The use of m-sequences in the analysis of visual neurons: Linear receptive field properties

1997 ◽  
Vol 14 (6) ◽  
pp. 1015-1027 ◽  
Author(s):  
R. C. Reid ◽  
J. D. Victor ◽  
R. M. Shapley
Keyword(s):  
Receptive Field ◽  
Time Course ◽  
Receptive Fields ◽  
Response Dynamics ◽  
Visual Neurons ◽  
Response Properties ◽  
Time To Peak ◽  
M Sequence ◽  
Sequence Method ◽  
Time Courses

AbstractWe have used Sutter's (1987) spatiotemporal m-sequence method to map the receptive fields of neurons in the visual system of the cat. The stimulus consisted of a grid of 16 X 16 square regions, each of which was modulated in time by a pseudorandom binary signal, known as an m-sequence. Several strategies for displaying the m-sequence stimulus are presented. The results of the method are illustrated with two examples. For both geniculate neurons and cortical simple cells, the measurement of first-order response properties with the m-sequence method provided a detailed characterization of classical receptive-field structures. First, we measured a spatiotemporal map of both the center and surround of a Y-cell in the lateral geniculate nucleus (LGN). The time courses of the center responses was biphasic: OFF at short latencies, ON at longer latencies. The surround was also biphasic—ON then OFF—but somewhat slower. Second, we mapped the response properties of an area 17 directional simple cell. The response dynamics of the ON and OFF subregions varied considerably; the time to peak ranged over more than a factor of two. This spatiotemporal inseparability is related to the cell's directional selectivity (Reid et al., 1987, 1991; McLean & Palmer, 1989; McLean et al., 1994). The detail with which the time course of response can be measured at many different positions is one of the strengths of the m-sequence method.

scholarly journals Sodium and calcium currents in dispersed mammalian septal neurons.

1991 ◽  
Vol 97 (2) ◽  
pp. 303-320 ◽  
Author(s):  
A Castellano ◽  
J López-Barneo
Keyword(s):  
Time Constant ◽  
Time Course ◽  
Calcium Currents ◽  
Closing Time ◽  
Patch Clamp Technique ◽  
Average Value ◽  
Time To Peak ◽  
Time Courses ◽  
Fast Activation ◽  
Septal Neurons

Voltage-gated Na+ and Ca2+ conductances of freshly dissociated septal neurons were studied in the whole-cell configuration of the patch-clamp technique. All cells exhibited a large Na+ current with characteristic fast activation and inactivation time courses. Half-time to peak current at -20 mV was 0.44 +/- 0.18 ms and maximal activation of Na+ conductance occurred at 0 mV or more positive membrane potentials. The average value was 91 +/- 32 nS (approximately 11 mS cm-2). At all membrane voltages inactivation was well fitted by a single exponential that had a time constant of 0.44 +/- 0.09 ms at 0 mV. Recovery from inactivation was complete in approximately 900 ms at -80 mV but in only 50 ms at -120 mV. The decay of Na+ tail currents had a single time constant that at -80 mV was faster than 100 microseconds. Depolarization of septal neurons also elicited a Ca2+ current that peaked in approximately 6-8 ms. Maximal peak Ca2+ current was obtained at 20 mV, and with 10 mM external Ca2+ the amplitude was 0.35 +/- 0.22 nA. During a maintained depolarization this current partially inactivated in the course of 200-300 ms. The Ca2+ current was due to the activity of two types of conductances with different deactivation kinetics. At -80 mV the closing time constants of slow (SD) and fast (FD) deactivating channels were, respectively, 1.99 +/- 0.2 and 0.11 +/- 0.03 ms (25 degrees C). The two kinds of channels also differed in their activation voltage, inactivation time course, slope of the conductance-voltage curve, and resistance to intracellular dialysis. The proportion of SD and FD channels varied from cell to cell, which may explain the differential electrophysiological responses of intracellularly recorded septal neurons.

Receptive Field Size and Response Latency Are Correlated Within the Cat Visual Thalamus

2005 ◽  
Vol 93 (6) ◽  
pp. 3537-3547 ◽  
Author(s):  
Chong Weng ◽  
Chun-I Yeh ◽  
Carl R. Stoelzel ◽  
Jose-Manuel Alonso
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Response Latency ◽  
Time Course ◽  
Frequency Tuning ◽  
Receptive Fields ◽  
Cortical Cell ◽  
Field Size ◽  
Receptive Field Size ◽  
Spatial Frequency Tuning

Each point in visual space is encoded at the level of the thalamus by a group of neighboring cells with overlapping receptive fields. Here we show that the receptive fields of these cells differ in size and response latency but not at random. We have found that in the cat lateral geniculate nucleus (LGN) the receptive field size and response latency of neighboring neurons are significantly correlated: the larger the receptive field, the faster the response to visual stimuli. This correlation is widespread in LGN. It is found in groups of cells belonging to the same type (e.g., Y cells), and of different types (i.e., X and Y), within a specific layer or across different layers. These results indicate that the inputs from the multiple geniculate afferents that converge onto a cortical cell (approximately 30) are likely to arrive in a sequence determined by the receptive field size of the geniculate afferents. Recent studies have shown that the peak of the spatial frequency tuning of a cortical cell shifts toward higher frequencies as the response progresses in time. Our results are consistent with the idea that these shifts in spatial frequency tuning arise from differences in the response time course of the thalamic inputs.

Average but not continuous speed match between motoneurons and muscle units of rat tibialis anterior

1993 ◽  
Vol 70 (4) ◽  
pp. 1300-1306 ◽  
Author(s):  
R. Bakels ◽  
D. Kernell
Keyword(s):  
Tibialis Anterior ◽  
Time Course ◽  
Muscle Fibers ◽  
Total Duration ◽  
Medial Gastrocnemius ◽  
Tetanic Force ◽  
Time To Peak ◽  
Time Courses ◽  
Isometric Twitch ◽  
Fatigue Sensitivity

1. Properties of single motoneuron/muscle-unit combinations were determined for tibialis anterior (TA) in rats anesthetized with pentobarbital. The TA observations were systematically compared with those obtained earlier by the use of the same techniques from rat medial gastrocnemius (MG). 2. TA motoneurons were investigated with regard to afterhyperpolarization (AHP; total duration 32-74 ms, amplitude 0.39-4.96 mV) and axonal conduction velocity (41-79 m/s). TA muscle-unit measurements included the time course of the isometric twitch (time-to-peak force 10.8-18.0 ms; total duration 42-92 ms), the maximum tetanic force (22-217 mN), and a measure of fatigue sensitivity (fatigue index 5-100%). The range of twitch and AHP durations ("speed range") was markedly smaller in the present TA material than for MG. 3. The mean duration of the TA motoneuronal AHP (49 +/- 8 ms, mean +/- SD) was close to that of its muscle-unit twitch (56 +/- 12 ms). Thus an "average" speed match existed between TA motoneurons and their muscle fibers. 4. For TA there was no correlation between the time courses of AHP and twitch. Thus there was for TA no "continuous" speed match between the motoneurons and their muscle fibers. 5. For TA twitches or AHPs studied separately, there was a significant correlation between different time course measures. Furthermore, compared with TA units having relatively fast twitches, those with slower twitches tended to show 1) a smaller maximum tetanic force and 2) a greater AHP amplitude. Fatigue-resistant units tended to have slower twitches than fatigue-sensitive ones.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Development of Thalamocortical Response Transformations in the Rat Whisker-Barrel System

2008 ◽  
Vol 99 (1) ◽  
pp. 356-366 ◽  
Author(s):  
Michael Shoykhet ◽  
Daniel J. Simons
Keyword(s):  
Cortical Neurons ◽  
Time Course ◽  
Receptive Fields ◽  
Second Phase ◽  
Adult Rats ◽  
Response Latencies ◽  
Thalamic Neurons ◽  
Response Properties ◽  
Temporal Domain

Extracellular single-unit recordings were used to characterize responses of thalamic barreloid and cortical barrel neurons to controlled whisker deflections in 2, 3-, and 4-wk-old and adult rats in vivo under fentanyl analgesia. Results indicate that response properties of thalamic and cortical neurons diverge during development. Responses to deflection onsets and offsets among thalamic neurons mature in parallel, whereas among cortical neurons responses to deflection offsets become disproportionately smaller with age. Thalamic neuron receptive fields become more multiwhisker, whereas those of cortical neurons become more single-whisker. Thalamic neurons develop a higher degree of angular selectivity, whereas that of cortical neurons remains constant. In the temporal domain, response latencies decrease both in thalamic and cortical neurons, but the maturation time-course differs between the two populations. Response latencies of thalamic cells decrease primarily between 2 and 3 wk of life, whereas response latencies of cortical neurons decrease in two distinct steps—the first between 2 and 3 wk of life and the second between the fourth postnatal week and adulthood. Although the first step likely reflects similar subcortical changes, the second phase likely corresponds to developmental myelination of thalamocortical fibers. Divergent development of thalamic and cortical response properties indicates that thalamocortical circuits in the whisker-to-barrel pathway undergo protracted maturation after 2 wk of life and provides a potential substrate for experience-dependent plasticity during this time.

Visual Response Properties of Neurons in the LGN of Normally Reared and Visually Deprived Macaque Monkeys

2001 ◽  
Vol 85 (5) ◽  
pp. 2111-2129 ◽  
Author(s):  
Jonathan B. Levitt ◽  
Robert A. Schumer ◽  
S. Murray Sherman ◽  
Peter D. Spear ◽  
J. Anthony Movshon
Keyword(s):  
Receptive Field ◽  
Receptive Fields ◽  
Optic Chiasm ◽  
Monocular Deprivation ◽  
Specific Cell ◽  
Visual Response ◽  
Response Latencies ◽  
Macaque Monkeys ◽  
Response Properties ◽  
Parvocellular Neurons

It is now well appreciated that parallel retino-geniculo-cortical pathways exist in the monkey as in the cat, the species in which parallel visual pathways were first and most thoroughly documented. What remains unclear is precisely how many separate pathways pass through the parvo- and magnocellular divisions of the macaque lateral geniculate nucleus (LGN), what relationships—homologous or otherwise—these pathways have to the cat's X, Y, and W pathways, and whether these are affected by visual deprivation. To address these issues of classification and trans-species comparison, we used achromatic stimuli to obtain an extensive set of quantitative measurements of receptive field properties in the parvo- and magnocellular laminae of the LGN of nine macaque monkeys: four normally reared and five monocularly deprived of vision by lid suture near the time of birth. In agreement with previous studies, we find that on average magnocellular neurons differ from parvocellular neurons by having shorter response latencies to optic chiasm stimulation, greater sensitivity to luminance contrast, and better temporal resolution. Magnocellular laminae are also distinguished by containing neurons that summate luminance over their receptive fields nonlinearly (Y cells) and whose temporal response phases decrease with increasing stimulus contrast (indicative of a contrast gain control mechanism). We found little evidence for major differences between magno- and parvocellular neurons on the basis of most spatial parameters except that at any eccentricity, the neurons with the smallest receptive field centers tended to be parvocellular. All parameters were distributed unimodally and continuously through the parvo- and magnocellular populations, giving no indications of subpopulations within each division. Monocular deprivation led to clear anatomical effects: cells in deprived-eye laminae were pale and shrunken compared with those in nondeprived eye laminae, and Cat-301 immunoreactivity in deprived laminae was essentially uniformly abolished. However, deprivation had only subtle effects on the response properties of LGN neurons. Neurons driven by the deprived eye in both magno- and parvocellular laminae had lower nonlinearity indices (i.e., summed signals across their receptive fields more linearly) and were somewhat less responsive. In magnocellular laminae driven by the deprived eye, neuronal response latencies to stimulation of the optic chiasm were slightly shorter than those in the nondeprived laminae, and receptive field surrounds were a bit stronger. No other response parameters were affected by deprivation, and there was no evidence for loss of a specific cell class as in the cat.

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

1993 ◽  
Vol 69 (4) ◽  
pp. 1091-1117 ◽  
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)

scholarly journals Differences in the Time Course of Short-Term Depression Across Receptive Fields Are Correlated With Directional Selectivity in Electrosensory Neurons

2009 ◽  
Vol 102 (6) ◽  
pp. 3270-3279 ◽  
Author(s):  
Maurice J. Chacron ◽  
Natalia Toporikova ◽  
Eric S. Fortune
Keyword(s):  
Time Course ◽  
Moving Objects ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Weakly Electric Fish ◽  
Common Mechanism ◽  
Directional Selectivity ◽  
Short Term ◽  
Nervous Systems ◽  
Time Courses

Directional selectivity, in which neurons respond preferentially to one direction of movement (“preferred”) over the opposite direction (“null”), is a critical computation that is found in the nervous systems of many animals. Here we show the first experimental evidence for a correlation between differences in short-term depression and direction-selective responses to moving objects. As predicted by quantitative models, the observed differences in the time courses of short-term depression at different locations within receptive fields were correlated with measures of direction selectivity in awake, behaving weakly electric fish ( Apteronotus leptorhynchus ). Because short-term depression is ubiquitous in the central nervous systems of vertebrate animals, it may be a common mechanism used for the generation of directional selectivity and other spatiotemporal computations.

Receptive-field properties of neurons in binocular and monocular segments of striate cortex in cats raised with binocular lid suture

1978 ◽  
Vol 41 (2) ◽  
pp. 322-337 ◽  
Author(s):  
D. W. Watkins ◽  
J. R. Wilson ◽  
S. M. Sherman
Keyword(s):  
Receptive Field ◽  
Cortical Neurons ◽  
Striate Cortex ◽  
Ocular Dominance ◽  
Visual Stimuli ◽  
Receptive Fields ◽  
Total Sample ◽  
Orientation Selectivity ◽  
Peak Response ◽  
Response Properties

1. We studied the receptive fields of 171 striate cortical neurons from 17 cats raised with binocular lid suture. Of these, 102 fields were within 10 degrees of the area centralis and the remaining 69 were at least 38 degrees from the vertical meridian. 2. Based on their different response properties, cells were divided into three broad groups: the mappable cells (49%) had clearly defined receptive fields, the unmappable cells (31%) were activated by visual stimuli but had diffuse fields which could not be hand plotted, and the visually inexcitable cells (20%) could not be activated by visual stimuli. Very few (less than or equal to 12% of the total sample) normal simple or complex cells could be found. 3. Orientation selectivity was assessed in these cells. Only 12% displayed orientation selectivity within normal bounds, and these were all mappable cells. None of the unmappable cells had discernible orientation selectivity. 4. Ocular dominance was assessed for 62 of the centrally located receptive fields. Among mappable cells, there was an abnormally low proportion of binocular fields, while no such abnormality was seen for unmappable cells. 5. For 47 of the neurons, average response histograms were compiled for moving stimuli of various parameters in an effort to evoke the maximum discharge or peak response. This peak response was normal for mappable cells but reduced for unmappable cells. 6. We devised a technique for studying potential inhibitory receptive-field zones in these neurons, validated the method in normal striate cortex, and used it to test 20 mappable cells in the lid-sutured cats. None showed the pattern of strong inhibitory side bands seen in normal simple cells, although six showed weak or abnormal inhibitory zones. Interestingly, six of the seven visually inexcitable cells tested by this method had purely inhibitory receptive fields. 7. The effects of binocular suture were essentially identical for the binocular and monocular segments since the cell types and their response properties did not differ between these two areas of cortex. Furthermore, the cortical monocular segments of these cats seemed qualitatively different from the deprived cortical monocular segment after monocular suture. This extends an analogous difference for these cats reported for the monocular segments of the lateral geniculate nucleus. We thus conclude that monocularly and binocularly sutured cats develop by qualitatively different mechanisms. For the former, competition between central synapses related to each eye is a prominent feature of geniculocortical development, whereas, for the latter, such specific forms of geniculocortical development may not obtain.

Effects of neonatal enucleation on receptive-field properties of visual neurons in superior colliculus of the golden hamster

1980 ◽  
Vol 43 (3) ◽  
pp. 595-611 ◽  
Author(s):  
R. W. Rhoades ◽  
L. M. Chalupa
Keyword(s):  
Receptive Field ◽  
Receptive Fields ◽  
Field Size ◽  
Directional Selectivity ◽  
Visual Responses ◽  
Visual Neurons ◽  
Retinotectal Projection ◽  
Visual Cells ◽  
Response Characteristics ◽  
Tectal Neurons

1. Monocular enucleation in infant hamsters results in a marked expansion of the normally very limited ipsilateral retinotectal projection (13). In 34 hamsters subjected to removal of one eye within 12 h of birth, the receptive-field characteristics of superior collicular neurons ipsilateral and contralateral to the remaining eye were investigated quantitatively and compared to those of normal animals. In six additional neonatal enucleates, the density of the expanded retinotectal projection was studied with the autoradiographic method and an attempt was made to relate the anatomical reorganization with the electrophysiological findings, 2. The response characteristics of visual cells in the colliculus contralateral to the remaining eye were not significantly different from those observed in normal animals. In the ipsilateral tectum, however, numerous changes were observed. Visual receptive fields were abnormally large. The incidence of directional selectivity was markedly reduced, as were the magnitudes of the discharges elicited by either flashed or moving stimuli. Fewer cells were activated by small flashed spots and most of the units that were responsive to such stimulation failed to exhibit the surround suppression typical for the majority of tectal neurons in normal hamsters. Most cells in the ipsilateral colliculus responded only to relatively low (less than 50 degrees/s) stimulus velocities and response decrements resulting from repeated stimulation also occurred much more readily for the neurons tested on this side. 3. The results of additional experiments in neonatal enucleates (n = 8), which were also subjected to acute bilateral removal of the visual cortex, demonstrated that such damage resulted in a marked reduction in the incidence of directional selectivity in the colliculus contralateral to the remaining eye but had no effect on the responses of cells innervated by the aberrant ipsilateral pathway. 4. A correlation between the relative density of the ipsilateral retinal projection at different points in the colliculus, as demonstrated by the autroradiography and the nature of the visual responses obtained in different portions of the structure, indicated that receptive-field size was negatively correlated with the density of the aberrant retinotectal projection and that absolute responsivity (number of impulses elicited by an optimal stimulus) was positively correlated with autoradiographic grain density. 5. These findings demonstrate that while the aberrant retinocollicular projection can, along with the other visual inputs to the tectum, result in the organization of normal response properties for a small number of tectal neurons, the majority of the visual cells innervated by this pathway have responses that are appreciably different from normal.

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