Auditory cortex projections target the peripheral field representation of primary visual cortex

AbstractUntil the late 20th Century, it was believed that different sensory modalities were processed by largely independent pathways in the primate cortex, with cross-modal integration only occurring in specialized polysensory areas. This model was challenged by the finding that the peripheral representation of the primary visual cortex (V1) receives monosynaptic connections from areas of the auditory cortex in the macaque. However, auditory projections to V1 have not been reported in other primates. We investigated the existence of direct interconnections between V1 and auditory areas in the marmoset, a New World monkey. Labelled neurons in auditory cortex were observed following 4 out of 10 retrograde tracer injections involving V1. These projections to V1 originated in the caudal subdivisions of auditory cortex (primary auditory cortex, caudal belt and parabelt areas), and targeted parts of V1 that represent parafoveal and peripheral vision. Injections near the representation of the vertical meridian of the visual field labelled few or no cells in auditory cortex. We also placed 8 retrograde tracer injections involving core, belt and parabelt auditory areas, none of which revealed direct projections from V1. These results confirm the existence of a direct, nonreciprocal projection from auditory areas to V1 in a different primate species, which has evolved separately from the macaque for over 30 million years. The essential similarity of these observations between marmoset and macaque indicate that early-stage audiovisual integration is a shared characteristic of primate sensory processing.

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Context-dependent signaling of coincident auditory and visual events in primary visual cortex

eLife ◽

10.7554/elife.44006 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 11

Author(s):

Thomas Deneux ◽

Evan R Harrell ◽

Alexandre Kempf ◽

Sebastian Ceballo ◽

Anton Filipchuk ◽

...

Keyword(s):

Visual Cortex ◽

Auditory Cortex ◽

Primary Visual Cortex ◽

Cell Types ◽

Dependent Manner ◽

Visual Responses ◽

Loud Sound ◽

Visual Events ◽

Dominant Feature ◽

Context Dependent

Detecting rapid, coincident changes across sensory modalities is essential for recognition of sudden threats or events. Using two-photon calcium imaging in identified cell types in awake, head-fixed mice, we show that, among the basic features of a sound envelope, loud sound onsets are a dominant feature coded by the auditory cortex neurons projecting to primary visual cortex (V1). In V1, a small number of layer 1 interneurons gates this cross-modal information flow in a context-dependent manner. In dark conditions, auditory cortex inputs lead to suppression of the V1 population. However, when sound input coincides with a visual stimulus, visual responses are boosted in V1, most strongly after loud sound onsets. Thus, a dynamic, asymmetric circuit connecting AC and V1 contributes to the encoding of visual events that are coincident with sounds.

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Uniformity and diversity of response properties of neurons in the primary visual cortex: Selectivity for orientation, direction of motion, and stimulus size from center to far periphery

Visual Neuroscience ◽

10.1017/s0952523813000448 ◽

2013 ◽

Vol 31 (1) ◽

pp. 85-98 ◽

Cited By ~ 15

Author(s):

HSIN-HAO YU ◽

MARCELLO G.P. ROSA

Keyword(s):

Visual Cortex ◽

Visual Field ◽

Primary Visual Cortex ◽

Spatial Information ◽

Visual Fields ◽

Receptive Fields ◽

Visual Space ◽

Central Visual Field ◽

Field Representation ◽

Response Properties

AbstractAlthough the primary visual cortex (V1) is one of the most extensively studied areas of the primate brain, very little is known about how the far periphery of visual space is represented in this area. We characterized the physiological response properties of V1 neurons in anaesthetized marmoset monkeys, using high-contrast drifting gratings. Comparisons were made between cells with receptive fields located in three regions of V1, defined by eccentricity: central (3–5°), near peripheral (5–15°), and far peripheral (>50°). We found that orientation selectivity of individual cells was similar from the center to the far periphery. Nonetheless, the proportion of orientation-selective neurons was higher in central visual field representation than in the peripheral representations. In addition, there were similar proportions of cells representing all orientations, with the exception of the representation of the far periphery, where we detected a bias favoring near-horizontal orientations. The proportions of direction-selective cells were similar throughout V1. When the center/surround organization of the receptive fields was tested with gratings with varying diameters, we found that the population of neurons that was suppressed by large gratings was smaller in the far periphery, although the strength of suppression in these cells tended to be stronger. In addition, the ratio between the diameters of the excitatory centers and suppressive surrounds was similar across the entire visual field. These results suggest that, superimposed on the broad uniformity of V1, there are subtle physiological differences, which indicate that spatial information is processed differently in the central versus far peripheral visual fields.

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