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Wen C, Horiuchi TK. The Curved Openspace Algorithm and a Spike-Latency Model for Sonar-Based Obstacle Avoidance. Front Neurorobot 2022; 16:850013. [PMID: 35721278 PMCID: PMC9198458 DOI: 10.3389/fnbot.2022.850013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/04/2022] [Indexed: 11/13/2022] Open
Abstract
The rapid control of a sonar-guided vehicle to pursue a goal while avoiding obstacles has been a persistent research topic for decades. Taking into account the limited field-of-view of practical sonar systems and vehicle kinematics, we propose a neural model for obstacle avoidance that maps the 2-D sensory space into a 1-D motor space and evaluates motor actions while combining obstacles and goal information. A two-stage winner-take-all (WTA) mechanism is used to select the final steering action. To avoid excessive scanning of the environment, an attentional system is proposed to control the directions of sonar pings for efficient, task-driven, sensory data collection. A mobile robot was used to test the proposed model navigating through a cluttered environment using a narrow field-of-view sonar system. We further propose a spiking neural model using spike-timing representations, a spike-latency memory, and a “race-to-first-spike” WTA circuit.
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Affiliation(s)
- Chenxi Wen
- Department of Electrical and Computer Engineering, University of Maryland, College Park, MD, United States
| | - Timothy K. Horiuchi
- Department of Electrical and Computer Engineering, University of Maryland, College Park, MD, United States
- Neuroscience and Cognitive Sciences Program, University of Maryland, College Park, MD, United States
- *Correspondence: Timothy K. Horiuchi
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Anderson MJ, Sullivan JG, Horiuchi TK, Fuller SB, Daniel TL. A bio-hybrid odor-guided autonomous palm-sized air vehicle. Bioinspir Biomim 2020; 16:026002. [PMID: 33002883 DOI: 10.1088/1748-3190/abbd81] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/01/2020] [Indexed: 06/11/2023]
Abstract
Biohybrid systems integrate living materials with synthetic devices, exploiting their respective advantages to solve challenging engineering problems. One challenge of critical importance to society is detecting and localizing airborne volatile chemicals. Many flying animals depend their ability to detect and locate the source of aerial chemical plumes for finding mates and food sources. A robot with comparable capability could reduce human hazard and drastically improve performance on tasks such as locating disaster survivors, hazardous gas leaks, incipient fires, or explosives. Three advances are needed before they can rival their biological counterparts: (1) a chemical sensor with a much faster response time that nevertheless satisfies the size, weight, and power constraints of flight, (2) a design, sensor suite, and control system that allows it to move toward the source of a plume fully autonomously while navigating obstacles, and (3) the ability to detect the plume with high specificity and sensitivity among the assortment of chemicals that invariably exist in the air. Here we address the first two, introducing a human-safe palm-sized air vehicle equipped with the odor-sensing antenna of an insect, the first odor-sensing biohybrid robot system to fly. Using this sensor along with a suite of additional navigational sensors, as well as passive wind fins, our robot orients upwind and navigates autonomously toward the source of airborne plumes. Our robot is the first flying biohybrid system to successfully perform odor localization in a confined space, and it is able to do so while detecting and avoiding obstacles in its flight path. We show that insect antennae respond more quickly than metal oxide gas sensors, enabling odor localization at an improved speed over previous flying robots. By using the insect antennae, we anticipate a feasible path toward improved chemical specificity and sensitivity by leveraging recent advances in gene editing.
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Affiliation(s)
- Melanie J Anderson
- University of Washington, Department of Mechanical Engineering, Seattle WA-98195, United States of America
| | - Joseph G Sullivan
- University of Washington, Department of Electrical and Computer Engineering, Seattle WA-98195, United States of America
| | - Timothy K Horiuchi
- University of Maryland, Department of Electrical and Computer Engineering, College Park MD-20742, United States of America
| | - Sawyer B Fuller
- University of Washington, Department of Mechanical Engineering, Seattle WA-98195, United States of America
- University of Washington, Paul G. Allen School of Computer Science, Seattle WA-98195, United States of America
| | - Thomas L Daniel
- University of Washington, Department of Mechanical Engineering, Seattle WA-98195, United States of America
- University of Washington, Department of Biology, Seattle WA-98195, United States of America
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Isbell JD, Horiuchi TK. Echo View Cells From Bio-Inspired Sonar. Front Neurorobot 2020; 14:567991. [PMID: 33250733 PMCID: PMC7674830 DOI: 10.3389/fnbot.2020.567991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 10/08/2020] [Indexed: 11/19/2022] Open
Abstract
Place recognition is naturally informed by the mosaic of sensations we remember from previously visiting a location and general knowledge of our location in the world. Neurons in the mammalian brain (specifically in the hippocampus formation) named “place cells” are thought to reflect this recognition of place and are involved in implementing a spatial map that can be used for path planning and memory recall. In this research, we use bat-inspired sonar to mimic how bats might sense objects in the environment and recognize the views associated with different places. These “echo view cells” may contribute (along with odometry) to the creation of place cell representations observed in bats. Although detailed sensory template matching is straightforward, it is quite unlikely that a flying animal or robot will return to the exact 3-D position and pose where the original memory was captured. Instead, we strive to recognize views over extended regions that are many body lengths in size, reducing the number of places to be remembered for a map. We have successfully demonstrated some of this spatial invariance by training feed-forward neural networks (traditional neural networks and spiking neural networks) to recognize 66 distinct places in a laboratory environment over a limited range of translations and rotations. We further show how the echo view cells respond between known views and how their outputs can be combined over time for continuity.
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Affiliation(s)
- Jacob D Isbell
- Department of Electrical and Computer Engineering, University of Maryland, College Park, MD, United States
| | - Timothy K Horiuchi
- Department of Electrical and Computer Engineering, University of Maryland, College Park, MD, United States.,Institute for Systems Research, University of Maryland, College Park, MD, United States.,Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD, United States
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Isbell J, Horiuchi TK. Managing Clutter in a High Pulse Rate Echolocation System. Front Neurosci 2018; 12:177. [PMID: 29618968 PMCID: PMC5871687 DOI: 10.3389/fnins.2018.00177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/05/2018] [Indexed: 11/29/2022] Open
Abstract
The use of echolocation for navigating in dense, cluttered environments is a challenge due to the need for rapid sampling of nearby objects in the face of delayed echoes from distant objects. In the wild, echolocating bats frequently encounter this situation when leaving the roost or while hunting. If long-delay echoes from a distant object are received after the next pulse is sent out, these “aliased” echoes appear as close-range phantom objects. Little is known about how bats cope with these situations. In this work, we demonstrate a novel strategy to manage aliasing in cases where a single target is actively being tracked at close range. This paper presents three reactive strategies for a high pulse-rate sonar system to combat aliased echoes: (1) changing the interpulse interval to move the aliased echoes away in time from the tracked target, (2) changing positions to create a geometry without aliasing, and (3) a phase-based, transmission beam-shaping strategy to illuminate the target and not the aliasing object.
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Affiliation(s)
- Jacob Isbell
- Electrical and Computer Engineering Department, University of Maryland, College Park, College Park, MD, United States
| | - Timothy K Horiuchi
- Electrical and Computer Engineering Department, University of Maryland, College Park, College Park, MD, United States.,Institute for Systems Research, University of Maryland, College Park, College Park, MD, United States.,Neuroscience and Cognitive Science Department, University of Maryland, College Park, College Park, MD, United States
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Abstract
It is well documented that place cells and grid cells in echolocating bats show properties similar to those described in rodents, and yet, continuous theta-frequency oscillations, proposed to play a central role in grid/place cell formation, are not present in bat recordings. These comparative neurophysiological data have raised many questions about the role of theta-frequency oscillations in spatial memory and navigation. Additionally, spatial navigation in three-dimensions poses new challenges for the representation of space in neural models. Inspired by the literature on space representation in the echolocating bat, we have developed a nonoscillatory model of 3-D grid cell creation that shares many of the features of existing oscillatory-interference models. We discuss the model in the context of current knowledge of 3-D space representation and highlight directions for future research.
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Affiliation(s)
- Timothy K Horiuchi
- Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland
| | - Cynthia F Moss
- Department of Psychology, Institute for Systems Research, University of Maryland, College Park, Maryland
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Affiliation(s)
- Giacomo Indiveri
- Institute of Neuroinformatics, University of Zurich and ETH Zurich Zurich, Switzerland
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MacLeod KM, Horiuchi TK. A rapid form of activity-dependent recovery from short-term synaptic depression in the intensity pathway of the auditory brainstem. Biol Cybern 2011; 104:209-223. [PMID: 21409439 PMCID: PMC3257163 DOI: 10.1007/s00422-011-0428-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Accepted: 02/20/2011] [Indexed: 05/30/2023]
Abstract
Short-term synaptic plasticity acts as a time- and firing rate-dependent filter that mediates the transmission of information across synapses. In the avian auditory brainstem, specific forms of plasticity are expressed at different terminals of the same auditory nerve fibers and contribute to the divergence of acoustic timing and intensity information. To identify key differences in the plasticity properties, we made patch-clamp recordings from neurons in the cochlear nucleus responsible for intensity coding, nucleus angularis, and measured the time course of the recovery of excitatory postsynaptic currents following short-term synaptic depression. These synaptic responses showed a very rapid recovery, following a bi-exponential time course with a fast time constant of approximately 40 ms and a dependence on the presynaptic activity levels, resulting in a crossing over of the recovery trajectories following high-rate versus low-rate stimulation trains. We also show that the recorded recovery in the intensity pathway differs from similar recordings in the timing pathway, specifically the cochlear nucleus magnocellularis, in two ways: (1) a fast recovery that was not due to recovery from postsynaptic receptor desensitization and (2) a recovery trajectory that was characterized by a non-monotonic bump that may be due in part to facilitation mechanisms more prevalent in the intensity pathway. We tested whether a previously proposed model of synaptic transmission based on vesicle depletion and sequential steps of vesicle replenishment could account for the recovery responses, and found it was insufficient, suggesting an activity-dependent feedback mechanism is present. We propose that the rapid recovery following depression allows improved coding of natural auditory signals that often consist of sound bursts separated by short gaps.
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Affiliation(s)
- Katrina M MacLeod
- Department of Biology, University of Maryland, College Park, MD 20742, USA.
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Abstract
The sonar beam of an echolocating bat forms a spatial window restricting the echo information returned from the environment. Investigating the shape and orientation of the sonar beam produced by a bat as it flies and performs various behavioral tasks may yield insight into the operation of its sonar system. This paper presents recordings of vertical and horizontal cross sections of the sonar beam produced by Eptesicus fuscus (big brown bats) as they fly and pursue prey in a laboratory flight room. In the horizontal plane the sonar beam consists of one large lobe and in the vertical plane the beam consists of two lobes of comparable size oriented frontally and ventrally. In level flight, the bat directs its beam such that the ventral lobe is pointed forward and down toward the ground ahead of its flight path. The bat may utilize the downward directed lobe to measure altitude without the need for vertical head movements.
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Affiliation(s)
- Kaushik Ghose
- Neuroscience and Cognitive Science Program, Institute for Systems Research, Dept. of Psychology, University of Maryland, College Park, Maryland 20742, USA
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MacLeod KM, Horiuchi TK, Carr CE. A role for short-term synaptic facilitation and depression in the processing of intensity information in the auditory brain stem. J Neurophysiol 2007; 97:2863-74. [PMID: 17251365 PMCID: PMC3268177 DOI: 10.1152/jn.01030.2006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The nature of the synaptic connection from the auditory nerve onto the cochlear nucleus neurons has a profound impact on how sound information is transmitted. Short-term synaptic plasticity, by dynamically modulating synaptic strength, filters information contained in the firing patterns. In the sound-localization circuits of the brain stem, the synapses of the timing pathway are characterized by strong short-term depression. We investigated the short-term synaptic plasticity of the inputs to the bird's cochlear nucleus angularis (NA), which encodes intensity information, by using chick embryonic brain slices and trains of electrical stimulation. These excitatory inputs expressed a mixture of short-term facilitation and depression, unlike those in the timing nuclei that only depressed. Facilitation and depression at NA synapses were balanced such that postsynaptic response amplitude was often maintained throughout the train at high firing rates (>100 Hz). The steady-state input rate relationship of the balanced synapses linearly conveyed rate information and therefore transmits intensity information encoded as a rate code in the nerve. A quantitative model of synaptic transmission could account for the plasticity by including facilitation of release (with a time constant of approximately 40 ms), and a two-step recovery from depression (with one slow time constant of approximately 8 s, and one fast time constant of approximately 20 ms). A simulation using the model fit to NA synapses and auditory nerve spike trains from recordings in vivo confirmed that these synapses can convey intensity information contained in natural train inputs.
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Affiliation(s)
- K M MacLeod
- Dept. of Biology, University of Maryland, College Park, MD 20742, USA.
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Abstract
Acquisition of food in many animal species depends on the pursuit and capture of moving prey. Among modern humans, the pursuit and interception of moving targets plays a central role in a variety of sports, such as tennis, football, Frisbee, and baseball. Studies of target pursuit in animals, ranging from dragonflies to fish and dogs to humans, have suggested that they all use a
constant bearing (CB) strategy to pursue prey or other moving targets. CB is best known as the interception strategy employed by baseball outfielders to catch ballistic fly balls. CB is a time-optimal solution to catch targets moving along a straight line, or in a predictable fashion—such as a ballistic baseball, or a piece of food sinking in water. Many animals, however, have to capture prey that may make evasive and unpredictable maneuvers. Is CB an optimum solution to pursuing erratically moving targets? Do animals faced with such erratic prey also use CB? In this paper, we address these questions by studying prey capture in an insectivorous echolocating bat. Echolocating bats rely on sonar to pursue and capture flying insects. The bat's prey may emerge from foliage for a brief time, fly in erratic three-dimensional paths before returning to cover. Bats typically take less than one second to detect, localize and capture such insects. We used high speed stereo infra-red videography to study the three dimensional flight paths of the big brown bat,
Eptesicus fuscus, as it chased erratically moving insects in a dark laboratory flight room. We quantified the bat's complex pursuit trajectories using a simple delay differential equation. Our analysis of the pursuit trajectories suggests that bats use a
constant absolute target direction strategy during pursuit. We show mathematically that, unlike CB, this approach minimizes the time it takes for a pursuer to intercept an unpredictably moving target. Interestingly, the bat's behavior is similar to the interception strategy implemented in some guided missiles. We suggest that the time-optimal strategy adopted by the bat is in response to the evolutionary pressures of having to capture erratic and fast moving insects.
Analysis of the three dimensional flight paths of the big brown bat reveals a similar strategy to intercept targets as used by some guided missiles.
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Affiliation(s)
- Kaushik Ghose
- Neuroscience and Cognitive Science Program, University of Maryland, College Park, Maryland, USA.
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Abstract
One way to understand a neurobiological system is by building a simulacrum that replicates its behavior in real time using similar constraints. Analog very large-scale integrated (VLSI) electronic circuit technology provides such an enabling technology. We here describe a neuromorphic system that is part of a long-term effort to understand the primate oculomotor system. It requires both fast sensory processing and fast motor control to interact with the world. A one-dimensional hardware model of the primate eye has been built that simulates the physical dynamics of the biological system. It is driven by two different analog VLSI chips, one mimicking cortical visual processing for target selection and tracking and another modeling brain stem circuits that drive the eye muscles. Our oculomotor plant demonstrates both smooth pursuit movements, driven by a retinal velocity error signal, and saccadic eye movements, controlled by retinal position error, and can reproduce several behavioral, stimulation, lesion, and adaptation experiments performed on primates.
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Affiliation(s)
- T K Horiuchi
- Krieger Mind / Brain Institute, 338 Krieger Hall, Johns Hopkins University, 3400 North Charles Street, Baltimore MD 21218, USA.
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Herzog TJ, Horiuchi TK, Williams S, Camel HM, Mutch DG. Growth modulatory effects of granulocyte-macrophage colony-stimulating factor on human cell lines derived from gynecologic malignancies. Am J Obstet Gynecol 1996; 174:161-8. [PMID: 8572001 DOI: 10.1016/s0002-9378(96)70389-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE In spite of increased expression of granulocyte-macrophage colony-stimulating factor surface receptors on solid tumors, the growth modulatory effects of granulocyte-macrophage colony-stimulating factor have not been well defined in gynecologic malignancies. We assessed the in vitro growth effects of granulocyte-macrophage colony-stimulating factor on such cell lines. STUDY DESIGN By use of a chromium 51 incorporation assay the in vitro growth effects of granulocyte-macrophage colony-stimulating factor on 12 cell lines derived from human malignancies were measured. RESULTS No growth stimulatory or inhibitory effect was mediated by granulocyte-macrophage colony-stimulating factor on six cell lines, whereas three lines showed consistent but not statistically significant dose-dependent growth stimulation. There was, however, a statistically significant increase in growth of short duration in three other cell lines at clinically relevant doses of granulocyte-macrophage colony-stimulating factor. Fluorometric cell cycle analysis demonstrated no change in cell-cycle distribution. CONCLUSION Within this in vitro system, stimulation of gynecologic malignancies in patients receiving granulocyte-macrophage colony-stimulating factor for mitigation of the myelosuppressive effects of cytotoxic chemotherapy does not appear to be widespread nor sustained beyond 48 hours.
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Affiliation(s)
- T J Herzog
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, MO 63110, USA
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