Behaviour-dependent recruitment of long-range projection neurons in somatosensory cortex

• Published in: Nature (London) 2013-07, Vol.499 (7458), p.336-340
• Main Authors: Chen, Jerry L., Carta, Stefano, Soldado-Magraner, Joana, Schneider, Bernard L., Helmchen, Fritjof
• Format: Article
• Language: English
• Subjects: 631/378/2620/2623; Afferent Pathways; Analysis; Animals; Behavior, Animal; Biological and medical sciences; Brain; Calcium - analysis; Discrimination (Psychology) - physiology; Fundamental and applied biological sciences. Psychology; Humanities and Social Sciences; letter; Mice; multidisciplinary; Neurons; Neurons - chemistry; Neurons - physiology; Physiological aspects; Science; Somatosensory Cortex - cytology; Somatosensory Cortex - physiology; Somatosensory system; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Vertebrates: nervous system and sense organs; Vibrissae - innervation
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature12236

In the mouse whisker region of primary somatosensory cortex (S1), neurons projecting to secondary somatosensory cortex (S2) and primary motor cortex (M1), respectively, are differentially activated during distinct whisker-based behavioural tasks; sensory stimulus features alone do not elicit these differences, suggesting that selective transmission of S1 information to S2 and M1 is driven by behaviour. Separate streams in somatosensory cortex In order to understand one's environment, it is necessary to know both the identity and the location of the objects within it. It is thought that in the visual system these two properties are processed in separate streams, but how different stimulus aspects are represented in the somatosensory system is less clear. Fritjof Helmchen and colleagues now show that in rats, distinct and largely non-overlapping projections from primary somatosensory cortex to secondary cortex and motor cortex are active during different tasks, demonstrating how information within an area can be segregated into separate outputs. In the mammalian neocortex, segregated processing streams are thought to be important for forming sensory representations of the environment 1 , 2 , but how local information in primary sensory cortex is transmitted to other distant cortical areas during behaviour is unclear. Here we show task-dependent activation of distinct, largely non-overlapping long-range projection neurons in the whisker region of primary somatosensory cortex (S1) in awake, behaving mice. Using two-photon calcium imaging, we monitored neuronal activity in anatomically identified S1 neurons projecting to secondary somatosensory (S2) or primary motor (M1) cortex in mice using their whiskers to perform a texture-discrimination task or a task that required them to detect the presence of an object at a certain location. Whisking-related cells were found among S2-projecting (S2P) but not M1-projecting (M1P) neurons. A higher fraction of S2P than M1P neurons showed touch-related responses during texture discrimination, whereas a higher fraction of M1P than S2P neurons showed touch-related responses during the detection task. In both tasks, S2P and M1P neurons could discriminate similarly between trials producing different behavioural decisions. However, in trials producing the same decision, S2P neurons performed better at discriminating texture, whereas M1P neurons were better at discriminating location. Sensory stimulus features alone were not suff