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PubMed1994

Effects of a sustained release formulation of thyrotropin-releasing hormone on behavioral abnormalities in senescence-accelerated mice.

Effects of a sustained release formulation of thyrotropin-releasing hormone (TRH-SR) on reduced anxiety-like behavior and learning impairment in senescence-accelerated mice (SAM) were examined. SAMP8/Ta (SAMP8) mice showing age-related emotional changes as well as learning and memory impairments, and SAMR1TA (SAMR1) mice exhibiting normal aging were used at 8 months of age. Subcutaneous injection of TRH-SR (2.8 mg/kg as free TRH) produced a sustained increase in immunoreactive plasma TRH levels up to about 4 weeks after dosing in SAMP8. TRH-SR antagonized the reduced neophobia to novel food in SAMP8 in a dose-dependent manner when tested 10 days but not 3 days after the injection. In the elevated plus-maze test, the SAMP8 control group treated with vehicle had significant increases in the number of entries into open arms and the time spent in open arms in comparison to SAMR1 mice. TRH-SR showed dose-dependent decreases in the number of entries into open arms, and reduced the time spent in open arms in SAMP8 mice. Furthermore, TRH-SR significantly improved the impairment of water maze learning in SAMP8 mice. In contrast, bolus administration of TRH had no significant effects on behavioral abnormalities in SAMP8 even at high doses, implying that long-term and continuous infusion of TRH may be important for amelioration of the behavioral abnormalities. These results suggest that TRH-SR may be useful for treatment of age-related emotional disorders and memory disturbance in dementia.

Aging↗
PubMed2002

Effects of hippocampal lesions on patterned motor learning in the rat.

Motor skill learning in rats has been linked to cerebellar function as well as to cortical and striatal influences. The present study evaluated the contribution of the hippocampus to motor learning. Adult male rats received electrolytic lesions designed to selectively destroy the hippocampus; a sham-lesioned group of animals served as a control. The animals with hippocampal lesions acquired a patterned motor learning task as well as sham controls. In contrast, rats with hippocampal lesions were impaired in spatial, but not cued, learning in the Morris water maze. In addition, lesioned rats showed profound impairment in the novel object recognition memory task, when a 1-h delay was used between training and testing. Taken together, these results suggest that the hippocampus is not necessary during acquisition of the motor learning task.

Animals↗
PubMed2006

One percent ability and ninety-nine percent perspiration: a study of a Japanese memorist.

In 1987, Hideaki Tomoyori, a Japanese memorist, set a world record for reciting the first 40,000 digits of pi. The authors report results from a series of tests that give a view of Tomoyori's memory performance compared with that of a control group, matched for age and educational level. He showed very good scores on tasks with digits, such as digit memory span tasks and 5 x 5 number matrix learning, although some of the control participants were nearly as good. In contrast, his performance was not particularly good for learning word lists and story recall. Overall, his performance on the tasks does not suggest that he has superior cognitive abilities. We believe that his extraordinary memory performance in reciting the digits of pi results from his effective use of a combination of digit-syllable transformations and imagery mnemonics developed from extensive practice. These results are consistent with the skilled memory framework.

Aged↗
PubMed2004

The attitudes of undergraduate students and staff to the use of electronic learning.

BACKGROUND: Computer-aided learning (CAL) offers advantages over traditional methods of learning as it allows students to work in their own time and pace. The School of Dentistry at the University of Birmingham has created an electronic learning website, named the Ecourse. This is designed to be a web-based supplement to the dental undergraduate curriculum. AIM: The aim of this study was to determine the attitudes of third year dental students and members of staff about the Ecourse website. METHOD: A questionnaire was produced and piloted before being distributed to all 65 third year dental students to obtain their opinions about the Ecourse website. The views of Ecourse were sought from four members of staff by performing qualitative, semi-structured interviews. RESULTS: Lecture handouts and textbooks were reported as the sources used most often, by 96% of students. Eighty-six per cent of students are accessing the Ecourse mainly at the School of Dentistry, but 53% are also accessing it at home. Students liked the multiple-choice questions, downloading extra notes and looking at pictures and animation to explain clinical procedures. The majority of the students (79%) want the Ecourse to be used as a supplement to the undergraduate programme and 7% wanted it to replace formal lectures. Staff recognised the benefits of the Ecourse but were concerned about plagiarism, the effect on lecture attendance and the lack of feedback from students on existing CAL material. CONCLUSION: Students consider the Ecourse as a positive method of supplementing traditional methods of learning in the dental undergraduate programme. However in contrast teaching staff expressed negative views on the use of e-learning.

Attitude↗
PubMed1982

[Association psychology versus learning psychology theory of schizophrenia (author's transl)].

This study has been stimulated by the parallel process of knowledge gained by association psychology and learning psychology approaches to the theory of schizophrenia. It is based on the hypothesis that this parallel must entail structural agreement for the symptomatologies influenced in each case. In order to examine whether this hypothesis is correct, the basic disturbance concept by G. Huber and L. Súllwold, which has been developed on the lines of learning psychology, is compared and contrasted with the theory of symptoms according to E. Bleuler, which has been developed by association psychology. This comparison shows an indeed far-reaching agreement in all structure-determining categories, besides differences in specificity problems and in the psychoreactive derivation model. The original concept of schizophrenia, therefore, emerges after half a century of phenomenological and holistic-psychological schizophrenia research, as a highly topical precursor of the modern concept of this disease.

Association↗
PubMed2006

Performance feedback drives caudate activation in a phonological learning task.

Adults have difficulty discriminating nonnative phonetic contrasts, but under certain circumstances training can lead to improvement in this ability. Despite the ubiquitous use of performance feedback in training paradigms in this and many other domains, the mechanisms by which feedback affects learning are not well understood. In this event-related functional magnetic resonance imaging study, we examined how performance feedback is processed during perceptual learning. Thirteen Japanese speakers for whom the English phonemes [r] and [l] were nondistinct performed an identification task of the words "road" and "load" that has been shown to be effective in inducing learning only when performance feedback is present. Each subject performed alternating runs of training with and without feedback, followed by performance of a card-guessing task with monetary reward and punishment outcomes. We found that the caudate nucleus was more robustly activated bilaterally when performing the perceptual identification task with feedback than without feedback, and the right caudate nucleus also showed a differential response to positive and negative feedback. Moreover, using a within-subjects design, we found that the caudate nucleus also showed a similar activation pattern to monetary reward and punishment outcomes in the card-guessing task. These results demonstrate that the caudate responds to positive and negative feedback during learning in a manner analogous to its processing of extrinsic affective reinforcers and indicate that this region may be a critical moderator of the influence of feedback on learning. These findings impact our broader understanding of the mechanisms underlying nondeclarative learning and language acquisition.

Adult↗
PubMed2005

Dissociable memory effects after medial thalamus lesions in the rat.

Variable neuropathology in cases of diencephalic amnesia has led to uncertainty in identifying key thalamic nuclei and their potential role in learning and memory. Based on the principal neural connections of the medial thalamus, the current study tested the hypothesis that different aggregates of thalamic nuclei contribute to separate memory systems. Lesions of the anterior thalamic aggregate (AT), which comprises the anterodorsal, anteromedial and anteroventral nuclei produced substantial deficits in both working and reference spatial memory in a radial arm maze task in rats, supporting the view that the AT is an integral part of a hippocampal memory system. Lesions to the lateral thalamic aggregate (LT), which comprises the intralaminar nuclei (centrolateral, paracentral and rostral central medial nuclei) and lateral mediodorsal thalamic nuclei (lateral and paralamellar nuclei) produced a mild working memory impairment only, while lesions to the posteromedial thalamic aggregate (MT), which comprises the central and medial mediodorsal thalamic nuclei and the intermediodorsal nucleus had no effect on radial arm maze performance. In contrast, only MT lesions impaired learning associated with memory for reward value, consistent with the idea that the MT contributes to an amygdala memory system. Compared with chance discrimination, the control and AT groups, but not MT or LT groups, showed evidence for temporal order memory for two recently presented objects; all groups showed intact object recognition for novel vs. familiar objects. These new dissociations show that different medial thalamic aggregates participate in multiple memory systems and reinforce the idea that memory deficits in diencephalic amnesics may vary as a function of the relative involvement of different thalamic regions.

Animals↗
PubMed2004

Working memory: its role in dyslexia and other specific learning difficulties.

This paper reports a study contrasting dyslexic children against a control group of children without special educational needs (SEN) and a group with varied SENs. Children's abilities were compared on tasks assessing phonological processing, visuo-spatial/motor coordination and executive/inhibitory functioning; being targeted for assessment based on theoretical proposals related to the working memory model. Primary and secondary school level children were tested: 21 assessed as dyslexic with no comorbid difficulties, 26 children assessed with difficulties including dyspraxia, emotional/behavioural problems and attention deficits, 40 children with no known education-related deficits were controls. Results indicated both SEN groups performed worse than controls on working memory phonological loop measures. However, SEN groups could only be differentiated on phonological awareness measures: the dyslexics showing lower scores. Dyslexics performed as well as controls on working memory visuo-spatial scratch pad measures and one of two additional visual-motor coordination tasks, whereas the performance of the other SEN children was lowest on the majority of these measures. Central executive and interference measures engendered mixed performances, both SEN groups showing evidence of deficits in one or more of these areas of functioning, although, of the two SEN groups, the dyslexics seem to have performed the worse when digit name processing was required.

Adolescent↗
PubMed2002

Participation of the homing pigeon thalamofugal visual pathway in sun-compass associative learning.

The ascending thalamofugal visual pathway in pigeons (Columba livia) terminates in the telencephalic wulst. Characterizing the role of this pathway in visually guided behaviour has remained a challenge. To determine whether this pathway, and in particular the wulst, may participate in sun-compass-guided behaviour in homing pigeons, intact, ectostriatum-lesioned or wulst-lesioned pigeons were trained to use their sun compass to locate the direction of a food reward in an outdoor, octagonal arena. Control and ectostriatum-lesioned pigeons learned the task well, and orientated appropriately during the first trial of the last three training sessions and after a phase-shift manipulation. In contrast, the wulst-lesioned pigeons learned the task but they took more sessions to learn, and their directional choices were more scattered during the first trial of the last three training sessions and after the phase-shift manipulation. A subsequent regression analysis indicated that deeper layers of the wulst might have made more of a contribution to the observed behavioural impairments. The data indicate that the homing pigeon wulst participates in visually guided behaviour when the sun compass is used to learn the directional location of a goal.

Animals↗
PubMed1994

Influences of categorization on perceptual discrimination.

Four experiments investigated the influence of categorization training on perceptual discrimination. Ss were trained according to 1 of 4 different categorization regimes. Subsequent to category learning, Ss performed a Same-Different judgment task. Ss' sensitivities (d's) for discriminating between items that varied on category-(ir)relevant dimensions were measured. Evidence for acquired distinctiveness (increased perceptual sensitivity for items that are categorized differently) was obtained. One case of acquired equivalence (decreased perceptual sensitivity for items that are categorized together) was found for separable, but not integral, dimensions. Acquired equivalence within a categorization-relevant dimension was never found for either integral or separable dimensions. The relevance of the results for theories of perceptual learning, dimensional attention, categorical perception, and categorization are discussed.

Adult↗
PubMed1994

Reflections on radiotherapy in Vietnam: political lessons still to be learned.

Radiotherapy in Vietnam represents a stark contrast to the level of care available in the United States. The issue of efficient administration of cancer care with available resources is common to both nations. The challenge for each country is to develop treatment strategies and political policies for effective and accessible care within budgetary constraints. Results of therapy, defined as the restoration of function, must be the measure of efficacy and efficiency. This demands a balance between control of tumor-related symptoms and treatment-related morbidity. The most inefficient use of resources is an ineffective treatment that results in complications, as we observed in Vietnam. As health care policies continue to develop in the United States, we must not fail to focus upon therapeutic outcome as the single most important parameter for measuring success relative to the personal and public investment in medicine.

Cancer Care Facilities↗
PubMed2004

Differential cortical responses in second language learners to different vowel contrasts.

Near-infrared spectroscopy was used to measure hemodynamic responses in Korean subjects learning Japanese as a second-language to Japanese phonemic contrasts that are either phonologically distinctive or non-distinctive in their first-language. These results were compared with those of Japanese native listeners reported previously. Unlike the results observed in the Japanese subjects, the Korean subjects did not show category-specific neural responses to a durational contrast that is non-distinctive in their first-language. The /a-e/ contrast elicited the larger response in the left auditory area, consistent with the results of the Japanese. These phoneme-dependent responses imply that the neuronal networks subserving the first and second-languages are either shared or exclusive according to the mutual relationship between the phonemic properties of the first and second-languages.

Acoustic Stimulation↗
PubMed1999

Can macaques perceive place of articulation from formant transition information?

An important problem in speech perception is to determine how humans extract the perceptually invariant place of articulation information in the speech wave across variable acoustic contexts. Although analyses have been developed that attempted to classify the voiced stops /b/ versus /d/ from stimulus onset information, most of the human perceptual research to date suggests that formant transition information is more important than onset information. The purpose of the present study was to determine if animal subjects, specifically Japanese macaque monkeys, are capable of categorizing /b/ versus /d/ in synthesized consonant-vowel (CV) syllables using only formant transition information. Three monkeys were trained to differentiate CV syllables with a "go-left" versus a "go-right" label. All monkeys first learned to differentiate a /za/ versus /da/ manner contrast and easily transferred to three new vowel contexts /[symbol: see text], epsilon, I/. Next, two of the three monkeys learned to differentiate a /ba/ versus /da/ stop place contrast, but were unable to transfer it to the different vowel contexts. These results suggest that animals may not use the same mechanisms as humans do for classifying place contrasts, and call for further investigation of animal perception of formant transition information versus stimulus onset information in place contrasts.

Animals↗
PubMed1995

Convergent processing in honeybee vision: multiple channels for the recognition of shape.

Advanced mammalian visual systems can recognize a familiar shape under a variety of viewing conditions. Recognition is possible whether the shape is presented in simple outline, as a random dot stereogram, or by motion contrast. We report here that bees have a similar ability: they can recognize a shape when it is learned through visual signals of one kind and subsequently viewed through another. The results reveal that (i) bees that have learned a shape defined in terms of luminance contrast can recognize the same shape when it is defined in terms of motion contrast, (ii) shapes that are delineated by motion contrast are discriminated through a channel that receives input only from the green photoreceptors, (iii) a shape learned through one class of signal is subsequently recognized via any of these other classes, and (iv) shape is memorized in a generic form regardless of whether it is initially sensed by green-contrast, blue-contrast, luminance-contrast, or motion-contrast signals.

Journal Article↗
PubMed2001

Procedural learning deficit in children with Williams syndrome.

The present study was aimed at evaluating implicit memory processes in subjects with Williams syndrome (WS) and comparing them to mental-age (MA) matched normal children. For this purpose, tests of verbal and visuo-perceptual explicit memory, verbal and visual repetition priming as well as procedural learning tasks were administered to 12 WS and 12 MA matched subjects. WS subjects showed a level of repetition priming similar to that of MA normal controls. In contrast, WS children showed a reduced learning rate in the two procedural tasks. Although deficient explicit memory and executive dysfunction cannot be excluded from the performance of WS subjects, these results suggest a specific deficit of procedural learning in this particular group of mentally retarded children. This finding is relevant for our knowledge about the qualitative aspects of the anomalous cognitive development in mentally retarded people and the neurobiological substrate underlying this development.

Adolescent↗
PubMed2004

Habit learning in Tourette syndrome: a translational neuroscience approach to a developmental psychopathology.

BACKGROUND: The etiology of Tourette syndrome (TS) involves disturbances in the structure and function of the basal ganglia. The basal ganglia mediate habit learning. OBJECTIVE: To study habit learning in persons with TS. DESIGN: Patients with TS were compared with normal controls in performance on a probabilistic classification, or habit-learning task (weather prediction). SETTING: University research institute. PARTICIPANTS: One hundred twenty-three children and adults, 56 with a diagnosis of TS and 67 healthy control subjects. MAIN OUTCOME MEASURES: Habit learning was assessed by the extent of improvement in accuracy of predictions and reaction times over trial blocks during performance of the weather prediction task. Declarative learning was assessed by performance on 3 tasks that required intact declarative memory functioning. RESULTS: Children with TS were impaired at habit learning relative to normal controls (P = .01). This finding was replicated in the independent sample of adults with TS (P = .01). The rate of learning correlated inversely with the severity of tic symptoms across both samples (r = -0.34; P = .01). Thus, impaired learning accompanied more severe symptoms. Measures of declarative memory functioning, in contrast, were normal in the TS groups. CONCLUSIONS: Striatal learning systems are uniquely dysfunctional in both children and adults with TS. The correlation of habit learning with symptom severity suggests that the number and severity of tics are a function of the degree to which the system for habit learning is dysfunctional. Thus, both the deficits in habit learning and the tic symptoms of TS are likely to be consequences of the previously reported anatomical and functional disturbances of the striatum in children and adults who have TS. The existence of a well-developed animal model for this learning system, which permits study of the neural and molecular bases of habit learning, has important implications for the neurobiological study of TS and for the development of new or improved therapeutics for this condition.

Attention Deficit Disorder with Hyperactivity↗
PubMed1989

Differential effects of pimozide and SCH 23390 on acquisition of learning in mice.

Our main purpose was to clarify the differences between the effects of dopamine D-1 (SCH 23390) and D-2 (pimozide) antagonists on memory acquisition in a water-finding and a one-trial passive avoidance task with ddY mice. In the water-finding task, pimozide (0.1 and 0.2 mg/kg i.p.) enhanced the acquisition of latent learning of mice although it suppressed exploratory behavior. In contrast, SCH 23390 (0.1 mg/kg i.p.) attenuated the acquisition of latent learning and suppressed exploratory behavior. In the passive avoidance task, pimozide (0.1 and 0.2 mg/kg i.p.) enhanced the acquisition of the passive avoidance response of mice. SCH 23390 (0.05 and 0.1 mg/kg i.p.) failed to enhance the acquisition of the passive avoidance response. These results could suggest that a moderate block of D-2 receptors enhances memory acquisition but blocking D-1 receptors affects it in an opposite way.

Animals↗