Receptive field

About: Receptive field is a research topic. Over the lifetime, 8537 publications have been published within this topic receiving 596428 citations.

Estimating spatio-temporal receptive fields of auditory and visual neurons from their responses to natural stimuli.

Abstract: We present a generalized reverse correlation technique that can be used to estimate the spatio-temporal receptive fields (STRFs) of sensory neurons from their responses to arbitrary stimuli such as auditory vocalizations or natural visual scenes. The general solution for STRF estimation requires normalization of the stimulus-response cross-correlation by the stimulus autocorrelation matrix. When the second-order stimulus statistics are stationary, normalization involves only the diagonal elements of the Fourier-transformed auto-correlation matrix (the power spectrum). In the non-stationary case normalization requires the entire auto-correlation matrix. We present modelling studies that demonstrate the feasibility and accuracy of this method as well as neurophysiological data comparing STRFs estimated using natural versus synthetic stimulus ensembles. For both auditory and visual neurons, STRFs obtained with these different stimuli are similar, but exhibit systematic differences that may be functionally significant. This method should be useful for determining what aspects of natural signals are represented by sensory neurons and may reveal novel response properties of these neurons.

Dynamic representation of whisker deflection by synaptic potentials in spiny stellate and pyramidal cells in the barrels and septa of layer 4 rat somatosensory cortex.

Abstract: The elaborate morphology of cortical neurons has been established for a long time (Ramon y Cajal, 1893), yet the functional significance of the differences in the architecture of the dendritic and axonal arbors of cells located in the same or different cortical layers is still unclear. Layer 4 of rodent somatosensory cortex is divided cytoarchitectonically into barrels with a high density of neurons, and septa between barrels with a lower density (Woolsey & Van der Loos, 1970). Barrel cells are targeted by thalamic inputs from the ventral posterior medial nucleus (VPM; for review see Diamond, 1995) while septum cells are innervated by thalamic afferents projecting from the posterior medial nucleus (PoM; for review see Kim & Ebner, 1999). A functional equivalent of the cytoarchitectonically defined barrels are the barrel-columns, ensembles of cells in the different cortical layers which share functional properties such as a response preference for the deflection of a particular whisker. The receptive fields (RFs) of barrel-column cells are characterised by a dominant input from a principal whisker (PW) and weaker inputs from surround whiskers (SuW). In L4 the barrel-columns correspond in their dimensions roughly to barrels (Welker, 1976). Barrel borders can be visualised simultaneously with the dendritic morphology of individual cells (Ito, 1992), and both the laminar location of a cell's soma and the spread of dendrites and axon collaterals can be determined relative to the barrel borders. Thus possible anatomical determinants of RF structure, such as the geometry of the dendritic and axonal arbor can be delineated. Spiny stellate cells are confined to the borders of barrels and their dendritic arbor is asymmetric (Woolsey et al. 1975; Simons & Woolsey 1984; Feldmeyer et al. 1999; Lubke et al. 2000). They relay thalamic output to other cortical layers via axon collaterals projecting to L2/3 and to L5 or L6. Although most anatomical studies on L4 neurons have focused on spiny stellate cells, pyramidal neurons have also been described in somatosensory (Lorente de No, 1922; Elston et al. 1997; Lubke et al. 2000) and in visual cortex (Martin & Whitteridge, 1984). In the somatosensory cortex neurons in layer 4 are selective in their responses to the direction of whisker deflection and they respond with short latency. Their RF structure is somewhat controversial, however. Intracellular recordings with microelectrodes (Carvel & Simons, 1988) and more recently, whole-cell voltage recordings have demonstrated afferent inputs from several whiskers and large subthreshold RFs (Moore & Nelson, 1998; Zhu & Connors, 1999). Most (Simons, 1995) but not all (Armstrong-James, 1995) extracellular unit-recording studies report small, often single-whisker RFs. In addition multielectrode unit recordings indicate that RF properties are time dependent (Petersen & Diamond, 2000). We report in vivo whole-cell voltage recordings combined with morphological reconstruction of the recorded neurons and determination of their columnar position. The aim was to establish firstly the dependency of RF structure on the geometry of dendritic and axonal arborisation of the different classes of neurons to identify possible constraints of RF structure given by cell morphology. Secondly we wanted to determine possible relationships between a cell's location and morphology and the time dependent structure of sub- and suprathreshold RFs. Such relations are essential to elucidate how different tactile object cues are represented at the input (PSPs) and the output stage (APs) of specific ensembles of cells in the cortical input layer.

Visual behaviour mediated by retinal projections directed to the auditory pathway

Abstract: An unresolved issue in cortical development concerns the relative contributions of intrinsic and extrinsic factors to the functional specification of different cortical areas. Ferrets in which retinal projections are redirected neonatally to the auditory thalamus have visually responsive cells in auditory thalamus and cortex, form a retinotopic map in auditory cortex and have visual receptive field properties in auditory cortex that are typical of cells in visual cortex. Here we report that this cross-modal projection and its representation in auditory cortex can mediate visual behaviour. When light stimuli are presented in the portion of the visual field that is 'seen' only by this projection, 'rewired' ferrets respond as though they perceive the stimuli to be visual rather than auditory. Thus the perceptual modality of a neocortical region is instructed to a significant extent by its extrinsic inputs. In addition, gratings of different spatial frequencies can be discriminated by the rewired pathway, although the grating acuity is lower than that of the normal visual pathway.

Receptive fields of optic nerve fibres in the spider monkey.

Abstract: Our present knowledge ofhow mammalian retinal ganglion-cell receptive fields are organized is based mainly on findings in the cat by Kuffler (1953). These results have since been confirmed and extended (Barlow, FitzHugh & Kuffler, 1957; Hubel, 1960; Wiesel, 1960), but up to now similar studies have not been made in primates. The retina of the monkey is of interest, since in most species, including Ateles (spider monkey) and Macaca mulatta, it is deeply pigmented and has a well defined fovea. It appears to be much closer to the human retina than to that of the cat, which has a highly reflectile tapetum and lacks a fovea. The purpose of this report is to describe the receptive fields of single optic nerve fibres in the spider monkey. In view of the monkey's ability to discriminate colours, some observations were also made on ganglion cell responses to monochromatic stimuli.

A bimodal map of space: somatosensory receptive fields in the macaque putamen with corresponding visual receptive fields

Abstract: The macaque putamen contains neurons that respond to somatosensory stimuli such as light touch, joint movement, or deep muscle pressure. Their receptive fields are arranged to form a map of the body. In the face and arm region of this somatotopic map we found neurons that responded to visual stimuli. Some neurons were bimodal, responding to both visual and somatosensory stimuli, while others were purely visual, or purely somatosensory. The bimodal neurons usually responded to light cutaneous stimulation, rather than to joint movement or deep muscle pressure. They responded to visual stimuli near their tactile receptive field and were not selective for the shape or the color of the stimuli. For cells with tactile receptive fields on the face, the visual receptive field subtended a solid angle extending from the tactile receptive field to about 10 cm. For cells with tactile receptive fields on the arm, the visual receptive field often extended further from the animal. These bimodal properties provide a map of the visual space that immediately surrounds the monkey. The map is organized somatotopically, that is, by body part, rather than retinotopical ly as in most visual areas. It could function to guide movements in the animal's immediate vicinity. Cortical areas 6, 7b, and VIP contain bimodal cells with very similar properties to those in the putamen. We suggest that the bimodal cells in area 6, 7b, VIP, and the putamen form part of an interconnected system that represents extrapersonal space in a somatotopic fashion.