared to controls with few overlapping active regions. Specific brain regions were activated in this group but not in controls including the sensorimotor cortex, supramarginal gyrus, and lateral occipital cortex. By taking a more individual approach in examination of neural activity post-concussion, we may be able to gain a better understanding of this heterogeneous injury.

Structure and behavior of white pelican formation flocks

1982 ◽  
Vol 60 (6) ◽  
pp. 1388-1396 ◽  
Author(s):  
J. Brian E. O'Malley ◽  
Roger M. Evans
Keyword(s):  
Response Times ◽  
Formation Flight ◽  
Flock Size ◽  
Wingbeat Frequency ◽  
Percent Time ◽  
Column Formation ◽  
Highly Correlated ◽  
And Behavior

Observations of white pelicans commuting between nesting colonies and foraging areas revealed transitions from small, simple linear flock formations to larger, more complex vee and jay formations during departures, and the reverse during the return approach. Large, less-organized types of formations were relatively uncommon and short lived.Formation angles measured for filmed flocks ranged from 24° to 122° and were highly correlated with mean relative interbird distances within flocks. The number of wingbeats per hour, calculated from wingbeat frequency (beats per minute) and percent time flapping, was lowest in vee formation, progressively greater in jay, echelon, and column formation, and greatest for single birds. Wingbeats per hour decreased behind the lead bird, which usually had the highest rate, within each type of formation.Shifts between flapping and gliding were usually initiated by lead birds. Response times for these shifts were negatively related to flock size, and were shorter in vee and jay formations than in column and echelon formations.Our data suggests formation flight provides both aerodynamic–energetic and communication advantages over solitary flight.

scholarly journals Neural substrates of propranolol-induced impairments in the reconsolidation of nicotine-associated memories in smokers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiao Lin ◽  
Jiahui Deng ◽  
Kai Yuan ◽  
Qiandong Wang ◽  
Lin Liu ◽  
...  
Keyword(s):  
Neural Activity ◽  
Neural Substrates ◽  
Brain Regions ◽  
Reward Processing ◽  
Memory Reconsolidation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Postcentral Gyrus ◽  
Propranolol Group ◽  
Propranolol Administration

AbstractThe majority of smokers relapse even after successfully quitting because of the craving to smoking after unexpectedly re-exposed to smoking-related cues. This conditioned craving is mediated by reward memories that are frequently experienced and stubbornly resistant to treatment. Reconsolidation theory posits that well-consolidated memories are destabilized after retrieval, and this process renders memories labile and vulnerable to amnestic intervention. This study tests the retrieval reconsolidation procedure to decrease nicotine craving among people who smoke. In this study, 52 male smokers received a single dose of propranolol (n = 27) or placebo (n = 25) before the reactivation of nicotine-associated memories to impair the reconsolidation process. Craving for smoking and neural activity in response to smoking-related cues served as primary outcomes. Functional magnetic resonance imaging was performed during the memory reconsolidation process. The disruption of reconsolidation by propranolol decreased craving for smoking. Reactivity of the postcentral gyrus in response to smoking-related cues also decreased in the propranolol group after the reconsolidation manipulation. Functional connectivity between the hippocampus and striatum was higher during memory reconsolidation in the propranolol group. Furthermore, the increase in coupling between the hippocampus and striatum positively correlated with the decrease in craving after the reconsolidation manipulation in the propranolol group. Propranolol administration before memory reactivation disrupted the reconsolidation of smoking-related memories in smokers by mediating brain regions that are involved in memory and reward processing. These findings demonstrate the noradrenergic regulation of memory reconsolidation in humans and suggest that adjunct propranolol administration can facilitate the treatment of nicotine dependence. The present study was pre-registered at ClinicalTrials.gov (registration no. ChiCTR1900024412).

A High-Performance Signal Processing System for Monopulse Tracking Radar

2011 ◽  
Vol 383-390 ◽  
pp. 471-475
Author(s):  
Yong Bin Hong ◽  
Cheng Fa Xu ◽  
Mei Guo Gao ◽  
Li Zhi Zhao
Keyword(s):  
Signal Processing ◽  
High Performance ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Processing System ◽  
Digital Signal ◽  
Radar Signal ◽  
Signal Processing System ◽  
Parallel Pipelined ◽  
Tracking Radar

A radar signal processing system characterizing high instantaneous dynamic range and low system latency is designed based on a specifically developed signal processing platform. Instantaneous dynamic range loss is a critical problem when digital signal processing is performed on fixed-point FPGAs. In this paper, the problem is well resolved by increasing the wordlength according to signal-to-noise ratio (SNR) gain of the algorithms through the data path. The distinctive software structure featuring parallel pipelined processing and “data flow drive” reduces the system latency to one coherent processing interval (CPI), which significantly improves the maximum tracking angular velocity of the monopulse tracking radar. Additionally, some important electronic counter-countermeasures (ECCM) are incorporated into this signal processing system.

scholarly journals High-speed high-resolution laser diode-based photoacoustic microscopy for in vivo microvasculature imaging

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiufeng Li ◽  
Victor T C Tsang ◽  
Lei Kang ◽  
Yan Zhang ◽  
Terence T W Wong
Keyword(s):  
High Resolution ◽  
High Speed ◽  
High Performance ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Cost Effective ◽  
High Signal ◽  
Photoacoustic Microscopy ◽  
Mouse Ear

AbstractLaser diodes (LDs) have been considered as cost-effective and compact excitation sources to overcome the requirement of costly and bulky pulsed laser sources that are commonly used in photoacoustic microscopy (PAM). However, the spatial resolution and/or imaging speed of previously reported LD-based PAM systems have not been optimized simultaneously. In this paper, we developed a high-speed and high-resolution LD-based PAM system using a continuous wave LD, operating at a pulsed mode, with a repetition rate of 30 kHz, as an excitation source. A hybrid scanning mechanism that synchronizes a one-dimensional galvanometer mirror and a two-dimensional motorized stage is applied to achieve a fast imaging capability without signal averaging due to the high signal-to-noise ratio. By optimizing the optical system, a high lateral resolution of 4.8 μm has been achieved. In vivo microvasculature imaging of a mouse ear has been demonstrated to show the high performance of our LD-based PAM system.

Nicotinamide adenine dinucleotide is released from sympathetic nerve terminals via a botulinum neurotoxin A-mediated mechanism in canine mesenteric artery

2006 ◽  
Vol 290 (5) ◽  
pp. H1818-H1825 ◽  
Author(s):  
Lisa M. Smyth ◽  
Leanne T. Breen ◽  
Violeta N. Mutafova-Yambolieva
Keyword(s):  
Neural Activity ◽  
Nicotinamide Adenine Dinucleotide ◽  
High Performance ◽  
Botulinum Neurotoxin ◽  
Mesenteric Arteries ◽  
Nicotinamide Adenine ◽  
System Control ◽  
Nerve Terminals ◽  
Botulinum Neurotoxin A ◽  
Different Populations

Using high-performance liquid chromatography techniques with fluorescence and electrochemical detection, we found that β-nicotinamide adenine dinucleotide (β-NAD) is released in response to electrical field stimulation (4–16 Hz, 0.3 ms, 15 V, 120 s) along with ATP and norepinephrine (NE) in the canine isolated mesenteric arteries. The release of β-NAD increases with number of pulses/stimulation frequencies. Immunohistochemistry analysis showed dense distribution of tyrosine hydroxylase-like immunoreactivity (TH-LI) and sparse distribution of TH-LI-negative nerve processes, suggesting that these blood vessels are primarily under sympathetic nervous system control with some contribution of other (e.g., sensory) neurons. Exogenous NE (3 μmol/l), α,β-methylene ATP (1 μmol/l), neuropeptide Y (NPY, 0.1 μmol/l), CGRP (0.1 μmol/l), vasoactive intestinal peptide (VIP, 0.1 μmol/l), and substance P (SP, 0.1 μmol/l) had no effect on the basal release of β-NAD, suggesting that the overflow of β-NAD is evoked by neither the sympathetic neurotransmitters NE, ATP, and NPY, nor the neuropeptides CGRP, VIP, and SP. Botulinum neurotoxin A (BoNTA, 0.1 μmol/l) abolished the evoked release of NE, ATP, and β-NAD at 4 Hz, suggesting that at low levels of neural activity, release of these neurotransmitters results from N-ethylmaleimide-sensitive factor attachment protein receptor/synaptosomal-associated protein of 25 kDa-mediated exocytosis. At 16 Hz, however, the evoked release of NE, ATP, and β-NAD was reduced by BoNTA by ∼90, 60, and 80%, respectively, suggesting that at higher levels of neural activity, β-NAD is likely to be released from different populations of synaptic vesicles or different populations of nerve terminals (i.e., sympathetic and sensory terminals).

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