scholarly journals THE FUNCTION OF THE BRAIN IN LOCOMOTION OF THE POLYCLAD WORM, YUNGIA AURANTIACA

1923 ◽  
Vol 6 (1) ◽  
pp. 73-76 ◽  
Author(s):  
A. R. Moore
Keyword(s):  
Mechanical Stimulation ◽  
Sensory Stimulation ◽  
The Body ◽  
Anterior Region ◽  
Spontaneous Movement ◽  
Peripheral Stimulation ◽  
Motor Nerves ◽  
Low Threshold ◽  
The Brain ◽  
Stimulation Of

Coordinated swimming movements in Yungia are not dependent upon the presence of the brain. The neuromuscular mechanism necessary for spontaneous movement and swimming is complete in the body of the animal apart from the brain. Normally this mechanism is set in motion by sensory stimulation arriving by way of the brain. The latter is a region of low threshold and acts as an amplifier by sending the impulses into a great number of channels. When the head is cut off these connections with the sensorium are broken, consequently peripheral stimulation does not have its usual effect. If, however, the motor nerves are stimulated directly as by mechanical stimulation of the median anterior region, then swimming movements result. Also if the threshold of the entire nervous mechanism is lowered by phenol or by an increase in the ion ratios See PDF for Equation and See PDF for Equation then again peripheral stimulation throws the neuromuscular mechanism into activity and swimming movements result.

Fictive swimming elicited by electrical stimulation of the midbrain in goldfish

1993 ◽  
Vol 70 (2) ◽  
pp. 765-780 ◽  
Author(s):  
J. R. Fetcho ◽  
K. R. Svoboda
Keyword(s):  
Brain Stimulation ◽  
Beat Frequency ◽  
Motor Pattern ◽  
The Body ◽  
Motor Output ◽  
Stimulus Strength ◽  
Motor Nerves ◽  
Tail Beat ◽  
The Brain ◽  
Stimulation Of

1. We developed a fictive swimming preparation of goldfish that will allow us to study the cellular basis of interactions between swimming and escape networks in fish. 2. Stimulation of the midbrain in decerebrate goldfish produced rhythmic alternating movements of the body and tail similar to swimming movements. The amplitude and frequency of the movements were dependent on stimulus strength. Larger current strengths or higher frequencies of stimulation produced larger-amplitude and/or higher-frequency movements. Tail-beat frequency increased roughly linearly with current strength over a large range, with plateaus in frequency sometimes evident at the lowest and highest stimulus strengths. 3. Electromyographic (EMG) recordings from axial muscles on opposite sides at the same rostrocaudal position showed that stimulation of the midbrain led to alternating EMG bursts, with bursts first on one side, then the other. These bursts occurred at a frequency equal to the tail-beat frequency and well below the frequency of brain stimulation. EMG bursts recorded from rostral segments preceded those recorded from caudal segments on the same side of the body. The interval between individual spikes within EMG bursts sometimes corresponded to the interval between brain stimuli. Thus, whereas the frequency of tail beats and EMG bursts was always much slower than the frequency of brain stimulation, there was evidence of individual brain stimuli in the pattern of spikes within bursts. 4. After paralyzing fish that produced rhythmic movement on midbrain stimulation, we monitored the motor output during stimulation of the midbrain by using extracellular recordings from spinal motor nerves. We characterized the motor pattern in detail to determine whether it showed the features present in the motor output of swimming fish. The fictive preparations showed all of the major features of the swimming motor pattern recorded in EMGs from freely swimming fish. 5. The motor nerves, like the EMGs produced by stimulating midbrain, showed rhythmic bursting at a much lower frequency than the brain stimulus. Bursts on opposite sides of the body alternated. The frequency of bursting ranged from 1.5 to 13.6 Hz and was dependent on stimulus strength, with higher strengths producing faster bursting. Activity in rostral segments preceded activity in caudal ones on the same side of the body. Some spikes within bursts of activity occurred at the same frequency as the brain stimulus, but individual brain stimuli were not as evident as those seen in some of the EMGs. 6. The duration of bursts of activity in a nerve was positively and linearly correlated with the time between successive bursts (cycle time).(ABSTRACT TRUNCATED AT 400 WORDS)

The Brain as Treasury and as Aqueduct

2018 ◽  
Vol 2 (4) ◽  
pp. 542-566
Author(s):  
Jessica Wright
Keyword(s):  
Fifth Century ◽  
The Body ◽  
Late Antique ◽  
Material Resources ◽  
Brain Functions ◽  
Motor Nerves ◽  
Architectural Structures ◽  
A Site ◽  
The City ◽  
The Brain

In late antique theological texts, metaphors of the brain were useful tools for talking about forms of governance: cosmic, political, and domestic; failed and successful; interior discipline and social control. These metaphors were grounded in a common philosophical analogy between the body and the city, and were also supported by the ancient medical concept of the brain as the source of the sensory and motor nerves. Often the brain was imagined as a monarch or civic official, governing the body from the head as from an acropolis or royal house. This article examines two unconventional metaphors of the brain in the work of the fifth-century Greco-Syrian bishop Theodoret of Cyrrhus—the brain as a treasure within the acropolis, and the brain as a node in an urban aqueduct—both of which adapt the structural metaphor of governance to reflect the changing political and economic circumstances of imperial Christianity. Drawing upon medical theories of the brain, Theodoret expands upon the conventional governance metaphor of brain function to encompass the economic and the spiritual responsibilities of the bishop-administrator. Just as architectural structures (acropolis, aqueduct) contain and distribute valuable resources (treasure, water) within the city, so the brain accumulates and redistributes nourishing substances (marrow, blood, pneuma) within the body; and just as the brain functions as a site for the transformation of material resources (body) into spiritual goods (mind), so the bishop stands as a point of mediation between earthly wealth and the treasures of heaven.

Convergence of heterotopic nociceptive information onto neurons of caudal medullary reticular formation in monkey (Macaca fascicularis)

1990 ◽  
Vol 63 (5) ◽  
pp. 1118-1127 ◽  
Author(s):  
L. Villanueva ◽  
K. D. Cliffer ◽  
L. S. Sorkin ◽  
D. Le Bars ◽  
W. D. Willis
Keyword(s):  
Electrical Stimulation ◽  
Reticular Formation ◽  
Mechanical Stimulation ◽  
Background Activity ◽  
The Body ◽  
Thermal Stimulation ◽  
Medullary Reticular Formation ◽  
Nociceptive Information ◽  
Noxious Mechanical Stimulation ◽  
Stimulation Of

1. Recordings were made in anesthetized monkeys from neurons in the medullary reticular formation (MRF) caudal to the obex. Responses of 19 MRF neurons to mechanical, thermal, and/or electrical stimulation were examined. MRF neurons exhibited convergence of nociceptive cutaneous inputs from widespread areas of the body and face. 2. MRF neurons exhibited low levels of background activity. Background activity increased after periods of intense cutaneous mechanical or thermal stimulation. Nearly all MRF neurons tested failed to respond to heterosensory stimuli (flashes, whistle sounds), and none responded to joint movements. 3. MRF neurons were excited by and encoded the intensity of noxious mechanical stimulation. Responses to stimuli on contralateral limbs were greater than those to stimuli on ipsilateral limbs. Responses were greater to stimuli on the forelimbs than to stimuli on the hindlimbs. 4. MRF neurons responded to noxious thermal stimulation (51 degrees C) of widespread areas of the body. Mean responses from stimulation at different locations were generally parallel to those for noxious mechanical stimulation. Responses increased with intensity of noxious thermal stimulation (45-50 degrees C). 5. MRF neurons responded with one or two peaks of activation to percutaneous electrical stimulation applied to the limbs, the face, or the tail. The differences in latency of responses to stimulating two locations along the tail suggested that activity was elicited by activation of peripheral fibers with a mean conduction velocity in the A delta range. Stimulation of the contralateral hindlimb elicited greater responses, with lower thresholds and shorter latencies, than did stimulation of the ipsilateral hindlimb. 6. Electrophysiological properties of monkey MRF neurons resembled those of neurons in the medullary subnucleus reticularis dorsalis (SRD) in the rat. Neurons in the caudal medullary reticular formation could play a role in processing nociceptive information. Convergence of nociceptive cutaneous input from widespread areas of the body suggests that MRF neurons may contribute to autonomic, affective, attentional, and/or sensory-motor processes related to pain.

scholarly journals Muscular Movements in Man, and their Evolution in the Infant: a Study of Movement in Man, and its Evolution, together with Inferences as to the Properties of Nerve-Centres and their Modes of Action in expressing Thought

1889 ◽  
Vol 35 (149) ◽  
pp. 23-44 ◽  
Author(s):  
Francis Warner
Keyword(s):  
Brain Area ◽  
Muscular Contraction ◽  
The Body ◽  
Brain Areas ◽  
Modes Of Action ◽  
Central Nerve System ◽  
Nerve System ◽  
The Brain ◽  
Compound Series ◽  
Stimulation Of

(1) Movement in mau has long been a subject of profitable study. Visible movement in the body is produced by muscular contraction following upon stimulation of the muscles by efferent currents passing from the central nerve-system. Modern physiological experiments have demonstrated that when a special brain-area discharges nerve-currents, these are followed by certain visible movements or contraction of certain muscles corresponding. So exact are such reactions, as obtained by experiment upon the brain-areas, that movements similar to those produced by experimental excitation of a certain brain-area may be taken as evidence of action in that area, or as commencing in discharge from that area (see Reinforcement of Movements, 35; Compound Series of Movements, 34).

The Giant Fibre Reflex of the Earthworm, Lumbricus Terrestris L

1962 ◽  
Vol 39 (2) ◽  
pp. 219-227
Author(s):  
M. B. V. ROBERTS
Keyword(s):  
Nerve Cord ◽  
Lumbricus Terrestris ◽  
The Body ◽  
Muscle Preparation ◽  
Direct Stimulation ◽  
Giant Fibre ◽  
Low Threshold ◽  
Giant Fibres ◽  
Nerve Muscle ◽  
Stimulation Of

1. A nerve-muscle preparation including the longitudinal musculature and the giant fibres in the nerve cord of the earthworm is described. 2. Direct stimulation of the nerve cord with single shocks of increasing intensity results in two types of response: (a) a low threshold, very small twitch, resulting from a single impulse in the median giant fibre, and (b) a higher threshold, slightly larger twitch, resulting from single impulses in the median and lateral giant fibres. Both responses are highly susceptible to fatigue. 3. Stimulation of the body surface evokes a much more powerful contraction which is associated with a burst of impulses in the giant fibre. The strength of the contraction depends upon the number of impulses in the burst and this in turn upon the intensity and duration of the stimulus.

Nociceptive responses of neurons in medial thalamus and their relationship to spinothalamic pathways

1978 ◽  
Vol 41 (6) ◽  
pp. 1592-1613 ◽  
Author(s):  
W. K. Dong ◽  
H. Ryu ◽  
I. H. Wagman
Keyword(s):  
Mechanical Stimulation ◽  
The Body ◽  
Direct Stimulation ◽  
Spinothalamic Tract ◽  
Medial Thalamus ◽  
C Fibers ◽  
Nociceptive Responses ◽  
C Fiber ◽  
Noxious Mechanical Stimulation ◽  
Stimulation Of

1. An extracellular study of the cat medial thalamus has revealed four types of somatosensory neurons. These were located primarily in the n. parafascicularis, n. subparafascicularis, and n. centralis lateralis; none were found in the n. centrum medianum. There was no functional segregation of neurons within each nucleus or between nuclei. Each type of neuron had large and often bilateral receptive areas. No somatotopic organization of neurons was found within the medial thalamus. 2. Noxious (N) and noxious-tap (NT) neurons comprising 72% of the sample (78 of 109 total) were considered to be nociceptive. N cells responded exclusively to noxious mechanical stimulation of skin, muscle fascia, tendons, and joints, and to direct stimulation of A-delta- and C-fiber groups in cutaneous, articular, and muscle nerves. NT cells responded to noxious and tap stimulation in a differential manner and to stimulation of the entire spectrum of A- and C-fibers. N and NT cells accurately signaled the duration of noxious mechanical stimulation. Their nociceptive responses were also graded as a function of both noxious stimulus intensity and the number of activated A-delta- and C-fibers. Stimulation of A- and C-fibers evoked, respectively, an inital burst and a late burst of discharges. A brief period of inhibition intervened between the initial and late bursts of NT cells. Prolonged afterdischarge was often observed following noxious natural stimulation or stimulation of A-delta- and C-fibers. The phenomenon of discharge "windup" was observed during iterative stimulation of C-fibers. 3. Tap (T) neurons (10%) responded only to brisk but innocuous taps applied to skin or underlying tissue. These cells were driven only by activation of A-alpha- and A-beta-fibers. The response to such stimulation was seen as an initial burst of discharges followed by an inhibitory period. 4. Inhibited (I) neurons (18%) had resting discharges that were inhibited by noxious stimuli and stimulation of A-beta- and C-fiber groups. 5. The results obtained from monitoring the peripherally evoked responses of nociceptive N and NT neurons before and after selective lesions of the spinal cord strongly suggested that the spinothalamic tracts were the only spinal projections mediating A- and C-fiber input to these cells. Each spinothalamic tract apparently carried information originating from both sides of the body.

The Neurophysiology of Acupuncture: A Viewpoint

1997 ◽  
Vol 15 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Miltiades Karavis
Keyword(s):  
Sensory Stimulation ◽  
The Body ◽  
Psychiatric Disease ◽  
Neural Pathways ◽  
Enzyme Release ◽  
Pain Syndromes ◽  
Inhibitory Mechanisms ◽  
Electric Injury ◽  
Sensory Neural ◽  
The Brain

Acupuncture is a specialised sensory stimulation that is analysed through sensory neural pathways. Therefore to understand its action we have to analyse the anatomy, physiology and pharmacology of the nervous system, aided with a knowledge of neuroendocrinology and the chemoarchitecture of the brain. Various neural theories have been developed to explain the mechanisms of acupuncture. It is now evident that acupuncture reacts at local, regional (spinal cord) and general (brain) levels. Therefore, inserting one or more needles at particular points (or areas) of the body activates neural pathways on three different levels, provoking local, regional, and general reactions. The local reaction is a multifactorial phenomenon. The electric injury potential due to the needle, the presence and synthesis of opioid peptides at the site of injury, and substance P, histamine like substances, bradikinin, serotonin and proteolitic enzyme release around the needle, all occur during needling. The regional reaction concerns the activation of a larger area (2–3 dermatomes) via reflex arches. We can analyse the viscero-cutaneous, cutaneo-visceral, cutaneo-muscular and viscero-muscular reflexes and also the vegetative, stretch and polysynaptic segmental reflexes. The general reaction mainly activates the brain central mechanism of internal homoeostasis. We can explain the action of acupuncture in acute and chronic pain syndromes, in addiction and in psychiatric disease through the role of central neurotransmitters and the modulatory systems that are activated by acupoints: opioid, non-opioid and central sympathetic inhibitory mechanisms.

scholarly journals Luminescent Flash Avoidance in the Nocturnal Crab Portunus Xantusii: I. The Effects of Luminescence and Mechanical Stimulation on Heart Rate

1990 ◽  
Vol 148 (1) ◽  
pp. 415-426
Author(s):  
MATTHEW S. GROBER
Keyword(s):  
Heart Rate ◽  
Body Size ◽  
Mechanical Stimulation ◽  
Cardiac Activity ◽  
Sensory Stimulation ◽  
The Body ◽  
Cardiac Response ◽  
Mechanical Stimuli ◽  
Sensory Stimuli ◽  
Cardiac Responses

In crabs, the ratio of the heart rate before to that after sensory stimulation (the response ratio) provides a reliable indicator of the effects of sensory stimulation on cardiac activity. The nocturnally active crab Portunus xantusii (Stimpson) exhibits rapid decreases in heart rate in response to the luminescent flashes produced by the sea pansy Renilla kollikeri (Pfeffer) and to mechanical stimulation. Crabs move away from luminescent and mechanical stimuli and this behavior is well correlated with the cardiac responses. Therefore, cardiac response ratios can be used as a reliable bioassay to determine the components of sensory stimuli that are important in eliciting behavioral responses. The similar cardiac responses to both luminescent and mechanical stimuli suggest that a single command pathway may be responsiblefor triggering startle behavior in response to a wide variety of rapid, brief and intense sensory stimuli. Heart rate also varied depending on the body size of the crab and the ambient temperature. Small crabs had faster heart rates than larger crabs, and the relationship between heart rate and body size is described by the equation: fH=794.3x−059222, where fH is heart rate in beats per minute and x is carapace length in millimeters.Heart rate increased with increasing temperature over a range of 10–22 °C, but no further increases occurred at higher temperatures. The Q10 for the range 10–20°C was 1.8.

Vertical banding evoked by electrical stimulation of the brain in anaesthetized green sunfish, Lepomis cyanellus, and bluegills, Lepomis macrochirus

1980 ◽  
Vol 84 (1) ◽  
pp. 149-160
Author(s):  
D. H. Bauer ◽  
L. S. Demski
Keyword(s):  
Electrical Stimulation ◽  
Transition Zone ◽  
Lepomis Macrochirus ◽  
Optic Tract ◽  
Colour Change ◽  
The Body ◽  
Lepomis Cyanellus ◽  
Green Sunfish ◽  
The Brain ◽  
Stimulation Of

A pattern of dark vertical bands is a characteristic agonistic display in the green sunfish, Lepomis cyanellus and the bluegill, L. macrochirus. The rapidity with which the display can appear and disappear indicates that it is neurally controlled. Electrical stimulation of the brain was carried out in anaesthetized green sunfish and bluegills to map those regions from which this colour change can be elicited. Banding was evoked by stimulation of sites near the midline in the preoptic area, ventral thalamic-dorsal hypothalmic transition zone, the midbrain tegmentum (just dorsal to the nucleus prerotundus pars medialis), in and near the torus semicricularis, in the basal midbrain (region of the crossing tectobulbar tracts), and in the rostral basomedial medulla. A ‘transition’ zone was located basally in the middle medulla, caudal to which only paling was evoked. Areas found to be negative for evoked banding included the telencephalic lobe, the inferior lobe of the hypothalamus, the optic tract, the optic tectum, the body and valvula of the cerebellum and the caudal medulla. It is postulated that the vertical banding pattern is made up of a separate, selectively controlled system of dermal melanophores. The possible neural mechanisms controlling banding are discussed.

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