Central Mechanism of Hearing in Insects

1961 ◽  
Vol 38 (3) ◽  
pp. 545-558 ◽  
Author(s):  
NOBUO SUGA ◽  
YASUJI KATSUKI
Keyword(s):  
Sound Source ◽  
Threshold Curve ◽  
Inhibitory Interaction ◽  
Response Range ◽  
Metathoracic Ganglion ◽  
Hair Sensilla ◽  
Prothoracic Ganglion ◽  
Tympanic Organ ◽  
Large Fibre ◽  
The Brain

1. The impulses from the tympanic organ are transmitted at the prothoracic ganglion to a central neuron, the auditory T large fibre, which lies in the cord between the brain and the metathoracic ganglion. The impulses in the T large fibre are conducted rostrally and caudally with the same discharge pattern. Information is sent up to the brain, and down to the metathoracic ganglion, after a delay of about 12 msec. 2. The impulses from the cercal hair sensilla are transmitted to two similar auditory C large fibres which lie in the cord between the metathoracic and last (6th) abdominal ganglia and are then sent up to the mesothoracic ganglia by other auditory large fibres. 3. Central inhibitory interaction between the impulses from the tympanic nerves of the two sides are shown by a marked increase of impulses in the T large fibre following section of one of the tympanic nerves. No inhibitory interaction is found between the impulses from the two cercal nerves. 4. The auditory T large fibre receives not only the excitatory effect from the ipsilateral tympanic nerve at the prothoracic ganglion, but also the inhibitory and weak excitatory effects from the contralateral one. 5. The response range of the T large fibre is narrower than the threshold curve of the tympanic nerve and corresponds with one type of response range in the tympanic neurons. The response ranges of the C large fibres correspond closely with the threshold curve of the cercal nerve. 6. A large difference in threshold between the two T large fibres is found in the response to sound incident from the side. The number of impulses in the T large fibre nearer to the sound source is greater than in that farther from the source. 7. The difference in the number of impulses between the two T large fibres is most marked in the response to sound of the frequency which is dominant in stridulation. This difference is due to the mutual inhibitory interaction of neurons which modifies the number of impulses without changing the threshold of the tympanic large fibre. 8. It is suggested that the central inhibitory interaction increases the information about a sound source and plays an important role in the mechanism of the directional sense. 9. The stridulation of the group activates the tympanic nerve and evokes synchronized discharge in the T large fibre, but scarcely at all in the primary C large fibre. The tympanic organ and its neural network seem well adapted to reception of stridulation. 10. It is concluded that though neither of the two sound receptive organs--the tympanic organ and the cercal hair sensilla--can perform frequency analysis, the insect may be able to do so by making use of both organs, since they have different frequency ranges and are served by different auditory large-fibre tracts.

Pitch discrimination in locusts

1961 ◽  
Vol 155 (959) ◽  
pp. 218-231 ◽  
Keyword(s):  
Schistocerca Gregaria ◽  
Locusta Migratoria ◽  
Pitch Discrimination ◽  
High Pitch ◽  
Sound Stimulation ◽  
Sensory Axons ◽  
Metathoracic Ganglion ◽  
Tympanic Organ ◽  
The Brain ◽  
Stimulation Of

Sound stimulation of the tympanic organ of Locusta migratoria and Schistocerca gregaria initiates responses in the tympanic nerve and these in turn stimulate a few interneurones which ascend the ventral cord from the metathoracic ganglion to the brain. Some of the preparations show the following evidence of pitch discrimination. The response of the whole tympanic nerve to a pulsed note of low pitch cannot be made identical to the response to the same pulse at high pitch no matter how the relative inten­sities are adjusted. A continuous note, which presumably adapts some but not all of the primary receptors, modifies the relation between pre- and post-ganglionic responses in a way which depends on the pitch of the continuous note. The relative intensities of a pure tone of high pitch (10 to 15 kc/s) and one of low pitch (0.5 to 2.0 kc/s) can, in a preparation showing only ‘on' responses, be adjusted so that there is a post-ganglionic response to the former but not to the latter, although the latter causes a larger response in the tympanic nerve. Certain large interneurones, identifiable by their spike height, do not have the same curve of threshold to pulses of various pitch as does the summed response from the whole tympanic nerve. The post-ganglionic response is, therefore, towards a selected fraction of the sensory axons. In each of the above tests the effects are small and pitch discrimination cannot be of great significance for the life of the animal.

Pharmacological Studies on the Auditory Synapses in a Grasshopper

1961 ◽  
Vol 38 (4) ◽  
pp. 759-770
Author(s):  
NOBUO SUGA ◽  
YASUJI KATSUKI
Keyword(s):  
Inhibitory Effect ◽  
Inhibitory Synapses ◽  
Inhibitory Interneurons ◽  
Excitatory Synapses ◽  
Nerve Fibres ◽  
Inhibitory Interaction ◽  
Natural Activity ◽  
Pharmacological Studies ◽  
Prothoracic Ganglion ◽  
Large Fibre

1. Picrotoxin, eserin, butyrylcholine and acetylcholine bring about increase of impulse discharges on the T large fibre in the cord. Picrotoxin gives conspicuous increase of impulse discharges in the response of the T large fibres to sound, while the excitatory effects of the latter three agents are not so conspicuous. 2. Such effects can be explained on the assumption that picrotoxin inhibits the inhibitory synapses, so that the T large fibre is fully activated by both tympanic nerves, while the latter three agents activate both the excitatory and inhibitory fibres. 3. GABA, γ-aminobutyrylcholine and D-tubocurarine act reversibly as inhibitors of the activity of the T large fibre. The response evoked in the T large fibre may be suppressed by the activities of the inhibitory interneurons activated by the tympanic nerve fibres. 4. After the application of picrotoxin solution to the prothoracic ganglion the threshold of the T large fibre near to a sound source rises while that of the opposite side falls. The inhibitory effect seems to be eliminated by the drug action and the T large fibre is activated by both the ipsilateral and the contralateral excitatory fibres. 5. The increased information about a source of sound which arises from the central inhibitory interaction is disturbed by the application of picrotoxin. 6. The conclusion that the T large fibre has excitatory synapses with the tympanic nerves, and inhibitory synapses with the inhibitory interneurons activated by the tympanic neurons, has been confirmed pharmacologically. 7. The inhibitory interneurons are activated not only by the natural activity of the tympanic nerve, but also by activity elicited electrically with square pulses.

The Anatomy of a Locust Visual Interneurone; the Descending Contralateral Movement Detector

1974 ◽  
Vol 60 (1) ◽  
pp. 1-12
Author(s):  
M. O'SHEA ◽  
C. H. F. ROWELL ◽  
J. L. D. WILLIAMS
Keyword(s):  
Visual Field ◽  
Optic Lobe ◽  
Morphological Description ◽  
Movement Detector ◽  
Branching Pattern ◽  
Suboesophageal Ganglion ◽  
Metathoracic Ganglion ◽  
Prothoracic Ganglion ◽  
Contralateral Movement ◽  
The Brain

1. The DCMD neurone is physiologically well-known and runs from the brain to the metathoracic ganglion. It responds to novel movement of small contrasting objects in the visual field and synapses on metathoracic motoneurones which mediate the jump of the locust. Its anatomy, here reported, has been visualized by intracellular cobalt staining. 2. The soma is 50 µm in diameter and lies on the upper posterior face of the protocerebrum, lateral to the midline. A neurite runs to a thickened integrating segment 20 µm. in diameter, which bears numerous dendrites; none of these extends to the optic lobe. An axon leaves the integrating segment, crosses the brain, thickens to about 17µm and descends the contralateral nerve cord. 3. The descending axon terminates in the metathoracic ganglion, where it has three major branches both ipsi- and contralateral. Its branching in the mesothoracic ganglion is similar, but extends only ipsilaterally; in the prothoracic ganglion there is reduced branching, and in the suboesophageal ganglion none at all. 4. The branching pattern in the metathorax is compatible with, and entirely explicable by, the known synaptic connexions with motoneurones. 5. The morphological description of the cell has made possible intracellular recording from axon, integrating segment and soma.

scholarly journals Conformational Spread Drives the Evolution of the Calcium-calmodulin Protein Kinase II

2021 ◽  
Author(s):  
Shahid Khan
Keyword(s):  
Protein Kinase ◽  
Bioinformatic Analysis ◽  
Dynamic Simulations ◽  
Ring Assembly ◽  
Response Range ◽  
Collective Motions ◽  
Protein Kinase Ii ◽  
Dependent Protein ◽  
Ring Architecture ◽  
The Brain

Abstract The calcium calmodulin (Ca2+CAM) dependent protein kinase II (CaMKII) decodes Ca2+ frequency oscillations. It has a central role in learning. I matched residue and organismal evolution to collective motions deduced from the atomic structure of the human CaMKIIa holoenzyme. Protein dynamic simulations and bioinformatic analysis showed its stacked ring architecture conformationally couples kinase domains (KDs) via its central hub. The simulations revealed underlying b-sheet collective motions in the hub ab association domain (AD) map onto a coevolved residue network and partition it into two distinct sectors. The holoenzyme evolved in metazoans by stabilization of ancient enzyme dimers and fold elongation to create a second, metastable sector for ring assembly. Continued evolution targeted the ring contacts for lateral conformational spread. The a isoform, predominantly expressed in the brain, emerged last and evolved rapidly in sync with the poikilotherm-homeotherm jump in the evolution of memory. The correlation between CaMKII dynamics and phylogenetics argues single residue evolution fine-tunes hub conformational spread. The central role of CaMKII ringed architecture In the brain could be to increase Ca2+ frequency response range for complex learning functions.

scholarly journals Representation of auditory motion directions and sound source locations in the human planum temporale

2018 ◽  
Author(s):  
Ceren Battal ◽  
Mohamed Rezk ◽  
Stefania Mattioni ◽  
Jyothirmayi Vadlamudi ◽  
Olivier Collignon
Keyword(s):  
Sound Source ◽  
Visual Motion ◽  
Functional Organization ◽  
Temporal Cortex ◽  
Spatial Hearing ◽  
Neural Representation ◽  
Motion Processing ◽  
Planum Temporale ◽  
Auditory Motion ◽  
The Brain

ABSTRACTThe ability to compute the location and direction of sounds is a crucial perceptual skill to efficiently interact with dynamic environments. How the human brain implements spatial hearing is however poorly understood. In our study, we used fMRI to characterize the brain activity of male and female humans listening to left, right, up and down moving as well as static sounds. Whole brain univariate results contrasting moving and static sounds varying in their location revealed a robust functional preference for auditory motion in bilateral human Planum Temporale (hPT). Using independently localized hPT, we show that this region contains information about auditory motion directions and, to a lesser extent, sound source locations. Moreover, hPT showed an axis of motion organization reminiscent of the functional organization of the middle-temporal cortex (hMT+/V5) for vision. Importantly, whereas motion direction and location rely on partially shared pattern geometries in hPT, as demonstrated by successful cross-condition decoding, the responses elicited by static and moving sounds were however significantly distinct. Altogether our results demonstrate that the hPT codes for auditory motion and location but that the underlying neural computation linked to motion processing is more reliable and partially distinct from the one supporting sound source location.SIGNIFICANCE STATEMENTIn comparison to what we know about visual motion, little is known about how the brain implements spatial hearing. Our study reveals that motion directions and sound source locations can be reliably decoded in the human Planum Temporale (hPT) and that they rely on partially shared pattern geometries. Our study therefore sheds important new lights on how computing the location or direction of sounds are implemented in the human auditory cortex by showing that those two computations rely on partially shared neural codes. Furthermore, our results show that the neural representation of moving sounds in hPT follows a “preferred axis of motion” organization, reminiscent of the coding mechanisms typically observed in the occipital hMT+/V5 region for computing visual motion.

scholarly journals Descending and Ascending Signals That Maintain Rhythmic Walking Pattern in Crickets

2021 ◽  
Vol 8 ◽  
Author(s):  
Keisuke Naniwa ◽  
Hitoshi Aonuma
Keyword(s):  
Nervous System ◽  
Gait Pattern ◽  
Gait Patterns ◽  
Control Center ◽  
Walking Gait ◽  
Thoracic Ganglia ◽  
Metathoracic Ganglion ◽  
Tripod Gait ◽  
The Brain ◽  
Leg Movements

The cricket is one of the model animals used to investigate the neuronal mechanisms underlying adaptive locomotion. An intact cricket walks mostly with a tripod gait, similar to other insects. The motor control center of the leg movements is located in the thoracic ganglia. In this study, we investigated the walking gait patterns of the crickets whose ventral nerve cords were surgically cut to gain an understanding of how the descending signals from the head ganglia and ascending signals from the abdominal nervous system into the thoracic ganglia mediate the initiation and coordination of the walking gait pattern. Crickets whose paired connectives between the brain and subesophageal ganglion (SEG) (circumesophageal connectives) were cut exhibited a tripod gait pattern. However, when one side of the circumesophageal connectives was cut, the crickets continued to turn in the opposite direction to the connective cut. Crickets whose paired connectives between the SEG and prothoracic ganglion were cut did not walk, whereas the crickets exhibited an ordinal tripod gait pattern when one side of the connectives was intact. Crickets whose paired connectives between the metathoracic ganglion and abdominal ganglia were cut initiated walking, although the gait was not a coordinated tripod pattern, whereas the crickets exhibited a tripod gait when one side of the connectives was intact. These results suggest that the brain plays an inhibitory role in initiating leg movements and that both the descending signals from the head ganglia and the ascending signals from the abdominal nervous system are important in initiating and coordinating insect walking gait patterns.

The Function of Hair Sensilla on the Locust's Leg: The Role of Tibial Hairs

1980 ◽  
Vol 87 (1) ◽  
pp. 163-176
Author(s):  
HANS-JOACHIM PFLÜGER
Keyword(s):  
Avoidance Response ◽  
Muscle Activity ◽  
Hind Tibia ◽  
Schistocerca Americana ◽  
Metathoracic Ganglion ◽  
Delay Times ◽  
Hair Sensilla ◽  
Stimulation Of

In Schistocerca americana gregaria hairs of the simple trichoid sensillum type on the hind tibia near the tibia-tarsus joint can mediate an avoidance response during which the hind leg is lifted by flexion of several joints. The responsiveness of this reflex can be improved by partially isolating the metathoracic ganglion. In these operated animals, the response can even be elicited after stimulation of one hair. Myograms from various muscles in the tibia, femur, coxa and thorax revealed which muscles were active during the avoidance response. The delay times between the stimulus (bending several hairs with an eyelash) and the first muscle activity are variable (median values 150–200 msec). It is concluded that the pathway is polysynaptic and situated within the metathoracic ganglion. Note:

Central Control of an Insect Segmental Reflex

1969 ◽  
Vol 50 (1) ◽  
pp. 191-201
Author(s):  
C. H. FRASER ROWELL
Keyword(s):  
Action Potentials ◽  
Central Control ◽  
Specific Inhibition ◽  
Signal Flow ◽  
Arousal System ◽  
Metathoracic Ganglion ◽  
Total Input ◽  
Prothoracic Ganglion ◽  
Segmental Reflex

1. The prothoracic grooming reflex of the locust is normally inhibited by the rest of the C.N.S. This paper examines the effect of removing the most powerful inhibitory source, the metathoracic ganglion, on the signal flow in and out of the prothoracic ganglion. 2. Removal of the metathoracic ganglion decreases the number of action potentials entering the prothoracic ganglion; the number of action potentials leaving the prothoracic ganglion increases. Since the recording samples only about 1% of the axons in the connective, mainly large ones, and since the sample is probably different in different preparations, it is concluded that removal of the input from the metathoracic ganglion causes a general disinhibition of the prothoracic ganglion. 3. Inhibition of the grooming reflex is probably due to this general inhibition of the ganglion, not to a specific inhibitory connexion with the metathoracic ganglion. It is suggested that the total input to the ganglion may, apart from its specific functions, contribute to a non-specific inhibition, possibly via a ganglionic arousal system.

The Physiology of the Tettigoniid Ear

1974 ◽  
Vol 60 (3) ◽  
pp. 853-859
Author(s):  
D. B. LEWIS
Keyword(s):  
Sound Source ◽  
Mechanical Vibration ◽  
Sound Intensity ◽  
Threshold Curve ◽  
Sound Reception

1. The threshold curve obtained for the whole organ, with a lateral sound source 30 cm from the insect, indicates the degree of interaction that occurs between the spiracular and tympanal slits inputs. 2. The threshold curve for the whole organ with the spiracle blocked shows an increase in threshold to the level of the tympanal slits, and suggests that diffraction phenomena may be important during sound reception. 3. Measurement of the sound intensity emitted by mechanical vibration of the tegmen shows that there is a fall in sound intensity from 124 dB at source to 54 dB at the spiracle; the spiracular intensity is still above the spiracular threshold, however.

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