Hand preference and performance on unimanual and bimanual tasks in capuchin monkeys (Cebus apella).

Patterns of manual preference and the extent to which preference provided a benefit in performance (movement time) were evaluated in 7 young adult capuchin monkeys (Cebus apella). Directions of preference were inconsistent within individual animals across home-cage activities, unimanual, and bimanual experimental tasks. Preferences were more strongly expressed in the experimental tasks than in the home cage. A left bias in the population for prehension, predicted by recent theories, was not evident in any setting. Movement time was moderately negatively correlated with degree of preference within experimental tasks. The benefit to performance conferred by lateral preference was not dependent on whether the right or the left hand was preferred. Lateralization of prehension appears to be a flexible process in these monkeys, which can result in quickly realized benefits in some conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuronal activity in the primate supplementary motor area and the primary motor cortex in relation to spatio-temporal bimanual coordination

Single neuronal activity was recorded from the supplementary motor area (SMA-proper and pre-SMA) and primary motor cortex (M1) in two Macaca fascicularis trained to perform a delayed conditional sequence of coordinated bimanual pull and grasp movements. The behavioural paradigm was designed to distinguish neuronal activity associated with bimanual coordination from that related to a comparable motor sequence but executed unimanually (left or right arm only). The bimanual and unimanual trials were instructed in a random order by a visual cue. Following the cue, there was a waiting period until presentation of a "go-signal", signalling the monkey to perform the instructed movement. A total of 143 task-related neurons were recorded from the SMA (SMA-proper, 62; pre-SMA, 81). Most SMA units (87%) were active in both unimanual contralateral and unimanual ipsilateral trials (bilateral neurons), whereas 9% of units were active only in unimanual contralateral trials and 3% were active only in unimanual ipsilateral trials. Forty-eight per cent of SMA task-related units were classified as bimanual, defined as neurons in which the activity observed in bimanual trials could not be predicted from that associated with unimanual trials when comparing the same events related to the same arm. For direct comparison, 527 neurons were recorded from M1 in the same monkeys performing the same tasks. The comparison showed that M1 contains significantly less bilateral neurons (75%) than the SMA, whereas the reverse was observed for contralateral neurons (22% in M1). The proportion of M1 bimanual cells (53%) was not statistically different from that observed in the SMA. The results suggest that both the SMA and M1 may contribute to the control of sequential bimanual coordinated movements. Interlimb coordination may then take place in a distributed network including at least the SMA and M1, but the contribution of other cortical and subcortical areas such as cingulate motor cortex and basal ganglia remains to be investigated.     

Hand preferences in unimanual and bimanual feeding by wild vervet monkeys (Cercopithecus aethiops).

Lateral preference was examined in spontaneous feeding actions in 2 troops of wild vervet monkeys (Cercopithecus aethiops). Processing of 4 foods (termites, leaf shoots, sugarcane, and fruit) was studied. Actions included unimanual reaching to moving objects, operating from an unstable posture, and coordinated bimanual processing. Between 19 and 31 subjects were available, according to the task. In 2 tasks, laterality of 2 independent stages was measured separately, giving 6 measures in all. On 4 of these measures, most monkeys were ambipreferent, and only a few showed significant hand preferences. Only for termite feeding and detaching material from fruits did the majority show significant lateralization; no tasks elicited exclusive use of 1 hand. Preference appeared labile, because in 2 tasks, population trends reversed with increasing age. No population trends to left or right were found; instead, these monkeys showed ambilaterality, with lateralization associated with task complexity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of lesions in the mesial frontal cortex on bimanual co-ordination in monkeys

The hypothesis was tested that the mesial frontal cortex, including the supplementary motor area, is engaged in bimanual co-ordination. Three monkeys, trained in a well-co-ordinated bimanual pull-and-grasp task, were subjected to unilateral or bilateral lesions of the mesial frontal cortex. With unilateral lesions, the deficit consisted in a delay in movement initiation of the contralateral arm. With a bilateral lesion, the deficit was more pronounced with marked bilateral delays in movement onset and slowing in reaching. However, in the three monkeys bimanual co-ordination at the moment of goal achievement remained intact with an excellent temporal co-variation of the two limbs. In the two unilateral cases, an adaptive strategy developed after a few sessions, either by catching up during reaching with the limb contralateral to the lesion (monkey M1) or by delaying movement initiation of the limb ipsilateral to the lesion (monkey M2). This outcome is discussed in terms of Lashley's principle of motor equivalence, i.e. invariant goal achievement with variable means. Bilateral lesions led to a transient and near-total impairment in movement self-initiation when all external cues were absent. It is concluded that in monkeys the mesial frontal cortex does not play a crucial role in bimanual co-ordination but rather in movement initiation, especially when sensory cues are absent.     

The role of the pedunculopontine tegmental nucleus in relation to conditioned motor performance in the cat. II. Effects of reversible inactivation by intracerebral microinjections

OBJECTIVE: To describe lower-extremity functioning in community-dwelling older Mexican Americans and to examine its relationship with medical problems. DESIGN: Cross-sectional analyses of survey and performance-based data obtained in a population-based study employing area probability sampling. SETTING: Households within selected census tracts of five Southwestern states: Arizona, California, Colorado, New Mexico, and Texas. PARTICIPANTS: A total of 2873 Mexican Americans aged 65 years and older. MEASUREMENTS: A multidimensional questionnaire assessing demographic, sociocultural, and health variables. Standardized tests of lower-extremity physical functioning included measures of standing balance, repeated chair stands, walking, and an overall summary measure. RESULTS: Regression analyses revealed that being more than age 75 and female, having arthritis diabetes, visual impairments, or being obese or underweight were all significantly associated with performance on both individual and summary tests of lower-extremity functioning. In separate regression analyses, the total number of medical conditions was also associated with performance. CONCLUSIONS: The likelihood of predicting performance or inability to complete tests of lower-extremity functioning was greatest for those aged 80 and older, those with arthritis or diabetes, and those with three or more medical conditions. Because of the high prevalence of diabetes in Mexican Americans, documentation of the association of diabetes with performance-based tests of lower-extremity functioning may help guide early interventions targeted to prevent progression to more severe limitations or disability.     

Effects of competition on video-task performance in monkeys.

The effects of competition on performance of a video-formatted task were examined in a series of experiments. Two rhesus monkeys (Macaca mulatta) were trained to manipulate a joystick to shoot at moving targets on a computer screen. The task was made competitive by requiring both animals to shoot at the same target and by rewarding only the animal that hit the target first each trial. The competitive task produced a significant and robust speed–accuracy trade-off in performance. The monkeys hit the target in significantly less time on contested than on uncontested trials. However, they required significantly more shots to hit the target on contested trials in relation to uncontested trials. This effect was unchanged when various schedules of reinforcement were introduced in the uncontested trials. This supports the influence of competition qua competition on performance, a point further bolstered by other findings of behavioral contrast presented here. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for direct connections between the hand region of the supplementary motor area and cervical motoneurons in the macaque monkey

In primates the corticospinal neurons of the hand representation of the primary motor cortex (M1) give rise to direct contacts with the cervical motoneurons that control distal forelimb muscles. We investigated, at the light-microscopy level, whether corticospinal cells present in the hand area of the supplementary motor area (SMA) also establish direct connections with cervical motoneurons, particularly those innervating hand and finger muscles. The hand representation of the M1 (two monkeys) or SMA (two monkeys) was located using intracortical microstimulation and injected with the anterograde tracer biotinylated dextran amine to label corticospinal terminals. Forearm muscles acting on the wrist and hand as well as hand muscles acting on the thumb and index finger, thus including those activated by intracortical stimulation, were injected with the retrograde tracer cholera-toxin B subunit, in order to label the motoneurons. A consistent zone of overlap between the two markers was found in the cervical cord. Close appositions between corticospinal axonal terminals and the somata or dendrites of motoneurons were found after injection in the M1, confirming previous observations. The new finding is the observation of similar close appositions after injection in the SMA, suggesting its control of hand movements in parallel with the M1.     

Changing directions of forthcoming arm movements: neuronal activity in the presupplementary and supplementary motor area of monkey cerebral cortex

1. To understand roles played by two cortical motor areas, the presupplementary motor area (pre-SMA) and supplementary motor area (SMA), in changing planned movements voluntarily, cellular activity was examined in two monkeys (Macaca fuscata) trained to perform an arm-reaching task in which they were asked to press one of two target buttons (right or left) in three different task modes. 2. In the first mode (visual), monkeys were visually instructed to result and press either a right or left key in response to a forth coming trigger signal. In the second mode (stay), monkeys were required to wait for the trigger signal and press the same target key as pressed in preceding trials. In the third mode (shift), a 50 Hz auditory cue instructed the monkey to shift the target of the future reach from the previous target to the previous nontarget. 3. While the monkeys were performing this task, we recorded 399 task-related cellular activities from the SMA and the pre-SMA. Among them, we found a group of neurons that exhibited activity changes related specifically to shift trials (shift-related cells). The following properties characterized these 112 neurons. First, they exhibited activity changes after the onset of the 50-Hz auditory cue and before the movement execution when the monkeys were required to change the direction of forthcoming movement. Second, they were not active when the monkeys pressed the same key without changing the direction of the movements. Third, they were not active when the monkeys received the 50-Hz auditory cue but failed to change the direction of the movements by mistake. These observations indicate that the activity of shift-related cells is related to the redirection of the forthcoming movements, but not to the auditory instruction itself or to the location of the target key or the direction of the forthcoming movements. 4. Although infrequently, monkeys made errors in the stay trials and changed directions of the reach voluntarily. In that case, a considerably high proportion of shift-related neurons (12 of 19) exhibited significant activity changes long before initiation of the reach movement. These long-lasting activities were not observed during the preparatory period in correct stay trials, but resembled the shift-related activity observed when the target shift was made toward the same direction. Thus these activity changes were considered to be also related to the process of changing the intended movements voluntarily. 5. We found another population of neurons that showed activity modulation when the target shift was induced by the visual instruction in visual trials (visually guided shift-related neurons). These neurons were active when the light-emitting diode (LED) guided the forthcoming reach to the previous nontarget but not to the previous target. Therefore their activity was not a simple visual response to the LED per se. A majority of them also showed shift-related activity in shift trials (19 of 22 in monkey 2). 6. Neurons exhibiting the shift-related activity were distributed differentially among the two areas. In the pre-SMA, 31% of the neurons recorded showed the shift-related activity, whereas in the SMA, only 7% showed such an activity. These results suggest that pre-SMA and SMA play differential roles in updating the motor plans in accordance with current requirements.     

Effects of concreteness-abstractness and anxiety on intellectual and motor performance.

Administered O. J. Harvey's "This I Believe" Test to undergraduates. 55 Ss were selected with concrete belief systems and 29 with abstract systems. Ss then played the role of arguing against their own stand on an ego-involving issue which was scored for 5 attributes: number to topics discussed, number of approaches utilized in the arguments, openness to negative evaluation, ethnocentrism, and absolutism. Ss also completed the WAIS Digit-Symbol Substitution test, a vocabulary test, an arithmetic test, the A-State scale of the State-Trait Anxiety Inventory. On the basis of the anxiety measure, Ss were divided into "high" and "low" anxiety groups, and a 2-way analysis of variance (Concreteness-Abstractness * Anxiety) was run for each of the 8 dependent variables. Anxiety exercised a significant main effect on none of the 8 dependent variables, while concreteness-abstractness significantly affected 5. The interaction of these 2 variables, while in the anticipated direction in all instances, significantly affected performance only on the vocabulary measure. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of phencyclidine, pentobarbital, and d-amphetamine on the acquisition and performance of conditional discriminations in monkeys

In each of two components of a multiple schedule, monkeys were required to respond on a right or left lever depending upon the stimulus combination (a color and a geometric form) presented. Reinforcement of a response in the presence of one stimulus (the form) was therefore conditioned upon the other stimulus (the color). The completion of a two-member chain of discriminations produced a food pellet. Errors produced a brief timeout. One composition of the multiple schedule was a repeated-acquisition task where the discriminative stimuli for left- or right-lever responses changed each session (learning). In the other component, the discriminative stimuli for left- or right-lever responses were the same each session (performance). Phencyclidine, pentobarbital, and d-amphetamine each produced dose-related decreases in the overall rate of responding in both components of the multiple schedule. At high doses each drug increased the percent errors in each component. At lower doses, however, the three drugs produced selective effects on accuracy. Errors were increased in the learning component at lower doses than those required to disrupt the discrimination in the performance component. A signal detection analysis of the data revealed that none of the drugs tested increased errors by selectively affecting either discriminability or bias.     

Partial hippocampal inactivation: Effects on spatial memory performance in aged and young rats.

Changes in anatomical or functional connectivity during normal aging are thought to contribute to cognitive alterations over the lifespan. Neural network theories predict that synaptic loss in an aging brain could place the organism near the point of dysfunction in the nonlinear curve defining neural compromise versus performance. The present experiments examined whether aged rats are closer to this point of behavioral dysfunction by reversibly inactivating one or both hippocampal hemispheres. As expected, bilateral tetracaine inactivation of the hippocampus disrupted spatial memory in both age groups. Unilateral left hippocampal inactivation significantly increased errors only in aged rats; however, unilateral inactivation of the right hippocampus had no effect. The present outcome could reflect more extensive synaptic dysfunction in the aged right hippocampus or a greater involvement of the left hippocampus in spatial working memory problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of variability of practice in a movement-education program on motor skill performance

The study investigated the effects of the direct and exploration methods of teaching on the overhand throwing performance of kindergarten children. Variable throwing practice was provided in the exploration method by allowing children to throw 5 different types of balls at a variety of targets. Children given the direct method threw only one type of ball and received specific instruction and demonstrations. Throwing for distance and throwing accuracy were measured on pre- and posttests. A novel throwing task was administered on the posttest to measure skill transfer. The experimental groups received instruction three times per week for 4 wk. in throwing while a control group received no instruction. Significant sex differences in throws were found for distance and accuracy. Analysis of data from the novel task gave no significant effects. The two methods of teaching did not produce different levels of throwing skill.     

Cognitive and motor deficits in the performance of an object retrieval task with a barrier-detour in monkeys (Cercopithecus aethiops sabaeus) treated with MPTP: Long-term performance and effect of transparency of the barrier.

Studied 6 monkeys' performance on an object retrieval task to assess neural deficits produced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The task required retrieval of a reward from a transparent box open on 1 side and fastened to a tray in the cage. Orientation of open side, position on tray, and position of banana in box were manipulated to vary difficulty. Ss treated with MPTP were compared with 5 saline-treated controls. MPTP Ss had no gross neurological deficits but did have motor and cognitive deficits during task acquisition 8–22 mo after treatment (J. R. Taylor et al, in press). Task performance was examined for 3 mo after it had been learned. MPTP Ss reached at the barrier significantly more than controls and were less successful at retrieval on 1st reach than controls. Although MPTP Ss took longer to initiate the reach and had more motor problems, MPTP Ss were as likely as controls to retrieve the reward in the end. These deficits were stable throughout testing. An opaque but otherwise identical box was used randomly on some trials. MPTP Ss decreased barrier reaches to control levels on trials with the opaque box, whereas motor problems increased. The task detected performance deficits similar to those found in Parkinson's disease. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

GIS采集器(手持GPS)在地质普查中的应用

介绍了GPS系统的特点、组成及原理，叙述了GIS采集器在地质普查中的应用一般方法。     

GABA-induced inactivation of functionally characterized sites in cat visual cortex (area 18): effects on direction selectivity

1. Microiontophoresis of gamma-aminobutyric acid was used to reversibly inactivate small sites of defined orientation and direction specificity at a horizontal distance of 400-700 microns from single cells recorded in cat area 18. There was extensive or complete overlap between the receptive fields of cells at the recording and inactivation sites. A cell's directionality index [DI: 1 - (response to nonpreferred direction/response to preferred direction)], the response to the preferred direction, and orientation tuning width (measured at half the maximum response) were compared before and during inactivation of either iso-orientation sites (where the orientation preference was within 22.5 degrees) or cross-orientation sites (where it differed by 45-90 degrees). 2. During iso-orientation inactivation, 40 (73%) of 55 cells showed a significant (> 0.20) change in DI; the mean change in DI for these cells was 0.59. An additional cell showed a marked increase in response to the preferred direction that did not result in a change in DI. With one exception, the effects occurred in the absence of a significant (> 25%) change in orientation tuning width. 3. In most cases, the results were broadly predictable in the sense that iso-orientation inactivation predominantly affected a cell's response to the direction of motion of an optimally oriented bar that was closest to the preferred direction at the inactivation site: viz., a decrease in response to the preferred direction and an increase in response to the preferred or nonpreferred direction. 4. It is argued that the decreases in response were due to a reduction in the strength of intracortical iso-orientation excitatory connections made primarily between cells with similar direction preferences, whereas the increases in response involved a loss of iso-orientation inhibition. 5. In cases where remote inactivation caused an increase in response to the nonpreferred direction, comparable effects could be elicited when a mask left exposed only the excitatory subregion of the receptive field in S cells or the most responsive part of the excitatory discharge region in C cells. This implies extensive or complete spatial overlap between the profiles of excitation and inhibition in a cell's nonpreferred direction. 6. During cross-orientation inactivation, a significant change in DI was seen in only 14 (19%) of 73 cells and, with one exception, these changes were accompanied by increases in response to non-optimal orientations and significant broadening of orientation tuning. The effects of cross-orientation inactivation on directionality were presumably due to the loss of cross-orientation inhibition, which contributes primarily to orientation tuning. 7. Inactivation of the same site could cause an increase in response to the nonpreferred direction in cells recorded at iso-orientation sites and an increase in response to nonoptimal orientations and broadening of orientation tuning in cells recorded at cross-orientation sites. This is consistent with the notion that a single inhibitory neuron can contribute to the directionality or orientation tuning of different target cells depending on their location in the orientation map. 8. The results provide evidence for a major contribution of intrinsic mechanisms to the orientation tuning and direction selectivity of cells in cat area 18. It is proposed that two different intracortical processes are involved in the enhancement of orientation and direction selectivity: 1) suppression of responses to nonoptimal orientations and directions as a result of cross-orientation inhibition and iso-orientation inhibition; and 2) facilitation of responses to optimal orientations/directions via iso-orientation excitatory connections.     

Effects of one-stage and serial ablations of the middle third of sulcus principalis on delayed alternation performance in monkeys.

Investigated recovery of a spatial delayed alternation habit following partial frontal lesions in 9 mature rhesus monkeys. All Ss subjected to serial ablation of the middle third of sulcus principalis were found to be capable of reacquiring preoperative levels of performance on the task. However, 1-stage removal of the mid-principalis region resulted in both more severe and more protracted impairments than were evident after serial surgery. Results in conjunction with previous findings suggest that recovery following serially induced neurological insult may be dependent upon the integrity of neural tissue adjacent to the locus of injury. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dexterity in adult monkeys following early lesion of the motor cortical hand area: the role of cortex adjacent to the lesion

Infant monkeys were subjected to unilateral lesions of the motor cortex (mainly its hand representation). After maturation, they showed normal use of the contralateral hand for global grip movements. However, as compared with the ipsilateral hand, precision grip tasks requiring relatively independent finger movements were performed with less dexterity, particularly if adjustments of the wrist position were necessary. The purpose of this study was to investigate mechanisms which may be responsible for the rather well, although not complete, preservation of manipulative behaviour of these adult monkeys. To this end, the hand representations were mapped bilaterally with intracortical microstimulation in the mature monkeys, and the dexterity of both hands assessed quantitatively in a precision grip task. The behavioural effects of reversible inactivations of the primary (M1) and supplementary (SMA) motor cortical areas were then tested. The following were found. (i) The hand contralateral to the lesion exhibited subtle but significant dexterity deficits, as compared with the ipsilateral hand; the deficit was essentially for complex movements requiring dissociation of the thumb-index finger pinch from the other digits, involving also an arm rotation. (ii) Reversible inactivation of the M1 hand representation in the intact hemisphere dramatically impaired dexterity of the opposite hand without affecting the ipsilateral hand (contralateral to the early lesion). (iii) A relatively complete hand representation was found to occupy a new territory, medial to the old lesion. (iv) The role of this new displaced representation was crucial for the preserved dexterity of the opposite hand, as evidenced by its functional inactivation. In contrast, inactivation of both SMA cortices did not interfere with the manipulative behaviour. It is thus concluded that the preserved functional capacity of manipulations with the hand opposite the early lesion can be essentially attributed to a cortical reorganization around the old lesion. Under the present experimental conditions, contributions from either the SMA or the intact M1 appear not to be crucial.     

The effects of V4 and middle temporal (MT) area lesions on visual performance in the rhesus monkey

The effects of V4, MT, and combined V4 + MT lesions were assessed on a broad range of visual capacities that included measures of contrast sensitivity, wavelength and brightness discrimination, form vision, pattern vision, motion and flicker perception, stereopsis, and the selection of stimuli that were less prominent than those with which they appeared in stimulus arrays. The major deficit observed was a loss in the ability, after V4 lesions, to select such less prominent stimuli; this was the case irrespective of the manner in which the stimulus arrays were made visible, using either luminance, chrominance, motion, or stereoscopic depth as surface media. In addition, V4 lesions yielded mild deficits in color, brightness, and form vision whereas MT lesions yielded mild to moderate deficits in motion and flicker perception. Both lesions produced mild deficits in contrast sensitivity, shape-from-motion perception, and yielded increased reaction times on many of the tasks. The impairment resulting from combined V4 and MT lesions was not greater than the sum of the deficits of either lesion. None of the lesions produced significant deficits in stereopsis. The findings suggest that (1) area V4 is part of a neural system that is involved in extracting stimuli from the visual scene that elicit less neural activity early in the visual system than do other stimuli with which they appear and (2) several other extrastriate regions and more than just two major cortical processing streams contribute to the processing of basic visual functions in the extrastriate cortex.     

Trajectory-selective neuronal activity in the motor cortex of rhesus monkeys (Macaca mulatta).

Neuronal activity recorded in the primate motor cortex reflected movement parameters in addition to the distance and direction of a target. These neurons may reflect the selection, from memory, of a detailed movement trajectory to be executed in response to visuospatial instructions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)