Cerebral Cortex: Primary Auditory Cortex is Required for Anticipatory Motor Response
发布日期:2017-06-13    浏览次数:61

A recent paper entitled ‘Primary Auditory Cortex is Required for Anticipatory Motor Response’ published as a Research Article in Cerebral Cortex demonstrated that: (1) Anticipatory responses exist in L2/3, L4 and L5 neurons of primary auditory cortex (Au1); (2) Au1 anticipatory neuronal response is necessary and sufficient for the generation of anticipatory behavior response; 3) The auditory thalamus is not necessary for anticipatory responses. This work was performed in Dr. Chen Xiaowei ‘s lab at the CAS Center for Excellence in Brain Science and Intelligence Technology and Brain Research Center at the Third Military Medical University.

The brain is capable of predicting expected events based on the recent history of sensory stimuli, a process critical for cognition, decision-making, and eventually for guiding ongoing and imminent actions. For example, following rhythmic sensory stimulation that normally triggers a movement, animals often “overreact” after the cessation of simulation by moving once or more at the expected time of the next stimulus. Impaired ability to anticipate stimuli in the immediate future, as indicated by both brain activity measurements and neuropsychological performance, is often found in psychiatric disorders, including, for example, schizophrenia and anxiety. However, almost nothing is known about the underlying neural circuitry and the brain regions that are required for both coding expectation and generating anticipatory motor behavior. Such information may be relevant for understanding circuit malfunction in these disorders. Neural responses to expected events following repetitive sensory stimuli have been previously observed in different sensory systems of many species, from fish to rodents and to humans. For example, in the visual system, these expected responses, also termed omitted stimulus potentials, can be detected as early as in retina and also occur in the downstream brain regions following rhythmic sensory stimulation. In the auditory system, omitted stimulus-evoked responses have been detected in guinea pig thalamus and in human and monkey cortex. Although these neural correlates of expectation have been found broadly in multiple sensory areas in mammals, it is unclear whether any of these regions are key elements in the brain circuits relevant for transforming the expected neuronal responses into anticipatory behavioral consequences; alternatively, the activities in these regions could be epiphenomenal, without direct behavioral consequences.

In the present study, to address these questions, the authors studied the coding of expected auditory events in L2/3, L4, and L5 of mouse primary auditory cortex. They applied a variety of approaches including in vivo two-photon cellular Ca2+ imaging, fiber photometry, and optogenetic gain- and loss-of-function manipulations in combination with a simple auditory associative learning task. The results provide the first demonstration of the necessity of mammalian Au1 in the brain networks for generating anticipatory behavioral response following rhythmic auditory stimulation. 

The corresponding authors of this work are Dr. Chen Xiaowei and Dr. Liao Xiang. The first author is Mr. Li Jingcheng (PhD candidate). This work was supported by National Science Foundation of China (81671106,31400933, 31371113,91432107) and ‘973’ Programs from Ministry of Science and Technology of China (2015CB759500, 2014CB541600).

Layer 5 neurons in primary auditory cortex (Au1) were labelled by virus Syn-EGFP (green), nuclei were stained by DAPI (blue). Clock encircling the dendrites of L5 neurons implies that the Au1 is capable of timing in a scale of seconds. Following rhythmic sound stimulation, probably initiated by the L5 neurons, Au1 anticipates upcoming sound and guides corresponding anticipatory motor response. Artwork by Jia Lou. See Li et al. 2017. Primary Auditory Cortex is Required for Anticipatory Motor Response.