Orthogonal micro-organization of orientation and spatial frequency in primate primary visual cortex

Abstract

Orientation and spatial frequency tuning are highly salient properties of neurons in primary visual cortex (V1). The combined organization of these particular tuning properties in the cortical space will strongly shape the V1 population response to different visual inputs, yet it is poorly understood. In this study, we used two-photon imaging in macaque monkey V1 to provide the first data demonstrating the 3D cell-by-cell layout of both spatial frequency and orientation tuning in large mammals. We first show that spatial frequency tuning is organized into highly structured maps that remain consistent across the depth of layer II/III, similar to orientation. Next, we show that orientation and spatial frequency maps are intimately related at the fine spatial scale observed with two-photon imaging. We find that not only do the map gradients have a striking tendency toward orthogonality, but they also co-vary negatively from cell-to-cell at the spatial scale of cortical columns.

Local domains of motor cortical activity revealed by fiber-optic calcium recordings in behaving nonhuman primates

“…As in other mammalian species (12,13,19), neuronal activity in the primate brain is associated with large Ca 2+ signals (8). The method used here is an improved and adapted technique that was initially used for recordings in the mouse brain (9).…”

“…This question cannot be easily addressed with the presently available techniques. Microelectrode recordings as well as two-photon imaging at the level of identified cells (8) report accurate information on the firing pattern of individual neurons, but do not allow a direct and comprehensive mapping of larger circuits. On the other hand, functional magnetic resonance imaging (fMRI) studies are strong in producing functional maps, but the spatial and temporal resolutions are still very limited.…”

“…Investigations in many animal species have demonstrated that action potential activity is closely reflected by such neuronal Ca 2+ signals (e.g., refs. 8,[11][12][13]. Thus, the use of optical-fiber-based recordings could shed light on the intrinsic functional organization of M1 circuits during the motor components of the somatosensory detection task (14,15) and other tasks requiring motor responses (1,3,(16)(17)(18).…”

What the fly’s nose tells the fly’s brain

“…I make the distinction between these two ways information is represented by comparing the mammalian visual cortex (V1) with the mushroom body. V1 has a retinotopic map of the visual world but, on a finer scale, this visual area has a pinwheel organization where neurons with the same orientation preference are found along the spokes of the pinwheel, and neurons with the same receptive field size (spatial frequency) are arranged in concentric rings around the pinwheel center (note that V1 neurons are jointly selective for orientation and spatial frequency) (22). This means that all of the information about one tiny patch of the visual world can be found in the neurons making up one pinwheel.…”

An Introduction to Neuroscientific Methods: Single-cell Recordings

“…Thus, the choice of appropriate animal model ultimately depends on the research question. Within the domain of cognitive neuroscience, it seems to us that non-human primates are still the obvious choice, given their overall similarity with humans, and the fact that many of the new techniques first developed in rodents are now applied to primates [45][46][47][48][49].…”