Topic: cortical feedback

Why does the olfactory bulb contain two projection neuron populations? Called mitral and tufted cells (MCs and TCs), both sample receptor input at glomeruli but lie in different bulb layers, project to different regions of piriform cortex and form parallel circuits wherein TCs interact mainly with the anterior olfactory nucleus (AON), and MCs with piriform cortex (PC) proper. Experiments have revealed that (1) MCs are primarily driven by TCs, perhaps why (2) MC responses come later in the sniff cycle than TCs; (3) MCs receive excitatory cortical feedback from the AON; and (4) MC responses are

Visual representations become progressively more abstract along the cortical hierarchy. These abstract representations define notions like objects and shapes but at the cost of spatial specificity. By contrast, low-level regions represent spatially local but simple input features. How do spatially non-specific representations of abstract concepts in high-level areas flexibly modulate the low-level sensory representations in appropriate ways to guide context-driven and goal-directed behaviors across various tasks? We present a biologically motivated and trainable neural network model of dyna

How does the brain derive meaning from social vocalizations and drive behavior in response? Vocalizations are temporally complex, requiring integration across multiple time-scales for appropriate contextualization. We hypothesize that corticofugal projections modulate temporal integration in feed-forward auditory circuits to facilitate this. We tested this using an ethological mouse behavior that depends on left auditory cortex. Mothers find and retrieve isolated pups into the nest when pups emit ultrasonic vocalizations (USVs). Virgin females don’t usually retrieve pups, but learn after sever