NeuroLeman Network

Research on the effects of bilingualism on the structure of the brain has so far yielded variable patterns. Although it cannot be disputed that learning and using additional languages restructures the brain, the reported effects vary considerably, including both increases and reductions in grey matter volume and white matter diffusivity. This presentation reviews the available evidence and compares it to patterns from other domains of skill acquisition, culminating in the Dynamic Restructuring Model, a theory which synthesises the available evidence from the perspective of experience-based neuroplasticity. New corroborating evidence is also presented from healthy young and older bilinguals, and the presentation concludes with the implications of these effects for the ageing brain.

Precise synaptic connectivity is a prerequisite for the function of neural circuits, yet individual neurons, taken out of their developmental context, readily form unspecific synapses. How does genetically encoded brain wiring deal with this apparent contradiction? Brain wiring is a developmental growth process that is not only characterized by precision, but also flexibility and robustness. As in any other growth process, cellular interactions are restricted in space and time. Correspondingly, molecular and cellular interactions are restricted to those that 'get to see' each other during development. This seminar will explore the question how neurons decide when and where to make synapses using the Drosophila visual system as a model. New findings reveal that pattern formation during growth and the kinetics of live neuronal interactions restrict synapse formation and partner choice for neurons that are not otherwise prevented from making incorrect synapses in this system. For example, cell biological mechanisms like autophagy as well as developmental temperature restrict inappropriate partner choice through a process of kinetic exclusion that critically contributes to wiring specificity. The seminar will explore these and other neuronal strategies when and where to make synapses during developmental growth that contribute to precise, flexible and robust outcomes in brain wiring.

Exposure to sensory regularities in the environment induces the human brain to form expectations about incoming stimuli and remains partially preserved in the absence of consciousness (i.e. coma and sleep). While regularity often refers to stimuli presented at a fixed pace, we recently explored whether auditory prediction extends to pseudo-regular sequences where sensory prediction is induced by locking sound onsets to heartbeat signals and whether it can occur across vigilance states. In a series of experiments in healthy volunteers, we found neural and cardiac evidence of auditory prediction during heartbeat-based auditory regularities in wakefulness and N2 sleep. This process could represent an important mechanism for detecting unexpected stimuli in the environment even in states of limited conscious and attentional resources.

GABAergic interneurons play crucial roles in the regulation of neural activity in the cerebral cortex. In this Dual Lecture, Prof Oscar Marín and Prof Beatriz Rico will discuss several aspects of the formation of inhibitory circuits in the mammalian cerebral cortex. Prof. Marín will provide an overview of the mechanisms regulating the generation of the remarkable diversity of GABAergic interneurons and their ultimate numbers. Prof. Rico will describe the molecular logic through which specific pyramidal cell-interneuron circuits are established in the cerebral cortex, and how alterations in some of these connectivity motifs might be liked to disease. Our web pages for reference: https://devneuro.org.uk/marinlab/ & https://devneuro.org.uk/rico/default

Historically, retinotopic organisation (the spatial mapping of the retina across the cortical surface) was considered the purview of early regions of visual cortex (V1-V4) only and that anterior, more cognitively involved regions abstracted this information away. The contemporary view is quite different. Here, with Advancing technologies and analysis methods, we see that retinotopic information is not simply thrown away by these regions but rather is maintained to the potential benefit of our broader cognition. This maintenance of visuospatial coding extends not only through visual cortex, but is present in parietal, frontal, medial and subcortical structures involved with coordinating-movements, mind-wandering and even memory. In this talk, I will outline some of the key empirical findings from my own work and the work of others that shaped this contemporary perspective.