Learning Strategy Trumps Motivational Level In Determining Learning-Induced Auditory Cortical Plasticity

Associative memory for auditory-cued events involves specific plasticity in the primary auditory cortex (A1) that facilitates responses to tones which gain behavioral significance, by modifying representational parameters of sensory coding. Learning strategy, rather than the amount or content of learning, can determine this learning-induced cortical (high order) associative representational plasticity (HARP). Thus, tone-contingent learning with signaled errors can be accomplished either by (1) responding only during tone duration (“tone-duration” strategy, T-Dur), or (2) responding from tone onset until receiving an error signal for responses made immediately after tone offset (“tone-onset-to-error”, TOTE). While rats using both strategies achieve the same high level of performance, only those using the TOTE strategy develop HARP, viz., frequency-specific decreased threshold (increased sensitivity) and decreased bandwidth (increased selectivity) (Berlau and Weinberger, 2008). The present study challenged the generality of learning strategy by determining if high motivation dominates in the formation of HARP. Two groups of adult male rats were trained to bar-press during a 5.0 kHz (10s, 70 dB) tone for a water reward under either high (HiMot) or moderate (ModMot) levels of motivation. The HiMot group achieved a higher level of correct performance. However, terminal mapping of A1 showed that only the ModMot group developed HARP, i.e., increased sensitivity and selectivity in the signal frequency band. Behavioral analysis revealed that the ModMot group used the TOTE strategy while HiMot subjects used the T-Dur strategy. Thus, type of learning strategy, not level of learning or motivation, is dominant for the formation of cortical plasticity.

from Neurobiology of Learning and Memory

Learning under stress impairs memory formation

Converging lines of evidence indicate that stress either before or after learning influences memory. Surprisingly little is known about how memory is affected when people learn while they are stressed. Here, we examined the impact of learning under stress in 48 healthy young men and women. Participants were exposed to stress (socially evaluated cold pressor test) or a control condition while they learned emotional words and neutral words that were either conceptually associated with or unrelated to the stressor. Memory was assessed in free recall and recognition tests 24 hours after learning. Learning under stress reduced both free recall and recognition performance, irrespective of the emotionality and the stress context relatedness of the words. While the effect of stress was comparable in men and women, women outperformed men in the free recall test. These findings show a memory impairing effect of learning under stress in humans and challenge some assumptions of current theories about the impact of stress around the time of learning on memory formation.

from Neurobiology of Learning and Memory

Aging, Hearing Acuity, and the Attentional Costs of Effortful Listening

A dual-task interference paradigm was used to investigate the effect of perceptual effort on recall of spoken word lists by young and older adults with good hearing and with mild-to-moderate hearing loss. In addition to poorer recall accuracy, listeners with hearing loss, especially older adults, showed larger secondary task costs while recalling the word lists even though the stimuli were presented at a sound intensity that allowed correct word identification. Findings support the hypothesis that extra effort at the sensory–perceptual level attendant to hearing loss has negative consequences to downstream recall, an effect that may be further magnified with increased age.

from Psychology and Aging

A Nonword Repetition Task for Speakers With Misarticulations: The Syllable Repetition Task (SRT)

Purpose: Conceptual and methodological confounds occur when non(sense) word repetition tasks are administered to speakers who do not have the target speech sounds in their phonetic inventories or who habitually misarticulate targeted speech sounds. In this article, the authors (a) describe a nonword repetition task, the Syllable Repetiton Task (SRT), that eliminates this confound and (b) report findings from 3 validity studies.

Method: Ninety-five preschool children with speech delay and 63 with typical speech completed an assessment battery that included the Nonword Repetition Task (NRT; C. Dollaghan & T. F. Campbell, 1998) and the SRT. SRT stimuli include only 4 of the earliest occurring consonants and 1 early occurring vowel.

Results: Study 1 findings indicated that the SRT eliminated the speech confound in nonword testing with speakers who misarticulate. Study 2 findings indicated that the accuracy of the SRT to identify expressive language impairment was comparable to findings for the NRT. Study 3 findings illustrated the SRT’s potential to interrogate speech processing constraints underlying poor nonword repetition accuracy. Results supported both memorial and auditory–perceptual encoding constraints underlying nonword repetition errors in children with speech-language impairment.

Conclusion: The SRT appears to be a psychometrically stable and substantively informative nonword repetition task for emerging genetic research and other research with speakers who misarticulate.

from the Journal of Speech, Language, and Hearing Research

Subtyping Children’s Reading Disabilities Using a Comprehensive Neuropsychological Measure

This study examined subtypes of children with reading disabilities using the NEPSY (series of Neuropsychological tests authored by Marit Korkman, Ursula Kirk and Sally Kemp). Multiple methods of cluster analysis were performed with 80 elementary school-age children identified as reading disabled. Students completed the NEPSY Language Domain and the NEPSY Memory and Learning Domain. Three clusters emerged which were interpreted as: (1) a No Language or Memory Deficit Subtype, (2) a Global Language and Memory Deficit Subtype, and (3) a Global Memory Deficit Subtype. This study suggested that memory-related processes, not exclusively phonologically related processes, might contribute to reading difficulties. This investigation supported the utility of a neuropsychological approach to subtyping children’s reading disabilities.

from the Journal of Neuroscience

A Nonword Repetition Task for Speakers with Misarticulations: The Syllable Repetition Task (SRT)

Conclusion: The SRT appears to be a psychometrically stable and substantively informative nonword repetition task for emerging genetic and other research with speakers who misarticulate.

from the Journal of Speech, Language, and Hearing Research

Procedural and declarative memory in children with and without specific language impairment

Conclusions & Implications: The results were interpreted to suggest an uneven profile of memory functioning in specific language impairment. On measures of declarative memory, specific language impairment appears to be associated with difficulties learning verbal information. At the same time, procedural memory is also appears to be impaired. Collectively, this study indicates multiple memory impairments in specific language impairment.

from the International Journal of Language and Communication Disorders

Procedural and declarative memory in children with and without specific language impairment

Outcomes & Results: The results from the SRT Task showed the children with specific language impairment did not learn the sequence at levels comparable with the non-impaired children. On the measures of declarative memory, differences between the groups were observed on the verbal but not the visual task. The differences on the verbal declarative memory task were found after statistically controlling for differences in vocabulary and phonological short-term memory.

Conclusions & Implications: The results were interpreted to suggest an uneven profile of memory functioning in specific language impairment. On measures of declarative memory, specific language impairment appears to be associated with difficulties learning verbal information. At the same time, procedural memory is also appears to be impaired. Collectively, this study indicates multiple memory impairments in specific language impairment.

from the International Journal of Language and Communication Disorders

Brain atrophy associated with baseline and longitudinal measures of cognition

The overall goal was to identify patterns of brain atrophy associated with cognitive impairment and future cognitive decline in non-demented elders. Seventy-one participants were studied with structural MRI and neuropsychological testing at baseline and 1-year follow-up. Deformation-based morphometry was used to examine the relationship between regional baseline brain tissue volume with baseline and longitudinal measures of delayed verbal memory, semantic memory, and executive function. Smaller right hippocampal and entorhinal cortex (ERC) volumes at baseline were associated with worse delayed verbal memory performance at baseline while smaller left ERC volume was associated with greater longitudinal decline. Smaller left superior temporal cortex at baseline was associated with worse semantic memory at baseline, while smaller left temporal white and gray matter volumes were associated with greater semantic memory decline. Increased CSF and smaller frontal lobe volumes were associated with impaired executive function at baseline and greater longitudinal executive decline. These findings suggest that baseline volumes of prefrontal and temporal regions may underlie continuing cognitive decline due to aging, pathology, or both in non-demented elderly individuals.

from Neurobiology of Aging

Genetic variance in processing speed drives variation in aging of spatial and memory abilities.

Previous analyses have identified a genetic contribution to the correlation between declines with age in processing speed and higher cognitive abilities. The goal of the current analysis was to apply the biometric dual change score model to consider the possibility of temporal dynamics underlying the genetic covariance between aging trajectories for processing speed and cognitive abilities. Longitudinal twin data from the Swedish Adoption/Twin Study of Aging, including up to 5 measurement occasions covering a 16-year period, were available from 806 participants ranging in age from 50 to 88 years at the 1st measurement wave. Factors were generated to tap 4 cognitive domains: verbal ability, spatial ability, memory, and processing speed. Model-fitting indicated that genetic variance for processing speed was a leading indicator of variation in age changes for spatial and memory ability, providing additional support for processing speed theories of cognitive aging. (PsycINFO Database Record (c) 2009 APA, all rights reserved)

from Developmental Psychology

Investigating the cause of language regularization in adults: Memory constraints or learning effects?.

When language learners are exposed to inconsistent probabilistic grammatical patterns, they sometimes impose consistency on the language instead of learning the variation veridically. The authors hypothesized that this regularization results from problems with word retrieval rather than from learning per se. One prediction of this, that easing the demands of lexical retrieval leads to less regularization, was tested. Adult learners were exposed to a language containing inconsistent probabilistic patterns and were tested with either a standard production task or one of two tasks that reduced the demands of lexical retrieval. As predicted, participants tested with the modified tasks more closely matched the probability of the inconsistent items than did those tested with the standard task. (PsycINFO Database Record (c) 2009 APA, all rights reserved)

from Journal of Experimental Psychology: Learning, Memory, and Cognition

Adult Aging Effects on Semantic and Episodic Priming in Word Recognition

Two experiments compared automatic semantic and episodic priming effects in adult aging. In the 1st experiment, target words were semantically primed; in the 2nd experiment, targets were primed by repetition of semantically unrelated words. Both experiments involved a pronunciation task with response signals at fixed times following target onset. Consequently, priming was measured as improvement in the percentage of correct responses. Priming was also calculated with speed–accuracy measures of intercept and slope. Both types of priming effect were significant in the percentage correct and slope measures, but no age group differences were found. Furthermore, the magnitudes of the priming effects were equivalent. The age-resistant nature of semantic and episodic priming, as well as evidence for a common theoretical mechanism, is discussed.

from Psychology and Aging

The Use of a Self-Generation Memory Encoding Strategy to Improve Verbal Memory and Learning in Patients with Traumatic Brain Injury

Abstract
The generation effect refers to the theory that optimal acquisition and retention of information is achieved by active participation rather than by passive observation. The efficacy of a self-generation memory encoding strategy was tested using a verbal paired-associate task for free recall, cued recall, and recognition memory in 40 traumatically brain-injured outpatients in two studies. In study #1, self-generation encoding procedures improved recognition memory, but not free recall, compared with the didactic presentation of information. In study #2, self-generation procedures improved cued recall test performance, but the results demonstrated that the type of cue that is provided moderates the efficacy of self-generation procedures. Results provide preliminary empirical support for the use of self-generation encoding procedures in improving upon verbal memory and learning abilities in individuals with TBI.

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from Applied Neuropsychology

The nature of preschool phonological processing abilities and their relations to vocabulary, general cognitive abilities, and print knowledge.

The development of reading-related phonological processing abilities represents an important developmental milestone in the process of learning to read. In this cross-sectional study, confirmatory factor analysis was used to examine the structure of phonological processing abilities in 129 younger preschoolers (M = 40.88 months, SD = 4.65) and 304 older preschoolers (M = 56.49 months, SD = 5.31). A 2-factor model in which Phonological Awareness and Phonological Memory were represented by 1 factor and Lexical Access was represented by a 2nd factor provided the best fit for both samples and was largely invariant across samples. Measures of vocabulary, cognitive abilities, and print knowledge were significantly correlated with both factors, but Phonological Awareness/Memory had unique relations with word reading. Despite significant development of phonological processing abilities across the preschool years and into kindergarten, these results show that the structure of these skills remains invariant. (PsycINFO Database Record (c) 2009 APA, all rights reserved)

from the Journal of Educational Psychology

Electrophysiological correlates of semantic processing during encoding of neutral and emotional pictures in patients with ADHD

Abstract
The current study investigated the relevance of semantic processing and stimulus salience for memory performance in young ADHD patients and healthy control participants. 18 male ADHD patients and 15 healthy control children and adolescents participated in an ERP study during a visual memory paradigm with two different encoding tasks requiring either perceptual or semantic processing of neutral and emotional pictures. ADHD patients and healthy controls both showed a more negative slow-wave in response to task cues signalling semantic as compared to perceptual stimulus processing. In contrast to ADHD patients, healthy control children showed a larger increase in memory performance for deeply processed neutral pictures which was accompanied by a more positive mid-latency ERP component (so-called P300) after stimulus-onset. Our results demonstrate that ADHD patients succeeded in allocating neural resources in preparation of different task demands. However, this increase in preparatory activation to the semantic task cue did not suffice to support successful processing and encoding of neutral stimuli to the same extent as in healthy controls. These findings provide evidence that ADHD patients show deficits in translating pre-stimulus mobilization of neural resources to successful memory formation in the absence of salient stimulus material.

from Neuropsychology