Intact text-specific reading skill in amnesia.

Amnesic patients were studied to determine whether the acquisition and retention of item-specific skills can be supported by nondeclarative (implicit) memory. In Exp 1, Ss read 2 different passages 3 times in succession. Reading speed improved at a similar rate in both amnesic patients and normal Ss and was specific to the text that was read. In Exp 2, amnesic patients and normal Ss read a passage 3 successive times and then reread the same passage after a 0-sec, 10-min, 2-hr, or 1-day delay. In both groups, facilitation persisted for at least 10 min and disappeared within 2 hrs. It is suggested that facilitated reading speed depends importantly on both semantic and perceptual information and that such information can be supported by nondeclarative memory. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Intact mirror-tracing and impaired rotary-pursuit skill learning in patients with Huntington's disease: evidence for dissociable memory systems in skill learning

Skill learning in early-stage Huntington's disease (HD) patients was compared with that of normal controls on 2 perceptual-motor tasks, rotary pursuit and mirror tracing. HD patients demonstrated a dissociation between impaired rotary-pursuit and intact mirror-tracing skill learning. These results suggest that different forms of perceptual-motor skill learning are mediated by separable neural circuits. A striatal memory system may be essential for sequence or open-loop skill learning but not for skills that involve the closed-loop learning of novel visual-response mappings. It is hypothesized that working memory deficits in HD resulting from frontostriatal damage may account broadly for intact and impaired long-term learning and memory in HD patients.     

Intact implicit habit learning in Alzheimer's disease.

Habit learning refers to the incremental implicit learning of associations. Patients with Alzheimer's disease (AD) exhibit deficits in explicit memory and in conceptual implicit memory tasks that rely on the cortical areas damaged in AD. The authors tested patients with AD and controls on a probabilistic classification task in which participants implicitly acquire cue-outcome associations. Both groups showed evidence of learning across 50 trials, and performance did not differ significantly between the groups. In contrast, patients with AD exhibited a profound impairment in explicit memory for the testing episode. These results are consistent with the idea that habit learning relies on subcortical structures, including the basal ganglia, and is independent of the medial temporal and cortical areas damaged in AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact and long-lasting repetition priming in amnesia.

In 2 experiments, the ability of amnesic patients to exhibit long-lasting perceptual priming after a single exposure to pictures was evaluated. Ss named pictures as quickly as possible on a single occasion and later named the same pictures mixed with new pictures. In Exp 1, amnesic patients exhibited fully intact priming effects lasting at least 7 days. In Exp 2, the priming effect for both groups was shown to depend on both highly specific visual information and on less visual, more conceptual information. In contrast, recognition memory was severely impaired in the patients, as assessed by both accuracy and response time. The results provide the 1st report of a long-lasting priming effect in amnesic patients, based on a single encounter, which occurs as strongly in the patients as in normal Ss. Together with other recent findings, the results suggest that long-lasting priming and recognition memory depend on separate brain systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal coding and display coding in the acquisition and retention of tracking skill.

120 Ss were trained on a pursuit tracking task with an irregular step-function input. Cues for coding the task were introduced via pretraining and rehearsal of a numerical code and by display overlays in a 2 X 2 X 3 design. 3 levels of specificity of cues were provided by the overlays with the most specific condition providing a numerical code like that of pretraining. The results showed that both pretraining and display coding facilitated early reduction of tracking error, but that neither these nor rehearsal of the numerical code affected retention performance after 1 wk. Taken together, these findings suggested that the verbal and display cues were used in the early coding of the task, but were less important later in practice and at retention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact text-specific implicit memory in patients with Alzheimer's disease.

The ability of patients with Alzheimer's disease (AD) to acquire and retain text-specific knowledge was investigated in a rereading study. Ten AD patients (aged 59–84 yrs) and 10 normal control Ss read 2 passages 3 times, each as quickly as possible, and answered recognition memory questions after the 3rd reading of each passage. The AD patients had poor explicit memory as evidenced by impaired recognition memory for the passages. In contrast, normal decreases in the times required for successive readings of each passage for AD patients indicated intact implicit memory for the passages. The absence of facilitation across passages indicated that the rereading effect was text specific, suggesting that AD patients may retain the ability to form certain kinds of implicit new associations. Alternative accounts of the mechanism underlying text-specific priming, and of the nature of intact and impaired implicit memory in AD, are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact and impaired conceptual memory processes in amnesia.

To examine the status of conceptual memory processes in amnesia, a conceptual memory task with implicit or explicit task instructions was given to amnesic and control groups. After studying a list of category exemplars, participants saw category labels and were asked to generate as many exemplars as possible (an implicit memory task) or to generate exemplars that had been in the prior study list (an explicit memory task). After incidental deep or shallow encoding of exemplars, amnesic patients showed normal implicit memory performance (priming), a normal levels-of-processing effect on priming, and impaired explicit memory performance. After intentional encoding of exemplars, amnesic patients showed impaired implicit and explicit memory performance. Results suggest that although amnesic patients can show impairments on implicit and explicit conceptual memory tasks, their deficit does not generalize to all conceptual memory tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning and retention in preclinical and early Alzheimer's disease.

Accelerated forgetting has been proposed as the first sign in preclinical and early Alzheimer's disease (AD). The authors investigated learning and retention in participants who later developed AD with free and cued selective reminding (FCSR; H. Buschke, 1984; E. Grober & H. Buschke, 1987), a test that maximizes learning by inducing deep semantic processing and by controlling study and test conditions. AD patients in the preclinical stage recalled significantly fewer words than did matched control participants, indicating an impairment of learning; nonetheless, patients' retention was identical to that of control participants. A retention deficit was documented 3 years later for AD patients but not for control participants, whose retention was still perfect. Thus, a retention deficit is not present in preclinical AD when hallmark learning deficits can be documented. Detection of preclinical and very early AD may be best accomplished by using robust learning tests that control cognitive processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual and conceptual memory processes in global amnesia.

To determine whether global amnesia reflects a selective deficit in conceptual processing, amnesic and control Ss performed 4 memory tasks that varied processing and retrieval requirements. A study-phase modality (auditory/visual) manipulation validated the nature of processing (perceptual and conceptual) engaged by each task. Amnesic patients were impaired on perceptual and conceptual explicit memory tasks (word-fragment and word-associate cued recall) and were intact on perceptual and conceptual implicit memory tasks (word-fragment completion and word association). These results are consistent with the view that limbic-diencephalic structures damaged in amnesia mediate, in part, processes typically engaged during explicit retrieval. The results are inconsistent, however, with the characterization of that deficit as being one of conceptual processing per se. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acquisition and retention of a letter-detection skill.

In two experiments, we examined the acquisition and retention of a letter-detection skill with a consistent-mapping procedure. In Experiment 1, subjects were trained from 0 to 4 sessions at detecting the letter H in displays containing random letters, and retesting occurred after a 1-month delay. Performance improved and in some cases became more automatic, and the performance level was maintained over the retention interval. When tested with a prose passage, the high error rate on the word THE was eliminated after training and after the retention interval, regardless of the amount of training. In Experiment 2, two subjects were given 12 sessions of training followed by a retention test 6 months later. For 1 subject there was also a retention test 15 months after acquisition. Performance improved dramatically with training, and substantial but not complete automaticity was achieved. Performance on the retention tests was close to the final acquisition level. The surprising lack of forgetting in this study was contrasted with the substantial forgetting typically found in studies of verbal learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of rehearsal of temporal and spatial aspects on the long-term retention of a procedural skill.

The study examined several rehearsal techniques as means of facilitating the retention of a discrete procedural task. 4 rehearsal conditions were defined as: whole task rehearsal, temporal rehearsal, spatial rehearsal, and no rehearsal. All groups were trained for 5 days, given 10 days of no practice, 5 days of rehearsal, 11 more days of no practice, and a retention test. The number of commissive errors showed significant retention differences, with the whole rehearsal group performing best. Omissive errors and reaction time did not show group differences. It was also found that Ss emphasized those metrics of performance which gave the most immediate feedback. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact baseline performance and priming in amnesia: Reply to Ostergaard and Jernigan.

In their comment on the article by S. B. Hamann et al (see record 1995-14158-001), A. L. Ostergaard and T. L. Jernigan (see PA, Vol 83:23639) reaffirmed their position that baseline perceptual identification performance and priming are impaired in amnesia. They also suggested certain shortcomings in the experiments of Hamann et al, who found normal baseline performance and normal priming in amnesia across a wide range of performance accuracies. In reply, the authors of this article suggest that the position of Ostergaard and Jernigan rests on selective consideration of data, inaccurate assumptions concerning 1 patient's priming performance (A.B.), and debatable concerns about the masking stimuli, ceiling effects, and presentation time of study items that were used. In addition, the authors of the present article suggest that Ostergaard and Jernigan have based their own experimental work on a task and test method that may not be optimal for studying priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting self-efficacy and performance during skill acquisition.

Ss completed 7 trials of a complex computer task that simulated the job of an air traffic controller. Performance was calculated by combining points for the number of planes landed minus penalty points. Throughout the trials, Ss completed questionnaires assessing their self-efficacy goals, expected performance, and the degree to which certain judgments required more or less cognitive processing. The results show that during skill acquisition people report reductions in their cognitive processing for working on the task and for making self-efficacy judgments. Also, on early trials, self-efficacy is a better predictor of performance than are expected score or goals, whereas the reverse is true for later trials. The discussion focuses on understanding motivational processes during skill acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dual learning processes in interactive skill acquisition.

Acquisition of interactive skills involves the use of internal and external cues. Experiment 1 showed that when actions were interdependent, learning was effective with and without external cues in the single-task condition but was effective only with the presence of external cues in the dual-task condition. In the dual-task condition, actions closer to the feedback were learned faster than actions farther away but this difference was reversed in the single-task condition. Experiment 2 tested how knowledge acquired in single and dual-task conditions would transfer to a new reward structure. Results confirmed the two forms of learning mediated by the secondary task: A declarative memory encoding process that simultaneously assigned credits to actions and a reinforcement-learning process that slowly propagated credits backward from the feedback. The results showed that both forms of learning were engaged during training, but only at the response selection stage, one form of knowledge may dominate over the other depending on the availability of attentional resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the acquisition of new declarative knowledge in amnesia.

In 2 experiments, the acquisition of new declarative knowledge was examined in amnesic patients and in 7 groups of controls, with a study-only procedure that delayed testing until the conclusion of training. The study-only procedure was compared with a standard procedure in which study and test trials alternated (study-test). The amnesic patients acquired new factual (declarative) knowledge at an abnormally slow rate, learning more with the study-only procedure than with the study-test procedure. Controls exhibited the opposite pattern. The advantage of the study-only procedure for amnesic patients was related to the presence of frontal lobe dysfunction. The 2 groups exhibited a similar ability to use their knowledge flexibly, suggesting that the information acquired by amnesic patients was based on their residual capacity for declarative memory. In addition, the capacity for factual learning in amnesia was proportional to the capacity to recollect specific events in the learning session. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and skill acquisition: Learning-performance distinctions.

This research examined the hypothesis that a conservative response bias in older persons interferes with the acquisition and mastery of cognitive skill. Twenty younger and 20 older Ss performed both consistent mapping and varied mapping versions of a memory search task. Half of the Ss in each group performed under speed stress instructions, whereas the remaining Ss performed under accuracy stress instructions. Older Ss exhibited less skilled performance than did younger Ss. A power function analysis attributed this to both age-related differences in the rate of associative learning and differences in asymptotic levels of performance. These results are at odds with A. D. Fisk and W. A. Rogers's (1991) hypothesis that age-related differences in automatization do not occur in memory search tasks. Results are interpreted in terms of a learning vs performance distinction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measuring skill acquisition and retention with an ATM simulator: the need for age-specific training

The high-effective polysynaptic transcallosal connections were revealed in the motor cortex of anesthetized rats. Polysynaptic connections were manifested in crosscorrelation histograms as high narrow peaks of width 1-2 ms and latencies up to the end of the analyzed interval in 50 ms. In most cases the polysynaptic transcallosal connections were reciprocal. The incidence of transcallosal polysynaptic connections was twice as high as of the ipsilateral. Gamma oscillations were observed in the same neural assemblies. Interhemispheric oscillations were 1.5-fold more frequent than the ipsilateral ones. The peak latencies were multiples of gamma-oscillation periods. The distribution of peak latencies was similar to the distribution of gamma oscillations. It was suggested that synchronous discharges in neurons in a polysynaptic interhemispheric pathway in consequence of gamma oscillations cause potentiation in efficacy of neural connections, which promotes the high-effective transmission of a signal from one hemisphere to another.     

Motor skills have diverse neural bases: Spared and impaired skill acquisition in Huntington's disease.

The striatum contributes to the learning of some, but not all, motor skills. The researchers suggest that the striatum plays a role when participants learn a repeating sequence of movements, but it does not contribute when they learn a new mapping between perceptual cues and the appropriate motor response. The researchers tested patients with striatal damage due to Huntington's disease (HD) on 2 versions of a tracking task. In 1 task, the target moved randomly, allowing participants to learn the relationship between the joystick and cursor. Patients showed normal learning. In the other task, the target moved in a repeating pattern, and participants could improve performance by learning the repeating sequence of movements necessary to track the pattern. Patients were impaired on this task. Learning sequences is impaired in HD, whereas learning new mappings between perceptual cues and responses is not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotion enhanced retention of cognitive skill learning.

Ample evidence suggests that emotional arousal enhances declarative/episodic memory. By contrast, there is little evidence that emotional enhancement of memory (EEM) extends to procedural skill based memory. We examined remote EEM (1.5-month delay) for cognitive skill learning using the weather prediction (WP) probabilistic classification task. Participants viewed interleaved emotionally arousing or neutral pictures during WP acquisition. Arousal retarded initial WP acquisition. While participants in the neutral condition showed substantial forgetting of WP learning across the 1.5-month delay interval, the arousal condition showed no evidence of forgetting across the same time period. Thus, arousal during encoding determined the mnemonic fate of cognitive skill learning. Emotional enhancement of WP retention was independent of verbally stated knowledge of WP learning and EEM for the picture contexts in which learning took place. These results reveal a novel demonstration of EEM for cognitive skill learning, and suggest that emotional arousal may in parallel enhance the neural systems that support procedural learning and its declarative context. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Strategy selection and use during classification skill acquisition.

Two experiments examined 3 variables affecting accuracy, response time, and reports of strategy use in a binary classification skill task. In Experiment 1, higher rule cue salience, allowing faster rule application, produced higher aggregate rule use than lower rule cue salience. After participants were pretrained on the relevant classification rule, rule reports were high but generally declined across training trials; after participants were pretrained on an irrelevant rule, reports of the relevant rule increased across training trials. In Experiment 2, no rule pretraining produced a pattern of results like that obtained with irrelevant rule pretraining in Experiment 1. Presenting novel stimuli during training in Experiment 2 elevated aggregate rule reports relative to conditions where they were absent. Two participant subgroups were identified: those persisting in rule reports and those transitioning from rule to memory reports during training. The proportion of persistent rule users was higher after rule discovery than after relevant rule pretraining. Overall, the results indicate that differences among prior experiments can be reconciled. Further, they raise questions about the inevitability of memory-based automaticity in binary classification, favoring instead strategy choice based on the costs and benefits of a particular strategy and of a shift from one strategy to another. (PsycINFO Database Record (c) 2010 APA, all rights reserved)