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At least 811 records · Page 45Linked to original sources
PubMed1994

Laminar selectivity of the cholinergic suppression of synaptic transmission in rat hippocampal region CA1: computational modeling and brain slice physiology.

ACh may set the dynamics of cortical function to those appropriate for learning new information. In models of the putative associative memory function of piriform cortex, selective suppression of intrinsic but not afferent fiber synaptic transmission by ACh prevents recall of previous input from interfering with the learning of new input (Hasselmo, 1993). Selective cholinergic suppression may play a similar role in the hippocampal formation, where Schaffer collateral synapses in stratum radiatum (s. rad) may store associations between activity in region CA3 and the entorhinal cortex input to region CA1 terminating in stratum lacunosum-moleculare (s. l-m). A computational model of region CA1 predicts that for effective associative memory function of the Schaffer collaterals, cholinergic suppression of synaptic transmission should be stronger in s. rad than in s. l-m. In the hippocampal slice preparation, we tested the effect of the cholinergic agonist carbachol (0.01-500 microM) on synaptic transmission in s. rad and s. l-m. Stimulating and recording electrodes were simultaneously placed in both layers, allowing analysis of the effect of carbachol on synaptic potentials in both layers during the same perfusion in each slice. Carbachol produced a significantly stronger suppression of stimulus-evoked EPSPs in s. rad than in s. l-m at all concentrations greater than 1 microM. At 100 microM, EPSP initial slopes were suppressed by 89.1 +/- 3.0% in s. rad, but only by 40.1 +/- 4.1% in s. l-m. The muscarinic antagonist atropine (1 microM) blocked cholinergic suppression in both layers. These data support the hypothesis that synaptic modification of the Schaffer collaterals may store associations between activity in region CA3 and the afferent input to region CA1 from the entorhinal cortex. In simulations, feedback regulation of cholinergic modulation based on activity in region CA1 sets the appropriate dynamics of learning for novel associations, and recall for familiar associations.

Animals↗
PubMed1995

Whole body metabolism is not restricted to D-sugars because energy metabolism of L-sugars fits a computational model in rats.

Can L-sugars contribute to whole body energy metabolism? Energy balance studies were undertaken in rats fed L-sugars at a rate of 10 g/100 g basal diet. Partial metabolizable energy values (MEVp) during the last 28 of 56 d while consuming the L-sugar diets showed that L-glucose contributed no energy (0.3 +/- 0.9 kJ/g, P > 0.5, mean +/- SEM), whereas L-fructose and L-glucose contributed 6.9 +/- 0.9 (P < 0.001) and 8.8 +/- 1.8 (P < 0.001) kJ/g, respectively. Over periods from 0 to 28 and 0 to 56 d of L-sugar treatment, measurements were made of energy intake, the average lean mass of animals, fat and lean mass deposition. Using these measurements and a computational model, estimates were made of each supplement's net metabolizable energy value for maintenance (NEVs). These estimates confirmed the supply of energy from L-fructose, with NEVs of 5.6 +/- 3.2 (P < 0.32) and 6.1 +/- 1.7 (P < 0.01) kJ/g over 28 and 56 d, respectively, and L-gulose with NEVs of 10.2 +/- 3.4 (P < 0.01) and 11.4 +/- 1.8 (P < 0.001) kJ/g over 28 and 56 d, respectively. A lack of energy supply from L-glucose was confirmed with NEVs of -2.6 +/- 3.2 (P > 0.5) and 0.0 +/- 1.6 (P > 0.5) kJ/g over 28 and 56 d, respectively. As reference substrates, sucrose and cellulose gave expected energy values in all determinations. Methods comparison analysis showed no differences between MEVp and NEVS. The assimilation of energy from L-fructose and L-gulose is probably via large bowl microorganisms. These observations show that L-gulose and L-fructose contribute to whole body energy metabolism while L-glucose does not.

Animals↗
PubMed1998

First- and second-order motion perception in Gabor micropattern stimuli: psychophysics and computational modelling.

This paper examines the perception of first- and second-order motion in human vision. In an extension of previous work by Boulton and Baker [J.B. Boulton, C.L. Baker, Motion detection is dependent on spatial frequency not size, Vision Res., 31 (1991) 77-87; J.B. Boulton, C.L. Baker, Different parameters control motion perception above and below a critical density, Vision Res., 33 (1993) 1803-1811], the direction of two-frame apparent motion is measured for stimuli composed of Gabor or Gaussian micropatterns. Three conditions are investigated. Condition 1 is that used by Boulton and Baker, in which motion is defined by the displacement of Gabor micropatterns. In condition 2, motion is defined by the displacement of Gaussian micropatterns. In condition 3, the envelopes of Gabor micropatterns are displaced while their carriers remain static. Using sparsely distributed micropatterns, direction judgements in all three conditions are determined by the spacing of the micropatterns. With a dense stimulus, direction judgements vary as a function of displacement in qualitatively different ways for the three conditions. The psychophysical results are predicted by a two-channel computational model. In one channel, motion is calculated directly from stimulus luminance, while in the other it is preceded by a texture-grabbing operation. The relative activities of the two channels dictates which governs direction judgements for any given stimulus.

Computer Simulation↗
PubMed2001

Stem design and dislocation after revision total hip arthroplasty: clinical results and computer modeling.

The effect of the size and shape of the neck and the taper of the femoral stem on dislocation rate after revision total hip arthroplasty was examined. Design I had a large (14/16), long taper with a circular neck cross-section; a fixed 42-mm offset; and a neck that was anteverted relative to the stem. Design II was characterized by a smaller (12/14), shorter taper; a trapezoidal neck cross-section; a progressive (40-50 mm) offset; and no neck anteversion relative to the stem. The stems were digitized and placed through a range of motion using virtual reality software, and the cross-sectional area of the neck, length of the taper, and total arc of motion before impingement between the neck and liner were compared. The dislocation rate at a minimum of 2 years' follow-up was 15.4% (8 of 52) for design I compared with 4.3% (2 of 46) for design II. This finding was consistent with the results of computer modeling, which showed that design I had a cross-sectional area that was 32% greater and a total arc of motion that was 76% less compared with design II. The results suggest that neck and taper design may be an important factor in dislocation after revision total hip arthroplasty.

Arthroplasty, Replacement, Hip↗
PubMed2006

Computational models for neurogenic gene expression in the Drosophila embryo.

The early Drosophila embryo is emerging as a premiere model system for the computational analysis of gene regulation in development because most of the genes, and many of the associated regulatory DNAs, that control segmentation and gastrulation are known. The comprehensive elucidation of Drosophila gene networks provides an unprecedented opportunity to apply quantitative models to metazoan enhancers that govern complex patterns of gene expression during development. Models based on the fractional occupancy of defined DNA binding sites have been used to describe the regulation of the lac operon in E. coli and the lysis/lysogeny switch of phage lambda. Here, we apply similar models to enhancers regulated by the Dorsal gradient in the ventral neurogenic ectoderm (vNE) of the early Drosophila embryo. Quantitative models based on the fractional occupancy of Dorsal, Twist, and Snail binding sites raise the possibility that cooperative interactions among these regulatory proteins mediate subtle differences in the vNE expression patterns. Variations in cooperativity may be attributed to differences in the detailed linkage of Dorsal, Twist, and Snail binding sites in vNE enhancers. We propose that binding site occupancy is the key rate-limiting step for establishing localized patterns of gene expression in the early Drosophila embryo.

Animals↗
PubMed1999

Dual intracellular recordings and computational models of slow inhibitory postsynaptic potentials in rat neocortical and hippocampal slices.

Dual intracellular recordings in slices of adult rat neocortex and hippocampus investigated slow, putative GABA(B) receptor-mediated inhibitory postsynaptic potentials. In most pairs tested in which the interneuron elicited a fast inhibitory postsynaptic potential in the pyramid, this GABA(A) receptor mediated inhibitory postsynaptic potential was entirely blocked by bicuculline or picrotoxin (3:3 in neocortex, 6:8 in CA1, all CA1 basket cells), even when high-frequency presynaptic spike trains were elicited. However, in three of 85 neocortical paired recordings involving an interneuron, although no discernible response was elicited by single presynaptic interneuronal spikes, a long latency (> or =20 ms) inhibitory postsynaptic potential was elicited by a train of > or =3 spikes at frequencies > or =50-100 Hz. This slow inhibitory postsynaptic potential was insensitive to bicuculline (one pair tested). In neocortex, slow inhibitory postsynaptic potential duration reached a maximum of 200 ms even with prolonged presynaptic spike trains. In contrast, summing fast, GABA(A) inhibitory postsynaptic potentials, elicited by spike trains, lasted as long as the train. Between four and 10 presynaptic spikes, mean peak slow inhibitory postsynaptic potential amplitude increased sharply to 0.38, 2.6 and 2.9 mV, respectively, in the three neocortical pairs (membrane potential -60 to -65 mV). Thereafter increases in spike number had little additional effect on amplitude. In two of eight pairs in CA1, one involving a presynaptic basket cell and the other a putative bistratified interneuron, the fast inhibitory postsynaptic potential was blocked by bicuculline revealing a slow inhibitory postsynaptic potential that was greatly reduced by 100 microM CGP 35348 (basket cell pair). The sensitivity of this slow inhibitory postsynaptic potential to spike number was similar to that of neocortical 'pure' slow inhibitory postsynaptic potentials, but was of longer duration, its plateau phase outlasting 200 ms spike trains and its maximum duration exceeding 400 ms. Computational models of GABA release, diffusion and uptake suggested that extracellular accumulation of GABA cannot alone account for the non-linear relationship between spike number and inhibitory postsynaptic potential amplitude. However, cooperativity in the kinetics of GABA(B) transduction mechanisms provided non-linear relations similar to experimental data. Different kinetic models were considered for how G-proteins activate K+ channels, including allosteric models. For all models, the best fit to experimental data was obtained with four G-protein binding sites on the K+ channels, consistent with a tetrameric structure for the K+ channels associated with GABA(B) receptors. Thus some inhibitory connections in neocortex and hippocampus appear mediated solely by fast GABA(A) receptors, while others appear mediated solely by slow, non-ionotropic, possibly GABA(B) receptors. In addition, some inhibitory postsynaptic potentials arising in proximal portions of CA1 pyramidal cells are mediated by both GABA(A) and GABA(B) receptors. Our data indicate that the GABA released by a single interneuron can saturate the GABA(B) receptor mechanism(s) accessible to it and that 'spillover' to extrasynaptic sites need not necessarily be proposed to explain these slow inhibitory postsynaptic potential properties.

Algorithms↗
PubMed1993

Mechanosensory inputs to the central pattern generators for locomotion in the lamprey spinal cord: resetting, entrainment, and computer modeling.

1. Mechanoreceptors in the lamprey spinal cord have inputs to the central pattern generator (CPG) for locomotion. In the present study, imposed sinusoidal and pulsed movements were applied to the end of the in vitro lamprey spinal cord to excite the mechanoreceptors so that the relationship between entrainment and resetting of the locomotor rhythm could be examined. 2. The range over which the locomotor rhythm could be entrained by sinusoidal movements was asymmetric and occurred mostly at movement cycle times below the resting cycle time. During entrainment at the shortest cycle times, the movement phases were relatively small. 3. The phase response curves (PRCs) displayed the greatest shortening of cycle times (phase advance) for movement pulses applied during the first half of the locomotor cycle, whereas movement pulses applied during the second half of the cycle were largely ineffective. The amplitude of phase shifts in the PRC correlated with the ranges of cycle times over which entrainment occurred. 4. During resetting from movement pulses applied early in the cycle, the burst and interburst parts of the cycle shortened by about the same percentage. In addition, resetting effects occurred simultaneously along the spinal cord, suggesting a rapid distribution of timing information. 5. A computer model of the CPGs, consisting of left and right oscillators and inputs from mechanosensory elements, produced entrainment ranges that were symmetric around the resting cycle time. The PRCs from the model showed phase advance for movement pulses applied during the first half of the cycle and phase delay for pulses applied during the second half of the cycle. 6. Because of the asymmetric experimental PRCs for the lamprey spinal cord, gating was incorporated into the cooffter model such that oscillators on one side of the model gated inputs from mechanosensory elements on the same side. With gating, the model produced entrainment ranges that were asymmetric and confined to cycle times below the resting cycle time. The PRCs still showed phase advance for pulses applied at the beginning of the cycle, and the amount of phase delay produced during the second half of the cycle was substantially reduced compared with the simulations without gating.

Animals↗
PubMed1991

A computational model for the overall pattern of ocular dominance.

In layer IV of the primary visual cortex, in both the macaque monkey and the cat, geniculocortical terminals representing the two eyes are segregated into alternating zones known as ocular dominance bands. Viewed tangentially, in the monkey these bands take the form of a series of branching parallel stripes that run roughly perpendicular to the border of striate cortex. In the cat, the overall ocular dominance pattern consists of irregularly branching, beaded bands that exhibit no predominant orientation. If the striking differences in the appearance of these two patterns reflect important differences in the basic rules governing cortical ocular dominance, then this poses a problem for attempts to formulate general principles of visual cortical organization. However, it has been suggested that the differences in the appearance of the ocular dominance patterns in these two species could result simply from known differences in the boundary conditions of their geniculocortical pathways. This article describes the formulation and testing of a single computational model that accurately predicts the quite dissimilar ocular dominance patterns in cats and monkeys. This model also generalizes to predict the different ocular dominance patterns observed in young and old three-eyed frogs, supporting the notion that the overall pattern of ocular dominance is governed by a common set of rules. The significance of these results is discussed in terms of previous models, which have focused largely on local processes underlying the development of ocular dominance segregation. Although the present model is not a developmental one, it does shed some light on potential mechanisms for establishing retinotopy in striate cortex and on possible developmental relationships between the geniculostriate pathway and intrinsic modularity of the striate cortex.

Animals↗
PubMedDate not supplied

Computer modeling of three-dimensional reconstruction algorithm of cathodoluminescence material properties, analysis of errors, and optimization of variable parameters.

Three-dimensional (3-D) reconstruction of cathodoluminescence (CL) properties of materials (Saparin et al. 1997) is a new nondestructive technique that measures quantum yield information of subsurface layers as a set of two-dimensional image sections. This technique is able to synthesize a 3-D image without destroying the sample. The basis for this technique is the fact that the electrons in scanning electron microscopy penetrate the sample at different depths with a variation of accelerating voltage. The detected CL emission integrates the information from the full volume occupied by the charge carriers. Estimating the errors that occur during the reconstruction process is complex since these errors are caused by necessary approximations, noise, and the imperfection of the 3-D reconstruction algorithm that is employed. An analysis of the factors that affect the accuracy of the technique has been made. The estimation of systematic errors and the optimization of variable parameters were calculated by computer modeling.

Journal Article↗
PubMed1997

Analysis of the step response of the saccadic feedback: computational models.

We present results of theoretical analysis and computational simulations of two models of the saccadic burst generator: the Scudder model and the Jurgens model. We used the experimental paradigm of prolonged stimulation in monkey superior colliculus (SC) to compare the performance of the two models. We excluded the Scudder model since it was not capable of reproducing the experimentally observed staircase movements. We modified the Jurgens model by replacing the originally proposed feedback integrator with an active reset mechanism by a leaky integrator. With this modification we have shown that the staircase movement elicited by prolonged stimulation in the SC can be modeled as a damped oscillatory step response of this model. Furthermore, to replicate the changes in the kinetic profiles of the staircase movements with increased stimulation we modified the functionality of the model. Our results suggest that prolonged stimulation of the SC dynamically changes the gains and time constant of the saccadic feedback.

Animals↗
PubMed1997

Descending control of turning locomotor activity in larval lamprey: neurophysiology and computer modeling.

The purpose of the present study was to examine the mechanisms that produce natural spontaneous turning maneuvers in larval lamprey. During swimming, spontaneous turning movements began with a larger-than-normal bending of the head to one side. Subsequently, undulations propagated down the body with greater amplitude on the side ipsilateral to the turn. During turning to one side, which usually occurred within one cycle, the amplitude and duration of ipsilateral muscle burst activity as well as overall cycle time increased significantly with increasing turn angle. In in vitro brain/spinal cord preparations, brief electrical stimulation applied to the left side of the oral hood at the onset of locomotor burst activity on the right side of the spinal cord produced turninglike motor activity. During the perturbed cycle, the duration and amplitude of the burst on the right as well as cycle time were significantly larger than during preceding control cycles. In several lower vertebrates, unilateral stimulation in brain stem locomotor regions elicits asymmetric, turninglike locomotor activity. In the lamprey, unilateral chemical microstimulation in brain stem locomotor regions elicited continuous asymmetric locomotor activity, but there was little change in cycle time, as occurs during the single turning cycles in whole animals. The descending mechanisms responsible for producing turning locomotor activity were examined with the use of a computer model consisting of left and right phase oscillators in the spinal cord that were coupled by net reciprocal inhibition. With relatively weak reciprocal coupling, a brief unilateral descending excitatory input to one oscillator produced effects ipsilaterally, but there was little effect on the contralateral oscillator. Turninglike patterns could be produced by each of the following modifications of the model: 1) unilateral descending input and relatively strong reciprocal coupling; 2) unilateral descending input that phase shifted as well as increased the amplitude of the waveform generated by an oscillator on one side; and 3) brief descending modulatory inputs that excited the oscillator on one side and inhibited the contralateral oscillator. In all three cases, there was an increase in "burst" duration ipsilateral to the excitatory input and an increase in cycle time, similar to turning locomotor activity in whole animals. It is likely that turning maneuvers are mediated by descending modulatory inputs primarily to the spinal oscillator networks, which control the timing of burst activity, but perhaps also to motoneurons for axial musculature.

Animals↗
PubMed1979

Cross-sectional views of hemoglobin S fibers by electron microscopy and computer modeling.

Fibers of deoxyHb S have been investigated by thin-section electron microscopy, utilizing a tannic acid embedding procedure. On the basis of numerous measurements of cross-sectional center-to-center distances for adjacent fibers in pairs or arrays, fiber diameters (mean +/- SD) of 205 +/- 5 A in embedded cells and 212 +/- 8 A in embedded hemolysates were obtained. This is an agreement with values obtained by conventional embedding procedures [Crepeau, R. H., Dykes, G., Garrell, R. L. & Edelstein, S. J. (1978) Nature (London) 274, 616--617]. The use of tannic acid has resulted in improved resolution of fiber cross sections, revealing individual strands of Hb S molecules. Because the section thickness corresponds to approximately one-fifth of the fiber helical repeat distance, the strands in projection superimpose to form characteristic image patterns. Additional superposition patterns arise in sections taken at small deviations from perpendicularity to the longitudinal fiber axis. These patterns are consistent with the 14-strand structure for hemoglobin S fibers [Dykes, G., Crepeau, R. H. & Edelstein, S. J. (1978) Nature (London) 272, 506--510], as indicated by computer models of cross-sectional patterns for various thicknesses and angular deviations of sections.

Hemoglobin, Sickle↗
PubMed2001

Computational model of thalamo-cortical networks: dynamical control of alpha rhythms in relation to focal attention.

EEG/MEG rhythmic activities such as alpha rhythms, of the visual or of the somato-sensory cortex, are commonly modulated as subjects perform certain tasks or react to specific stimuli. In general, these activities change depending on extrinsic or intrinsic events. A decrease of the amplitude of alpha rhythmic activity occurring after a given event, which manifests as a decrease of a spectral peak, is called event-related desynchronization (ERD), whereas the inverse is called event-related synchronization (ERS), since it is assumed that the power of a spectral peak is related to the degree of synchrony of the underlying oscillating neuronal populations. An intriguing observation in this respect [Pfurtscheller and Neuper, Neurosci. Lett. 174 (1994) 93-96] was that ERD of alpha rhythms recorded over the central areas was accompanied by ERS, within the same frequency band, recorded over neighboring areas. In case the event was a hand movement, ERD was recorded over the scalp overlying the hand cortical area, whereas ERS was concomitantly recorded over the midline, whereas if the movement was of the foot the opposite was found. We called this phenomenon 'focal ERD/surround ERS'. The question of how this phenomenon may be generated was approached by means of a computational model of thalamo-cortical networks, that incorporates basic properties of neurons and synaptic interactions. These simulation studies revealed that this antagonistic ERD/ERS phenomenon depends on the functional interaction between the populations of thalamo-cortical cells (TCR) and reticular nucleus cells (RE) and on how this interaction is modulated by cholinergic inputs. An essential feature of this interaction is the existence of cross-talk between different sectors of RE that correspond to distinct sensory modules (e.g. hand, foot). These observations led us to formulate the hypothesis that this basic neurophysiological mechanism can account for the general observation that enhanced attention given to a certain stimulus (the focus) is coupled to inhibition of attention to other stimuli (the surround).

Alpha Rhythm↗
PubMed2005

Dependence of visual cell properties on intracortical synapses among hypercolumns: analysis by a computer model.

The role of intracortical synapses in affecting the property of visual cells is investigated by means of an original mathematical model of cortical circuitry in V1. The model represents a compromise between computational simplicity and physiological reliability. The model incorporates four different inputs into a cortical cell: thalamic input from the lateral geniculate nucleus, according to an even Gabor function; short-range inhibition confined within the hypercolumn; a long-range excitation, which emphasizes the properties of the input; and a long-range inhibition. In the model we assume that all cells receive a similar thalamic input, which differs simply according to its position in the retina and orientation preference. Simulations were performed, with different parameter values, to assess the main characteristics of cell response (i.e., the width and locations of subregions in the receptive field (RF), orientation tuning curve, and response to drifting and counterphase gratings) as a function of the strength and extension of intracortical excitatory synapses. Results suggest that, if intracortical excitation is confined within the hypercolumn, the cells exhibit the same properties as simple cells, both with regards to the width and shape of the RF, orientation tuning curve, and response to drifting and counterphase gratings. By contrast, if excitatory synapses extend beyond the hypercolumn with sufficient strength, the cells exhibit the typical characteristics of complex cells. A progressive shift from complex to simple cells can be realized with a monotonic variation in parameters. Simulations are also performed with a hierarchical model, to suggest possible experiments able to discriminate the present recurrent mechanism from the classical hierarchical one. Results support the assumptions of previous simpler models (Chance et al., 1999) and may help to understand and assess the role of intracortical synapses in rigorous quantitative terms.

Algorithms↗
PubMed2004

Haemodynamics and mechanics following partial left ventriculectomy: a computer modeling analysis.

Mechanics following partial left ventriculectomy is still poorly understood. A computational cylindrical model of the left ventricle was developed, based on the myocardial fibre behaviour for the evaluation of the mechanical and haemodynamical effects of the operation. A healthy left ventricle with physiological geometry and function and a dilated hypokinetic heart were investigated. Haemodynamic and mechanical data were obtained at baseline and compared with those obtained at different degrees of volume reduction. Data included: ejection fraction (EF); stroke volume (SV); end-systolic and end-diastolic pressure-volume relationships (ESPVR and EDPVR), and efficiency. EF increases following volume reduction in both simulation but, concurrently, SV shows modest improvement (dilated ventricle) or reduction (healthy ventricle) at progressive degrees of resection. The ESPVR and EDPVR slope increases and shifts leftward with the resection extent, but the increase of the ESPVR slope is more pronounced in dilated ventricle. Efficiency is improved in the dilated heart after resections, while does not improve when the healthy-heart volume is reduced. The simulation of partial left ventriculectomy suggests an improvement of systolic performance, counterbalanced by increased diastolic stiffness following inverse remodelling. Efficiency of simulated dilated ventricles is enhanced by volume reduction, suggesting a favourable effect of reduction of the metabolic demand of the failing heart.

Animals↗
PubMed1995

The maintenance of self-replicating plasmids in Saccharomyces cerevisiae: mathematical modelling, computer simulations and experimental tests.

A distributive model has been constructed to describe the maintenance of the native 2 microns and 2 micron-based plasmids in the yeast Saccharomyces cerevisiae. This model includes elements which represent the influence of selection, segregation, replication and amplification on plasmid stability. A computer program has been written in TURBO PASCAL to implement the model and a number of simulation experiments have been carried out. These simulations permitted the choice of a form of the model which is compatible with the available experimental evidence. The form chosen involves an amplification system in which the RAF gene product binds to the Rep1/Rep2 dimer to prevent the latter acting to repress the activity of the FLP gene. At the same time an upper limit (or 'ceiling') was imposed on the number of plasmid molecules able to replicate. Maternal bias was accommodated by 'tagging' a small proportion of molecules for inheritance by the mother nucleus and these tags being removed (or 'cleared') by the Rep1/Rep2 dimers. This final form of the model makes specific predictions about the stability of 2 microns and YEp plasmids in yeast populations and about the distribution of plasmid copy number between cells in such populations. The predictions on stability have been subjected to experimental test and results provide good support for the model.

Cell Division↗
PubMed2005

Learning from humans: computational modeling of face recognition.

In this paper, we propose a computational architecture of face recognition based on evidence from cognitive research. Several recent psychophysical experiments have shown that humans process faces by a combination of configural and component information. Using an appearance-based implementation of this architecture based on low-level features and their spatial relations, we were able to model aspects of human performance found in psychophysical studies. Furthermore, results from additional computational recognition experiments show that our framework is able to achieve excellent recognition performance even under large view rotations. Our interdisciplinary study is an example of how results from cognitive research can be used to construct recognition systems with increased performance. Finally, our modeling results also make new experimental predictions that will be tested in further psychophysical studies, thus effectively closing the loop between psychophysical experimentation and computational modeling.

Area Under Curve↗