Different Strategies Modulate the Activity of Inhibitory VIP Neurons in Visual Cortex

In the world of neuroscience, understanding the intricacies of the human brain is a constant journey of discovery. One recent study, led by Dr. Alex Piet and his team, titled "Behavioral strategy shapes activation of the VIP-SST disinhibitory circuit in visual cortex," offers fascinating insights into how our brains process visual information based on our strategies. They show the activity of inhibitory VIP neurons in the visual cortex is dynamically modulated by different cognitive strategies, revealing the intricate adaptability of neural circuitry in processing visual information.

The study examines the VIP-SST mutual inhibition circuit, which plays a crucial role in modulating the activity of pyramidal neurons in the visual cortex. VIP (Vasoactive Intestinal Peptide) and SST (Somatostatin) neurons are both inhibitory neurons, with VIP neurons inhibiting SST neurons and vice versa. However, what sets this circuit apart is its ability to dynamically adjust its activity based on the cognitive strategy being employed. 

To demonstrate this, Piet et al. conducted experiments using mice as subjects. The mice were repeatedly shown an image with gray gaps of half a second or so. After a while, they presented with a different image, and were rewarded for detecting the change in image. The pause between the image change was a bit longer than the normal gap between the same image. So the mice could rely on the timing of the gap to detect the change (timing strategy), or the actual change in the image (visual strategy). Occasionally the experimenters would have a longer gap but keep the image the same. Mice using the timing strategy would get tricked, while the mice using the visual strategy would not be tricked.

They experimenters recorded from the VIP, SST, and pyramidal neurons. Upon analyzing the activity of VIP neurons, the researchers observed a pattern: higher activity in the VIP neurons when the mice were employing a visual strategy and lower activity when focusing on timing. Using the VIP neuron activity alone, one could predict which task the mice were using. This suggests that VIP neurons are the cognitive strategy being utilized. Furthermore, these VIP neurons play a crucial role in priming/shaping excitatory pyramidal neuron’s response to visual stimuli.

This study underscores the importance of VIP neurons as contextual feedback neurons that shape the processing of inputs in cortical regions. By understanding how these neurons modulate brain activity based on cognitive strategies, we gain deeper insights into the complex mechanisms underlying visual perception and cognition.

Dr. Alex Piet's study highlights the remarkable adaptability of the brain and its ability to adjust its neural circuitry based on the demands of different cognitive tasks. As we continue to unravel the mysteries of the brain, studies like these pave the way for advancements in neuroscience and our understanding of human cognition.

Author: Alexander White

Paper: Alex Piet, Nick Ponvert, Douglas Ollerenshaw, Marina Garrett, Peter A. Groblewski, Shawn Olsen, Christof Koch, Anton Arkhipov. (2024) Behavioral strategy shapes activation of the Vip-Sst disinhibitory circuit in visual cortex. Neuron