Acoustic similarity of flight calls corresponds with the composition and structure of mixed-species flocks of migrating birds: evidence from a three-dimensional microphone array.

Animals that migrate in mixed-species groups may communicate with both conspecific and heterospecific individuals, providing a low-cost mechanism for navigation whenever individuals share similar migratory routes or destinations. Many migratory birds produce calls while flying, but the function of these calls, and the forces contributing to their evolution, are poorly known. We studied flight calls in mixed-species groups of wood warblers (Parulidae), a biodiverse group of migratory songbirds. We used a spatial approach to examine whether acoustic similarity of flight calls varies with group composition, recording flight calls of mixed-species flocks with a wireless microphone array and triangulating the positions of birds in three dimensions. We found that the acoustic similarity of flight calls was correlated with spatial proximity: birds with similar calls fly closer together during migration. We also found relationships between acoustic similarity, flock size and mixed-species flock diversity: birds with similar calls fly in smaller flocks and in flocks with lower species diversity. Our results support the idea that migrating birds use flight calls to maintain contact with acoustically similar individuals in mixed-species flocks, with communication transcending species boundaries. These results suggest that acoustically similar flight calls are used as cues of group assembly for migratory animals. This article is part of the theme issue 'Mixed-species groups and aggregations: shaping ecological and behavioural patterns and processes'.

The evolution of wood warbler flight calls: Species with similar migrations produce acoustically similar calls.

Diverse animal species engage in long-distance migrations. Many migrants travel in groups, and communication within these groups may be important to survival and successful migration. We examined migration and communication in 36 species of wood warblers (Parulidae), songbirds that breed in North America and migrate in mixed-species flocks to their wintering grounds. During migration, wood warblers produce short vocalizations called "flight calls." The function of flight calls and the patterns of acoustic similarity between species are poorly understood. We investigated whether acoustic similarity of flight calls of different species of warbler reflects the similarity in their migratory journeys or their phylogenetic relatedness. We found that phylogeny, similarity in breeding latitude, and overlap in the timing of migration predict acoustic flight call similarity across warbler species. Further, we found that phylogeny, similarity in migration distance, and overlap in wintering range predict acoustic flight call similarity in a subset of 12 species with highly similar calls, although this analysis has a small sample size. We conclude that migratory similarity may be an important force driving the evolution of acoustically similar calls in wood warblers, in addition to phylogenetic relatedness. Acoustic convergence in these species may facilitate communication between individuals with similar migrations.

Genomic insights into natural selection in the common loon (Gavia immer): evidence for aquatic adaptation.

BACKGROUND: The common loon (Gavia immer) is one of five species that comprise the avian order Gaviiformes. Loons are specialized divers, reaching depths up to 60 m while staying submerged for intervals up to three minutes. In this study we used comparative genomics to investigate the genetic basis of the common loon adaptations to its ecological niche. We used Illumina short read DNA sequence data from a female bird to produce a draft assembly of the common loon (Gavia immer) genome. RESULTS: We identified 14,169 common loon genes, which based on well-resolved avian genomes, represent approximately 80.7% of common loon genes. Evolutionary analyses between common loon and Adelie penguin (Pygoscelis adeliae), red-throated loon (Gavia stellata), chicken (Gallus gallus), northern fulmar (Fulmarus glacialis), and rock pigeon (Columba livia) show 164 positively selected genes in common and red-throated loons. These genes were enriched for a number of protein classes, including those involved in muscle tissue development, immunoglobulin function, hemoglobin iron binding, G-protein coupled receptors, and ATP metabolism. CONCLUSIONS: Signatures of positive selection in these areas suggest the genus Gavia may have adapted for underwater diving by modulating their oxidative and metabolic pathways. While more research is required, these adaptations likely result in (1) compensations in oxygen respiration and energetic metabolism, (2) low-light visual acuity, and (3) elevated solute exchange. This work represents the first effort to understand the genomic adaptations of the common loon as well as other Gavia and may have implications for subsequent studies that target particular genes for loon population genetic, ecological or conservation studies.

Modifying the Functional Movement Screen Deep Squat Test: The Effect of Foot and Arm Positional Variations.

The functional movement screen (FMS) was developed as an evaluation tool for assessing the fundamental movement patterns believed to be prerequisites for functional activity. However, some of the FMS component movements, such as the deep overhead squat test (DST), likely represent novel motor challenges on which poor performance might reflect inexperience with the task rather than a movement impairment. The purpose of this study was to examine the effects of positional variations on DST scores in a population of young, healthy adults. We hypothesized that self-selecting foot positioning, removal of an overhead component, or changing both aspects of the DST would result in improvement in FMS scores. Twenty healthy subjects completed 4 squatting conditions in a counterbalanced sequence to eliminate carry over effects: DST, modified squat with hands at chest level and feet in the DST position (DSTO), modified squat with arms in the DST position and self-selected foot placement (DSTF), and modified squat with hands at chest level and self-selected foot placement (DSTB). A Friedman's analysis of variance and Wilcoxon signed-ranks' post hoc analysis revealed a significant difference between all squat conditions (p = 0.036), between DSTB-DST groups (p < 0.001), DSTO-DST groups (p = 0.004), and DSTO-DSTB groups (p = 0.046). Each modified squat condition had an average score higher than the DST. These findings suggest that the FMS DST might underestimate an individual's ability to squat during functional tasks that involve self-selected foot and arm placement.

Outreach impact study: the case of the Greater Midwest Region.

OBJECTIVES: The purpose of the study was to assess the impact that funding from the National Network of Libraries of Medicine (NN/LM), Greater Midwest Region (GMR), has on member institutions' ability to conduct outreach on behalf of NN/LM. METHODS: The study employed both content analysis and survey methodologies. The final reports from select GMR-funded outreach projects (n = 20) were analyzed based on a set of evaluation criteria. Project principal investigators (n = 13) were then surveyed using the same evaluation criteria. RESULTS: Results indicated that outreach projects supported by GMR funding improved access to biomedical information for professionals and the general public. Barriers to conducting outreach projects included time constraints or commitments, staffing, scheduling and absenteeism, inadequate space, and issues associated with technology (e.g., hardware and software, Internet connectivity and firewall issues, and creation and use of new technologies). CONCLUSIONS: The majority of project principal investigators indicated that their attempts to conduct outreach were successful. Moreover, most noted that outreach had a positive impact on professionals as well as the general public. In general, it seems that negative outcomes, as with most barriers to conducting outreach, can be mitigated by more thorough planning.

The short-term effect of hippotherapy on spasticity in patients with spinal cord injury.

STUDY DESIGN: Assessment of spasticity before and after hippotherapy treatment. OBJECTIVE: To evaluate the short-term effect of hippotherapy on spasticity of spinal cord injured patients (SCIs). SETTING: Swiss Paraplegic Centre, Nottwil. METHODS: 32 patients with spinal cord injury with various degrees of spasticity had repeated sessions (mean 11) of Hippotherapy-K. Spasticity of the lower extremities was scored according to the Ashworth Scale. RESULTS: In primary rehabilitation patients Ashworth values after hippotherapy were significantly lower than before (Wilcoxon's signed-rank test: P<0.001). Highest improvements were observed in SCIs with very high spasticity. No significant difference between short-term effect in paraplegic and short-term effect in tetraplegic subjects was found. CONCLUSIONS: Hippotherapy significantly reduces spasticity of lower extremities in SCIs.

Characteristics of sleep apnea syndrome in tetraplegic patients.

OBJECTIVE: To include a larger number of tetraplegics than in previous studies, in order to more reliably characterize the pathogenesis and predisposing factors of sleep apnea in tetraplegia. METHODS: Sleep breathing data and oxymetric values were investigated in 50 randomly selected tetraplegic patients and discussed in context with age, gender, BMI, neck circumference, type and height of lesion, time after injury, spirometric values and medication. A non-validated short questionnaire on daytime complaints was added. RESULTS: Thirty-one patients out of 50 had an RDI > or =15, defined as sleep disordered breathing (SDB); 24 of them combined with an apnea index of 5 or more, these cases were diagnosed as sleep apnea syndrome (SAS). SAS was apparent in 55% and 20% of the studied men and women, respectively. Regression analyses showed no significant correlation between RDI and lesion level, ASIA impairment scale or spirometric values. In contrast, a significant correlation between RDI and age, BMI, neck circumference and time after injury could be shown. Kruskal-Wallis test for dichotomous non-parametric factors, such as gender, cardiac medication and daytime complaints, showed significant differences with regard to RDI. In contrast to able-bodied people with SAS, daytime complaints were only present in tetraplegic patients with severe pathology (RDI>40). CONCLUSION: Incidence of SAS is high in tetraplegia, particularly in older male patients with large neck circumference, long standing spinal cord injury and under cardiac medication. As tetraplegics with RDI between 15 and 40 reported no daytime complaints and often have normal BMI, these tetraplegics are not clinically suspicious for SAS. The increased use of cardiac medication in tetraplegics with SAS may implicate a link between SAS and cardiovascular morbidity, one of the leading causes of death in tetraplegia.

[MRI in spinal injuries]. / MRT bei Myelonverletzungen.

The improvement of preclinical emergency medicine has increased the long-term survival of patients which sustained severe injuries of the spinal cord. However, the incidence of late complications has been increased due to the long-term survival. With the increasing use of magnetic resonance imaging (MRI) in this patient group the diagnosis of typical late complications of the spinal cord has improved. In this article we suggest the following terms to describe late complications of the spinal cord: syrinx, atrophy, cyst, malacia, disruption, and thethering.

Arterial properties of the carotid and femoral artery in endurance-trained and paraplegic subjects.

In humans, the relationships of blood flow changes to structure, function, and shear rate of conducting arteries have not been thoroughly examined. Therefore, the purpose of this study was to investigate these parameters of the elastic-type, common carotid artery (CCA) and the muscular-type, common femoral artery (CFA) in long-term highly active and extremely inactive individuals, assuming that the impact of activity-induced blood flow changes on conduit arteries, if any, should be seen in these subjects. We examined 21 highly endurance-trained athletes (A), 10 paraplegic subjects (P), and 20 sedentary subjects (S) by means of noninvasive ultrasound. As a result, the CFA diameter and compliance were highest in A (9.7+/-0.81 mm; 1.84 +/-0.54 mm(2)/kPa) and lowest in P (5.9+/-0.7 mm; 0.54+/-0.27 mm(2)/kPa) compared with S (8.3+/-1.0 mm; 0.92+/-0.48 mm(2)/kPa) with P <0.01 among the groups. Both parameters correlated with each other (r = 0.62; P<0.01). Compared with A (378+/-84 s(-1); 37+/-15 s(-1)) and S (356+/-113 s(-1); 36+/-20 s(-1)), the peak and mean shear rates of the CFA were almost or more than doubled in P (588+/-120 s(-1); 89+/-26 s(-1)). In the CCA, only the compliance and peak shear rate showed significant differences among the groups (A: 1.28+/-0.47 mm(2)/kPa, 660+/-138 s(-1); S: 1.04+/-0.27 mm(2)/kPa, 588+/-109 s(-1); P: 0.65+/- 0.22 mm(2)/kPa, 490+/-149 s(-1); P<0.05). In conclusion, the results suggest a structural and functional adaptation in the CFA and a predominantly functional adaptation of the arterial wall properties to differences in the physical activity level and associated exercise-induced blood flow changes in the CCA. The results for humans confirm those from animal experiments. Similar shear rate values of S and P in the CFA support the hypothesis of constant shear stress regulation due to local blood flow changes in humans. On the other hand, the increased shear rate in the CFA in P indicates an at least partially nonphysiological response of the arterial wall in long-term chronic sympathectomy due to a change in local blood flow.

Reorganization of the human central nervous system.

The key strategies on which the discovery of the functional organization of the central nervous system (CNS) under physiologic and pathophysiologic conditions have been based included (1) our measurements of phase and frequency coordination between the firings of alpha- and gamma-motoneurons and secondary muscle spindle afferents in the human spinal cord, (2) knowledge on CNS reorganization derived upon the improvement of the functions of the lesioned CNS in our patients in the short-term memory and the long-term memory (reorganization), and (3) the dynamic pattern approach for re-learning rhythmic coordinated behavior. The theory of self-organization and pattern formation in nonequilibrium systems is explicitly related to our measurements of the natural firing patterns of sets of identified single neurons in the human spinal premotor network and re-learned coordinated movements following spinal cord and brain lesions. Therapy induced cell proliferation, and maybe, neurogenesis seem to contribute to the host of structural changes during the process of re-learning of the lesioned CNS. So far, coordinated functions like movements could substantially be improved in every of the more than 100 patients with a CNS lesion by applying coordination dynamic therapy. As suggested by the data of our patients on re-learning, the human CNS seems to have a second integrative strategy for learning, re-learning, storing and recalling, which makes an essential contribution of the functional plasticity following a CNS lesion. A method has been developed by us for the simultaneous recording with wire electrodes of extracellular action potentials from single human afferent and efferent nerve fibres of undamaged sacral nerve roots. A classification scheme of the nerve fibres in the human peripheral nervous system (PNS) could be set up in which the individual classes of nerve fibres are characterized by group conduction velocities and group nerve fibre diameters. Natural impulse patterns of several identified single afferent and efferent nerve fibres (motoneuron axons) were extracted from multi-unit impulse patterns, and human CNS functions could be analyzed under physiologic and pathophysiologic conditions. With our discovery of premotor spinal oscillators it became possible to judge upon CNS neuronal network organization based on the firing patterns of these spinal oscillators and their driving afferents. Since motoneurons fire occasionally for low activation and oscillatory for high activation, the coherent organization of subnetworks to generate macroscopic function is very complex and for the time being, may be best described by the theory of coordination dynamics. Since oscillatory firing has also been observed by us in single motor unit firing patterns measured electromyographically, it seems possible to follow up therapeutic intervention in patients with spinal cord and brain lesions not only based on the activity levels and phases of motor programs during locomotion but also based on the physiologic and pathophysiologic firing patterns and recruitment of spinal oscillators. The improvement of the coordination dynamics of the CNS can be partly measured directly by rhythmicity upon the patient performing rhythmic movements coordinated up to milliseconds. Since rhythmic dynamic, coordinated, stereotyped movements are mainly located in the spinal cord and only little supraspinal drive is necessary to initiate, maintain, and terminate them, rhythmic, dynamic, coordinated movements were used in therapy to enforce reorganization of the lesioned CNS by improving the self-organization and relative coordination of spinal oscillators (and their interactions with occasionally firing motoneurons) which became pathologic in their firing following CNS lesion. Paraparetic, tetraparetic spinal cord and brain-lesioned patients re-learned running and other movements by an oscillator formation and coordination dynamic therapy. Our development in neurorehabilitation is in accordance with those of theoretical and computational neurosciences which deal with the self-organization of neuronal networks. In particular, jumping on a springboard 'in-phase' and in 'anti-phase' to re-learn phase relations of oscillator coupling can be understood in the framework of the Haken-Kelso-Bunz coordination dynamic model. By introducing broken symmetry, intention, learning and spasticity in the landscape of the potential function of the integrated CNS activity, the change in self-organization becomes understandable. Movement patterns re-learned by oscillator formation and coordination dynamic therapy evolve from reorganization and regeneration of the lesioned CNS by cooperative and competitive interplay between intrinsic coordination dynamics, extrinsic therapy related inputs with physiologic re-afferent input, including intention, motivation, supervised learning, interpersonal coordination, and genetic constraints including neurogenesis. (ABSTRACT TRUNCATED)

Neuronal reorganization through oscillator formation training in patients with CNS lesions.

A method has been developed for the simultaneous recording with wire electrodes of extracellular action potentials from single human afferent and efferent nerve fibres of undamaged sacral nerve roots. A classification scheme of the human peripheral nervous system (PNS) could be set up in which the individual classes of nerve fibres are characterized by group conduction velocities and group nerve fibre diameters. Natural impulse patterns of several identified single afferent and efferent nerve fibres can be extracted from the multi-unit impulse patterns, and human central nervous system (CNS) functions can be analyzed under physiologic and pathophysiologic conditions. With the discovery of premotor spinal oscillators it became possible to judge upon CNS neuronal network functions based on the firing patterns of these spinal oscillators. Since oscillatory firing has also been observed in electromyographic (EMG) single motor unit firing patterns, it seems possible to follow up therapeutic intervention in patients with spinal cord lesion not only based on the activity levels and phases of motor programs during locomotion but also based on the physiologic and pathophysiologic firing patterns and recruitment of spinal oscillators. Since rhythmic, dynamic, stereotyped, symmetric movements are mainly located in the spinal cord and only little supraspinal drive is necessary to initiate, maintain (especially), and terminate them, rhythm training methods were used to enforce reorganization of the CNS following spinal cord and CNS lesions to improve the self-organization and relative coordination of spinal oscillators which became pathologic in their firing following CNS lesion. Paraparetic, tetraparetic and brain-lesioned patients relearned running and other movements by an oscillator formation training. This development in neurorehabilitation is in accordance with those of theoretical and computational neurosciences which consider self-organization of neuronal networks. In particular, jumping on a springboard 'in phase' and 'in antiphase' to relearn phase relations of oscillator coupling can be understood in the Haken-Kelso-Bunz model. By introducing broken symmetry, intention, learning and spasticity in the landscape of the potential function of the integrated CNS activity, the change in self-organization becomes understandable. In conclusion, movement patterns relearned by oscillator formation training evolve from reorganization, and perhaps regeneration, of the lesioned CNS by cooperative and competitive interplay between intrinsic coordination dynamics, extrinsic training-related inputs with physiologic re-afferent input, including intention and supervised learning, and genetic constraints including neurogenesis.

The oral hygiene and gingival health of paraplegic inpatients--a cross-sectional survey.

Physical and/or mental handicaps are known to directly or indirectly compromise hygiene habits including oral hygiene. It is recommended that handicapped patients, their parents or care workers require from an early stage dental health education and active involvement in preventive programmes. This study surveyed the oral hygiene of paraplegic patients in a specialised centre to determine their oral hygiene needs. Most patients had moderate to poor oral hygiene and gingivitis was prevalent and severe. Plaque and gingivitis was increased in quadriplegic compared to hemiplegic patients. The data indicate that as part of rehabilitation of paraplegic patients there is a need for oral hygiene programmes to be established.

Antiseptic efficacy of disinfecting solutions in suspension test in vitro against methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli in pressure sore wounds after spinal cord injury.

In pressure sore wounds after spinal cord injury, methicillin-resistant Staphylococcus aureus can be detected in 2% of the cases. The elimination of the germ is the aim of the treatment. Pressure sore wounds are an often found complication after spinal cord injury. For local treatment five commercially available antiseptics for the skin and mucous membrane were tested in vitro. The method used is a modified qualitative and quantitative suspension test. The antiseptics were tested without and with addition of 5% albumin in order to simulate the conditions of the wound in vivo. The results show a superior efficacy of the povidone-iodine preparations. Betadine, probably due to the higher concentration, is more efficacious than Braunol; chlorhexidine is sufficiently efficacious without the addition of albumin. These results still have to be confirmed by in vivo studies.

Classification, oscillatory and alternating oscillatory firing of alpha 1 (FF) and alpha 2-motoneurons (FR) in patients with spinal cord lesion.

Single-nerve fibre action potentials (APs) were recorded extracellularly from sacral nerve roots of people with spinal cord lesion (patients with paraplegia). Single-fibre APs of certain fibres were identified by the conduction velocity and the AP waveform, and simultaneous impulse patterns were extracted from the summed impulse traffic and analysed with respect to spacio-temporal relationships. The velocity values of components of compound APs, induced by electrical nerve root stimulation or electrical intravesical stimulation, were similar to the group conduction velocity values obtained from single-nerve fibre APs of natural impulse traffic. When changing the root temperature in one case from 32 degrees C to 35.5 degrees C, the group conduction velocities changed in the following way: secondary muscle spindle afferents (SP2): 40 m/s (32 degrees C) to 50 m/s (35.5 degrees C); bladder stretch afferents (S1): 31.3 to 40 m/s; bladder tension afferents (ST): 25 to 33.8 m/s; mucosal afferents (M): 12.5 to 13.8 m/s; alpha 1:-; alpha 2-motoneurons: 40 to 50 m/s; alpha 3: 33 to 40 m/s. The group conduction velocities showed different temperature dependence apart from SP2 fibres and alpha 2-motoneurons, which were therefore used for calibration. The distance between two Pacinian corpuscle (PC) receptors in a sacral dermatome of one paraplegic patient was calculated to be approximately 20 mm. A similar distance between PC receptors was found in a brain-dead individual. Receptor densities seem therefore to remain unchanged following spinal cord lesion. Motoneurons fired irregularly repeatedly with impulse trains. In paraplegics the oscillation periods and the interspike intervals of the impulse trains varied much more than observed for brain-dead and normal individuals. Motoneurons could therefore not always be identified by their pattern of oscillatory firing. Alternating long and short oscillation periods (T) could be measured in an oscillatory firing alpha 1 (T = 125 ms) and alpha 2-motoneuron (T = 150 ms). In both cases the average difference between the alternating oscillation periods was 5 ms. Tremor, alternating long and short oscillation periods, cellular oscillator properties, and recurrent excitation and inhibition are discussed with respect to the oscillator theory of the functioning of the human central nervous system. Mathematical predictions from populations of interacting biological oscillators are compared to measurements on neuronal network data.

Mono- and polysynaptic drive of oscillatory firing alpha 1 (FF) and alpha 2-motoneurons (FR) in a patient with spinal cord lesion.

Single-nerve fibre action potentials (APs) were recorded extracellularly from lower sacral nerve roots of patients with spinal cord lesions (paraplegics), and simultaneous single-fibre impulse patterns of alpha 1 (FF) and alpha 2-motoneurons (FR) and primary and secondary muscle spindle afferents were analyzed. An alpha 1-motoneuron was activated in a time-locked manner by a primary spindle afferent fibre to fire oscillatory with an oscillation period of 110 to 140 ms. The distribution width for the time-locking (phase) was approx. 3 ms, which is interpreted as monosynaptic activation. A phase-correlated firing of a secondary muscle spindle afferent fibre gave rise to an additional oscillation period of the oscillatory firing alpha 1-motoneuron, when the primary fibre ceased firing. The phase distribution width was approx. 80 ms, and therefore indicates polysynaptic drive. The drive of the oscillatory firing alpha 1-motoneuron thus included a monosynaptic from a primary and a polysynaptic activation from a secondary muscle spindle afferent fibre. An alpha 2-motoneuron was simultaneously activated to fire oscillatory by a different secondary spindle afferent fibre. The phase distribution width between them was approx. 120 ms, which indicates polysynaptic drive. The alpha 1 and alpha 2-motoneurons fired in the occasional firing mode and in the transient and continuous oscillatory firing mode. Upon touch, pin-prick and bladder and anal catheter pulling, the alpha 1-motoneuron changed its firing rate more quickly than did the alpha 2-motoneuron. Thus, the alpha 1-motoneuron fired more dynamically than did the alpha 2-motoneuron. Synchronous oscillatory firing of the alpha 1 and alpha 2-motoneurons occurred transiently during pin-pricking. It is discussed that transient synchronization of oscillatory firing motoneurons points to relative coordination of self-organized oscillatory firing motoneuronal networks to generate locomotion and other integrative functions. It is further discussed that loss of specific properties of spinal oscillators following spinal cord lesion may give rise to pathologic synchronization, and in this way to disorders in movement.

Reflex stimulation of continuously oscillatory firing alpha and gamma-motoneurons in patients with spinal cord lesion.

Single nerve-fibre action potentials (APs) were recorded extracellularly from lower human sacral nerve roots, and simultaneous single-fibre impulse patterns of alpha and gamma-motoneurons and secondary muscle spindle afferents were analysed. Identified alpha and gamma-motoneurons fired oscillatory, due to the sustained stretch reflex of the external sphincters induced by an anal catheter (and, possibly, the bladder catheter). The motoneurons and the secondary muscle spindle afferents transiently synchronized their firing upon repetitive touch, pin-prick and dimpling stimulation of the perianal skin inside the anal reflex area, by reducing the duration of their oscillation period until resetting of the oscillation cycle. In one case, the anal reflex area extended approximately 6 cm laterally from the anus. The responses to pin-prick stimulation were different from those to touch stimulation in three aspects. Firstly, the response time till the shortening of the oscillation period was longer than the oscillation period (approximately 100 ms) for pin-prick, and it was shorter for touch. Second, the response to pain stimulus was longer (shortening of several oscillation periods) and stronger than for touch stimulation. Pin-prick stimulation reduced the oscillation period to between 5 and 40 ms (mean = 18 ms), and touch stimulation to between 8 and 28 ms (mean = 15 ms). Third, transient synchronization of afferents and efferents was most pronounced for pin-prick stimulation. The shortest latency following touch was approx. 10 ms when measuring from the afferent volley running in the direction of the spinal cord, and 30 ms when measuring from the beginning of the skin touch. It is discussed that repetitive touch stimulation reinforced the sustained stretch reflex of the anal sphincter which is possible with no network reorganization (variation of the same network state) and therefore fast, whereas repetitive pin-prick stimulation replaced the sustained stretch reflex by the protection reaction of the anal sphincter (change from one network state to a different one) which made time consuming network reorganization necessary. Different sacral reflexes were analysed by studying time-related activation changes of group conduction velocities in velocity distributions. During the reflex response to stretch of the external anal sphincter, the alpha 2-motoneurons (FR) (and the secondary muscle spindle afferents) were strongly activated whereas upon eliciting the bulbocavernosus reflex (squeezing of the glans penis) the alpha 3-motoneurons (S) were mainly activated. Sacral reflexes are discussed with respect to the organization and reorganization of preformated neuronal networks, and the synchronization of oscillatory firing networks is discussed with respect to the overlapping of synfire chains.