Leech Info

Identified neurons in the medicinal leech Hirudo verbana

Dorsal Aspect

Identified neurons on the dorsal aspect of segmental ganglia in the leech, Hirudo medicinalis.

Map numberc Major axon projectionb Color codea Descriptionb Behavioral Involvementbc
Motoneurons        
DE-3 CPNR green excitor of DLM swimming, LB
crawling
DE-5 CPNR green   swimming, LB
crawling
DE-18 CANR green   swimming
DE-107 CANR green   swimming, LB
VE-4 IPNR green excitor of VLM swimming, LB
crawling
VE-8 CPNR green   swimming, LB
VE-108 CANR green   swimming, LB
FE-109 CNR
CNR		 green excitor of lateral
dorsal-ventral
FM		 swimming, LB
FE-117 CNR blue excitor of medial
dorsoventral FM		  
DI-1 CNR red inhibitor of DLM swimming, LB
crawling
DI-102 CNR red   swimming, LB
VI-2 CNR red inhibitor of VLM swimming,
crawling
VI-7 CNR red   swimming
VI-119 CNR red   swimming
FI-101 CNR red inhibitor of
dorsoventral FM		 swimming, LB
CE-11 CNR blue excitor of CM  
CE-12 CNR blue    
CE-112 CNR blue    
L (Large LM neuron) LM blue excitor of other crawling
DE-6 CNR blue   local bending
LI-9 CNR blue inhibitor of LM  
LE-106 CNR blue excitor of lateral LM  
OE-110 CNR blue excitor or OM local bending
OE-111 CNR blue    
Interneurons        
21   green serotonergic, gating swimming
27 AIC,
one ganglion		 red oscillator
240° phase		 swimming
28 AIC,
one ganglion		 red oscillator
120° phase		 swimming
33 AIC,
one ganglion		 red oscillator
240° phase		 swimming
115 PCC red oscillator
0° phase		 swimming, LB
123 PIC, 
one ganglion		 red oscillator
0° phase		 swimming
125 PIC blue excitor, receives
input from P cells		 LB
34   blue interacts with 
T cells, S cells		  
Mechanosensory cells        
P INR, IC yellow mechanosensory responds to pressure
N INR, IC yellow mechanosensory responds to noxious
Neurosecretory cells        
50 IC pink secretary neuron LB, feeding

aColor codes correspond to the maps of segmental ganglia (Fig. 2). Coded with green and red are involved in swimming circuits.

bAbbreviations:
LM-longitudinal muscles     
DLM-dorsal LM            
VLM-ventral LM
FM-flattener muscles           
CM-circular muscles      
OM-oblique muscles
NR-nerve root                      
CANR-contralateral anterior NR
CNR-contralateral NR         
CPNR-contralateral posterior NR
INR-ipsilateral NR               
IPNR- ipsilateral posterior NR
IC-ipsilateral connectives     
AIC-anterior IC             
PIC-posterior IC
PCC-posterior contralateral connectives
LB-local bending
CM-circular muscle              
NR-nerve root                
CNR-contralateral NR
INR-ipsilateral NR               
CANR-contralateral anterior NR
IC-ipsilateral connectives     
AIC-anterior IC             
PIC-posterior IC
CC-contralateral connectives 
PCC-posterior CC
ACC-anterior CC                 
Fn-Favre’s nerve

cThis table provides an update of neurons listed in Muller KJ Nicholls JG Stent GS (1981) Neurobiology of the leech. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory.

 

 

Ventral Aspect

Identified neurons on the ventral aspect of segmental ganglia in the leech, Hirudo medicinalis.

Map numberc Major axon projectionb Color codea Descriptionb Behavioral Involvementbc
Motoneurons
Map numberc Major axon projectionb Color codea Descriptionb Behavioral Involvementbc
Motoneurons        
AE CNR blue annuli erector change skin surface
from smooth to ridged
input from T cell
CV CNR blue excitor of ventrolateral CM crawling
HE INR (M3-19) blue cardiac rhythmic movement control HN
AP CNR blue input from P cell position detection, 
crawling
152 CNR blue CM excitor crawling
166 CNR blue CM inhibitor crawling
Interneurons        
61 IC (2 ganglia) green serotonergic
gating		 swimming
204 Fn (unpaired) green gating swimming, crawling, 
behavioral decision
205 Fn (unpaired)
found in M9		 green gating swimming
208 IC (unpaired) green oscillator swimming
60 IC (2 ganglia) red oscillation 240° swimming
151 IC (NR) blue non-spiking a negative feedback
teo limit excessive
motor activity, 
crawling
153 CANR blue receive excitatory
photosensory input
oscillation 180°		 photoreception, swimming
154   blue photosensory input photoreception
157 CC blue EPSP long latency LB
159 PIC blue EPSP long latency LB, crawling
160   blue shifts swim phase but no oscillation swimming? 
161 IC blue EPSP from P cell LB
162 IC blue EPSP from P cell LB
169 CC blue EPSP long latency swimming, LB
201 CC blue receive inhibition from the SMRs water motion detection
202 CC blue receive excitation from the SMRs water motion detection
213 AIC blue ascending crawling
215   blue receive excitation
(ipsi-) sensillum 7		 photosensory reception
216   blue receive photosensory inputs photosensory reception
212 ACC blue EPSP from P cell LB
218 IC blue spotaneous EPSP LB
258 INR blue with large soma crawling
S Fn blue   LB, shortening, learning, crawling
HN IC (M1-M7) blue inhibitor IN 
heart oscillator		 control of heartbeat
E21 Fn M21 trigger/gating swimming
Mechanosensory cell        
T IC (NR)
(T1, T2, T3)		 yellow responds to tactile stimuli touch
P IC (NR)
(P1, P2)		 yellow responds to pressing stimuli on skin pressure
N IC (NR)
(N1, N2)		 yellow responds to noxious stimuli on skin, gut nociception
Neurosecretory cell        
R (Retzius) ICNR, IC pink contains serotonin swimming, feeding, muscle relaxation
50 (Leydig)   pink   LB, feeding

 

aColor codes correspond to the maps of segmental ganglia (Fig. 2). Coded with green and red are involved in swimming circuits.

bAbbreviations:
LM-longitudinal muscles     
DLM-dorsal LM            
VLM-ventral LM
FM-flattener muscles           
CM-circular muscles      
OM-oblique muscles
NR-nerve root                      
CANR-contralateral anterior NR
CNR-contralateral NR         
CPNR-contralateral posterior NR
INR-ipsilateral NR               
IPNR- ipsilateral posterior NR
IC-ipsilateral connectives     
AIC-anterior IC             
PIC-posterior IC
PCC-posterior contralateral connectives
LB-local bending
CM-circular muscle              
NR-nerve root                
CNR-contralateral NR
INR-ipsilateral NR               
CANR-contralateral anterior NR
IC-ipsilateral connectives     
AIC-anterior IC             
PIC-posterior IC
CC-contralateral connectives 
PCC-posterior CC
ACC-anterior CC                 
Fn-Favre’s nerve

cThis table provides an update of neurons listed in Muller KJ Nicholls JG Stent GS (1981) Neurobiology of the leech. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory, Appendix Table 1

References for additions to appendix Table 1

Cell DE-18  Nusbaum MP (1986) Synaptic basis of swim initiation in the leech. III. Synaptic effects of serotonin-containing interneurones (cells 21 and 61) on swim CPG neurones (cells 18 and 208). J Exp Biol 122:303-321

Cell 115  Friesen WO (1989) Neuronal control of leech swimming movements. II. Motor neruon feedback to oscillator cells 115 and 28. J Comp Physiol A 166:205-215

Cells CV, 152, 166, AP, 159, 213, 258  Baader AP (1997) Interneuronal and motor patterns during crawling behavior of semi-intact leeches. J Exp Biol 200:1369-1381

Leydig cell  Wilson RJ, Kristan WB Jr, Kleinhaus AL (1996) An increase in activity of serotonergic Retzius neurones may not be necessary for the consummatory phase of feeding in the leech Hirudo medicinalis. J Exp Biol 199:1405-1414

LB behavior Lockery SR, Kristan WB Jr. (1990) Distributed processing of sensory information in the leech. II. Identification of interneurons contributing to the local bending reflex. J Neurosci 10:1816-29

Garcia-Perez E, Zoccolan D, Pinato G, Torre V (2004) Dynamics and reproducibility of a moderately complex sensory-motor response in the medicinal leech. J Neurophysiol 92:1783-1795

Wittenberg G, Kristan WB Jr (1992) Analysis and modeling of the multisegmental coordination of shortening behavior in the medicinal leech. II. Role of identified interneurons. J Neurophysiol 68:1693-1707

AP cell  Shan D, Zhang RJ (2001) Frequency coding of positional information by an identified neuron, the AP cell, in the leech, Whitmania pigra. Brain Res Bull 56:511-515

AE cell  Rodriguez MJ, Iscla IR, Szczupak L (2004) Modulation of mechanosensory responses by motoneurons that regulate skin surface topology in the leech. J Neurophysiol 91:2366-2375

Cell 151 Wadepuhl M (1987) A morpho- and physiologically uncommon neuron in the leech CNS. Naturwissenschaften 74:43-45