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Imaging population dynamics of surround suppression in the superior colliculus
Author(s) -
Kasai Masatoshi,
Isa Tadashi
Publication year - 2016
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.13371
Subject(s) - neuroscience , superior colliculus , stimulus (psychology) , surround suppression , population , calcium imaging , gabaergic , inhibitory postsynaptic potential , biology , nerve net , visual perception , psychology , perception , chemistry , medicine , calcium , organic chemistry , psychotherapist , environmental health
The superior colliculus ( SC ) plays a key role in controlling spatial attention. It is hypothesized that some forms of spatial attention, such as the detection of a single salient object arise from lateral competitive interactions between different locations within the spatial map in the SC . This hypothesis is supported by a recent in vitro study showing that a ‘Mexican hat’‐like pattern of synaptic connectivity is implemented in the intrinsic circuit of the superficial layer of the SC ( sSC ). However, the neuronal population mechanisms responsible for this pattern still remain unclear. Here, we examined how spatial response modulations, for example lateral interactions and surround suppression, are represented at the neuronal population level using in vivo two‐photon calcium imaging in the mouse sSC . Observation of neuronal population responses with single‐cell resolution enabled us to identify a small subset of neurons that were activated by relatively small visual stimuli (< 1° diameter), and thus allowed us to detect the exact location of the ‘response center’ in the sSC to a visual stimulus presented at a given location. We demonstrated that presenting two‐point stimuli or one large stimulus modulated the spatial response pattern of the neuronal population, i.e. centre facilitation and surround suppression. Furthermore, we found that both GABA ergic and non‐ GABA ergic neurons showed a similar population response pattern of surround suppression. The population dynamics suggest the circuit mechanism underlying lateral inhibition and surround suppression may be supported by long‐range inhibitory neurons in the sSC .