Editing Lateral line (section)

== Electrophysiology ==

The mechanoreceptive hair cells of the lateral line structure are integrated into more complex circuits through their afferent and efferent connections. The synapses that directly participate in the transduction of mechanical information are excitatory afferent connections that utilize [[glutamate]].<ref>{{cite journal |last1=Flock |first1=A. |last2=Lam |first2=D. M. K. |year=1974 |title=Neurotransmitter synthesis in inner ear and lateral line sense organs |journal=[[Nature (journal)|Nature]] |volume=249 |issue=5453 |pages=142–144 |doi=10.1038/249142a0 |pmid=4151611 |bibcode=1974Natur.249..142F |s2cid=275004 }}</ref> Species vary in their neuromast and afferent connections, providing differing mechanoreceptive properties. For instance, the superficial neuromasts of the [[midshipman fish]], ''Porichthys notatus'', are sensitive to specific stimulation frequencies.<ref name="Weeg">{{cite journal |last1=Weeg |first1=M. S. |last2=Bass |first2=A. H. |year=2002 |title=Frequency Response Properties of Lateral Line Superficial Neuromasts in a Vocal Fish, With Evidence for Acoustic Sensitivity |journal=[[Journal of Neurophysiology]] |volume=88 |issue=3 |pages=1252–1262 |doi=10.1152/jn.2002.88.3.1252 |pmid=12205146 |doi-access= }}</ref> One variety is attuned to collect information about acceleration, at stimulation frequencies between 30 and 200 Hz. The other type obtains information about velocity, and is most receptive to stimulation below 30 Hz.<ref name="Weeg" />

[[File:Lateral line circuits.svg|thumb|center|upright=3|The motion detection system in fish works despite "noise" created by the fish itself. The brain copies the efferent commands it gives to the swimming muscles to the lateral line, effectively suppressing swimming noise and revealing small signals from the environment, such as from prey.<ref name="Montgomery Bodznick 1994"/>]]

The efferent synapses to hair cells are inhibitory and use [[acetylcholine]] as a transmitter. They are crucial participants in a [[corollary discharge]] system designed to limit self-generated interference. When a fish moves, it creates disturbances in the water that could be detected by the lateral line system, potentially interfering with the detection of other biologically relevant signals. To prevent this, an efferent signal is sent to the hair cell upon motor action, resulting in inhibition which counteracts the excitation resulting from reception of the self-generated stimulation. This allows the fish to detect external stimuli without interference from its own movements.<ref name="Montgomery Bodznick 1994">{{cite journal |last1=Montgomery |first1=J. C. |last2=Bodznick |first2=D. |year=1994 |title=An adaptive filter that cancels self-induced noise in the electrosensory and lateral line mechanosensory systems of fish |journal=[[Neuroscience Letters]] |volume=174 |issue=2 |pages=145–148 |doi=10.1016/0304-3940(94)90007-8 |pmid=7970170 |s2cid=15709516 }}</ref> Some efferent projections to lateral line hair cells use dopamine as a transmitter,<ref>{{cite journal |last1=Toro |first1=C |last2=Trapani |first2=JG |last3=Pacentine |first3=I |last4=Maeda |first4=R |last5=Sheets |first5=L |last6=Mo |first6=W |last7=Nicolson |first7=T |title=Dopamine Modulates the Activity of Sensory Hair Cells. |journal=The Journal of Neuroscience |date=16 December 2015 |volume=35 |issue=50 |pages=16494–503 |doi=10.1523/JNEUROSCI.1691-15.2015 |pmid=26674873 |pmc=4679827 }}</ref> likely enhancing the activity of hair cell presynaptic calcium channels and thereby increasing neurotransmission. 

Signals from the hair cells are transmitted along lateral neurons to the brain. The area where these signals most often terminate is the medial octavolateralis nucleus (MON), which probably processes and integrates mechanoreceptive information.<ref name="Maruska">{{cite journal |last1=Maruska |first1=K. P. |last2=Tricas |first2=T. C. |year=2009 |title=Central projections of octavolateralis nerves in the brain of a soniferous damselfish (Abudefduf abdominalis) |journal=The Journal of Comparative Neurology |volume=512 |issue=5|pages=628–650 |doi=10.1002/cne.21923 |pmid=19048640 |s2cid=13604689 }}</ref> The deep MON contains distinct layers of basilar and non-basilar crest cells, suggesting computational pathways analogous to the electrosensory lateral line lobe of [[electric fish]]. The MON is likely involved in the integration of excitatory and inhibitory parallel circuits to interpret mechanoreceptive information.<ref>{{cite journal |last1=Valera |last2=Markov |last3=Bijari |last4=Randlett |last5=Asgharsharghi  |last6=Baudoin |last7=Ascoli |last8=Portugues |last9=Lopez-Schier |year=2021 |title=A neuronal blueprint for directional mechanosensation in larval zebrafish |journal=[[Current Biology]] |volume=31 |issue=7 |pages=1463–1475 |doi=10.1016/j.cub.2021.01.045 |pmc=8044000 |pmid=33545047 |bibcode=2021CBio...31E1463V }}</ref>