Visuospatial working memory abilities in children analyzed by the bricks game task (BGT).

The study of the development of visuospatial memory processes is useful for devising personalized educational interventions as well as for understanding the changes in cognitive functioning in an era characterized by technological progress. The present research is aimed at investigating spatial working memory ability in children that attended the first three years of primary school by means of the Brick Game Task (BGT), a novel visuospatial working memory test. BGT is a small-scale ecological test inspired by behavioral walking tasks with nine white bricks in different spatial configurations as well as to Corsi Block-Tapping test.228 Italian children (121 F; mean age: 7.22 ± 1.18) were assigned to three groups based on the primary school class attended: Group 1 (N = 85; 40 F; mean age 6.18 ± .5), Group 2 (N = 61; 36 F; mean age 7.2 ± .83), and Group 3 (N = 82; 44 F; mean age 8.32 ± .94). All participants were asked to complete the Digit Span test, the Corsi Block-Tapping test, and to explore the three spatial configurations of the BGT with the form of Matrix, M-BGT, Cluster, CL-BGT, Cross, CR-BGT.MANOVA revealed a main significant effect for Group (F12,434 = 15.06; p < .0001) indicating that the group of older obtained a better global executive performance than 1 and 2 groups. Multiple linear regression indicated that Corsi Block-Tapping test performance and Age significantly predicted the M-BGT score. Moreover, Corsi Block-Tapping test and Digit Span significantly predicted the CL-BGT performance, showing how a higher score results in a better CL- BGT performance. Finally, Corsi Block-Tapping test, Digit Span, and Age were positively associated with the CR- BGT performance. The present findings evidenced that novel BGT is a sensible visuospatial working memory task suggesting thus its use to assess the children's executive performance in ecological way. These results open to the development of personalized educational interventions.

Visual perception skills: a comparison between patients with Noonan syndrome and 22q11.2 deletion syndrome.

Ventral and dorsal streams are visual pathways deputed to transmit information from the photoreceptors of the retina to the lateral geniculate nucleus and then to the primary visual cortex (V1). Several studies investigated whether one pathway is more vulnerable than the other during development, and whether these streams develop at different rates. The results are still discordant. The aim of the present study was to understand the functionality of the dorsal and the ventral streams in two populations affected by different genetic disorders, Noonan syndrome (NS) and 22q11.2 deletion syndrome (22q11.2DS), and explore the possible genotype-phenotype relationships. 'Form coherence' abilities for the ventral stream and 'motion coherence' abilities for the dorsal stream were evaluated in 19 participants with NS and 20 participants with 22q11.2DS. Collected data were compared with 55 age-matched controls. Participants with NS and 22q11.2DS did not differ in the form coherence task, and their performance was significantly lower than that of controls. However, in the motion coherence task, the group with NS and controls did not differ, and both obtained significantly higher scores than the group with 22q11.2DS. Our findings indicate that deficits in the dorsal stream are related to the specific genotype, and that in our syndromic groups the ventral stream is more vulnerable than the dorsal stream.

Explorative function in Prader-Willi syndrome analyzed through an ecological spatial task.

This study was aimed at evaluating the spatial abilities in individuals with Prader-Willi syndrome (PWS) by using an ecological large-scale task with multiple rewards. To evaluate the extent of spatial deficit in PWS individuals, we compare their performances with those of individuals with Williams Syndrome (WS) in which the spatial deficits have been widely described. Participants had to explore an open space to search nine rewards placed in buckets arranged according to three spatial configurations: a Cross, a 3×3 Matrix and a Cluster composed by three groups of three buckets each. PWS individuals exhibited an explorative deficit in Cluster and Cross configurations, while WS participants in Matrix and Cross configurations. The findings indicate that the structural affordances of the environment influence the explorative strategies and can be related to how spatial information is processed.

Explorative function in Williams syndrome analyzed through a large-scale task with multiple rewards.

This study aimed to evaluate spatial function in subjects with Williams syndrome (WS) by using a large-scale task with multiple rewards and comparing the spatial abilities of WS subjects with those of mental age-matched control children. In the present spatial task, WS participants had to explore an open space to search nine rewards placed in buckets arranged according to three spatial configurations: a cross, a 3 × 3 matrix and a cluster composed by three groups of three buckets each. The findings demonstrate that WS individuals were impaired in efficiently exploring the environment and in building cognitive spatial maps. In exploring the three spatial configurations, they performed worse than control subjects on all parameters analyzed. In fact, WS individuals took more time to complete the task, made more errors, performed a reduced number of error-free trials, displayed lower search efficiency, exhibited shorter spatial spans, showed a higher number of no-visits and displayed marked tendencies to perseverate and to neglect some buckets. Furthermore, WS individuals showed disorganized explorative patterns in comparison to control children. WS influenced performances differentially as a specific effect of the susceptibility of the configurations to being explored in a principled way. In the cross configuration that had strong spatial constraints, both groups exhibited their worst performances. In the matrix configuration, the altered explorative strategies of the WS subjects primarily affected their central exploration. The performances in the cluster configuration indicated that chunking was a strategy of strength in both TD and WS groups. In conclusion, WS individuals' deficits exhibited in the present explorative test may be considered an index of their difficulties in spatial orientation and motion perception displayed in the real world. The marked impairment in spatial information processing is discussed in neuro-anatomical alterations reported in WS.

Features of sequential learning in hemicerebellectomized rats.

Because the sequencing property is one of the functions in which cerebellar circuits are involved, it is important to analyze the features of sequential learning in the presence of cerebellar damage. Hemicerebellectomized and control rats were tested in a four-choice visuomotor learning task that required both the detection of a specific sequence of correct choices and the acquisition of procedural rules about how to perform the task. The findings indicate that the presence of the hemicerebellectomy did not affect the first phases of detection and acquisition of the sequential visuomotor task, delayed but did not prevent the learning of the sequential task, slowed down speed-up and proceduralization phases, and loosened the reward-response associative structure. The performances of hemicerebellectomized animals in the serial learning task as well as in the open field task demonstrated that the delayed sequential learning task could not be ascribed to impairment of motor functions or discriminative abilities or to low levels of motivation. The delay in sequential learning observed in the presence of a cerebellar lesion appeared to be related mainly to a delay of the automatization of the response. In conclusion, it may be advanced that, through cortical and subcortical connections, the cerebellum provides the acquisition of rapid and accurate sensory-guided sequence of responses.

Children' s radial arm maze performance as a function of age and sex.

The present study analyzes the development of the spatial abilities in children aged 36-95 months and the sex-related differences by means of the free-choice and forced-choice paradigms of the eight-arm radial maze task. Clear age-related improvements were evidenced. However, a temporal window with an abrupt acceleration of specific spatial competencies acquisition was detected. The females aged 51-58 months started the task performing about 2.5 errors and ended it performing no more than 0.5 errors. The same pattern of performance was exhibited by the males aged 59-66 months. Also in the final span the 4.5-year-old females behave as the 6-year-old males. The significant correlations between 45 degrees angles and span values in the free-choice paradigm indicated that all children tended to solve the task by employing low working memory load and by using mainly efficient procedural strategies. Furthermore, children's ability to retain earlier information was influenced by both age and sex factors as indicated by the forced-choice paradigm findings. The present findings demonstrating the earlier acquisition of spatial competencies of the females in comparison to males, could reflect differences in foraging strategies between sexes, and/or differences in the anatomo-physiological development of specific brain structures, and/or different modulating effects of sexual hormones.

Spatial competences in Williams syndrome: a radial arm maze study.

This study was aimed at evaluating spatial function in subjects with Williams syndrome by using the radial arm maze task and comparing their spatial abilities with those of mental age-matched control subjects. Two different paradigms were administered: the free-choice version for analyzing the aspects linked mainly to procedural and mnesic components, the forced-choice version for disentangling components linked to spatial working memory from the procedural ones. The findings evidenced a deficit in the acquisition of procedural competences as well as in the spatial memory processes in Williams subjects. In the free-choice paradigm, they performed worse than control subjects on all parameters analyzed. Namely, they needed more time to complete the task, did not collect all rewards, exhibited low values of the spatial span as well as low percentages of correct visits, and displayed a reduced use of the most efficient exploration strategies. Even in the forced-choice paradigm, Williams subjects made a number of errors significantly higher than control subjects. The marked impairment in spatial information processing is discussed on the light of neuro-anatomical alterations reported in Williams subjects.

Cerebellar involvement in cognitive flexibility.

The aim of the present study was to investigate whether the cerebellar structures are involved in functions requiring cognitive flexibility abilities. The flexibility of the hemicerebellectomized and control animals in learning a four-choice learning task, adapting to ever-changing response rules was investigated. While in the initial phase of the task both experimental groups exhibited similar performances, only the control animals significantly improved their performance as the sessions went by. The lack of improvement in lesioned animals' performance rendered their responses particularly defective in the final phases of the task, when conversely intact animals performed best, exploiting their "learning to learn" ability. The findings demonstrate the defective influence of the cerebellar lesion on the acquisition, not the execution, of new responses. The results underline the crucial role of the cerebellum in mediating cognitive flexibility behaviors.

Environmental enrichment mitigates the effects of basal forebrain lesions on cognitive flexibility.

The aim of the present study was to investigate whether basal forebrain lesions were able to impair a task requiring cognitive flexibility abilities and analyzing the effect of the rearing in an enriched environment on such form of flexibility in rats with or without basal forebrain cholinergic lesions. In adult rats reared in enriched or standard conditions of the cholinergic projection to the neocortex damage was inflicted by 192 IgG-saporin injection into Ch4 region of basal forebrain. Their performance was compared with those of intact animals reared in analogous conditions in a four-choice serial learning task which taps flexibility in adapting to changing response rules. The results underlined the crucial role of the basal forebrain in mediating cognitive flexibility behaviors and revealed that the increase in social interactions, cognitive stimulation and physical activity of the rearing in enriched environment attenuated impairments caused by the cholinergic lesion. These findings demonstrate that rearing in an enriched environment can improve the ability to cope with brain damage suffered in adulthood.

Cerebellar contribution to spatial event processing: do spatial procedures contribute to formation of spatial declarative knowledge?

Spatial knowledge of an environment involves two distinct competencies: declarative spatial knowledge, linked to where environmental cues are and where the subject is with respect to the cues, and, at the same time, procedural spatial knowledge, linked to how to move into the environment. It has been previously demonstrated that hemicerebellectomized (HCbed) rats are impaired in developing efficient exploration strategies, but not in building spatial maps or in utilizing localizing cues. The aim of the present study was to analyse the relationships between spatial procedural and declarative knowledge by using the open field test. HCbed rats have been tested in two different protocols of the open field task. The results indicate that HCbed animals succeeded in moving inside the arena, in contacting the objects and in habituating to the new environment. However, HCbed animals did not react to environmental changes, when their impaired explorative pattern was inappropriate to the environment, suggesting that they were not able to represent a new environment because they were not able to explore it appropriately. Nevertheless, when their altered procedures were favoured by object arrangement, they detected environmental changes as efficiently as did normal rats. This finding suggests that no declarative spatial learning is possible without appropriate procedural spatial learning.

Learning power of single behavioral units in acquisition of a complex spatial behavior: an observational learning study in cerebellar-lesioned rats.

By combining an observational spatial learning paradigm with a cerebellar lesion that blocks the acquisition of new spatial strategies, it is possible to separate a complex spatial behavior into its fundamental units to study which relationships among units have to be maintained so that the entire behavior might be acquired. Normal rats were first allowed to observe demonstrator rats performing single explorative behaviors (circling, extended searching, direct finding), then were hemicerebellectomized and, finally, tested in the Morris water maze. In spite of the cerebellar lesion, the observer rats displayed exploration abilities that closely matched the previously observed behaviors. These results indicate that the single facets that form the strategy repertoire can be independently acquired.

Cerebellar contribution to spatial event processing: involvement in procedural and working memory components.

Spatial function is one of the cognitive functions altered in the presence of cerebellar lesions. We investigated the cerebellar contribution to the acquisition of spatial procedural and working memory components by means of a radial maze. To establish whether a cerebellar lesion would cause a deficit in solving the radial maze, a first experiment was carried out by using a full-baited maze procedure in different experimental groups, with or without cerebellar lesion and with or without pretraining. Non-pretrained hemicerebellectomized (HCbed) animals exhibited impaired performances in all (motor, spatial and procedural) task aspects. Pre-trained HCbed animals performed similarly to control animals in the task aspects linked to the processing of spatial and procedural factors. To distinguish procedural from working memory components, a forced-choice paradigm of the radial maze was used in the second experiment. Non-pretrained HCbed rats continued to make a lot of errors and show severe perseverative tendencies, already observed in the first experiment, supporting a specific cerebellar role in acquiring new behaviours and in modifying them in relation to the context. Interestingly, hindered from putting the acquired explorative patterns into action and compelled to use only working memory abilities, the pretrained HCbed group exhibited a dramatic worsening of performance. In conclusion, the present findings demonstrate that cerebellar damage induces a specific behaviour in radial maze tasks, characterized by an inflexible use of the procedures (if indeed any procedure was acquired before the lesion) and by a severe impairment in working memory processes.

Representation of actions in rats: the role of cerebellum in learning spatial performances by observation.

Experimental evidence demonstrates that cerebellar networks are involved in spatial learning, controlling the acquisition of exploration strategies without blocking motor execution of the task. Action learning by observation has been considered somehow related to motor physiology, because it provides a way of learning performances that is almost as effective as the actual execution of actions. Neuroimaging studies demonstrate that observation of movements performed by others, imagination of actions, and actual execution of motor performances share common neural substrates and that the cerebellum is among these shared areas. The present paper analyzes the effects of observation in learning a spatial task, focusing on the cerebellar role in learning a spatial ability through observation. We allowed normal rats to observe 200 Morris water maze trials performed by companion rats. After this observation training, "observer" rats underwent a hemicerebellectomy and then were tested in the Morris water maze. In spite of the cerebellar lesion, they displayed no spatial defects, exhibiting exploration abilities comparable to controls. When the cerebellar lesion preceded observation training, a complete lack of spatial observational learning was observed. Thus, as demonstrated already for the acquisition of spatial procedures through actual execution, cerebellar circuits appear to play a key role in the acquisition of spatial procedures also through observation. In conclusion, the present results provide strong support for a common neural basis in the observation of actions that are to be reproduced as well as in the actual production of the same actions.

Cerebellar contribution to spatial event processing: characterization of procedural learning.

Recently, we demonstrated the prevalent role of cerebellar networks in the acquisition of the procedural components of spatial information by testing hemicerebellectomized (HCbed) rats in a classical spatial task, the Morris water maze (MWM). As procedures used in the water maze are a mixture of different components (that is, general procedures, exploration procedures, direct reaching procedures), for optimally solving a spatial task all procedural components must be opportunely managed. Thus, severely impaired procedural learning of cerebellar origin can be better comprehended by fractionating the procedural facets. To this aim, a two-step water-maze paradigm was employed. Normal rats were first trained to search for a hidden platform moved to a different position in each trial, utilizing a water maze setting in which visual cues were abolished by heavy black curtains surrounding the tank. In this paradigm, normal animals solved the task by using general and exploration procedures, but they could not use direct reaching skills. A subgroup of these pretrained animals was then HCbed and, after recovery from cerebellar lesion, was tested in a water maze with normal environmental cues available, a paradigm in which normal animals develop abilities for reaching the target with very direct trajectories. Pretrained HCbed animals, however, did not display the typical spatial deficits of naive HCbed rats, persisted in exhibiting the scanning strategy learned during pretraining, and never displayed direct reaching skills. In conclusion, cerebellar networks appear to be involved in the acquisition of all procedural facets necessary for shifting behavior within the maze until direct reaching of the platform. The lack of flexibility in changing exploration strategies displayed by pretrained HCbed rats is interpreted by taking into account the well-known cerebellar frontal interplay sculpting a specific cerebellar role in the acquisition of spatial procedural steps.