Habituation of heart rate in functionally decorticate rats.

Studied habituation of acoustically evoked heart-rate responses and retention of this habituation in 60 male HAN Wistar functionally decorticate rats in 2 experiments. It is concluded that the rat's cortex was not necessary for habituation of acoustically evoked heart-rate responses and retention of this habituation over a moderately long interval. However, the results suggest that the cortex is involved in long-term habituation (LTH) and that the neuronal substrates of short-term habituation and LTH are, in significant part, different. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reversal of H-reflex operant conditioning in the rat

After developing a rapid gel filtration method to prepare pure and stable apoenzyme forms of D-amino acid oxidase from the yeast Rhodotorula gracilis, we carried out comparative kinetic studies on the reconstitution to holoenzyme (with FAD) of the intact (40 kDa) and proteolyzed (38.3 kDa) apoenzyme forms of this oxidase. Changes in catalytic activity and flavin and protein fluorescence revealed that in both cases reconstitution was biphasic. The proteolyzed enzyme was catalytically competent, but unlike the intact form was unable to dimerize following formation of the apoprotein-FAD complex. We present evidence that reconstitution of holoenzyme from apoenzyme plus FAD does not involve dimerization, and that dimerization is not necessary for expression of DAAO activity. We propose that both apoenzyme forms share a common reconstitution mechanism, which includes a step of conformational interconversion of an enzymatically active intermediate to the final holoenzyme.     

Reversal learning and resistance to extinction: A review of the rat literature.

Observation of an overtraining reversal effect (ORE) seems to be favored by the use of exteroceptive discriminative stimuli while training on a position response most frequently results in no ORE or a reverse ORE. The review of this literature is preceded by reviews of the literature on resistance to extinction following varying amounts of 100% reinforcement, nondiscriminative training, varying amounts of 100% reinforcement, discrimination training, and reversal learning without overtraining. The data in the last 3 topics provide support for the distinction between exteroceptive stimuli and position response training and suggestions about the variables accounting for the differences in results obtained with the 2 training methods. (2 p. ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Manual asymmetries in visually directed aiming.

Hypothesized that the right hand–hemisphere system is faster at processing visual feedback. In Study 1, 12 male undergraduates pointed at a target using a range of movement times under 2 illumination conditions: lights-on and lights-off in which only the target light remained visible following initiation of the aiming movement. While the results confirm that movement accuracy deteriorated less with increased speed for the right hand, the feedback interpretation for hand differences in speed–accuracy tradeoff was not supported. In Study 2, with the same Ss, no effect of illumination was apparent, suggesting that visual information available during the course of the movement was not useful. The right-hand advantage in pointing accuracy remained. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensory reinforcement of eyeblink rate in a decorticate human

An unusual case of hydranencephaly was reported. The child survived for 19 years and showed evidence on three occasions of an increase in eyeblink rate with tactile reinforcement. Diagnosis was confirmed by an autopsy which revealed no preserved cortex in either hemisphere.     

Discrimination learning and attentional set formation in a mouse model of Fragile X.

Fragile X Syndrome is the most prevalent genetic cause of mental retardation. Selective deficits in executive function, including inhibitory control and attention, are core features of the disorder. In humans, Fragile X results from a trinucleotide repeat in the Fmr1 gene that renders it functionally silent and has been modeled in mice by targeted deletion of the Fmr1 gene. Fmr1 knockout (KO) mice recapitulate many features of Fragile X syndrome, but evidence for deficits in executive function is inconsistent. To address this issue, we trained wild-type and Fmr1 KO mice on an experimental paradigm that assesses attentional set-shifting. Mice learned to discriminate between stimuli differing in two of three perceptual dimensions. Successful discrimination required attending only to the relevant dimension, while ignoring irrelevant dimensions. Mice were trained on three discriminations in the same perceptual dimension, each followed by a reversal. This procedure normally results in the formation of an attentional set to the relevant dimension. Mice were then required to shift attention and discriminate based on a previously irrelevant perceptual dimension. Wild-type mice exhibited the increase in trials to criterion expected when shifting attention from one perceptual dimension to another. In contrast, the Fmr1 KO group failed to show the expected increase, suggesting impairment in forming an attentional set. Fmr1 KO mice also exhibited a general impairment in learning discriminations and reversals. This is the first demonstration that Fmr1 KO mice show a deficit in attentional set formation. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Reversal of stereoselectivity in the hepatic availability of verapamil in isolated perfused rat livers. Role of protein binding

The effects of serum proteins on the stereoselective kinetics of the high clearance drug verapamil (VER) and its metabolite, norverapamil (NOR), were studied in isolated perfused rat livers (IPRLs). Livers were perfused, in a recirculating manner, with a solution containing human serum albumin (HSA), bovine serum albumin (BSA), or no serum albumin (N = 5 for each group). After presystemic administration of a single dose of racemic VER (2 mg), the concentrations of VER and NOR enantiomers in the perfusate were measured over 90 min. In addition, the fraction of the enantiomers bound to the plasma of perfusate was determined. Perfusate concentrations of both VER and NOR were stereoselective in all of the perfusates studied. However, the direction of stereoselectivity in the concentrations of VER enantiomers in the BSA perfusate (S-VER > R-VER) was opposite that in the HSA and albumin-free perfusates (R-VER > S-VER); this was associated with an opposite stereoselectivity in the concentrations of NOR in the BSA perfusate was higher than that in the HSA and albumin-free perfusates, an observation in agreement with the higher stereoselectivity in the binding of NOR to BSA. These data, along with other kinetic parameters such as apparent hepatic availability and intrinsic clearance, suggest that the apparent stereoselectivity in the presystemic elimination of VER by IPRLs is significantly influenced by the stereoselectivity in the protein binding of the drug.     

Size cue to visually perceived distance.

Evidence indicates that both perceived size S' and retinal size Θ are involved in both the relative and familiar size cue to relative depth. There is also evidence to indicate that the familiar size cue cannot be subsumed under the relative size cue. But both types of size cues can be included under the concept of perceived size per unit of retinal size (S'/Θ). It is asserted that the perceived depth between objects, as determined by the size cue, is a function of the value of S'/Θ associated with each of the objects. Evidence relevant to specifying the relation between values of S'/Θ and perceived depth is evaluated with respect to methodological problems involved in the use of comparison fields. (21 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in the cortical electrical activity during the formation in man of a visual set

The EEG spectra were studied in 75 healthy adult patients during formation, actualization, and extinction of the visual set. In the group of subjects which had formed the stable set, the spectral power in the alpha band was higher and that in the delta and theta bands lower than in the group of subjects with unstable set. In the course of the experiment, such relationships remained basically the same. These findings suggest that the subjects who had the longer mismatch between the unconscious "internal image" and the real stimuli presented in a new situation (i.e., the subjects with the stable set) were closer to the state of physiological rest.     

Response set in the F scale.

"An attempt was made to evaluate acquiescence response-set variance in the F scale measure of authoritarian personality trends by employing reversed wordings of items. Response set is found to be an important factor in the F scale which cannot easily be corrected by the practice usual in attitude test construction of employing both positively and negatively worded items. Evidence seems to indicate in addition that the content component of the F scale is correlated with the acquiescence response set." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Environmental constraints on motor abilities used in grooming, swimming, and eating by decorticate rats.

Successive tests reexamined the grooming, swimming, and eating behaviors of 20 decorticate male Long-Evans rats by evoking the behaviors in various circumstances (stimulus conditions). Ss showed normal-length grooming sequences during spontaneous home cage grooming; when grooming was elicited by removing them from their home cage and soaking their fur by a brief swim, grooming sequences were shorter. In cold water (18°C), Ss swam well and with exaggerated vigor and frequently inhibited forelimb movements; in warm water (37°C), they swam poorly and paddled with all 4 limbs. To eat small pieces of food, Ss sat up and used forepaws as do normal rats, but they frequently dropped the food; they did not use their forepaws to eat large pieces of food. When given powdered food, they first tried to grasp it in their mouth while they scratched at the floor surface with their front limbs; thereafter, they became increasingly proficient in licking it up. Thus, in a narrow range of stimulus conditions, decorticate rats can make movements resembling those of normal ones. They also improve with practice in some tasks but not in others. In order to elucidate the role of the cortex in control of motor behavior, it is considered necessary to obtain "behavior profiles" of each behavior by testing the animals repeatedly and under widely varying test conditions. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavior of the rat after removal of the neocortex and hippocampal formation.

A study with 55 adult male hooded rats showed that after surgical removal of the neocortex and hippocampal formation, Ss retained most of the movement patterns of locomotion, climbing, grooming, feeding, and fighting. However, forepaw immobility during swimming was abolished. Feeding behavior was suppressed temporarily but recovered partially. The distinctive postures of sleep and waking and a circadian rhythm of motor activity were retained. However, behaviors were often not performed at the appropriate time and place. The normal sequence of grooming behavior was disrupted; food hoarding and social behavior were essentially abolished. Removal of the neocortex alone had much the same effect as removal of neocortex and hippocampus together. Removal of hippocampus alone produced only a mild disruption of behavior. It is suggested that ascending nonspecific projections to the cerebral cortex play an important role in the moment-to-moment control of behavior but are not essential for the sleep–waking cycle. (1? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual space perception and visually directed action.

The results of 2 types of experiments are reported. In 1 type, Ss matched depth intervals on the ground plane that appeared equal to frontal intervals at the same distance. The depth intervals had to be made considerably larger than the frontal intervals to appear equal in length, with this physical inequality of equal-appearing intervals increasing with egocentric distance of the intervals (4–22 min). In the other type of experiment, Ss viewed targets lying on the ground plane and then, with eyes closed, attempted either to walk directly to their locations or to point continuously toward them while walking along paths that passed off to the side. Performance was quite accurate in both motoric tasks, indicating that the distortion in the mapping from physical to visual space evident in the visual matching task does not manifest itself in the visually open-loop motoric task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Group therapy and the visually handicapped: A case study.

Describes how the issues of deviance and competence were addressed when a visually handicapped 25-yr-old male joined an ongoing, process-oriented therapy group. The process of treatment is described through 3 stages: entrance, conflict/resolution, and outcome. Recommendations for group therapists and the results of a 4-mo follow-up visit are presented. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Medications and the visually impaired elderly

Based on his experience with treatment of 112 children the author considers that severe and various disturbances of the rectum abturative apparatus function arising from surgical interventions in the anorectal area require the differentiated approach to choice of the method of surgical correction of the incontinence. The transplantation of the denervated muscle, transplantation of the vascular-nervous thoraco-dorsal flap, a lavsan band were used to make a pubo-rectal loop, plasty of the outer and inner sphincters being performed mainly with local tissues.     

Search for "closure" in a visually perceived pattern.

From the Gestalt concept of closure, it has been predicted that the memory trace for a gapped circle pattern will go through a progressive change such that the gap will be recalled as having been smaller. The research on this, the most basic prediction from the concept of closure, is reviewed and evaluated. Rather than supporting the prediction of closure, results of most studies indicated that the predominant change in the memory trace was in the direction of opening the gap. (45 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task set switching in schizophrenia.

The authors used a task-switching paradigm to investigate set shifting ability in schizophrenia. This paradigm included 2 choice reaction time (RT) tasks: up–down and right–left. Switching tasks were associated with costs (i.e., longer RT in task-switch trials than in task-repetition trials); patients responded more slowly than controls and suffered greater switching costs, were as efficient as controls in engaging in an upcoming task set, and were faster than controls in disengaging from the previous task set. There were indications that patients quickly forgot what each keypress indicated, making it necessary for them to acquire response meaning information anew in each trial. To test this notion, the authors subsequently tested normal participants in conditions in which response meaning information needed to be acquired anew in each trial. These participants produced a pattern of switching costs resembling that of patients. Results suggest that set switching difficulties in schizophrenia, as exhibited in the present paradigm, reflect poor memory for task context information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acquiescence response set in aphasics.

2 tests of sentence comprehension and 2 tests requiring detection of word errors in sentences were administered to normal and aphasic patients. Each sentence could be responded to with "yes" or "no" or "right" or "wrong." Sentence content involved simple facts known to most adults. Little evidence of acquiescence response set was found for normals, but aphasics showed significant and marked acquiescence response bias on all tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dimethylamine formation in the rat from various related amine precursors

Inflammatory processes are a key event in various respiratory disorders. Adhesion to microvascular endothelial cells is essential for the migration of leukocytes into inflamed tissues. Intercellular adhesion molecule-1 (ICAM-1) is a member of the immunoglobulin superfamily and a ligand for lymphocyte function-associated antigen-1 alpha (LFA-1 alpha). It has been shown to be required for leukocyte migration into inflamed tissues, and to play a significant role in inflammatory diseases, including rhinovirus infections. Clinical and experimental investigations have demonstrated a close relationship between the ICAM-1/LFA-1 alpha pathway and the pathogenesis of asthmatic responses and acute respiratory distress syndrome. Further progress in research on the antagonism of ICAM-1 and LFA-1 alpha may provide new therapeutic approaches to inflammatory lung diseases.