Context-dependent spatially periodic activity in the human entorhinal cortex

The spatially periodic activity of grid cells in the entorhinal cortex (EC) of the rodent, primate, and human provides a coordinate system that, together with the hippocampus, informs an individual of its location relative to the environment and encodes the memory of that location. Among the most defining features of grid-cell activity are the 60 degrees rotational symmetry of grids and preservation of grid scale across environments. Grid cells, however, do display a limited degree of adaptation to environments. It remains unclear if this level of environment invariance generalizes to human grid-cell analogs, where the relative contribution of visual input to the multimodal sensory input of the EC is significantly larger than in rodents. Patients diagnosed with nontractable epilepsy who were implanted with entorhinal cortical electrodes performing virtual navigation tasks to memorized locations enabled us to investigate associations between grid-like patterns and environment. Here, we report that the activity of human entorhinal cortical neurons exhibits adaptive scaling in grid period, grid orientation, and rotational symmetry in close association with changes in environment size, shape, and visual cues, suggesting scale invariance of the frequency, rather than the wavelength, of spatially periodic activity. Our results demonstrate that neurons in the human EC represent space with an enhanced flexibility relative to neurons in rodents because they are endowed with adaptive scalability and context dependency

Up, down, near, far: an online vestibular contribution to distance judgement

Whether a visual stimulus seems near or far away depends partly on its vertical elevation. Contrasting theories suggest either that perception of distance could vary with elevation, because of memory of previous upwards efforts in climbing to overcome gravity, or because of fear of falling associated with the downwards direction. The vestibular system provides a fundamental signal for the downward direction of gravity, but the relation between this signal and depth perception remains unexplored. Here we report an experiment on vestibular contributions to depth perception, using Virtual Reality. We asked participants to judge the absolute distance of an object presented on a plane at different elevations during brief artificial vestibular inputs. Relative to distance estimates collected with the object at the level of horizon, participants tended to overestimate distances when the object was presented above the level of horizon and the head was tilted upward and underestimate them when the object was presented below the level of horizon. Interestingly, adding artificial vestibular inputs strengthened these distance biases, showing that online multisensory signals, and not only stored information, contribute to such distance illusions. Our results support the gravity theory of depth perception, and show that vestibular signals make an on-line contribution to the perception of effort, and thus of distance

Az okoseszközök használata kognitív idegtudományi nézőpontból

A szerzők az okoseszközök használatát megalapozó kognitív tényezők változásának néhány jellemzőjét bemutatva a 21. század oktatási lehetőségeit és kihívásait elemzik. A tanulmány kitér a digitális eszközök használatának kezdeti szakaszaira, az okostelefonok alkalmazásának lehetséges előnyeire, akadályaira, valamint veszélyeire. A tanulás neurális alapfolyamatainak bemutatásából kiinduló elemzés bemutatja az okoseszközök használatát kísérő agyi változások szisztematikus kutatásának feltételeit, az összefüggések tudományos szigorúsággal feltárandó tényezőit. Az alapkészségek fejlődését és eltéréseit meghatározó agyi változások vizsgálatából származó adatok és az azokra épülő modellek megbízhatóságát a szerzők az olvasás és szövegértés, a korai matematika, valamint a zenei nevelés területén kiemelve számos példát mutatnak be arra vonatkozóan, miért kevés a megbízható idegtudományi adat az okoseszközökkel támogatott tanulásra vonatkozóan. Külön kitér a tanulmány a függőségekre, valamint az okoseszközök használatát megalapozó kognitív és motivációs tényezőkre. A tanulmány a virtuális valóság és a gamifikáció típusú oktatási módszerek területén feltárandó ismeretek bemutatásával hangsúlyozza, hogy az agyi hálózatok változásában mérhető hatást ezen a területen miért ismerjük kevésbé, mint a tanulás más faktoraival kapcsolatban

Location learning in virtual environments: The effect of saliency of landmarks and boundaries

In the present paper, we investigated the learning of object location in a virtual reality environment. Previous studies suggested that learning is essentially different when participants rely on landmarks (i.e., single stationary objects in the space) or boundaries (i.e., terrain features), the former requiring associative reinforcement learning, while the latter relying on incidental learning. However, in previous studies the saliency of the spatial cues and the position of objects relative to spatial cues were not carefully controlled, which could account for the specific learning effect found. In our study, we controlled these effects. We presented a virtual arena on a computer screen, featuring a landmark and a boundary cue, and four everyday objects, the location of which had to be learned and recalled. In the learning phase, either one or both cues were present, while in the test phase only one cue was present. Contrary to previous results, we did not obtain the overshadowing effect, as there was no difference in the location errors between the four conditions. At the same time, we found that location errors were influenced by the relative spatial position of the object and cue. This suggests that it is the distance from the cue and not the cue type, which is the main factor behind localization errors

Effect of stimulus intensity on response time distribution in multisensory integration

To increase the efficiency of multimodal user interfaces, one has to design them according to how multimodal features appear in the real world. Although spatial coincidence and matching intensity levels are important for perception, these factors received little attention in human–computer interaction studies. In our present study we aimed to map how spatial coincidence and different intensity levels influence response times. Sixteen participants performed a simple auditory localization task, where sounds were presented either alone or together with visual non-targets. We found that medium intensity visual stimuli facilitated responses to low intensity sounds. Analyses of response time distributions showed that intensity of target and non-target stimuli affected different parameters of the ex-Gaussian distribution. Our results suggest that multisensory integration and response facilitation may occur even if the non-target has low predictive power to the location of the target. Furthermore, we show that the parameters of the ex-Gaussian distribution can be related to distinct cognitive processes. The current results are potentially applicable in the design of an intelligent warning system that employs the user’s reaction time to adapt the warning signal for optimal results