Gastric mill rhythms in intact crabs

Feeding and digestion in low salinity in an osmoconforming crab, Cancer gracilis II. Gastric evacuation and motility

“…In the X-ray preparations these were seen as small amplitude 'pumping' type contractions. The contractions were more stable and rapid than those of the cardiac region; rates of 60-85·min -1 agree with data for other species (Morris and Maynard, 1970;Powers, 1973;Heinzel, 1988;Heinzel et al, 1993). Pyloric contractions varied with both time and salinity.…”

“…Movements of the cardiac region of the foregut were sporadic and were not observed in every animal. This sporadic pattern of contraction is also reported for Homarus americanus (Morris and Maynard, 1970), Cancer magister, Cancer productus (Powers, 1973), Panulirus interruptus (Heinzel, 1988) and Cancer pagurus (Heinzel et al, 1993). Because movements were sporadic and the crabs were only observed under the fluoroscope for about 60·s at a time, this probably accounted for the lack of a discernible pattern of cardiac stomach activity in low salinity (Fig.·6A).…”

Feeding and digestion in low salinity in an osmoconforming crab, Cancer gracilis II. Gastric evacuation and motility

“…In the X-ray preparations these were seen as small amplitude 'pumping' type contractions. The contractions were more stable and rapid than those of the cardiac region; rates of 60-85·min -1 agree with data for other species (Morris and Maynard, 1970;Powers, 1973;Heinzel, 1988;Heinzel et al, 1993). Pyloric contractions varied with both time and salinity.…”

“…Movements of the cardiac region of the foregut were sporadic and were not observed in every animal. This sporadic pattern of contraction is also reported for Homarus americanus (Morris and Maynard, 1970), Cancer magister, Cancer productus (Powers, 1973), Panulirus interruptus (Heinzel, 1988) and Cancer pagurus (Heinzel et al, 1993). Because movements were sporadic and the crabs were only observed under the fluoroscope for about 60·s at a time, this probably accounted for the lack of a discernible pattern of cardiac stomach activity in low salinity (Fig.·6A).…”

Neural mechanisms underlying the generation of the lobster gastric mill motor pattern

“…There are therefore seven total synchronized phases produced by this simplified network operating at a frequency of about 0.1 Hz. This is somewhat faster than the in vivo gastric mill rhythms that have been reported in crabs (Powers, 1973 ; Heinzel et al, 1993 ) and lobsters (Turrigiano and Selverston, 1990 ). In addition to the intrinsic burst frequency of Int 1, the presence of synapses with different strengths and time constants also contribute to the long bursts of motoneuron activity (Elson and Selverston, 1995 ).…”

State-dependent sensorimotor gating in a rhythmic motor system

“…The gastric mill rhythm (cycle period range~10 -20 s) is a two-phase motor pattern consisting of a protraction phase and a retraction phase that define the movement of the teeth toward and away from the midline, respectively, during chewing (Diehl et al 2013;Heinzel 1988;Heinzel et al 1993;Powers 1973). During gastric mill rhythms generated in the isolated STNS (Fig.…”

Feeding and digestion in low salinity in an osmoconforming crab, Cancer gracilis II. Gastric evacuation and motility

“…In the X-ray preparations these were seen as small amplitude 'pumping' type contractions. The contractions were more stable and rapid than those of the cardiac region; rates of 60-85·min -1 agree with data for other species (Morris and Maynard, 1970;Powers, 1973;Heinzel, 1988;Heinzel et al, 1993). Pyloric contractions varied with both time and salinity.…”

“…Movements of the cardiac region of the foregut were sporadic and were not observed in every animal. This sporadic pattern of contraction is also reported for Homarus americanus (Morris and Maynard, 1970), Cancer magister, Cancer productus (Powers, 1973), Panulirus interruptus (Heinzel, 1988) and Cancer pagurus (Heinzel et al, 1993). Because movements were sporadic and the crabs were only observed under the fluoroscope for about 60·s at a time, this probably accounted for the lack of a discernible pattern of cardiac stomach activity in low salinity (Fig.·6A).…”

Neural mechanisms underlying the generation of the lobster gastric mill motor pattern

“…There are therefore seven total synchronized phases produced by this simplified network operating at a frequency of about 0.1 Hz. This is somewhat faster than the in vivo gastric mill rhythms that have been reported in crabs (Powers, 1973 ; Heinzel et al, 1993 ) and lobsters (Turrigiano and Selverston, 1990 ). In addition to the intrinsic burst frequency of Int 1, the presence of synapses with different strengths and time constants also contribute to the long bursts of motoneuron activity (Elson and Selverston, 1995 ).…”

State-dependent sensorimotor gating in a rhythmic motor system

“…The gastric mill rhythm (cycle period range~10 -20 s) is a two-phase motor pattern consisting of a protraction phase and a retraction phase that define the movement of the teeth toward and away from the midline, respectively, during chewing (Diehl et al 2013;Heinzel 1988;Heinzel et al 1993;Powers 1973). During gastric mill rhythms generated in the isolated STNS (Fig.…”

Feeding and digestion in low salinity in an osmoconforming crab, Cancer gracilis II. Gastric evacuation and motility

“…In the X-ray preparations these were seen as small amplitude 'pumping' type contractions. The contractions were more stable and rapid than those of the cardiac region; rates of 60-85·min -1 agree with data for other species (Morris and Maynard, 1970;Powers, 1973;Heinzel, 1988;Heinzel et al, 1993). Pyloric contractions varied with both time and salinity.…”

“…Movements of the cardiac region of the foregut were sporadic and were not observed in every animal. This sporadic pattern of contraction is also reported for Homarus americanus (Morris and Maynard, 1970), Cancer magister, Cancer productus (Powers, 1973), Panulirus interruptus (Heinzel, 1988) and Cancer pagurus (Heinzel et al, 1993). Because movements were sporadic and the crabs were only observed under the fluoroscope for about 60·s at a time, this probably accounted for the lack of a discernible pattern of cardiac stomach activity in low salinity (Fig.·6A).…”

Neural mechanisms underlying the generation of the lobster gastric mill motor pattern

“…There are therefore seven total synchronized phases produced by this simplified network operating at a frequency of about 0.1 Hz. This is somewhat faster than the in vivo gastric mill rhythms that have been reported in crabs (Powers, 1973 ; Heinzel et al, 1993 ) and lobsters (Turrigiano and Selverston, 1990 ). In addition to the intrinsic burst frequency of Int 1, the presence of synapses with different strengths and time constants also contribute to the long bursts of motoneuron activity (Elson and Selverston, 1995 ).…”

State-dependent sensorimotor gating in a rhythmic motor system

“…The gastric mill rhythm (cycle period range~10 -20 s) is a two-phase motor pattern consisting of a protraction phase and a retraction phase that define the movement of the teeth toward and away from the midline, respectively, during chewing (Diehl et al 2013;Heinzel 1988;Heinzel et al 1993;Powers 1973). During gastric mill rhythms generated in the isolated STNS (Fig.…”