Computer-based automatic finger- and speech-tracking system

This article presents the first technology ever for online registration and interactive and automatic analysis of finger movements during tactile reading (Braille and tactile pictures). Interactive software has been developed for registration (with two cameras and a microphone), MPEG-2 video compression and storage on disk or DVD as well as an interactive analysis program to aid human analysis. An automatic finger-tracking system has been implemented which also semiautomatically tracks the reading aloud speech on the syllable level. This set of tools opens the way for large scale studies of blind people reading Braille or tactile images. It has been tested in a pilot project involving congenitally blind subjects reading texts and pictures.     

IMPLICIT MEMORY IN THE TACTILE MODALITY:

Abstract— Research on perceptual priming has previously focused exclusively on priming in the visual and auditory modalities. The present study explored whether perceptual priming also extends to the tactile modality. Tactile priming for Braille words was examined in a group of blind participants, using a Braille analogue of the stem-completion task. The results for tactile priming paralleled previous stem-completion results in other modalities. Manipulating the encoding task at study (semantic vs nonsemantic) dissociated implicit and explicit Braille stem-completion performance, and priming was unaffected by the number of study presentations (one vs three). Finally, Braille stem-completion priming was found in a cross-modal paradigm to have both a specifically tactile component and a cross-modal component. These results demonstrate for the first time that verbal priming can occur in the tactile domain and that tactile priming has basic functional similarities with stem-completion priming in the visual and auditory domains.     

Strategy choices by young Braille readers

The hypotheses that in Braille learning coding strategies change with reading level, and coding differs between normal and retarded readers were tested with oddity judgments by blind children. Experiment 1 showed that strategy choices varied with reading level only in association with mental age. By contrast, shape neglect and preference for phonological strategies were shown by retarded readers rather than by matched normal readers. Experiment 2 showed that under instructions to use given coding strategies the retarded were as accurate as normal readers. Accuracy for all forms of coding increased with reading level, but coding word shape was significantly less accurate than other forms of coding, and even correct coding of shape was no faster than semantic or phonological coding. It is concluded that coding the shape of Braille words is unlikely to be a major factor in producing faster Braille reading, and retarded Braille readers differ from normal readers in their spontaneous choice of strategy rather than in the ability to use the relevant codes.     

Somatosensory processes subserving perception and action

The functions of the somatosensory system are multiple. We use tactile input to localize and experience the various qualities of touch, and proprioceptive information to determine the position of different parts of the body with respect to each other, which provides fundamental information for action. Further, tactile exploration of the characteristics of external objects can result in conscious perceptual experience and stimulus or object recognition. Neuroanatomical studies suggest parallel processing as well as serial processing within the cerebral somatosensory system that reflect these separate functions, with one processing stream terminating in the posterior parietal cortex (PPC), and the other terminating in the insula. We suggest that, analogously to the organisation of the visual system, somatosensory processing for the guidance of action can be dissociated from the processing that leads to perception and memory. In addition, we find a second division between tactile information processing about external targets in service of object recognition and tactile information processing related to the body itself. We suggest the posterior parietal cortex subserves both perception and action, whereas the insula principally subserves perceptual recognition and learning.     

Tracing trajectories of audio‐visual learning in the infant brain

Although infants begin learning about their environment before they are born, little is known about how the infant brain changes during learning. Here, we take the initial steps in documenting how the neural responses in the brain change as infants learn to associate audio and visual stimuli. Using functional near‐infrared spectroscopy (fNRIS) to record hemodynamic responses in the infant cortex (temporal, occipital, and frontal cortex), we find that across the infant brain, learning is characterized by an increase in activation followed by a decrease. We take this U‐shaped response as evidence of repetition enhancement during early stages of learning and repetition suppression during later stages, a result that mirrors the Hunter and Ames model of infant visual preference. Furthermore, we find that the neural response to violations of the learned associations can be predicted by the shape of the learning curve in temporal and occipital cortex. These data provide the first look at the shape of the neural response during audio‐visual associative learning in infancy establishing that diverse regions of the infant brain exhibit systematic changes across the time‐course of learning.     

Contrasting effects of motor and visual spatial learning tasks on dendritic arborization and spine density in rats

Rats were trained in four different learning tasks including the Morris-water task, a T-maze delayed nonmatch-to-sample task, a skilled unilateral reaching task, and a skilled bilateral string-pulling task. At the end of training the brains were harvested and stained using a Golgi-Cox procedure. Learning the spatial navigation task produced increased dendritic length and branching as well as decreased spine density in layer III pyramidal cells in occipital cortex. Learning the T-maze task increased dendritic branching in layer III medial but not orbital frontal cortex pyramidal cells and increased spine density in both regions. The motor learning tasks produced increased dendritic length and branching in layer V pyramidal cells in the forelimb cortex in the hemisphere contralateral to the trained limb in the unilateral skilled reaching task and in both limbs in the bilateral skilled pulling task. There were no changes in spine density in layer V in the motor tasks, but there was a decrease in spine density in layer III in the unilateral reaching task. Spatial and motor learning thus produce different patterns of change in layer III cortical pyramidal neurons. Furthermore, changes in spine density and dendritic length and branching are not tightly correlated and can increase and/or decrease independently of one another in learning tasks.     

盲生错误记忆和真实记忆研究

错误记忆指的是人们会回忆或再认那些没有出现过的事件。目前,针对错误记忆的研究多集中于视力正常的人群。国外近年来有针对视障人群错误记忆的研究认为,在听觉学习情境中视障成人有更好的真实记忆和更低的错误记忆。目前对于盲生的错误记忆特征尚缺乏研究。而盲文摸读作为视障人群重要的学习方式,其对视障人群的真实记忆和错误记忆的影响尚未有研究者关注。本研究以初中盲生和视力正常学生作为研究对象,采用DRM范式,发现被试采用阅读学习(盲生摸读盲文,视力正常学生阅读屏幕文字)和听觉学习两种学习方式下,都发现被试身上存在稳定的错误记忆;盲生的错误记忆显著低于视力正常学生。在摸读学习方式下,盲生真实记忆好于听觉学习方式。     

Residual differences in language processing in compensated dyslexics revealed in simple word reading tasks

Using regional cerebral blood flow as an index of cerebral activity we studied dyslexic and control subjects during simple word reading tasks. The groups were pre-tested for reading skill and the dyslexic group had a lower reading performance but could read and comprehend standard texts. The aim was to elucidate differences in the cerebral activation pattern during reading. The tasks were simple enough that performance differences between the groups could be excluded. We found specific differences between the two groups that were dependent on the language task. When the visual route for language information was used, minor qualitative differences were found between the groups pertaining to the dominant hemisphere. Increasing the complexity of the task by using pseudowords activated the left frontal region more in the dyslexic group than in the control group. A similar effect was seen in a minor region in extrastriate lateral occipital cortex (BA 19). This finding indicates that the dyslexics used areas in these regions that the controls did not. On the other hand, the dyslexics activated less in the right angular gyrus, right dorsolateral prefrontal cortex, and in the right pallidum. Reading skill correlated with the level of activity in the right frontal cortex. We conclude, that cerebral activation pattern elicited by reading is different in dyslexics compared to controls in spite of an almost complete functional compensation.     

Neuroanatomical correlates of oral reading in acute left hemispheric stroke

Oral reading is a complex skill involving the interaction of orthographic, phonological, and semantic processes. Functional imaging studies with nonimpaired adult readers have identified a widely distributed network of frontal, inferior parietal, posterior temporal, and occipital brain regions involved in the task. However, while functional imaging can identify cortical regions engaged in the process under examination, it cannot identify those brain regions essential for the task. The current study aimed to identify those neuroanatomical regions critical for successful oral reading by examining the relationship between word and nonword oral reading deficits and areas of tissue dysfunction in acute stroke. We evaluated 91 patients with left hemisphere ischemic stroke with a test of oral word and nonword reading, and magnetic resonance diffusion-weighted and perfusion-weighted imaging, within 24-48 h of stroke onset. A voxel-wise statistical map showed that impairments in word and nonword reading were associated with a distributed network of brain regions, including the inferior and middle frontal gyri, the middle temporal gyrus, the supramarginal and angular gyri, and the middle occipital gyrus. In addition, lesions associated with word deficits were found to be distributed more frontally, while nonword deficits were associated with lesions distributed more posteriorly.     

Tactile perception in blind Braille readers: a psychophysical study of acuity and hyperacuity using gratings and dot patterns

It is not clear whether the blind are generally superior to the sighted on measures of tactile sensitivity or whether they excel only on certain tests owing to the specifics of their tactile experience. We compared the discrimination performance of blind Braille readers and age-matched sighted subjects on three tactile tasks using precisely specified stimuli. Initially, the blind significantly outperformed the sighted at a hyperacuity task using Braille-like dot patterns, although, with practice, both groups performed equally well. On two other tasks, hyperacute discrimination of gratings that differed in ridge width and spatial-acuity-dependent discrimination of grating orientation, the performance of the blind did not differ significantly from that of sighted subjects. These results probably reflect the specificity of perceptual learning due to Braille-reading experience.     

Visual and tactile guidance of dexterous manipulation tasks: an fMRI study

Models of motor guidance that dynamically adjust to the availability and quality of sensory information are based on the observation that dexterous tasks are routinely performed using various combinations of visual and tactile inputs. However, a dynamic neural system that acquires and processes relevant visual and tactile information remains relatively uncharacterized in humans. In this study, whole-brain functional magnetic resonance images were acquired during a dexterous manipulation task, compression of the end caps of a slender spring prone to buckling, to investigate the neural systems associated with motor guidance under four visual and tactile guidance conditions: (1) eyes closed (no visual input), smooth end caps, (2) eyes dosed, rough end caps, (3) eyes open and watching hand, smooth end caps, and (4) eyes open and watching hand, rough end caps. Performance of the dexterous task remained constant in all conditions. Variations in the two levels of visual input resulted in modulation of activity in the middle and inferior occipital gyrii and inferior parietal lobule, and variation in the two levels of tactile input during the task resulted in modulation of activity in the precentral (primary motor) gyrus. Although significantly active in all conditions, cingulate gyrus, medial frontal gyrus, postcentral gyrus, and cerebellum activities were not modulated by levels of either visual or somatosensory input, and no interaction effects were observed. Together, these data indicate that a fine-tuned motor task guided by varying visual and tactile information engages a distributed and integrated neural complex consisting of control and executive functions and regions that process dynamic sensory information related to guidance functions.     

Left occipital lobectomy and the preangular anatomy of reading

Two patients had alexias after left occipital lobectomies. Case 1 was a 55-year-old man with a glioblastoma. At 4 months after surgery he could read slowly, but reading was neither efficient nor pleasant. Case 2 was a 19-year-old male who had a more restricted, medial occipital lobectomy for an encapsulated mesenchymal chondrosarcoma. The tumor did not invade brain initially, and the patient recovered efficient reading after 15 months. It is postulated that Case 2 was able to recover efficient reading because he still had a field of left ventrolateral occipitotemporal cortex connected to homologous cortex on the right.     

Multidimensional scaling of schematically represented faces based on dissimilarity estimates and evoked potentials of differences amplitudes

This study researches the input of the cerebral occipital and temporal cortex in the analysis of facial configuration and expressive characteristics. Analysis is based on the construction of a spherical model for the differentiation of schematically presented faces with quantitatively altering curvature of the mouth and brows. The model is designed using the method of multidimensional scaling of the dissimilarity judgments between stimuli (faces) and the amplitude of evoked potentials of differences (EPD) between abrupt stimulus changes recorded from the occipital and posterior temporal cortex. Analysis of the structure of the spherical model of facial differentiation depending on the electrode site and the latency of the EPD component within the duration of 120-240 ms has demonstrated that the activity of the occipital and posterior temporal cortex of the right hemisphere is associated with the emotional characteristics of the presented face, whereas facial configuration is reflected in the activation of both posterior temporal cortex and the occipital cortex of the left hemisphere. At all electrode sites maximum information of the emotional expression and configuration is represented in inter-peak amplitude P120-N180. With increasing latency there is increased distortion of the structure of differences in the spherical model of schematically presented faces, which is interpreted as an attenuation of electrical activity associated with the analysis of the emotional expression, which occurs more rapidly than configuration analysis.     

认知重评和表达抑制情绪调节策略的脑网络分析：来自EEG和ERP的证据

本文旨在对认知重评和表达抑制两种常用情绪调节策略的自发脑网络特征及认知神经活动进行深入探讨。研究采集36名在校大学生的静息态和任务态脑电数据, 经过源定位和图论分析发现节点效率与两种情绪调节显著相关的脑区, 以及脑区之间的功能连接。研究结果表明, 在使用认知重评进行情绪调节时会激活前额叶皮质、前扣带回、顶叶、海马旁回和枕叶等多个脑区, 在使用表达抑制进行情绪调节时会激活前额叶皮质、顶叶、海马旁回、枕叶、颞叶和脑岛等多个脑区。因此, 这些脑区的节点效率或功能连接强度可能成为评估个体使用认知重评和表达抑制调节情绪效果的指标。     

Varieties of alexia from fusiform, posterior inferior temporal and posterior occipital gyrus lesions

Reading impairments of three alexia patients, two pure alexia and one alexia with agraphia, due to different lesions were examined quantitatively, using Kanji (Japanese morphogram) words, Kana (Japanese phonetic writing) words and Kana nonwords. Kana nonword reading was impaired in all three patients, suggesting that widespread areas in the affected occipital and occipitotemporal cortices were recruited in reading Kana characters (corresponding to European syllables). In addition, the findings in patient 1 (pure alexia for Kanji and Kana from a fusiform and lateral occipital gyri lesion) and patient 2 (pure alexia for Kana from a posterior occipital gyri lesion) suggested that pure alexia could be divided into two types, i.e. ventromedial type in which whole-word reading, together with letter identification, is primarily impaired because of a disconnection of word-form images from early visual analysis, and posterior type in which letter identification is cardinally impaired. Another type of alexia, alexia with agraphia for Kanji from a posterior inferior temporal cortex lesion (patient 3), results from deficient whole-word images of words per se, and thus should be designated "orthographic alexia with agraphia". To account for these impairments, a weighted dual-route hypothesis for reading is suggested.     

Bimanual coordination and interhemispheric interaction

Bimanual coordination of skilled finger movements requires intense functional coupling of the motor areas of both cerebral hemispheres. This coupling can be measured non-invasively in humans with task-related coherence analysis of multi-channel surface electroencephalography. Since bimanual coordination is a high-level capability that virtually always requires training, this review is focused on changes of interhemispheric coupling associated with different stages of bimanual learning. Evidence is provided that the interaction between hemispheres is of particular importance in the early phase of command integration during acquisition of a novel bimanual task. It is proposed that the dynamic changes in interhemispheric interaction reflect the establishment of efficient bimanual ‘motor routines'. The effects of callosal damage on bimanual coordination and learning are reviewed as well as functional imaging studies related to bimanual movement. There is evidence for an extended cortical network involved in bimanual motor activities which comprises the bilateral primary sensorimotor cortex (SM1), supplementary motor area, cingulate motor area, dorsal premotor cortex and posterior parietal cortex. Current concepts about the functions of these structures in bimanual motor behavior are reviewed.     

面孔吸引力的回顾与前瞻

面孔吸引力是传递社会情感性信息的重要来源。面孔的平均化、对称性、性别二态性特征等因素会影响对面孔吸引力的评价。近年来, 研究者对面孔吸引力的研究已拓展到动态面孔上, 并采用fMRI技术发现当让被试评价有吸引力的面孔时, 杏仁核、眶额叶、腹侧枕叶等脑区被激活。研究者从进化论取向与认知取向两方面来解释人们为何偏好有吸引力的面孔。以往研究在研究内容、研究材料和研究对象等方面尚存不足, 这正是今后的研究方向。     

Vicarious responses to pain in anterior cingulate cortex: Is empathy a multisensory issue?

Results obtained with functional magnetic resonance imaging show that both feeling a moderately painful pinprick stimulus to the fingertips and witnessing another person’s hand undergo similar stimulation are associated with common activity in a pain-related area in the right dorsal anterior cingulate cortex (ACC). Common activity in response to noxious tactile and visual stimulation was restricted to the right inferior Brodmann’s area 24b. These results suggest a shared neural substrate for felt and seen pain for aversive ecological events happening to strangers and in the absence of overt symbolic cues. In contrast to ACC 24b, the primary somatosensory cortex showed significant activations in response to both noxious and innocuous tactile, but not visual, stimuli. The different response patterns in the two areas are consistent with the ACC’s role in coding the motivational-affective dimension of pain, which is associated with the preparation of behavioral responses to aversive events.     

Left inferior frontal cortex can compensate the inhibitory functions of right inferior frontal cortex and pre-supplementary motor area

Right-IFG and pre-SMA are associated with inhibitory responses. We used functional Magnetic Resonance Imaging to explore whether the contralateral homotopic regions can functionally replace them. An adolescent, with an extensive traumatic lesion of the right cerebral hemisphere having occurred 5 years earlier, performed a motor response inhibition task (Go/Nogo), which was properly accomplished and associated to activations in the left-IFC, precuneus and occipital cortex. Such functional remodelling is in line with the theory of ‘near equipotentiality’ of the cerebral hemispheres.     

Single units and visual cortical organization

The visual system has a parallel and hierarchical organization, evident at every stage from the retina onwards. Although the general benefits of parallel and hierarchical organization in the visual system are easily understood, it has not been easy to discern the function of the visual cortical modules. I explore the view that striate cortex segregates information about different attributes of the image, and dispatches it for analysis to different extrastriate areas. I argue that visual cortex does not undertake multiple relatively independent analyses of the image from which it assembles a unified representation that can be interrogated about the what and where of the world. Instead, occipital cortex is organized so that perceptually relevant information can be recovered at every level in the hierarchy, that information used in making decisions at one level is not passed on to the next level, and, with one rather special exception (area MT), through all stages of analysis all dimensions of the image remain intimately coupled in a retinotopic map. I then offer some explicit suggestions about the analyses undertaken by visual areas in occipital cortex, and conclude by examining some objections to the proposals.