Neural correlates of serial abacus mental calculation in children: a functional MRI study

Abacus experts have demonstrated extraordinary potential of mental calculation by using an imaginary abacus. But the neural correlates of abacus mental calculation and the imaginary abacus still remain unclear. Here, we report, respectively, the analysis of fMRI images of abacus experts and non-experts in response to the performance of simple and complex serial calculation by visual stimuli as well as the images of the abacus experts with performance of the same tasks by auditory stimuli. We found that activated areas were quite different between two groups. In experts, enhanced activations were mainly observed in fronto-temporal circuit (lateral premotor cortex (LPMC) and posterior temporal areas) in simple addition, but in fronto-parietal circuit (lateral premotor cortex (LPMC) and posterior superior parietal lobe (PSPL)) in complex one. By contrast, in controls, the activated areas were almost similar in both simple and complex tasks, including bilateral inferior parietal lobule, prefrontal and premotor cortices. Furthermore, visual and auditory stimuli generated almost similar activations in experts. These observations reveal that (1) abacus mental calculation induces special patterns of brain response, and simple and complex tasks are sustained by dissociated brain circuits between the temporal and parietal cortices, respectively; (2) the abacus mental calculation may rely on neural resources of visuospatial representations with a super-modal form of abacus beads; (3) the posterior temporal areas and PSPL may be recruited for imaginary abacus.     

Negative BOLD in Sensory Cortices During Verbal Memory: A Component in Generating Internal Representations?

People tend to close their eyes when trying to retrieve an event or a visual image from memory. However the brain mechanisms behind this phenomenon remain poorly understood. Recently, we showed that during visual mental imagery, auditory areas show a much more robust deactivation than during visual perception. Here we ask whether this is a special case of a more general phenomenon involving retrieval of intrinsic, internally stored information, which would result in crossmodal deactivations in other sensory cortices which are irrelevant to the task at hand. To test this hypothesis, a group of 9 sighted individuals were scanned while performing a memory retrieval task for highly abstract words (i.e., with low imaginability scores). We also scanned a group of 10 congenitally blind, which by definition do not have any visual imagery per se. In sighted subjects, both auditory and visual areas were robustly deactivated during memory retrieval, whereas in the blind the auditory cortex was deactivated while visual areas, shown previously to be relevant for this task, presented a positive BOLD signal. These results suggest that deactivation may be most prominent in task-irrelevant sensory cortices whenever there is a need for retrieval or manipulation of internally stored representations. Thus, there is a task-dependent balance of activation and deactivation that might allow maximization of resources and filtering out of non relevant information to enable allocation of attention to the required task. Furthermore, these results suggest that the balance between positive and negative BOLD might be crucial to our understanding of a large variety of intrinsic and extrinsic tasks including high-level cognitive functions, sensory processing and multisensory integration.     

Spectra-temporal patterns underlying mental addition: An ERP and ERD/ERS study

Functional neuroimaging data have shown that mental calculation involves fronto-parietal areas that are composed of different subsystems shared with other cognitive functions such as working memory and language. Event-related potential (ERP) analysis has also indicated sequential information changes during the calculation process. However, little is known about the dynamic properties of oscillatory networks in this process. In the present study, we applied both ERP and event-related (de-)synchronization (ERS/ERD) analyses to EEG data recorded from normal human subjects performing tasks for sequential visual/auditory mental addition. Results in the study indicate that the late positive components (LPCs) can be decomposed into two separate parts. The earlier element LPC1 (around 360 ms) reflects the computing attribute and is more prominent in calculation tasks. The later element LPC2 (around 590 ms) indicates an effect of number size and appears larger only in a more complex 2-digit addition task. The theta ERS and alpha ERD show modality-independent frontal and parietal differential patterns between the mental addition and control groups, and discrepancies are noted in the beta ERD between the 2-digit and 1-digit mental addition groups. The 2-digit addition (both visual and auditory) results in similar beta ERD patterns to the auditory control, which may indicate a reliance on auditory-related resources in mental arithmetic, especially with increasing task difficulty. These results coincide with the theory of simple calculation relying on the visuospatial process and complex calculation depending on the phonological process.     

珠心算训练对儿童认知能力的影响

目的 观察珠心算训练对儿童认知能力的影响。方法 采用《基本认知能力测验》软件,对经过珠心算训练和未经过珠心算训练的三、四年级儿童进行测验。结果 ①珠心算训练对于提高儿童的心算效率、数字记忆广度和无意义图形记忆有显著影响。②珠心算训练可以提高儿童的感知速度并且对数字记忆广度和无意义图形的记忆成绩的提高作用发生较早。结论 珠心算训练对儿童的认知能力有一定影响。     

Cueing vocabulary during sleep increases theta activity during later recognition testing

Neural oscillations in the theta band have repeatedly been implicated in successful memory encoding and retrieval. Several recent studies have shown that memory retrieval can be facilitated by reactivating memories during their consolidation during sleep. However, it is still unknown whether reactivation during sleep also enhances subsequent retrieval‐related neural oscillations. We have recently demonstrated that foreign vocabulary cues presented during sleep improve later recall of the associated translations. Here, we examined the effect of cueing foreign vocabulary during sleep on oscillatory activity during subsequent recognition testing after sleep. We show that those words that were replayed during sleep after learning (cued words) elicited stronger centroparietal theta activity during recognition as compared to noncued words. The reactivation‐induced increase in theta oscillations during later recognition testing might reflect a strengthening of individual memory traces and the integration of the newly learned words into the mental lexicon by cueing during sleep.     

Grading of dysplasia in Barrett's oesophagus: substantial interobserver variation between general and gastrointestinal pathologists

AIMS: To determine interobserver variation in grading of dysplasia in Barrett's oesophagus (BO) between non-expert general pathologists and expert gastrointestinal pathologists on the one hand and between expert pathologists on the other hand. METHODS AND RESULTS: In this prospective multicentre study, non-expert and expert pathologists graded biopsy specimens of 920 patients with endoscopic BO, which were blindly reviewed by one member of a panel of expert pathologists (panel experts) and by a second panel expert in case of disagreement on dysplasia grade. Agreement between two of three pathologists was established as the final diagnosis. Analysis was performed by kappa statistics. Due to absence of intestinal metaplasia, 127/920 (14%) patients were excluded. The interobserver agreement for dysplasia [no dysplasia (ND) versus indefinite for dysplasia/low-grade dysplasia (IND/LGD) versus high-grade dysplasia (HGD)/adenocarcinoma (AC)] between non-experts and first panel experts and between initial experts and first panel experts was fair (kappa = 0.24 and kappa = 0.27, respectively), and substantial for differentiation of HGD/AC from ND/IND/LGD (kappa = 0.62 and kappa = 0.58, respectively). CONCLUSIONS: There was considerable interobserver variability in the interpretation of ND or IND/LGD in BO between non-experts and experts, but also between expert pathologists. This suggests that less subjective markers are needed to determine the risk of developing AC in BO.     

珠心算练习对儿童数字记忆能力的影响

目的 观察珠心算练习对儿童数字记忆能力的影响,从而说明珠心算练习对儿童数字的记忆能力有提高作用.方法 采用基本认知能力测验的方法来观察珠心算练习儿童与非珠心算练习儿童对数字记忆能力的影响差别.结果 殊心算练习儿童与非珠心算练习儿童对数字快速拷贝、心算效率、工作记忆广度、无意义图形再认有显著不同(P＜0.05).结论 珠心算练习能促进儿童对数字的记忆能力,对感觉记忆、短时记忆、长时记忆都有提高作用;通过珠心算练习,儿童对数字的记忆可以迁移到对图形的记忆和识别能力上,说明练习珠心算形成的记忆能力具有正迁移性.     

What does neuroimaging tell us about the role of prefrontal cortex in memory retrieval?

The past five years have seen an outpouring of neuroimaging studies of memory — using both positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). These studies have convincingly demonstrated that neuroimaging can be used to study the functional anatomy of normal human memory and that neuroimaging can precisely localize memory related brain activations within small areas of cortex. As one illustration of the application of neuroimaging in the study of memory, this review shows how several laboratories have produced data that converge on the notion that specific areas in the prefrontal cortex are active during long-term memory retrieval. Moreover, the data further suggest that distinct prefrontal brain areas might make differential contributions to different kinds of long-term memory retrieval.     

Selective neuronal degeneration in the retrosplenial cortex impairs the recall of contextual fear memory

The retrosplenial cortex (RSC) is one of the largest cortical areas in rodents, and is subdivided in two main regions, A29 and A30, according to their cytoarchitectural organization and connectivities. However, very little is known about the functional activity of each RSC subdivision during the execution of complex cognitive tasks. Here, we used a well-established fear learning protocol that induced long-lasting contextual fear memory and showed that during evocation of the fear memory, the expression of early growth response gene 1 was up-regulated in A30, and in other brain areas implicated in fear and spatial memory, however, was down-regulated in A29, including layers IV and V. To search for the participation of A29 on fear memory, we triggered selective degeneration of neurons within cortical layers IV and V of A29 by using a non-invasive protocol that takes advantage of the vulnerability that these neurons have MK801-toxicity and the modulation of this neurodegeneration by testosterone. Application of 5 mg/kg MK801 in intact males induced negligible neuronal degeneration of A29 neurons and had no impact on fear memory retrieval. However, in orchiectomized rats, 5 mg/kg MK801 induced overt degeneration of layers IV–V neurons of A29, significantly impairing fear memory recall. Degeneration of A29 neurons did not affect exploratory or anxiety-related behavior nor altered unconditioned freezing. Importantly, protecting A29 neurons from MK801-toxicity by testosterone preserved fear memory recall in orchiectomized rats. Thus, neurons within cortical layers IV–V of A29 are critically required for efficient retrieval of contextual fear memory.     

Localization of cortical areas activated by thinking

These experiments were undertaken to demonstrate that pure mental activity, thinking, increases the cerebral blood flow and that different types of thinking increase the regional cerebral blood flow (rCBF) in different cortical areas. As a first approach, thinking was defined as brain work in the form of operations on internal information, done by an awake subject. The rCBF was measured in 254 cortical regions in 11 subjects with the intracarotid 133Xe injection technique. In normal man, changes in the regional cortical metabolic rate of O2 leads to proportional changes in rCBF. One control study was taken with the subjects at rest. Then the rCBF was measured during three different simple algorithm tasks, each consisting of retrieval of a specific memory followed by a simple operation on the retrieved information. Once started, the information processing went on in the brain without any communication with the outside world. In 50-3 thinking, the subjects started with 50 and then, in their minds only, continuously subtracted 3 from the result. In jingle thinking the subjects internally jumped every second word in a nine-word circular jingle. In route-finding thinking the subjects imagined that they started at their front door and then walked alternatively to the left or the right each time they reached a corner. The rCBF increased only in homotypical cortical areas during thinking. The areas in the superior prefrontal cortex increased their rCBF equivalently during the three types of thinking. In the remaining parts of the prefrontal cortex there were multifocal increases of rCBF. The localizations and intensities of these rCBF increases depended on the type of internal operation occurring. The rCBF increased bilaterally in the angular cortex during 50-3 thinking. The rCBF increased in the right midtemporal cortex exclusively during jingle thinking. The intermediate and remote visual association areas, the superior occipital, posterior inferior temporal, and posterior superior parietal cortex, increased their rCBF exclusively during route-finding thinking. We observed no decreases in rCBF. All rCBF increases extended over a few square centimeters of the cortex. The activation of the superior prefrontal cortex was attributed to the organization of thinking. The activation of the angular cortex in 50-3 thinking was attributed to the retrieval of the numerical memory and memory for subtractions. The activation of the right midtemporal cortex was attributed to the retrieval of the nonverbal auditory memory.(ABSTRACT TRUNCATED AT 400 WORDS)     

Mushroom body efferent neurons responsible for aversive olfactory memory retrieval in Drosophila

Aversive olfactory memory is formed in the mushroom bodies in Drosophila melanogaster. Memory retrieval requires mushroom body output, but the manner in which a memory trace in the mushroom body drives conditioned avoidance of a learned odor remains unknown. To identify neurons that are involved in olfactory memory retrieval, we performed an anatomical and functional screen of defined sets of mushroom body output neurons. We found that MB-V2 neurons were essential for retrieval of both short- and long-lasting memory, but not for memory formation or memory consolidation. MB-V2 neurons are cholinergic efferent neurons that project from the mushroom body vertical lobes to the middle superiormedial protocerebrum and the lateral horn. Notably, the odor response of MB-V2 neurons was modified after conditioning. As the lateral horn has been implicated in innate responses to repellent odorants, we propose that MB-V2 neurons recruit the olfactory pathway involved in innate odor avoidance during memory retrieval.     

Processing of autobiographical memory retrieval cues in borderline personality disorder

BACKGROUND: Affective dysregulation in borderline personality disorder (BPD) in response to both external stimuli and memories has been shown to be associated with functional alterations of limbic and prefrontal brain areas. This study aimed to examine neuronal networks involved in autobiographical memory retrieval using standardized stimuli that gain autobiographical significance by illustrating marked solitary and social situations of human life. METHODS: Using event-related functional Magnetic Resonance Imaging (fMRI), we examined the processing of pictures from the Thematic Apperception Test (TAT) in 14 BPD patients and 14 controls. RESULTS: In both groups, TAT stimuli activated brain areas known to be involved in autobiographical memory retrieval. BPD subjects lacked differential amygdala, orbitofrontal and cingulate activations for TAT versus neutral stimuli. In the TAT condition, compared to controls, BPD subjects displayed increased BOLD responses in the bilateral orbitofrontal and insular regions, in the left anterior cingulate and medial prefrontal cortex, as well as in the parietal and parahippocampal areas, consistent with a more aversive and arousing experience assessed by self-reports. CONCLUSIONS: Increased BOLD responses during TAT processing in BPD subjects were in line with previously reported changes in anterior cingulate and orbitofrontal cortices, which are known to be involved in memory retrieval. However, BPD subjects displayed hyperactivation in these areas for both TAT and neutral stimuli. The deficit of selective activation of areas involved in autobiographical memory retrieval suggests a general tendency towards a self-referential mode of information processing in BPD, or a failure to switch between emotionally salient and neutral stimuli.     

Different strategies in solving series completion inductive reasoning problems: An fMRI and computational study

Neural correlate of human inductive reasoning process is still unclear. Number series and letter series completion are two typical inductive reasoning tasks, and with a common core component of rule induction. Previous studies have demonstrated that different strategies are adopted in number series and letter series completion tasks; even the underlying rules are identical. In the present study, we examined cortical activation as a function of two different reasoning strategies for solving series completion tasks. The retrieval strategy, used in number series completion tasks, involves direct retrieving of arithmetic knowledge to get the relations between items. The procedural strategy, used in letter series completion tasks, requires counting a certain number of times to detect the relations linking two items. The two strategies require essentially the equivalent cognitive processes, but have different working memory demands (the procedural strategy incurs greater demands). The procedural strategy produced significant greater activity in areas involved in memory retrieval (dorsolateral prefrontal cortex, DLPFC) and mental representation/maintenance (posterior parietal cortex, PPC). An ACT-R model of the tasks successfully predicted behavioral performance and BOLD responses. The present findings support a general-purpose dual-process theory of inductive reasoning regarding the cognitive architecture.     

Image transformation dissociated from visuospatial working memory

Abstract

A selective impairment in mental transformation in the absence of an impairment in visuospatial working memory is described in a patient with a left parieto-occipital lesion. The patient showed a severe impairment on three tests of mental rotation, the Flags test, the Ratcliff Manikin test, and Shepard and Metzler's Mental Rotation task. She also showed an impairment in mental scanning, being unable to scan between locations on the Kosslyn, Ball, and Reiser (1978) Island task or to perform a modified version of the Brooks Letter task involving mental rotation. In contrast, her spatial working memory was normal, with no impairment on the Corsi Block Span task or the Brooks Matrix task (Baddeley&Lieberman, 1980). In addition, on a series of imagery generation tasks, she showed normal retrieval of visual and spatial imagery. The results are interpreted as supporting a dissociation between spatial working memory and the transformation of visuo-spatial imagery, and are discussed in relation to models of working memory and higher visual processing.     

Fast-ball sports experts depend on an inhibitory strategy to reprogram their movement timing

The purpose of our study was to clarify whether an inhibitory strategy is used for reprogramming of movement timing by experts in fast-ball sports when they correct their movement timing due to unexpected environmental changes. We evaluated the influence of disruption of inhibitory function of the right inferior frontal gyrus (rIFG) on reprogramming of movement timing of experts and non-experts in fast-ball sports. The task was to manually press a button to coincide with the arrival of a moving target. The target moved at a constant velocity, and its velocity was suddenly either increased or decreased in some trials. The task was performed either with or without transcranial magnetic stimulation (TMS), which was delivered to the region of the rIFG. Under velocity change conditions without TMS, the experts showed significantly smaller timing errors and a higher rate of reprogramming of movement timing than the non-experts. Moreover, TMS application during the task significantly diminished the expert group’s performance, but not the control group, particularly in the condition where the target velocity decreases. These results suggest that experts use an inhibitory strategy for reprogramming of movement timing. In addition, the rIFG inhibitory function contributes to the superior movement correction of experts in fast-ball sports.     

Prefrontal [correction of Prefontal] cortex in long-term memory: an "interference" approach using magnetic stimulation

Neuroimaging has consistently shown engagement of the prefrontal cortex during episodic memory tasks, but the functional relevance of this metabolic/hemodynamic activation in memory processing is still to be determined. We used repetitive transcranial magnetic stimulation (rTMS) to transiently interfere with either left or right prefrontal brain activity during the encoding or retrieval of pictures showing complex scenes. We found that the right dorsolateral prefrontal cortex (DLPFC) was crucial for the retrieval of the encoded pictorial information, whereas the left DLPFC was involved in encoding operations. This 'interference' approach allowed us to establish whether a cortical area activated by a memory task actually contributes to behavioral performance.     

治疗创伤后应激障碍的新靶点:内源性大麻素系统

正负面情绪,如焦虑和恐惧会使个体对潜在的危险和伤害刺激保持警觉,从而提高生存能力,但是当个体对这些潜在的危险过度应答时,便会对身心功能造成伤害。创伤后应激障碍(post-traumatic stress disorder,PTSD)是一种个体因为经历或目睹对生命具有威胁性的事件或严重的创伤,从而导致系列精神症状并出现长期持续的精神障碍,是对异乎寻常的威胁性、灾难性事件的延迟和持久的反应。PTSD     

Neuronal correlates of encoding and retrieval in episodic memory during a paired-word association learning task: a functional magnetic resonance imaging study

The investigation of memory function using functional magnetic resonance imaging (fMRI) is an expanding field of research. The aim of this study was to demonstrate brain-activity patterns related to a word-pair association task employing a whole-brain EPI sequence. Six right-handed, healthy male volunteers (mean age: 27.5 years) took part in the study. fMRI was performed at a field strength of 1.5 Tesla with 26–32 slices parallel to the AC-PC line, depending on individual brain size. Distributed brain regions were activated in episodic encoding and retrieval with similarities, but also (distinct) differences in activation patterns. Bilateral prefrontal cortical areas were involved when comparing encoding as well as retrieval to the reference condition (nonsense words). Furthermore, activation was observed in cerebellar areas during encoding, and activation in bilateral parietal areas (precuneus and inferior parietal cortex) was differentially more pronounced during retrieval. The activation of left dorsomedial thalamus during retrieval of high imagery-content word-pair associates may point to the role of this structure in episodic retrieval. The direct cognitive subtraction of encoding minus retrieval yielded a differentially larger left prefrontal activation. There was a differentially higher right prefrontal activation during retrieval than during encoding, underlining the proposed right/left asymmetry for episodic memory processes. Received: 10 June 1998 / Accepted: 23 April 1999     

Blood glucose changes and memory: effects of manipulating emotionality and mental effort

Increasing the emotionality of target material often facilitates memory performance which may be linked to the liberation of glucose. Conversely, increasing mental effort leads to reduced performance and measurable falls in blood glucose. A 2 x 2, parallel groups experiment examined these two phenomena directly by assessing blood glucose levels and memory for neutral and emotional word lists, both with and without a secondary task. Co-performing the secondary task significantly reduced blood glucose in the neutral word condition only and resulted in a global reduction of memory performance in both neutral and emotional word conditions. Processing emotional material resulted in significantly raised blood glucose levels, however, there was no advantage for memory of emotional words. A follow-up study confirmed that the emotionality manipulation was effective. We conclude that there exists a clear relationship between reduced blood glucose and impaired memory performance during periods of mental effort. However, the relationship between physiological and cognitive processes associated with processing emotional material are more complex.     

Parallel processing of spatial and serial order information before moving to a remembered target

Information storage and retrieval from working memory is limited by the capacity of storage mechanisms and attentional processes. Nevertheless, it has been shown that processing of multiple features can proceed independently in working memory. In this study we investigated how serial order and directional information are processed when executing a movement to a remembered target direction. We compared the performance of 11 healthy subjects in 3 motor working memory tasks, one with a varying spatial memory load, one with a varying serial order memory load, and one in which memory load was varied for both features. We found that the spatial information memory load does not affect the ability to store information about serial order and vice versa. Furthermore, movement response latencies indicated that retrieval of information about both features proceeds simultaneously. These results strongly favor independent, parallel working memory systems for processing space and order information in the motor system.