Spinal Circuit for Escape in Goldfish and Zebrafish

2017 ◽  
pp. 517-520
Author(s):  
Joseph R. Fetcho
Keyword(s):  
Spinal Cord ◽  
Escape Behavior ◽  
The Body ◽  
M Cells ◽  
M Cell ◽  
Potential Threat ◽  
Reticulospinal Neurons ◽  
Bilateral Pair ◽  
The Brain ◽  
Spinal Circuit

Escape or startle responses are vital to organisms. In fishes, escape behavior is a rapid bend of the body and tail away from a potential threat that occurs within milliseconds after a stimulus. When properly executed, it is a fast, powerful body bend to only one side that takes precedence over any other movements. The behavior is initiated by the firing of one of a bilateral pair of hindbrain reticulospinal neurons (RSNs) called Mauthner cells (M-cells). The output of each cell occurs via an axon that crosses in the brain and extends the length of the spinal cord on the opposite side of the body. The circuit of the M-cell in spinal cord is based upon studies of goldfish and zebrafish. This circuit, repeated along the spinal cord, has several features that are well matched to the behavioral demands of escape movements.

Nondestructive imaging of the internal microstructure of vessels and nerve fibers in rat spinal cord using phase-contrast synchrotron radiation microtomography

2017 ◽  
Vol 24 (2) ◽  
pp. 482-489 ◽  
Author(s):  
Jianzhong Hu ◽  
Ping Li ◽  
Xianzhen Yin ◽  
Tianding Wu ◽  
Yong Cao ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Synchrotron Radiation ◽  
Phase Contrast ◽  
Three Dimensional ◽  
Nerve Fibers ◽  
The Body ◽  
Rat Spinal Cord ◽  
Nondestructive Imaging ◽  
Synchrotron Radiation Microtomography ◽  
The Brain

The spinal cord is the primary neurological link between the brain and other parts of the body, but unlike those of the brain, advances in spinal cord imaging have been challenged by the more complicated and inhomogeneous anatomy of the spine. Fortunately with the advancement of high technology, phase-contrast synchrotron radiation microtomography has become widespread in scientific research because of its ability to generate high-quality and high-resolution images. In this study, this method has been employed for nondestructive imaging of the internal microstructure of rat spinal cord. Furthermore, digital virtual slices based on phase-contrast synchrotron radiation were compared with conventional histological sections. The three-dimensional internal microstructure of the intramedullary arteries and nerve fibers was vividly detected within the same spinal cord specimen without the application of a stain or contrast agent or sectioning. With the aid of image post-processing, an optimization of vessel and nerve fiber images was obtained. The findings indicated that phase-contrast synchrotron radiation microtomography is unique in the field of three-dimensional imaging and sets novel standards for pathophysiological investigations in various neurovascular diseases.

Comparison of the Motor Effects of Individual Vestibulo- and Reticulospinal Neurons on Dorsal and Ventral Myotomes in Lamprey

2003 ◽  
Vol 90 (5) ◽  
pp. 3161-3167 ◽  
Author(s):  
P. V. Zelenin ◽  
E. L. Pavlova ◽  
S. Grillner ◽  
G. N. Orlovsky ◽  
T. G. Deliagina
Keyword(s):  
Spinal Cord ◽  
The Body ◽  
Spinal Motoneurons ◽  
Lower Vertebrate ◽  
Motor Synergies ◽  
Spike Triggered Averaging ◽  
Spinal Segments ◽  
Motor Effects ◽  
The Brain ◽  
Rostral Part

In the lamprey (a lower vertebrate), motor commands from the brain to the spinal cord are transmitted through the reticulospinal (RS) and vestibulospinal (VS) pathways. The axons of larger RS neurons reach the most caudal of approximately 100 spinal segments, whereas the VS pathway does not descend below the 15th segment. This study was carried out to compare functional projections of RS and VS neurons in the rostral spinal segments that the neurons innervate together. To reveal these projections, individual RS or VS neurons were stimulated, and the responses of different groups of spinal motoneurons were recorded in ventral root branches to dorsal and ventral parts of myotomes. The responses were detected using a spike-triggered averaging technique on the background of ongoing motoneuronal activity. Individual RS and VS neurons exerted uniform effects on segmental motor output within this rostral part of the spinal cord. The effects of VS neurons on different groups of motoneurons were weaker and less diverse than those of RS neurons. The results indicate that VS neurons are able to elicit a flexion of the rostral part of the body and to turn the head in different planes without affecting more caudal parts. By contrast, larger RS neurons can elicit head movement only together with movement of a considerable part of the body and thus seem to be responsible for formation of gross motor synergies.

Excitation of motoneurons by the Mauthner axon in goldfish: complexities in a "simple" reticulospinal pathway

1992 ◽  
Vol 67 (6) ◽  
pp. 1574-1586 ◽  
Author(s):  
J. R. Fetcho
Keyword(s):  
Escape Behavior ◽  
Mean Amplitude ◽  
Short Latency ◽  
The Body ◽  
Intracellular Recordings ◽  
M Cell ◽  
Mauthner Cell ◽  
Monosynaptic Connection ◽  
Direct Excitation ◽  
Descending Interneurons

1. The Mauthner cell in fish and amphibians initiates an escape behavior that has served as a model system for studies of the reticulospinal control of movement. This behavior consists of a very rapid bend of the body and tail that is thought to arise from the monosynaptic excitation of large primary motoneurons by the Mauthner cell. Recent work suggests that the excitation of primary motoneurons might be more complex than a solely monosynaptic connection. To examine this possibility, I used intracellular recording and staining to study the excitation of primary motoneurons by the M cell. 2. Simultaneous intracellular recordings from the M axon and ipsilateral primary motoneurons show that firing the M cell leads to complex postsynaptic potentials (PSPs) in the motoneurons. These PSPs usually have three components: an early, small, slow depolarization (component 1), a later, large, fast depolarization (component 2), and an even later, large, long-lasting depolarization (component 3). The first component has a latency of 0.52 +/- 0.15 (SD) ms, (n = 27) and most probably is a monosynaptic input from the M cell. This study focused on the two subsequent, less-understood parts of the PSP. Motoneurons typically fire off the second part of the PSP. This is usually (27 of 33 cells) the largest component, and it has a mean amplitude of 6.24 +/- 3.33 (SD) mV (n = 33) and a half-decay time of 0.44 +/- 0.18 (SD) ms (n = 27). The mean amplitude of the third component is 3.20 +/- 1.7 (SD) mV (n = 35), and its half-decay is 6.73 +/- 2.66 (SD) ms (n = 35). The latency of the second component averages 0.66 +/- 0.21 (SD) ms (n = 32), indicating that there are few synapses in the pathway mediating it. 3. One candidate pathway for the second component of the PSP involves a class of descending interneurons (DIs) that are monosynaptically, chemically excited by the M cell and appear in light microscopy to contact motoneurons. Simultaneous intracellular recordings from the M axon, a DI, and a primary motoneuron show that the interneurons are electrotonically coupled to motoneurons and produce the fast, second component of the PSP. Direct excitation of an interneuron leads to a very short-latency (less than 0.2 ms), fast PSP in a motoneuron similar to the second component of the PSP produced by the M axon. The short latency and fatigue resistance of this connection indicate it is electrotonic, and this is supported by evidence for DC coupling between the two cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Modifications of Locomotor Pattern Underlying Escape Behavior in the Lamprey

2008 ◽  
Vol 99 (1) ◽  
pp. 297-307 ◽  
Author(s):  
Salma S. Islam ◽  
Pavel V. Zelenin
Keyword(s):  
Spinal Cord ◽  
Escape Behavior ◽  
Sensory Information ◽  
The Body ◽  
Descending Pathways ◽  
Long Distance ◽  
Lower Vertebrate ◽  
Dorsal Roots ◽  
Tactile Stimuli ◽  
Undulatory Locomotion

Two forms of undulatory locomotion in the lamprey (a lower vertebrate) have been described earlier: fast forward swimming (FFS) used for long distance migrations and slow backward swimming (SBS) used for escape from adverse tactile stimuli. In the present study, we describe another form of escape behavior: slow forward swimming (SFS). We characterize the kinematic and electromyographic patterns of SFS and compare them with SBS and FFS. The most striking feature of SFS is nonuniformity of shape and speed of the locomotor waves propagating along the body: close to the site of stimulation, the waves slow down and the body curvature increases several-fold due to enhanced muscle activity. Lesions of afferents showed that sensory information critical for elicitation of SFS is transmitted through the dorsal roots. In contrast, sensory signals that induce SBS are transmitted through the dorsal roots, lateral line nerves, and trigeminal nerves. Persistence of SFS and SBS after different lesions of the spinal cord suggests that the ascending and descending pathways, necessary for induction of SBS and SFS, are dispersed over the cross section of the spinal cord. As shown previously, during FFS (but not SBS) the lamprey maintains the dorsal-side-up body orientation due to vestibular postural reflexes. In this study we have found that the orientation control is absent during SFS. The role of the spinal cord and the brain stem in generation of different forms of undulatory locomotion is discussed.

scholarly journals Survival and Axonal Outgrowth of the Mauthner Cell Following Spinal Cord Crush Does Not Drive Post-injury Startle Responses

2021 ◽  
Vol 9 ◽  
Author(s):  
Steven J. Zottoli ◽  
Donald S. Faber ◽  
John Hering ◽  
Ann C. Dannhauer ◽  
Susan Northen
Keyword(s):  
Spinal Cord ◽  
Control Fish ◽  
Emg Activity ◽  
M Cells ◽  
M Cell ◽  
Post Injury ◽  
Wound Site ◽  
Axonal Regrowth ◽  
Structural And Functional Properties ◽  
Cord Injury

A pair of Mauthner cells (M-cells) can be found in the hindbrain of most teleost fish, as well as amphibians and lamprey. The axons of these reticulospinal neurons cross the midline and synapse on interneurons and motoneurons as they descend the length of the spinal cord. The M-cell initiates fast C-type startle responses (fast C-starts) in goldfish and zebrafish triggered by abrupt acoustic/vibratory stimuli. Starting about 70 days after whole spinal cord crush, less robust startle responses with longer latencies manifest in adult goldfish, Carassius auratus. The morphological and electrophysiological identifiability of the M-cell provides a unique opportunity to study cellular responses to spinal cord injury and the relation of axonal regrowth to a defined behavior. After spinal cord crush at the spinomedullary junction about one-third of the damaged M-axons of adult goldfish send at least one sprout past the wound site between 56 and 85 days postoperatively. These caudally projecting sprouts follow a more lateral trajectory relative to their position in the fasciculus longitudinalis medialis of control fish. Other sprouts, some from the same axon, follow aberrant pathways that include rostral projections, reversal of direction, midline crossings, neuromas, and projection out the first ventral root. Stimulating M-axons in goldfish that had post-injury startle behavior between 198 and 468 days postoperatively resulted in no or minimal EMG activity in trunk and tail musculature as compared to control fish. Although M-cells can survive for at least 468 day (∼1.3 years) after spinal cord crush, maintain regrowth, and elicit putative trunk EMG responses, the cell does not appear to play a substantive role in the emergence of acoustic/vibratory-triggered responses. We speculate that aberrant pathway choice of this neuron may limit its role in the recovery of behavior and discuss structural and functional properties of alternative candidate neurons that may render them more supportive of post-injury startle behavior.

scholarly journals Identification of scavenger receptor B1 as the airway microfold cell receptor for Mycobacterium tuberculosis

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Haaris S Khan ◽  
Vidhya R Nair ◽  
Cody R Ruhl ◽  
Samuel Alvarez-Arguedas ◽  
Jorge L Galvan Rendiz ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Scavenger Receptor ◽  
Cell Receptor ◽  
The Body ◽  
M Cells ◽  
M Cell ◽  
Type Vii Secretion ◽  
Multiple Routes ◽  
Mechanistic Basis ◽  
Microfold Cells

Mycobacterium tuberculosis (Mtb) can enter the body through multiple routes, including via specialized transcytotic cells called microfold cells (M cell). However, the mechanistic basis for M cell entry remains undefined. Here, we show that M cell transcytosis depends on the Mtb Type VII secretion machine and its major virulence factor EsxA. We identify scavenger receptor B1 (SR-B1) as an EsxA receptor on airway M cells. SR-B1 is required for Mtb binding to and translocation across M cells in mouse and human tissue. Together, our data demonstrate a previously undescribed role for Mtb EsxA in mucosal invasion and identify SR-B1 as the airway M cell receptor for Mtb.

Introduction to the Nervous System

2017 ◽  
Author(s):  
Peggy Mason
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
The Body ◽  
Conscious Awareness ◽  
Sensory Stimuli ◽  
System P ◽  
Brainstem Stroke ◽  
Primary Deficit ◽  
The Central Nervous System ◽  
The Brain

The primary regions and principal functions of the central nervous system are introduced through the story of Jean-Dominique Bauby who became locked in after suffering a brainstem stroke. Bauby blinked out his story of locked-in syndrome one letter at a time. The primary deficit of locked-in syndrome is in voluntary movement because pathways from the brain to motoneurons in the brainstem and spinal cord are interrupted. Perception is also disturbed as pathways responsible for transforming sensory stimuli into conscious awareness are interrupted as they ascend through the brainstem into the forebrain. Homeostasis, through which the brain keeps the body alive, is also adversely affected in locked-in syndrome because it depends on the brain, spinal cord and autonomic nervous system. Abstract functions such as memory, language, and emotion depend fully on the forebrain and are intact in locked-in syndrome, as clearly evidenced by Bauby’s eloquent words.

Primate raphe- and reticulospinal neurons: effects of stimulation in periaqueductal gray or VPLc thalamic nucleus

1984 ◽  
Vol 51 (3) ◽  
pp. 467-480 ◽  
Author(s):  
W. D. Willis ◽  
K. D. Gerhart ◽  
W. S. Willcockson ◽  
R. P. Yezierski ◽  
T. K. Wilcox ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Reticular Formation ◽  
Receptive Fields ◽  
Periaqueductal Gray ◽  
The Body ◽  
Entire Body ◽  
Antidromic Activation ◽  
Reticulospinal Neurons ◽  
Reticulospinal Tract ◽  
The Mean

Recordings were made from 132 raphe- and reticulospinal tract neurons in the medial part of the lower brain stem in 32 anesthetized monkeys. Recording sites were in the nucleus raphe magnus, the rostral nucleus raphe obscurus, and the reticular formation adjacent to the raphe. The neurons were identified by antidromic activation from the upper lumbar spinal cord. Of the population sampled, 83 cells were activated antidromically from the left dorsal lateral funiculus (DLF), 32 from the right DLF, and 17 from both sides. The mean latency for antidromic activation was 8.2 +/- 7.1 ms, corresponding to a mean conduction velocity of 22.8 m/s. No conduction velocities characteristic of unmyelinated axons were observed. Collision tests indicated that raphe-spinal axons that bifurcated to descend in both DLFs branched within the spinal cord. The effects of stimulation in the periaqueductal gray (PAG) or adjacent midbrain reticular formation were tested on 102 spinally projecting neurons in the medial medulla. Of these, 60 cells were excited, 9 cells were inhibited, 8 showed mixed excitation and inhibition, and 25 cells were unaffected. The mean latency for excitation was 11.6 ms and for inhibition, 17.8 ms. Threshold for excitation of raphe- and reticulospinal neurons ranged from 50 to 400 microA. Raphe- and reticulospinal tract cells could often (31/46 cells tested) be excited following stimulation in the ventral posterior lateral nucleus of the thalamus. The mean latency of excitation was 35.6 ms (range, 6-112 ms). Receptive fields could be demonstrated for 80 raphe- and reticulospinal cells, while 48 neurons possessed no demonstrable cutaneous receptive field. Most cells had large excitatory receptive fields, often encompassing the surface of the entire body and face. Some neurons had complex excitatory and inhibitory receptive fields, whereas other cells had large inhibitory receptive fields over much of the surface of the body and face. For most cells (52/55) with excitatory receptive fields, the only effective stimuli were noxious mechanical or noxious heat stimuli. Nonnoxious mechanical stimuli, such as brushing the skin, were capable of activating only a few (3/55) raphe- and reticulospinal neurons, and these were more effectively excited by noxious stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

The Origin of the Interoceptive Pathway

2014 ◽  
Author(s):  
A. D. (Bud) Craig
Keyword(s):  
Spinal Cord ◽  
Motor Function ◽  
Contralateral Side ◽  
Dorsal Column ◽  
The Body ◽  
Sensory Loss ◽  
Anatomical Basis ◽  
Touch Sensation ◽  
Temperature Sensations ◽  
The Brain

This chapter describes the functional and anatomical characteristics of interoceptive processing at the levels of the primary sensory fiber and the spinal cord. The association of the spinothalamic pathway with pain and temperature had already been described in textbooks for years. The clinical evidence indicated that a knife cut that severed the spinal cord on one side produced a loss of pain and temperature sensations only on the opposite (contralateral) side of the body, as tested with pinprick and a cold brass rod, combined with the loss of discriminative touch sensation and skeletal motor function on the same (ipsilateral) side as the injury to the spinal cord. The anatomical basis for this dissociated pattern of sensory loss is the distinctness of the two ascending somatosensory pathways to the brain-discriminative touch sensation in the uncrossed (ipsilateral) dorsal column pathway, and pain and temperature sensations in the crossed (contralateral) spinothalamic pathway.

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