Topic: top-down modulation

Humans have the ability to quickly adapt to new tasks and generalise what they learned to improve the learning process itself. At the core of this capacity for meta-learning lies a difficult credit assignment problem. After a learning episode, the system needs to determine how to change the components of plasticity such that the next time a similar task is encountered, a better learning outcome can be arrived at more quickly. In machine learning, this problem is often approached by storing the entire learning trajectory and revisiting it in reverse-time order, a process that places large deman

The taste system detects 5 major categories of ethologically relevant stimuli (sweet, bitter, umami, sour and salt) and accordingly elicits acceptance or avoidance responses. While these taste responses are innate, the taste system retains a remarkable flexibility in response to changing external and internal contexts. Taste chemicals are first recognized by dedicated taste receptor cells (TRCs) and then transmitted to the cortex via a multi-station relay. I reasoned that if I could identify taste neural substrates along this pathway, it would provide an entry to decipher how taste signals are

Human vision flaunts a remarkable ability to recognize objects in the surrounding environment even in the absence of complete visual representation of these objects. This process is done almost intuitively and it was not until scientists had to tackle this problem in computer vision that they noticed its complexity. While current advances in artificial vision systems have made great strides exceeding human level in normal vision tasks, it has yet to achieve a similar robustness level. One cause of this robustness is the extensive connectivity that is not limited to a feedforward hierarchical p

Neural activity in the cortex exhibits a wide range of timescales, allowing animals to respond to rapidly changing sensory stimuli while maintaining information in working memory. The timescales of neural activity are not only affected by bottom-up sensory inputs, but also by top-down inputs originating from corticocortical and neuromodulatory pathways. In addition, cortical circuits comprise a large diversity of cell types connected in non-random ways, which are the subject of profound plasticity dynamics. Due to this complexity, understanding how top-down projections affect the timescales of