Research
My research investigates how cortical, subcortical, and neuromodulatory circuits regulate attention, perception, decision-making, and cognitive flexibility. A central focus is identifying the distinct cognitive and behavioral operations implemented by these circuits and understanding how their contributions change with behavioral demands.I develop visual behavioral paradigms that independently manipulate perceptual sensitivity, attentional allocation, decision criterion, and motor preparation. Combining these approaches with in vivo electrophysiology, cell-type-specific optogenetics, pharmacology, and computational modeling enables me to establish causal relationships between neuronal activity and cognitive function.1. Neuromodulatory Control of Cognitive Flexibility
Adaptive behavior requires continuously updating attentional priorities, modifying neural representations, and adjusting perceptual processing in response to changing environmental demands. My current research investigates how the locus coeruleus–norepinephrine (LC–NE) system interacts with cortical and subcortical circuits to regulate these processes across different spatial and temporal scales.LC–ACC–dlPFC interactions: A central direction of my current research examines how neuromodulatory and prefrontal circuits contribute to the reallocation of attention when behavioral priorities change. I study how locus coeruleus (LC), anterior cingulate cortex (ACC), and dorsolateral prefrontal cortex (dlPFC) contribute to detecting behavioral errors, reallocating attention, and establishing new attentional priorities when reward contingencies change.Local norepinephrine signaling: Using clonidine microinjections and simultaneous neuronal recordings, I investigate how noradrenergic signaling within the superior colliculus (SC) regulates attention-related activity and perceptual sensitivity.Temporal mechanisms of neuromodulation: I use white-noise optogenetic stimulation and reverse-correlation analysis to identify when LC–norepinephrine activity causally influences perceptual processing, revealing temporally specific contributions to visual detection.2. Neuromodulatory Control of Attention
My research establishes a causal role for the LC–norepinephrine system in selective visual attention. Using cell-type-specific optogenetics and neuronal recordings in nonhuman primates, I demonstrated that LC neurons exhibit spatially selective attention-related responses. Brief optogenetic activation selectively enhances perceptual sensitivity without changing decision or motor criteria. These findings challenge the traditional view of norepinephrine as a diffuse arousal signal and reveal its precise contribution to sensory processing and attentional performance.
Ghosh & Maunsell, Neuron (2024).3. Dissociating neuronal representations of attentional effort and selective attention in visual pathways
My studies examine how distinct components of attention and decision-making are represented in cortical and subcortical circuits. In visual area V4, I dissociated attentional selectivity from attentional effort and characterized their interactions in neuronal activity. Extending this approach to the superior colliculus, I demonstrated that attention-related neuronal modulation reflects perceptual sensitivity and motor response bias, but not abstract decision criterion or perceptual choice. Together, these findings clarify the functional organization of circuits supporting visual attention.
Ghosh & Maunsell, Nature Communications (2021, 2026); Science Advances (2022).4. Neural Circuits of Fear Generalization and Stress
My earlier research investigated how emotional learning and chronic stress alter neuronal activity and circuit interactions. I identified changes in lateral amygdala neuronal encoding associated with the transition from stimulus-specific to generalized fear. I also demonstrated that chronic stress produces persistent alterations in functional connectivity between the amygdala and hippocampus, providing insights into the neural mechanisms underlying maladaptive emotional responses.
Ghosh & Chattarji, Nature Neuroscience (2015); Ghosh, Laxmi & Chattarji, Journal of Neuroscience (2013).