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PubMed1987

[Effects of verbatim information on recognition of S-O-V sentences under incidental learning].

By means of a delayed recognition task, propositions were tested about the retention of verbatim information on Japanese S-O-V sentences based on spreading activation in memory representations. Subjects studied written sentences under incidental instructions, and a recognition test was made after a 10-minute delay. In the test, subjects verified whether the sentences were true or false for (a) original sentences, (b) synonymous distractors (verbs replaced by synonyms), and (c) non-synonymous distractors (verbs replaced by non-synonyms). In Experiment I, subjects verified original sentences more accurately, faster, and more confidently than those having distractors. Results of Experiment II, in which subjects retrieved two related sentences sequentially, showed an inhibition (fan) effect for hits. In addition, there was a facilitation (priming) effect for correct rejections. These findings provide evidence in support of the spreading activation theory of memory.

Cognition↗
PubMed2002

Learning where to look for danger: integrating affective and spatial information.

Although not previously addressed by researchers of spatial cognition or affect, the combination of spatial and affective information is essential for many approach and avoidance behaviors, and thus for survivaL We provide the first evidence that through incidental experience, people form representations that capture correlations between affective and spatial information. Participants were able to do so even when the correlation was weak, they were not told to look for the correlation, and the stimuli varied on multiple other dimensions besides valence. In addition, people were more sensitive to the presented correlation when stimuli were negative than when they were positive. This asymmetry in representation may stem from underlying differences in the activation functions for positive and negative hedonic information processing.

Adult↗
PubMed1980

Reference: the linguistic essential.

Three chimpanzees learned to label three edibles as "foods" and three inedibles as "tools". Two chimpanzees could then similarly categorize numerous objects during blind trial 1 tests when shown only objects' names. The language-like skills of the chimpanzee who failed (Lana) illustrates that apes can use symbols in ways that emulate human usage without comprehending their representational function.

Animal Communication↗
PubMed1998

Figure-ground perceptual organization and learning by three-year-old children.

We have elaborated a program for the instruction of 54 3-yr.-olds using visual aids (cards showing the graphic representation of a number printed on three different types of backgrounds). Analysis showed differences in the increase in scores obtained by the children before and after the application of the program depending on the type of background.

Child, Preschool↗
PubMed2005

Central muscarinic blockade interferes with retrieval and reacquisition of active allothetic place avoidance despite spatial pretraining.

Animal navigation to hidden goals (place navigation) ranks among the most intensively studied types of behaviour because it requires brain representations of environments in the form of cognitive maps, demonstrated to depend on hippocampal function. Intact function of muscarinic receptors in the brain was originally assumed to be crucial for place navigation, however, recent studies using non-spatial pretraining demonstrated that animals with central blockade of muscarinic acetylcholine receptors can also learn and retrieve spatial memory engrams. In the present study we addressed whether navigation in the active allothetic place avoidance (AAPA) task, which requires animals to separate spatial stimuli into coherent representations and navigate according to the representation relevant for the task, is dependent on intact muscarinic receptors in the brain. We studied the effect of three doses of scopolamine (0.5, 1.0 and 2.0mg/kg) administered 20 min prior to training on the retention of the AAPA and re-acquisition of the AAPA in a new environment. The dose of 2.0mg/kg was found to impair both AAPA retention and re-acquisition of the AAPA in a new environment, whereas the 1.0mg/kg dose only impaired the reinforced retention of AAPA. It is concluded that, unlike navigation in classic paradigms, efficient orientation in the AAPA task is critically dependent on muscarinic receptors in the brain.

Analysis of Variance↗
PubMed1998

Learning by imitation: a hierarchical approach.

To explain social learning without invoking the cognitively complex concept of imitation, many learning mechanisms have been proposed. Borrowing an idea used routinely in cognitive psychology, we argue that most of these alternatives can be subsumed under a single process, priming, in which input increases the activation of stored internal representations. Imitation itself has generally been seen as a "special faculty." This has diverted much research towards the all-or-none question of whether an animal can imitate, with disappointingly inconclusive results. In the great apes, however, voluntary, learned behaviour is organized hierarchically. This means that imitation can occur at various levels, of which we single out two clearly distinct ones: the "action level," a rather detailed and linear specification of sequential acts, and the "program level," a broader description of subroutine structure and the hierarchical layout of a behavioural "program." Program level imitation is a high-level, constructive mechanism, adapted for the efficient learning of complex skills and thus not evident in the simple manipulations used to test for imitation in the laboratory. As examples, we describe the food-preparation techniques of wild mountain gorillas and the imitative behaviour of orangutans undergoing "rehabilitation" to the wild. Representing and manipulating relations between objects seems to be one basic building block in their hierarchical programs. There is evidence that great apes suffer from a stricter capacity limit than humans in the hierarchical depth of planning. We re-interpret some chimpanzee behaviour previously described as "emulation" and suggest that all great apes may be able to imitate at the program level. Action level imitation is seldom observed in great ape skill learning, and may have a largely social role, even in humans.

Animals↗
PubMed1999

Task decomposition analysis of intertrial free recall performance on the Rey Auditory Verbal Learning Test in normal aging and Alzheimer's disease.

Task decomposition provides supplementary data that complement traditionally computed performance indexes of multi-trial list learning. Both traditional and decomposition approaches can be combined to permit a thorough assessment of multiple aspects of learning and memory in patients with memory impairment. We applied task decomposition to investigate the relative roles of acquisition and consolidation in mediating the multi-trial learning deficit in patients with Alzheimer's disease. This goal was accomplished by decomposing recall performance across the five study-and-test trials of the Rey Auditory Verbal Learning Tests into measures that presumably tap intertrial acquisition and intertrial consolidation. As compared to matched controls, patients diagnosed with mild Alzheimer's disease showed lower gained access across trials, indicating that Alzheimer's disease impairs the ability to produce a stable memory representation of new material in long-term memory. Additionally, patients with Alzheimer's disease manifested higher lost access, which suggests that deficient consolidation leading to rapid intertrial forgetting also contributes to their poor learning. We argue that analytically decomposing learning curves will help both in uncovering the cognitive processes that underlie disease-related learning deficits in persons with memory disorders and can help to characterize potential areas for remediation.

Aged↗
PubMed1994

Aging associations: influence of speed on adult age differences in associative learning.

Two studies, involving a total of nearly 500 Ss, were conducted to determine the mechanisms by which processing speed contributes to the relations between adult age and associative learning. Results of both studies indicated that increased age was related to poorer associative learning largely because of a failure to retain information about previously correct responses. This in turn was related to the effectiveness of encoding briefly presented information in an associative memory task, which was related to measures of processing speed. It is therefore suggested that age-related decreases in speed of processing lead to less effective encoding or elaboration, which results in a fragile representation that is easily disrupted by subsequent processing.

Adult↗
PubMed1997

Adiabatic pulses.

Adiabatic pulses are sometimes considered to be mysterious and exotic entities which are difficult to understand, complex to generate and impractical to implement. This work is an attempt to bring familiarity and to fulfill the preliminary needs of anyone interested in learning more about this subject. The response of magnetization to stimuli produced by adiabatic pulses is analyzed using vector representations in a frequency modulated rotating frame. The first section deals with basic principles of amplitude and frequency modulated pulses and a vector representation in a second rotating frame is used to explain how the adiabatic condition can be satisfied. The subsequent section explains the principles of offset independent adiabaticity. These principles are then used to design optimal functions for the amplitude, frequency, and magnetic field gradient modulations for adiabatic inversion pulses. The last section considers some practical aspects for those who want to develop methodologies involving adiabatic pulses.

Electromagnetic Fields↗
PubMed1993

Modulation of motor cortical outputs to the reading hand of braille readers.

We used focal transcranial magnetic stimulation to map the motor cortical areas targeting the first dorsal interosseous and the abductor digiti minimi muscles bilaterally in 10 proficient braille readers and 10 blind controls who were matched for age (mean, 50.6 yr) and age at time of blindness (mean, 7.5 yr). The proficient braille readers had learned braille at age 8 to 14 years and used it daily for 5 to 10 hours. Controls had not learned braille until age 17 to 21 years and used it daily for < 1 hour. In the controls, motor representations of the right and left first dorsal interosseous and abductor digiti minimi muscles were not significantly different. However, in the proficient braille readers, the representation of the first dorsal interosseous muscle in the reading hand was significantly larger than that in the nonreading hand or in either hand of the controls. Conversely, the representation of the abductor digiti minimi muscle in the reading hand was significantly smaller than that in the nonreading hand or in either hand of the controls. These differences were not due to differences in motor thresholds. Our results suggest that the cortical representation of the reading finger in proficient braille readers is enlarged at the expense of the representation of other fingers.

Adolescent↗
PubMed1991

On the computational architecture of the neocortex. I. The role of the thalamo-cortical loop.

This paper proposes that each area of the cortex carries on its calculations with the active participation of a nucleus in the thalamus with which it is reciprocally and topographically connected. Each cortical area is responsible for maintaining and updating the organism's knowledge of a specific aspect of the world, ranging from low level raw data to high level abstract representations, and involving interpreting stimuli and generating actions. In doing this, it will draw on multiple sources of expertise, learned from experience, creating multiple, often conflicting, hypotheses which are integrated by the action of the thalamic neurons and then sent back to the standard input layer of the cortex. Thus this nucleus plays the role of an 'active blackboard' on which the current best reconstruction of some aspect of the world is always displayed. Evidence for this theory is reviewed and experimental tests are proposed. A sequel to this paper will discuss the cortico-cortical loops and propose quite different computational roles for them.

Animals↗
PubMed2004

Action-effect coupling in pianists.

Recent theories have stressed the role of effect anticipation in action control. Such a mechanism requires the prior acquisition of integrated action-effect associations. The strength of such associations should directly depend on the amount of learning, and therefore be most pronounced in motor experts. Using an interference paradigm, we investigated whether evidence of such representations can be demonstrated in expert pianists. Participants were required to play chords on a keyboard in response to imperative visual stimuli. Concurrently, task-irrelevant auditory stimuli ("potential" action effects) were presented that were congruent or incongruent with the chords to be played. In Experiment 1 we found evidence that expert pianists, compared with non-musicians, have acquired such action-effects representations. Response times were slower when the auditory stimulus was incongruent with the required response. In order to ascertain the locus of interference, we varied imperative stimuli and responses in Experiments 2 and 3. The results indicate that, for the most part, interference occurs on the response level rather than on an abstract level. However, the perception of action effects also evokes processing of abstract features, like the concept of major-minor mode.

Acoustic Stimulation↗
PubMed2007

Functional organization within a neural network trained to update target representations across 3-D saccades.

The goal of this study was to understand how neural networks solve the 3-D aspects of updating in the double-saccade task, where subjects make sequential saccades to the remembered locations of two targets. We trained a 3-layer, feed-forward neural network, using back-propagation, to calculate the 3-D motor error the second saccade. Network inputs were a 2-D topographic map of the direction of the second target in retinal coordinates, and 3-D vector representations of initial eye orientation and motor error of the first saccade in head-fixed coordinates. The network learned to account for all 3-D aspects of updating. Hidden-layer units (HLUs) showed retinal-coordinate visual receptive fields that were remapped across the first saccade. Two classes of HLUs emerged from the training, one class primarily implementing the linear aspects of updating using vector subtraction, the second class implementing the eye-orientation-dependent, non-linear aspects of updating. These mechanisms interacted at the unit level through gain-field-like input summations, and through the parallel "tweaking" of optimally-tuned HLU contributions to the output that shifted the overall population output vector to the correct second-saccade motor error. These observations may provide clues for the biological implementation of updating.

Animals↗
PubMed1996

Telencephalic ablation in goldfish impairs performance in a 'spatial constancy' problem but not in a cued one.

This work was aimed to study if goldfish telencephalon is involved differentially in spatial and cue learning. With this purpose, animals were assigned to two learning conditions, 'spatial constancy' and 'directly cued', and their performance was recorded before and after ablation of the telencephalon. During the presurgical acquisition period, animals of both groups learned to solve the task with accuracy, and reached the goal in transfer tests, even though they were released from new starting positions and the response requirements were changed. Ablation impaired selectively the solution of the spatial constancy problem, but had no significant effects on the cued condition. However, with additional training, performance of the ablated animals in the spatial constancy condition improved to control levels. The above data suggest that fishes can implement multiple spatial learning strategies which have different neural substrata. These results are discussed in relation to the possible nature of the representation underlying each task.

Animals↗
PubMed2006

An apple a day keeps the doctor away: children's evaluative categories of food.

This study explores how children evaluatively categorize foods based on their nutritional value. Three-year-olds, four-year-olds, seven-year-olds, and adults completed a task in which they categorized a list of 70 foods as healthy or junky. The results showed important developmental differences in participants' ability to accurately classify foods as healthy/junky and to provide relevant justifications for these classifications. These results suggest that a large amount of category learning occurs with development, especially as children incorporate different types of information about food nutrition into their evaluative category representations.

Adult↗
PubMedDate not supplied

Associations with Minspeak icons.

UNLABELLED: Although the Minspeak approach is used on communication devices worldwide, little research has been conducted on its applicability within specific cultural contexts. The impact that users' familiarity of symbols and associations can have on learnability necessitates more systematic research. This study was an investigation into the associations which young South African adults from a tertiary education institution make with selected Minspeak icons, used in Unity software. Associations with the 12 core icons of the UniChat program were elicited from 480 able-bodied tertiary education students, using a cueing questionnaire. Each participant completed one questionnaire on one icon, so that 40 response questionnaires were obtained per icon. The responses from the questionnaires were pruned and computerised. Two analyses were done from these data: Firstly, the percentage of common associations per icon was calculated, and secondly, the elicited associations were compared to the current Unity vocabulary on a word and conceptual level. The results indicate that some of the icons and their encoded vocabulary items might be used successfully in the South African context, while others need to be adapted to be locally relevant. The results emphasize that iconic encoding systems based on commercially available graphic representational systems cannot merely be imported to South Africa due to the multicultural and multilingual nature of the context. LEARNING OUTCOMES: As a result of this activity (1) the participant will be able to understand different types of associational responses based on icons used in Minspeak; (2) the participant will be able to understand the cultural relevance of some aspects of the Unity application programme; and (3) the participant will be able to identify different strategies that can be used to describe the cultural relevance o of the Unity application programme.

Adolescent↗
PubMed1998

The sensorimotor and cognitive integration of gravity.

In order to demonstrate that gravity is not only a load acting locally and continuously on the body limbs, but is also used by higher levels of the nervous system as a dynamic orienting reference for the elaboration of the motor act, a review of several experiments conducted both in 1 g and 0 g are presented. During various locomotor tasks, the strategy that consists of stabilizing the head with respect to gravity illustrates one of the solutions used by the CNS to optimize the control of dynamic equilibrium. A question which remains to be solved when considering experimental results obtained in weightlessness concerns, however, the maintenance of motor schema that has evolved under normal gravity. Results have suggested that the concept of conservative processes, that would adapt postural control to weightlessness by using previously learned innate strategies, must be reconsidered during goal-oriented tasks. In fact, it is proposed that when conservative processes and existing solutions derived from a repertoire of terrestrial postural strategies do not provide efficient output, the CNS has to create novel strategies through a slow learning process. As with the study of postural control, three-dimensional arm reaching movements also illustrate the central representation of gravity. Indeed, gravity can be regarded as either initiating or braking arm movements and, consequently, may be represented in the motor command at the planning level. Finally, from a prospective point of view, there is a need to determine new experimental paradigms in order to study the specific motor control of man in space. It is suggested that the formulation of experimental paradigms should not consider man in space simply as a terrestrial biped.

Arm↗
PubMed2000

Effects of visual experience on the representation of objects in the prefrontal cortex.

The perception and recognition of objects are improved by experience. Here, we show that monkeys' ability to recognize degraded objects was improved by several days of practice with these objects. This improvement was reflected in the activity of neurons in the prefrontal (PF) cortex, a brain region critical for a wide range of visual behaviors. Familiar objects activated fewer neurons than did novel objects, but these neurons were more narrowly tuned, and the object representation was more resistant to the effects of degradation, after experience. These results demonstrate a neural correlate of visual learning in the PF cortex of adult monkeys.

Animals↗