Interhemispheric transfer of visual information in schizophrenics

Groups of 12 male schizophrenic inpatients and 12 normal controls of the same age, sex, and schooling underwent a tachistoscopic test. Each subject was shown an alphabetical letter which he subsequently had to recognize among various other alphabetical letters also shown tachistoscopically. The visual hemifields of the two displays were ipsilateral and crossed. Relative to the normal group the schizophrenics showed higher perceptual thresholds, lower over-all mean performance, and greater lateralization. The results are discussed in terms of rigidly and poorly integrated systems of analysis of information between one hemisphere and the other for schizophrenic patients.     

Interhemispheric transfer of lever pressing as stimulus generalization of the effects of spreading depression

Rats trained to lever-press with spreading depression in one cerebral hemisphere showed weak responding when tested with depression shifted to the trained hemisphere. The rats were then divided into two groups: one group (normal) was permitted a single reinforced response with neither hemisphere depressed, the other group (depressed) was permitted a single reinforced response with the trained hemisphere depressed; both groups were then tested with the trained hemisphere depressed. Responding during this second test increased for both groups, but the magnitude of the increase tended to be greater for the depressed than for the normal group. Since memory transfer could not have occurred with the trained hemisphere depressed, the results were taken to indicate that the single reinforced response strengthened stimulus generalization between train-test conditions.     

Recollection training and transfer effects in Alzheimer's disease: effectiveness of the repetition-lag procedure

Objective

This study was designed to extend the use of a memory training technique, known as the repetition-lag procedure, to Alzheimer patients. The specificity of this procedure is to target the process of recollection for improvement.

Method

A group of 12 patients were trained individually for 6 h. The training procedure consisted of a series of yes/no recognition tasks in which some words were repeated throughout the test list across gradually increasing delays. Their performance was evaluated on pre-and-post tests and compared with a recognition practice group and a no contact control group.

Results

Initially, recollection training patients only performed accurately when the delay between repetitions consisted of one intervening word, but by the end of training their performance increased up to four-word intervals. Interestingly, these benefits generalized to other measures of memory, such as working memory, visual memory and source recognition.

Conclusions

Effectiveness of the repetition-lag procedure in Alzheimer’s disease is discussed.     

Specificity effects in training and transfer of speeded responses

In 3 experiments, participants, on signal, moved a cursor from a central position to 1 of 8 numerically labeled locations on the circumference of a clock face. Movements were controlled by a mouse in 1 of 4 conditions: vertical reversal, horizontal reversal, combined reversals, or normal (i.e., no reversals). Participants were trained in 1, 2, or 3 of these conditions and were tested 1 week later with either the same or a different condition. There were improvements across training and perfect retention across the delay. There was little or no transfer, however, even when training involved combined reversals or multiple conditions. These results illustrate severe specificity of training and are interpreted in terms of acquired inhibition of normal responses.     

Interhemispheric transfer of extinction of the active avoidance reaction in rats.

Cortical spreading depression (CSD) was employed in rats to study the lateralization of extinction of a jumping avoidance reaction. Under unilateral CSD, 181 nonreinforced trials were needed to extinguish the avoidance reaction acquired in three 100-trial sessions of intact-brain training. During a second extinction session, either with the same or with the contralateral hemisphere depressed, the mean number of trials to the extinction criterion (9/10) was 39 (n = 12) or 186 (n = 15), respectively. Five extinction trials performed with the brain intact 1 hr before extinction with contralateral CSD decreased the number of trials to extinction of 98 (n = 11). Thus, extinction of active avoidance can be lateralized and interhemispherically transferred in the same way as acquisition of this habit.     

The visual system of the cat

So much of our current knowledge about the neurophysiology of vision has come from studying the visual system of the cat. Using microelectrode techniques, neurophysiologists have examined in great detail the spatial properties of receptive fields of neurons at various levels of the feline nervous system, and headway is now being made in discovering the patterns of neural connections which give rise to the remarkable degree of stimulus selectivity characteristic of these neurons. This paper reviews the major findings concerning the visual system of the normal adult cat, from optics to visual cortex, and summarizes the physiological consequences of early visual deprivation on the visual nervous system of the cat. The review concludes with remarks about the validity of generalizing from cat neurophysiology to human vision.     

Working memory training in older adults: evidence of transfer and maintenance effects

Few studies have examined working memory (WM) training-related gains and their transfer and maintenance effects in older adults. This present research investigates the efficacy of a verbal WM training program in adults aged 65-75 years, considering specific training gains on a verbal WM (criterion) task as well as transfer effects on measures of visuospatial WM, short-term memory, inhibition, processing speed, and fluid intelligence. Maintenance of training benefits was evaluated at 8-month follow-up. Trained older adults showed higher performance than did controls on the criterion task and maintained this benefit after 8 months. Substantial general transfer effects were found for the trained group, but not for the control one. Transfer maintenance gains were found at follow-up, but only for fluid intelligence and processing speed tasks. The results are discussed in terms of cognitive plasticity in older adults.     

On the validity and generality of transfer effects in cognitive training research

Evaluation of training effectiveness is a long-standing problem of cognitive intervention research. The interpretation of transfer effects needs to meet two criteria, generality and specificity. We introduce each of the two, and suggest ways of implementing them. First, the scope of the construct of interest (e.g., working memory) defines the expected generality of transfer effects. Given that the constructs of interest are typically defined at the latent level, data analysis should also be conducted at the latent level. Second, transfer should be restricted to measures that are theoretically related to the trained construct. Hence, the construct of interest also determines the specificity of expected training effects; to test for specificity, study designs should aim at convergent and discriminant validity. We evaluate the recent cognitive training literature in relation to both criteria. We conclude that most studies do not use latent factors for transfer assessment, and do not test for convergent and discriminant validity.     

Immediate and delayed transfer of training effects in statistical reasoning

Ss were trained on the law of large numbers in a given domain through the use of example problems. They were then tested either on that domain or on another domain either immediately or after a 2-week delay. Strong domain independence was found when testing was immediate. This transfer of training was not due simply to Ss' ability to draw direct analogies between problems in the trained domain and in the untrained domain. After the 2-week delay, it was found that (a) there was no decline in performance in the trained domain and (b) although there was a significant decline in performance in the untrained domain, performance was still better than for control Ss. Memory measures suggest that the retention of training effects is due to memory for the rule system rather than to memory for the specific details of the example problems, contrary to what would be expected if Ss were using direct analogies to solve the test problems.     

Mental rotation training: transfer and maintenance effects on spatial abilities

One of the aims of research in spatial cognition is to examine whether spatial skills can be enhanced. The goal of the present study was thus to assess the benefit and maintenance effects of mental rotation training in young adults. Forty-eight females took part in the study: 16 were randomly assigned to receive the mental rotation training (based on comparing pairs of 2D or 3D objects and rotation games), 16 served as active controls (performing parallel non-spatial activities), and 16 as passive controls. Transfer effects to both untrained spatial tasks (testing both object rotation and perspective taking) and visual and verbal tasks were examined. Across the training sessions, the group given mental rotation training revealed benefits in the time it took to make judgments when comparing 3D and 2D objects, but their mental rotation speed did not improve. When compared with the other groups, the mental rotation training group did show transfer effects, however, in tasks other than those practiced (i.e., in object rotation and perspective-taking tasks), and these benefits persisted after 1 month. The training had no effect on visual or verbal tasks. These findings are discussed from the spatial cognition standpoint and with reference to the (rotation) training literature.     

Generalization effects of social skills training in chronic schizophrenics: An experimental analysis

Social skills training was administered to three (one male and two female) chronic schizophrenic patients in a Partial Hospitalization Service. Treatment consisted of instructions. feedback and modeling, and was administered in 25. 26 and 31 sessions, respectively, for the three patients. Target behaviors were identified for each patient based on his/her responses to role-played interactions involving male and female partners in situations requiring commendatory or hostile assertion. Five to seven target behaviors were selected for each subject and were treated sequentially in a multiple baseline format. Skills training was highly successful for the two female patients but was only partially effective for the male patient. Two forms of generalization measures were included, indicating that the effects of training generalized from trained to untrained, and trained to novel role-played interactions. Follow-up assessments for the two female patients indicated that most of the effects persisted over 8–10-week post-treatment periods.     

Interhemispheric transfer of figural information in right- and non-right-handed subjects.

The capacity of normal human Ss to match abstract shapes across the cerebral hemispheres was studied as a function of exposure duration. A general right hemisphere superiority was found, and in the conditions where one stimulus was presented to each hemisphere, the order of stimuli (to the right or left hemisphere first) did not affect performance. Decreasing stimulus exposure was shown to interact with hemisphere differences. An overall superiority of non-right-handed subjects was found, although their pattern of results did not differ from right-handed Ss, and it is argued that this supports the hypothesis that the cerebral organisation of the non-right-hander is more diffuse in its general organisational structure.     

Training and transfer effects of long-term memory retrieval training

ABSTRACT

Long-term memory retrieval ability and working memory can share attention control ability. Based on cognitive plasticity, a hypothesis that cognitive training could improve long-term memory retrieval efficiency and that this could transfer to retrieval involving working memory was proposed. 60 undergraduates were randomly assigned to a group of training and an active control group; all the participants completed the same tasks in the same order before and after the training, the tasks included a long-term memory retrieval access task, a intelligence test, a switching task, a working memory updating task, a response inhibition task and an interference control task. The statistics results indicate that cognitive training can improve long-term memory retrieval efficiency and has a transfer effect on working memory updating, interference control and switching ability, but not on response inhibition or intelligence. This reveal the plasticity of long-term memory retrieval and its influence on working memory.     

The influence of training task stimuli on transfer effects of working memory training in aging

IntroductionWorking memory (WM) training is known to produce benefits in older adults’ WM. Transfer effects to untrained abilities, however, remain controversial and several aspects are thought to influence the generalization of benefits, including the kind of stimuli used in the training tasks, an aspect rarely addressed in older adults.ObjectiveThe present study had two aims: (1) to test the efficacy of a visuospatial WM training procedure in older adults, in terms of specific and transfer effects; (2) to examine in two experiments whether the type of stimuli used in the training task influences the training's effectiveness. Experiment 1 adopted images with a neutral valence while experiment 2 used emotionally positive images based on evidence that older adults tend to remember positive stimuli better. In both experiments, specific training-related gains in a visuospatial WM task (the criterion task) and transfer effects on measures of verbal WM, visuospatial short-term memory, processing speed and reasoning were examined. Maintenance of training benefits was also assessed at an 8-month follow-up.MethodSeventy older adult (63–75 years old) volunteers (35 for experiment 1, and 35 for experiment 2) were randomly assigned to a training or active control group. The same visuospatial WM training procedure was used in both experiments, manipulating only the type of stimuli used (neutral in experiment 1 and emotionally positive in experiment 2).ResultsIn both experiments, only trained participants showed specific benefits in the WM criterion task. These gains were also maintained at the follow-up, but no transfer effects were identified.ConclusionOverall, our findings using the present visuospatial WM training paradigm suggest that it is less effective, in terms of transfer effects, than the same paradigm administered verbally in a previous study, regardless of the type of stimuli used in WM training tasks (neutral or emotionally positive stimuli).