Space-Time receptive ﬁelds in the optic tectum of the chicken (Gallus gallus)

ABSTRACTInhibitory neurons in the midbrain spatial attention network, called isthmi pars magnocellularis (Imc), control stimulus selection by the sensorimotor and attentional hub, the optic tectum (OT). Here, we investigate in the barn owl how classical as well as extraclassical (global) inhibitory surrounds of Imc receptive fields (RFs), fundamental units of Imc computational function, are constructed. We find that focal, reversible blockade of GABAergic input onto Imc neurons disconnects their extraclassical inhibitory surrounds, but, surprisingly, leaves intact their classical surrounds. Subsequently, with paired recordings and iontophoresis, first at spatially aligned site-pairs in Imc and OT, and then, at mutually distant site-pairs within Imc, we demonstrate that classical inhibitory surrounds of Imc RFs are inherited from OT, but their extraclassical inhibitory surrounds are constructed within Imc. These results reveal key design principles of the midbrain spatial attention circuit, and attest to the critical importance of competitive interactions within Imc for its operation.

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Hearing Impairment Induces Frequency-Specific Adjustments in Auditory Spatial Tuning in the Optic Tectum of Young Owls

Journal of Neurophysiology ◽

10.1152/jn.1999.82.5.2197 ◽

1999 ◽

Vol 82 (5) ◽

pp. 2197-2209 ◽

Cited By ~ 24

Author(s):

Joshua I. Gold ◽

Eric I. Knudsen

Keyword(s):

Optic Tectum ◽

Frequency Tuning ◽

Receptive Fields ◽

Dependent Manner ◽

Frequency Dependent ◽

Auditory Space ◽

Spatial Tuning ◽

Auditory Experience ◽

Tectal Neurons ◽

Interaural Level Differences

Bimodal, auditory-visual neurons in the optic tectum of the barn owl are sharply tuned for sound source location. The auditory receptive fields (RFs) of these neurons are restricted in space primarily as a consequence of their tuning for interaural time differences and interaural level differences across broad ranges of frequencies. In this study, we examined the extent to which frequency-specific features of early auditory experience shape the auditory spatial tuning of these neurons. We manipulated auditory experience by implanting in one ear canal an acoustic filtering device that altered the timing and level of sound reaching the eardrum in a frequency-dependent fashion. We assessed the auditory spatial tuning at individual tectal sites in normal owls and in owls raised with the filtering device. At each site, we measured a family of auditory RFs using broadband sound and narrowband sounds with different center frequencies both with and without the device in place. In normal owls, the narrowband RFs for a given site all included a common region of space that corresponded with the broadband RF and aligned with the site's visual RF. Acute insertion of the filtering device in normal owls shifted the locations of the narrowband RFs away from the visual RF, the magnitude and direction of the shifts depending on the frequency of the stimulus. In contrast, in owls that were raised wearing the device, narrowband and broadband RFs were aligned with visual RFs so long as the device was in the ear but not after it was removed, indicating that auditory spatial tuning had been adaptively altered by experience with the device. The frequency tuning of tectal neurons in device-reared owls was also altered from normal. The results demonstrate that experience during development adaptively modifies the representation of auditory space in the barn owl's optic tectum in a frequency-dependent manner.

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Spatiotemporal organization of simple-cell receptive fields in the cat's striate cortex. I. General characteristics and postnatal development

Journal of Neurophysiology ◽

10.1152/jn.1993.69.4.1091 ◽

1993 ◽

Vol 69 (4) ◽

pp. 1091-1117 ◽

Cited By ~ 246

Author(s):

G. C. DeAngelis ◽

I. Ohzawa ◽

R. D. Freeman

Keyword(s):

Receptive Field ◽

Postnatal Development ◽

Striate Cortex ◽

Receptive Fields ◽

Space Time ◽

Field Structure ◽

Temporal Response ◽

Spatial Frequencies ◽

Spatiotemporal Receptive Field ◽

Time Courses

1. Most studies of cortical neurons have focused on the spatial structure of receptive fields. For a more complete functional description of these neurons, it is necessary to consider receptive-field structure in the joint domain of space and time. We have studied the spatiotemporal receptive-field structure of 233 simple cells recorded from the striate cortex of adult cats and kittens at 4 and 8 wk postnatal. The dual goal of this study is to provide a detailed quantitative description of spatiotemporal receptive-field structure and to compare the developmental time courses of spatial and temporal response properties. 2. Spatiotemporal receptive-field profiles have been measured with the use of a reverse correlation method, in which we compute the cross-correlation between a neuron's response and a random sequence of small, briefly presented bright and dark stimuli. The receptive-field profiles of some simple cells are space-time separable, meaning that spatial and temporal response characteristics can be dissociated. Other cells have receptive-field profiles that are space-time inseparable. In these cases, a particular spatial location cannot be designated, unambiguously, as belonging to either an on or off subregion. However, separate on and off subregions may be clearly distinguished in the joint space-time domain. These subregions are generally tilted along an oblique axis. 3. Our observations show that spatial and temporal aspects of receptive-field structure mature with clearly different time courses. By 4 wk postnatal, the spatial symmetry and periodicity of simple-cell receptive fields have reached maturity. The spatial extent (or size) of these receptive fields is adult-like by 8 wk postnatal. In contrast, the response latency and time duration of spatiotemporal receptive fields do not mature until well beyond 8 wk postnatal. 4. By applying Fourier analysis to spatiotemporal receptive-field profiles, we have examined the postnatal development of spatial and temporal selectivity in the frequency domain. By 8 wk postnatal, spatial frequency tuning has clearly reached maturity. On the contrary, temporal frequency selectivity remains markedly immature at 8 wk. We have also examined the joint distribution of optimal spatial and temporal frequencies. From 4 wk postnatal until 8 wk postnatal, the range of optimal spatial frequencies increases substantially, whereas the range of optimal temporal frequencies remains largely unchanged. From 8 wk postnatal until adulthood, there is a large increase in optimal temporal frequencies for cells tuned to low spatial frequencies. For cells tuned to high spatial frequencies, the distribution of optimal temporal frequencies does not change much beyond 8 wk postnatal.(ABSTRACT TRUNCATED AT 400 WORDS)

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Visual receptive fields of single cells in the pigeon's optic tectum

Brain Research ◽

10.1016/0006-8993(72)90136-9 ◽

1972 ◽

Vol 40 (2) ◽

pp. 303-317 ◽

Cited By ~ 75

Author(s):

Dora Jassik-Gerschenfeld ◽

Jack Guichard

Keyword(s):

Optic Tectum ◽

Single Cells ◽

Receptive Fields ◽

Visual Receptive Fields

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Synaptic and intrinsic mechanisms underlying development of cortical direction selectivity

10.1101/776534 ◽

2019 ◽

Author(s):

Arani Roy ◽

Jason J. Osik ◽

Benyamin Meschede-Krasa ◽

Wesley Alford ◽

Daniel P. Leman ◽

...

Keyword(s):

Neural Circuits ◽

Receptive Fields ◽

Direction Selectivity ◽

Space Time ◽

Input Output ◽

Intrinsic Properties ◽

Temporal Dimension ◽

Spatiotemporal Receptive Fields ◽

Activity Dependent ◽

Mixed Mechanism

AbstractSome neural circuits are constructed through an overproduction of initial connections followed by activity-dependent refinement. Under this paradigm, functional receptive fields would be expected to be narrowed from a diffuse immature condition to a sharper mature condition. Alternatively, neural activity might lead to formation of new connections, leading to expansion of an initially compact receptive field. In the simple cells of the ferret visual cortex undergoing developmental enhancement of direction selectivity, we found evidence for a mixed mechanism: an expansion of the spatiotemporal receptive fields along the temporal dimension combined with a narrowing in space-time through a marked loss of inputs with certain space-time selectivities. Further, the resulting increase in subthreshold direction selectivity was accompanied by increases in near-spike-threshold excitability and input-output gain that resulted in dramatically increased spiking responses. Increases in subthreshold membrane responses and the increased input-output spiking gain were both necessary to explain firing rates in experienced ferrets. These results demonstrate that cortical direction selectivity develops through a combination of plasticity in synaptic and cell-intrinsic properties.

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