Food-procuring skill in rats: prolongations of the extension phase in final movements of right-handed rats

In Wistar rats with different forepaw preference trained to get food spheres from a narrow horizontal tube feeder, the duration of the paw extension phase was studied in both preliminary and final (successful) food-procuring movements. In left-handed rats, the paw extension was fastly in both preliminary and final movements than in right-handed animals. In right-handed animals, the extension phase of the final successful movements was much slower than that of preliminary movements, whereas in left-handed rats the slowing of the final extension was poorly expressed. The prolongation of the extension phase suggests a possibility of correction of the extension phase of the goal-directed movements     

The reorganization of bimanual movements during formation of a lateralized motor food skill in rats

After 48 h food deprivation adult Wistar rats were trained to obtain food from a narrow tube feeder using the forepaw under conditions of free choice of limb. At the initial stage of training animals use both paws: the grasping and extraction with one paw can be alternated with food grasping and extraction with another paw, and both paws can be alternately involved in movements preceding this grasping. Character of reorganization of bimanual movements was analyzed during training rats with different motor preference (right-handed and left-handed animals). It was shown that in the process of acquisition of both right- and left-hand skills, bimanual reactions in the anticipating attempts disappeared later than in the final successful movements. The disappearance of bimanual movements in the anticipating attempts is considered as an index of the maximum skill lateralization and acquisition of a novel lateralized movement coordination. The results suggest that left-handed rats more rapidly learn a novel movement coordination than right-handed animals.     

Deficits and recovery of body stabilization during acrobatic locomotion after focal lesion to the somatosensory cortex: a kinematic analysis combined with cortical mapping

We used a kinematic analysis for assessing locomotor impairments and evaluating the time course of recovery after focal injury to the forepaw area of the primary somatosensory cortex (SI) in rats. The animals were trained to traverse a beam that was rotated at various speeds. Changes in orientation of the body and independent movement of the anterior and posterior parts of the body were reconstructed using a 3D motion analysis. In addition, we used electrophysiological cortical mapping to search for neurophysiological changes within the spared cortical zones surrounding the lesion. Neuronal recordings were performed in the same animals prior to and 3 weeks after the lesion induction. Our findings show that a focal lesion that destroyed about 60% of the forepaw representational zone was sufficient to cause conspicuous impairments in the rats' ability to produce adequate motor adjustments to compensate for the lateral shift of the beam and to avoid falling. The main deficits were reflected in a lack of appropriate coordination between the anterior and posterior parts of the body and an inability to maintain a regular gait during locomotion. Skilled locomotion was fully recovered within a 2-3 week period. Functional recovery cannot be ascribed to a restitution of the lost sensory representations. A permanent decrease of forepaw representation was recorded despite the re-emergence of restricted representational sectors in the peri-lesion zone. We suggest that alterations may have occurred in other cortical and subcortical areas interconnected with the injured area. It is also conceivable that the functional recovery involved an increased reliance on all the available sources of sensorimotor regulation as well as the use of behavioral strategies.     

The effects of handling on antibody production, mitogen responses, spleen cell number, and lymphocyte subpopulations

The effects of a simple psychosocial manipulation, handling, on immune function in BALB/c.ByJ mice were studied. Handling for two minutes/day prior to immunization was shown to be associated with a decreased primary IgG antibody response to the protein antigen keyhole limpet hemocyanin. Handling was also associated with decreased T cell proliferative responses to Concanavalin A. No reliable changes in spleen cell number or lymphocyte subsets were found. These findings demonstrate that simply picking up an animal results in modulation of the immune response. These data are also of interest for their obvious methodological implications.     

Validation of Computed Tomographic Estimates of Intra‐abdominal and Subcutaneous Adipose Tissue in Rats and Mice

We characterized the accuracy, sensitivity, and reliability of computed tomographic (CT) estimates of intra‐abdominal (IA) and subcutaneous (S) adipose tissue (AT) in rats and mice using the Aloka rodent CT. Here, we present the first comparisons of CT estimates of the weights of AT samples ex vivo to balance weights of the same samples, of CT estimates of AT weights in vivo to the weights of resected whole‐body AT, and of CT estimates of the weights of pieces of AT inserted IA or S in vivo to the weights of the same pieces ex vivo. CT underestimated AT weight ex vivo by ～10%, and correction of the automated categorization of IAAT and SAT by Aloka software was required. After these adjustments, correlations (r) of CT estimates and balance weights of resected AT were ≥0.99 in rats and ≥0.92 in mice. CT was impressively sensitive: the 95% probability range of CT estimates of 10,000 mg AT inserts into rats was ±780 mg and of 500 mg inserts into mice, ±20 mg. Scans limited to the abdominal region correlated well (r > 0.90) with whole‐body scan measures of IAAT and SAT in rats and with IAAT, but not SAT (r < 0.80), in mice. Sums of IAAT and SAT correlated well with body weight in rats (r > 0.90), but not in mice (r < 0.80). Coefficients of variance (CVs) of duplicate scans were <5%. We conclude that CT is a valid tool for studies of AT weight in rats and mice, especially when rapid throughput or longitudinal measures are desired.     

Music Attenuates Excessive Visual Guidance of Skilled Reaching in Advanced but Not Mild Parkinson's Disease

Parkinson''s disease (PD) results in movement and sensory impairments that can be reduced by familiar music. At present, it is unclear whether the beneficial effects of music are limited to lessening the bradykinesia of whole body movement or whether beneficial effects also extend to skilled movements of PD subjects. This question was addressed in the present study in which control and PD subjects were given a skilled reaching task that was performed with and without accompanying preferred musical pieces. Eye movements and limb use were monitored with biomechanical measures and limb movements were additionally assessed using a previously described movement element scoring system. Preferred musical pieces did not lessen limb and hand movement impairments as assessed with either the biomechanical measures or movement element scoring. Nevertheless, the PD patients with more severe motor symptoms as assessed by Hoehn and Yahr (HY) scores displayed enhanced visual engagement of the target and this impairment was reduced during trials performed in association with accompanying preferred musical pieces. The results are discussed in relation to the idea that preferred musical pieces, although not generally beneficial in lessening skilled reaching impairments, may normalize the balance between visual and proprioceptive guidance of skilled reaching.     

Suppression of Carrageenan Paw Oedema in Rats and Mice by Heparin-Induced Ec-Sods

Carrageenan-induced paw edemata of mice and rats were suppressed by 1–4 × 10³U/kg intravenous injection of heparin. High doses were less suppressive, corresponding well to the increase in plasma SOD activity. This biphasic dose response curve was also observed in our ischemic paw model of mice. Increased SOD appeared as high molecular EC-SOD C (in mice) and B (in rats) as a result of its sensitivity to a copper chelator and long retention time in the blood stream, compared to the short life of cytosolic Cu, Zn-SOD. EC-SOD C (135 kDa) failed to be detected in the plasma of heparin-injected mice by way of nitroblue tetrazolium staining after PAGE electrophoresis. Instead, SOD activity was found near 270 kDa. An excess heparin-loaded subunit of this enzyme might become inactivated or might not be able to fix to a pocket where EC-SOD eliminates O₂^?. to protect the endothelium, Electrophoresis dissociates the excess heparin resulting in an active form of [he enzyme. Paw edemata of rats were less sensitive because this species lacks the strongly heparin-binding EC-SOD C and has only the weakly heparin-binding EC-SOD B. Ischemia-induced mitochondrial swelling of the paw muscle was observed by electron microscopy and was prevented by heparin injection.     

Role of a goal in determining neuronal activity of the motor and visual areas of the rabbit cortex

In experiments on alert rabbits neuronal activity of the motor and visual cortical areas was studied in behavioural acts (BA) of grasping of a piece of plastics (P) and carrot (C) from consequently presented cups of the feeder; the animal had an opportunity to seize a C piece only after grasping and taking away from the previous cup the P piece. "Visual environment" in which BA were realized were identical; P and C pieces were identical in form and visual characteristics. Records were made of unit activity (201 cells), animal's movements (photoelectric method), EMG of the m. masseter; in parallel videorecords of behaviour were carried out. BA of P and C pieces grasping were identical in electromyo- and actographic characteristics; motor composition of these BA did not differ. 61 neurones were activated in both BA, 5--only in BA of P piece grasping, 22--only in BA of C piece grasping, i. e. 30% of neurones were activated only in one of the compared BA. Characteristics of activations, appearing in both acts could be significantly different: different frequency, connection with different stages of the compared BA. The obtained data are determined by changes of the motor and receptive fields of neurones in one BA in comparison to another, and are considered as an evidence supporting the suggestion that appearance of cortical neurones' activations in behaviour depends on BA goal and is not strictly determined by the parameters of movements and environment.     

Cutaneous mechanical sensory stimulation increases extracellular acetylcholine release in cerebral cortex in anesthetized rats.

The effects of noxious and innocuous mechanical stimulation of various segmental skin areas (face, forelimb and paw, back, hindlimb and paw) on extracellular acetylcholine release in the cerebral cortex in the parietal lobe were examined in halothane-anesthetized rats, by means of the microdialysis technique. Pinching of a forepaw or hindpaw and brushing of a hindlimb for 10 min produced significant increases in extracellular acetylcholine release, whereas pinching of the face or back and brushing of the face, forelimb or back produced no significant changes. These results demonstrate that cutaneous sensory stimulation can regulate extracellular acetylcholine release in the cerebral cortex, and that the efficacy of the stimulation on cortical acetylcholine release is dependent on the sensory modality and the region of skin stimulated.     

Suppressions of Ischemic Paw Oedema in Mice, Rats and Guinea Pigs by Superoxide Dismutases from Different Sources

Various sources of superoxide dismutases (SOD) suppressed ischaemic paw oedemata (tourniquet poditis) of mice, rats and guinea pigs with different potencies. Intravenous (i.v.) dosing of mouse Cu, Zn-SOD had no effect on mouse ischaemic oedema, yet rat and guinea pig Cu, Zn-SOD suppressed ischaemic oedemata of rats and guinea pigs. Homologous SOD was anti-inflammatory at least in these two models. Guinea pig SOD was one of the most potent in all models, but showed a very narrow range of effective dose. This bell-shape suppressive pattern was ameliorated by concomitant catalase injection. Bovine and human Cu, Zn-SOD had a rather broad range of effective dose. Bacterial Mn-SODS were suppressive in mice, as well as the oxygen radical scavenger MK-447 and cytochrome c. Dexamethasone was effective only when administered more than 3 hrs in advance. As ischaemic paw oedema of mice was not sensitive to cyclooxy-genase and lipoxygenase inhibitors, this model could serve for screening new types of anti-inflammatory or anti-ischaemic drugs.     

Links between vision and somatosensation. Vision can improve the felt position of the unseen hand.

During reaching movements, sensory signals must be transformed into appropriate motor commands. Anatomical, electrophysiological, and neuropsychological evidence suggest that there is no single, supramodal map of space that is used to guide reaching. Instead, movements appear to be planned and controlled within multiple coordinate systems, each one attached to a different body part. Recent neuropsychological investigations demonstrating that somatosensory impairments can be ameliorated by visual cues, and visual impairments by proprioceptive cues, have been interpreted as evidence that arm-centered representations may exist in humans. A critical difference between the findings obtained in the monkey and in humans, however, is that in the latter case, vision of the limb appears be critical for visual somatosensory binding. Here, we report a case study of a patient (C.T.) recovering from unilateral somatosensory impairment, including tactile extinction, who executed reaches toward visually defined or proprioceptively defined locations. We demonstrate that when the target location of a reach was defined proprioceptively, by passively positioning our patient's impaired hand beneath the table surface, vision of the workspace immediately adjacent to the unseen hand dramatically increased the endpoint accuracy of her reaching movements, even though such cues could not possibly signal the position of the target directly.     

Suppressions of Ischemic Paw Oedema in Mice,Rats and Guinea Pigs by Superoxide Dismutases from Different Sources

Various sources of superoxide dismutases (SOD) suppressed ischaemic paw oedemata (tourniquet poditis) of mice, rats and guinea pigs with different potencies. Intravenous (i.v.) dosing of mouse Cu, Zn-SOD had no effect on mouse ischaemic oedema, yet rat and guinea pig Cu, Zn-SOD suppressed ischaemic oedemata of rats and guinea pigs. Homologous SOD was anti-inflammatory at least in these two models. Guinea pig SOD was one of the most potent in all models, but showed a very narrow range of effective dose. This bell-shape suppressive pattern was ameliorated by concomitant catalase injection. Bovine and human Cu, Zn-SOD had a rather broad range of effective dose. Bacterial Mn-SODS were suppressive in mice, as well as the oxygen radical scavenger MK-447 and cytochrome c. Dexamethasone was effective only when administered more than 3 hrs in advance. As ischaemic paw oedema of mice was not sensitive to cyclooxy-genase and lipoxygenase inhibitors, this model could serve for screening new types of anti-inflammatory or anti-ischaemic drugs.     

A Within-Animal Comparison of Skilled Forelimb Assessments in Rats

A variety of skilled reaching tasks have been developed to evaluate forelimb function in rodent models. The single pellet skilled reaching task and pasta matrix task have provided valuable insight into recovery of forelimb function in models of neurological injury and disease. Recently, several automated measures have been developed to reduce the cost and time burden of forelimb assessment in rodents. Here, we provide a within-subject comparison of three common forelimb assessments to allow direct evaluation of sensitivity and efficiency across tasks. Rats were trained to perform the single pellet skilled reaching task, the pasta matrix task, and the isometric pull task. Once proficient on all three tasks, rats received an ischemic lesion of motor cortex and striatum to impair use of the trained limb. On the second week post-lesion, all three tasks measured a significant deficit in forelimb function. Performance was well-correlated across tasks. By the sixth week post-lesion, only the isometric pull task measured a significant deficit in forelimb function, suggesting that this task is more sensitive to chronic impairments. The number of training days required to reach asymptotic performance was longer for the isometric pull task, but the total experimenter time required to collect and analyze data was substantially lower. These findings suggest that the isometric pull task represents an efficient, sensitive measure of forelimb function to facilitate preclinical evaluation in models of neurological injury and disease.     

The participation of the cholinergic system of the rat sensorimotor cortex in regulating different types of movements

To study the role of the cholinergic system of the sensorimotor cortex in regulation of different manipulatory movements and locomotion of Wistar rats, the effects of injections of cholinergic drugs (a cholinergic agonist carbachol and an antagonist scopolamine) into the area of forepaw representation in the sensorimotor cortex on motor activity and performance of manipulatory movements (with prolonged and short pushing) were analyzed. The drugs were injected via special cannulae stereotaxically implanted into the cortex during surgery carried out under Nembutal anesthesia. Carbachol injections (0.03-3 micrograms in 1 microliter of physiologic solution) into the cortex resulted in a significant slowing down of both types of movements as well as an increase in locomotion in the open-field test. Injections of scopolamine (0.3-3 micrograms) into the same cortical area were accompanied by an increase in the number of fast manipulatory movements without significant changes in locomotor activity. The obtained evidence suggests that the cholinergic system of the sensorimotor cortex indifferent manners regulates the innate (locomotion) and acquired movements which require different periods of maintaining the muscle tone of the forepaw (short-time periods for the usual movements necessary for food taking from the narrow horizontal tube and prolonged periods for the learned slow movements with additional tactile and tonic components).     

Reaching behavior of rats during realization of a lateralized motor food skill

Adult Wistar rats were trained to obtain food pellets from a narrow horizontal tube with a preferred forepaw. The feeder was equipped with five photoelectric sensors with 5-mm spacing. The following parameters were recorded: total number of movements performed for a given task, amplitude (depth) of each movement, number of anticipatory movements performed with different amplitudes, and amplitude of a successful movement. It was shown that in rats with good skill acquisition, a successful food extraction was preceded by a series of differently organized sequence of preliminary movements. In some rats, such a series consisted of initial non-deep attempts followed by movements with high amplitude, whereas in other animals, it was represented, mainly, by deep attempts. Both groups of animals terminated the series by grasping and extracting food from a long distance. It is suggested that the observed organizations of the lateralized food-getting behavior of rats under the given experimental conditions represent fixed (stereotyped) action patterns.     

Effects of bleeding nonanesthetized wild rodents on handling mortality and subsequent recapture

Handling mortality and recapture rates of wild rodents that were bled from the retroorbital capillary plexus without anesthesia were assessed. In 9,670 captures of seven species of rodents from 1994 through 1998, we found no difference in handling mortality in bled mice compared to those from trapping grids where mice were not bled. Recapture rates of rodents on control (non-bleeding grids) and rodents on bleeding grids was not significantly different for any species. We conclude that bleeding in the absence of anesthesia does not affect immediate mortality or subsequent recapture.     

Validation of a new system for the automatic registration of behaviour in mice and rats

A newly developed behaviour registration system, Laboratory Animal Behaviour Observation, Registration and Analysis System (LABORAS) for the automatic registration of different behavioural elements of mice and rats was validated. The LABORAS sensor platform records vibrations evoked by animal movements and the LABORAS software translates these into the corresponding behaviours. Data obtained by using LABORAS were compared with data from conventional observation methods (observations of videotapes by human observers). The results indicate that LABORAS is a reliable system for the automated registration of eating, drinking, grooming, climbing, resting and locomotion of mice during a prolonged period of time. In rats, grooming, locomotion and resting also met the pre-defined validation criteria. The system can reduce observation labour and time considerably.     

The Structure of Skilled Forelimb Reaching in the Rat: A Movement Rating Scale

Skilled reaching for food is an evolutionary ancient act and is displayed by many animal species, including those in the sister clades of rodents and primates. The video describes a test situation that allows filming of repeated acts of reaching for food by the rat that has been mildly food deprived. A rat is trained to reach through a slot in a holding box for food pellet that it grasps and then places in its mouth for eating. Reaching is accomplished in the main by proximally driven movements of the limb but distal limb movements are used for pronating the paw, grasping the food, and releasing the food into the mouth. Each reach is divided into at least 10 movements of the forelimb and the reaching act is facilitated by postural adjustments. Each of the movements is described and examples of the movements are given from a number of viewing perspectives. By rating each movement element on a 3-point scale, the reach can be quantified. A number of studies have demonstrated that the movement elements are altered by motor system damage, including damage to the motor cortex, basal ganglia, brainstem, and spinal cord. The movements are also altered in neurological conditions that can be modeled in the rat, including Parkinson''s disease and Huntington''s disease. Thus, the rating scale is useful for quantifying motor impairments and the effectiveness of neural restoration and rehabilitation. Because the reaching act for the rat is very similar to that displayed by humans and nonhuman primates, the scale can be used for comparative purposes. from a number of viewing perspectives. By rating each movement element on a 3-point scale, the reach can be quantified. A number of studies have demonstrated that the movement elements are altered by motor system damage, including damage to the motor cortex, basal ganglia, brainstem, and spinal cord. The movements are also altered in neurological conditions that can be modeled in the rat, including Parkinson''s disease and Huntington''s disease. Thus, the rating scale is useful for quantifying motor impairments and the effectiveness of neural restoration and rehabilitation.Experiments on animals were performed in accordance with the guidelines and regulations set forth by the University of Lethbridge Animal Care Committee in accordance with the regulations of the Canadian Council on Animal Care.Download video file.^{(127M, mp4)}     

Cytokine and hormone profiles in mice subjected to handling combined with rectal temperature measurement stress and handling only stress

Stress is known to either up or down regulate immunity. In this study, mice were subjected to handling combined with rectal temperature measurement (RTM) stress or handling only stress. We investigated whether there were any significant differences in the effect of handling combined with RTM and handling only on NK cell activity, serum cytokine (IL-1beta, IL-6, and TNF-alpha) and ACTH and beta-endorphin levels, and splenic cytokine (IL-1beta, IL-6, TNF-alpha, IFN-alpha, and IFN-beta) levels. Circulating cytokines and hormones and splenic cytokine mRNA levels were measured in individual mice. NK cell activity was significantly increased in both stress groups when compared to the control group. Handling combined with RTM produced significantly increased serum levels of IL-1beta, IL-6, and beta-endorphin. Serum IL-1beta, ACTH, and beta-endorphin were elevated significantly in the handling only group. Splenic TNFalpha mRNA in both of the stress groups and IL-6 mRNA in handling only group decreased significantly. Our observations are supported by existing literature demonstrating that various stressors have differential effects on immune functions and the neuroendocrine hormones and cytokines, which regulate them.     

Fixation: What should the pathologist do?

Synopsis Pathologists handling surgical material must make a definitive diagnosis, usually on a Haematoxylin-Eosin stained section, but must also consider beforehand what supporting histochemical investigations may be needed. When only one small piece of tissue is available it should either be fixed in cold neutral or buffered formalin-calcium or formalin-sucrose or alternatively quenched; the first alternative offers a more practical all-round procedure and most investigations which are likely to be of use can be done following it. If the biopsy is divisible into two, one piece should be fixed and the second quenched; if 3 pieces are available, the third should be fixed in glutaraldehyde for possible electron microscopy.