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1.
Blood Purif ; 51(1): 31-37, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34107477

RESUMEN

AIM: This study aimed to evaluate the efficacy of the resin hemoperfusion device (HA380 hemoperfusion cartridge) on inflammatory responses during adult cardiopulmonary bypass (CPB). METHODS: Sixty patients undergoing surgical valve replacement were randomized into the HP group (n = 30) with an HA380 hemoperfusion cartridge in the CPB circuit or the control group (n = 30) with the conventional CPB circuit. The results of routine blood tests, blood biochemical indexes, and inflammatory factors were analyzed at V0 (pre-CPB), V1 (CPB 30 min), V2 (ICU 0 h), V3 (ICU 6 h), and V4 (ICU 24 h). RESULTS: The HP group had significantly lower levels of IL-6, IL-8, and IL-10. Significant estimation of group differences in the generalized estimating equation (GEE) models was also observed in IL-6 and IL-10. The HP group had significantly lower levels of creatinine (Cr), aminotransferase (AST), and total bilirubin (TBil) compared to the control group. The estimation of differences of Cr, AST, and TBil all reached statistical significance in GEE results. The HP group had significantly less vasopressor requirement and shorter mechanical ventilation time and ICU stay time as compared to the control group. CONCLUSION: The HA380 hemoperfusion cartridge could effectively reduce the systemic inflammatory responses and improve postoperative recovery of patients during adult CPB.


Asunto(s)
Puente Cardiopulmonar/instrumentación , Hemoperfusión/instrumentación , Inflamación/etiología , Adulto , Femenino , Hemodinámica , Humanos , Inflamación/sangre , Interleucina-10/sangre , Interleucina-6/sangre , Masculino , Persona de Mediana Edad
2.
Aesthet Surg J ; 40(12): 1280-1287, 2020 11 19.
Artículo en Inglés | MEDLINE | ID: mdl-31960890

RESUMEN

BACKGROUND: The aesthetic ideal of the nose eludes clear definition. Averageness may be an important determinant of ideal nasal shape: research has shown that averageness plays an important role in the human perception of facial attractiveness. OBJECTIVES: The aim of this study was to test whether an averaged nasal shape is attractive, and whether deviation away from average is associated with decreased attractiveness. METHODS: Photographic series of the face were obtained from 80 Caucasian female volunteers aged 25-40 years. A mathematically averaged composite image was created from the first 40 volunteers. Forty-one panel members were recruited to judge the attractiveness of the nose of each original image and the composite, based on a 5-point Likert scale ranging from 1 (very ugly) to 5 (very pretty). Deviation of nasal shape from average was calculated by principal components analysis of standardized nasal landmarks. RESULTS: Twenty-one respondents were male (51%). The mean age of the respondents was 35.3 [15.6] years. The rating of the composite was significantly higher than the distribution of ratings for the 80 original nose images (4.2 vs 2.8, t = 31.24, P < 0.001). The rating of the original nose images correlated negatively with deviation from average shape (r = -0.40, n = 80, P < 0.001). CONCLUSIONS: In Caucasian females, a mathematically averaged nose is an attractive nose. Furthermore, the more an individual nose shape resembles the average shape, the more attractive it is rated. Calculating deviation from average before and after rhinoplasty may aid in objectively measuring aesthetic rhinoplasty outcome.


Asunto(s)
Rinoplastia , Adolescente , Adulto , Estética , Cara , Femenino , Humanos , Masculino , Nariz/cirugía , Población Blanca
3.
Front Psychol ; 10: 2996, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-32010029

RESUMEN

While first impressions of dominance and competence can influence leadership preference, social transmission of leadership preference has received little attention. The capacity to transmit, store and compute information has increased greatly over recent history, and the new media environment may encourage partisanship (i.e., "echo chambers"), misinformation and rumor spreading to support political and social causes and be conducive both to emotive writing and emotional contagion, which may shape voting behavior. In our pre-registered experiment, we examined whether implicit associations between facial cues to dominance and competence (intelligence) and leadership ability are strengthened by partisan media and knowledge that leaders support or oppose us on a socio-political issue of personal importance. Social information, in general, reduced well-established implicit associations between facial cues and leadership ability. However, as predicted, social knowledge of group membership reduced preferences for facial cues to high dominance and intelligence in out-group leaders. In the opposite-direction to our original prediction, this "in-group bias" was greater under less partisan versus partisan media, with partisan writing eliciting greater state anxiety across the sample. Partisanship also altered the salience of women's facial appearance (i.e., cues to high dominance and intelligence) in out-group versus in-group leaders. Independent of the media environment, men and women displayed an in-group bias toward facial cues of dominance in same-sex leaders. Our findings reveal effects of minimal social information (facial appearance, group membership, media reporting) on leadership judgments, which may have implications for patterns of voting or socio-political behavior at the local or national level.

4.
Emotion ; 18(7): 1032-1042, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29172620

RESUMEN

Facial expressions of emotion contain important information that is perceived and used by observers to understand others' emotional state. While there has been considerable research into perceptions of facial musculature and emotion, less work has been conducted to understand perceptions of facial coloration and emotion. The current research examined emotion-color associations in the context of the face. Across 4 experiments, participants were asked to manipulate the color of face, or shape, stimuli along 2 color axes (i.e., red-green, yellow-blue) for 6 target emotions (i.e., anger, disgust, fear, happiness, sadness, surprise). The results yielded a pattern that is consistent with physiological and psychological models of emotion. (PsycINFO Database Record (c) 2018 APA, all rights reserved).


Asunto(s)
Emociones/fisiología , Cara/fisiología , Expresión Facial , Adulto , Color , Femenino , Humanos , Masculino , Adulto Joven
5.
Cognition ; 163: 146-154, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28342383

RESUMEN

Although recent work suggests that opposite-sex facial attractiveness is less salient in memory when individuals are in a committed romantic relationship, romantic relationship quality can vary over time. In light of this, we tested whether activating concerns about romantic relationship quality strengthens memory for attractive faces. Partnered women were exposed briefly to faces manipulated in shape cues to attractiveness before either being asked to think about a moment of emotional closeness or distance in their current relationship. We measured sensitivity in memory for faces as the extent to which they recognized correct versions of studied faces over versions of the same person altered to look either more or less-attractive than their original (i.e., studied) version. Contrary to predictions, high relationship quality strengthened hit rate for faces regardless of the sex or attractiveness of the face. In general, women's memories were more sensitive to attractiveness in women, but were biased toward attractiveness in male faces, both when responding to unfamiliar faces and versions of familiar faces that were more attractive than the original male identity from the learning phase. However, findings varied according to self-rated attractiveness and a psychometric measure of the quality of their current relationship. Attractive women were more sensitive to attractiveness in men, while their less-attractive peers had a stronger bias to remember women as more-attractive and men as less-attractive than their original image respectively. Women in better-quality romantic relationships had stronger positive biases toward, and false memories for, attractive men. Our findings suggest a sophisticated pattern of sensitivity and bias in women's memory for facial cues to quality that varies systematically according to factors that may alter the costs of female mating competition ('market demand') and relationship maintenance.


Asunto(s)
Emociones , Reconocimiento Facial , Relaciones Interpersonales , Memoria , Adulto , Femenino , Humanos , Psicometría , Reconocimiento en Psicología , Adulto Joven
6.
PLoS One ; 8(12): e80957, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24324651

RESUMEN

Judgments of leadership ability from face images predict the outcomes of actual political elections and are correlated with leadership success in the corporate world. The specific facial cues that people use to judge leadership remain unclear, however. Physical height is also associated with political and organizational success, raising the possibility that facial cues of height contribute to leadership perceptions. Consequently, we assessed whether cues to height exist in the face and, if so, whether they are associated with perception of leadership ability. We found that facial cues to perceived height had a strong relationship with perceived leadership ability. Furthermore, when allowed to manually manipulate faces, participants increased facial cues associated with perceived height in order to maximize leadership perception. A morphometric analysis of face shape revealed that structural facial masculinity was not responsible for the relationship between perceived height and perceived leadership ability. Given the prominence of facial appearance in making social judgments, facial cues to perceived height may have a significant influence on leadership selection.


Asunto(s)
Expresión Facial , Liderazgo , Percepción del Tamaño , Percepción Social , Señales (Psicología) , Cara , Femenino , Humanos , Juicio , Masculino , Masculinidad
7.
Q J Exp Psychol (Hove) ; 66(1): 200-8, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-22928658

RESUMEN

Facial appearance can motivate behaviour and elicit activation of brain circuits putatively involved in reward. Gender differences have been observed for motivation to view beauty in adult faces--heterosexual women are motivated by beauty in general, while heterosexual men are motivated to view opposite-sex beauty alone. Although gender differences have been observed in sensitivity to infant cuteness, infant faces appear to hold equal incentive salience among men and women. In the present study, we investigated the incentive salience of attractiveness and cuteness in adult and infant faces, respectively. We predicted that, given alternative viewing options, gender differences would emerge for motivation to view infant faces. Heterosexual participants completed a "pay-per-view" key-press task, which allowed them to control stimulus duration. Gender differences were found such that infants held greater incentive salience among women, although both sexes differentiated infant faces based on cuteness. Among adult faces, men exerted more effort than women to view opposite-sex faces. These findings suggest that, contrary to previous reports, gender differences do exist in the incentive salience of infant faces as well as opposite-sex faces.


Asunto(s)
Envejecimiento , Cara , Motivación/fisiología , Reconocimiento Visual de Modelos/fisiología , Caracteres Sexuales , Adolescente , Adulto , Análisis de Varianza , Emociones/fisiología , Femenino , Humanos , Lactante , Masculino , Estimulación Luminosa , Desempeño Psicomotor , Adulto Joven
8.
PLoS One ; 7(3): e32988, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22412966

RESUMEN

BACKGROUND: Fruit and vegetable consumption and ingestion of carotenoids have been found to be associated with human skin-color (yellowness) in a recent cross-sectional study. This carotenoid-based coloration contributes beneficially to the appearance of health in humans and is held to be a sexually selected cue of condition in other species. METHODOLOGY AND PRINCIPAL FINDINGS: Here we investigate the effects of fruit and vegetable consumption on skin-color longitudinally to determine the magnitude and duration of diet change required to change skin-color perceptibly. Diet and skin-color were recorded at baseline and after three and six weeks, in a group of 35 individuals who were without makeup, self-tanning agents and/or recent intensive UV exposure. Six-week changes in fruit and vegetable consumption were significantly correlated with changes in skin redness and yellowness over this period, and diet-linked skin reflectance changes were significantly associated with the spectral absorption of carotenoids and not melanin. We also used psychophysical methods to investigate the minimum color change required to confer perceptibly healthier and more attractive skin-coloration. Modest dietary changes are required to enhance apparent health (2.91 portions per day) and attractiveness (3.30 portions). CONCLUSIONS: Increased fruit and vegetable consumption confers measurable and perceptibly beneficial effects on Caucasian skin appearance within six weeks. This effect could potentially be used as a motivational tool in dietary intervention.


Asunto(s)
Frutas , Pigmentación de la Piel , Verduras , Adolescente , Adulto , Antioxidantes , Carotenoides , Dieta , Femenino , Humanos , Masculino , Factores de Tiempo , Adulto Joven
9.
Body Image ; 8(2): 190-3, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21354874

RESUMEN

Perceived facial adiposity plays an important role in perceptions of both facial attractiveness and health, but people might differentiate between the level of adiposity they find most attractive and healthy. The aim of this study was therefore to test whether or not similar levels of adiposity in faces were preferred for judgments of health and attractiveness. Fifty-three Caucasian university students were asked to make three-dimensional female faces appear as healthy and attractive as possible by changing faces along a continuum that portrays the facial adiposity change associated with a change in body mass index. Results showed that women preferred a significantly lower level of facial adiposity when judging attractiveness than when judging health, while men did not differentiate between the 'most attractive' and 'most healthy' looking level of facial adiposity. These findings are discussed in terms of the sociocultural portrayal of female body ideals and the preference for healthy individuals.


Asunto(s)
Adiposidad , Belleza , Estado de Salud , Juicio , Adolescente , Adulto , Índice de Masa Corporal , Señales (Psicología) , Cara , Femenino , Humanos , Masculino , Escocia , Distribución por Sexo , Percepción Social , Estudiantes/psicología , Adulto Joven
10.
PLoS One ; 6(3): e17859, 2011 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-21448270

RESUMEN

Blood oxygenation level is associated with cardiovascular fitness, and raising oxygenated blood colouration in human faces increases perceived health. The current study used a two-alternative forced choice (2AFC) psychophysics design to quantify the oxygenated blood colour (redness) change threshold required to affect perception of facial colour, health and attractiveness. Detection thresholds for colour judgments were lower than those for health and attractiveness, which did not differ. The results suggest redness preferences do not reflect a sensory bias, rather preferences may be based on accurate indications of health status. Furthermore, results suggest perceived health and attractiveness may be perceptually equivalent when they are assessed based on facial redness. Appearance-based motivation for lifestyle change can be effective; thus future studies could assess the degree to which cardiovascular fitness increases face redness and could quantify changes in aerobic exercise needed to increase facial attractiveness.


Asunto(s)
Belleza , Salud , Oxígeno/sangre , Pigmentación de la Piel/fisiología , Color , Discriminación en Psicología , Cara , Femenino , Humanos , Masculino , Estimulación Física , Adulto Joven
11.
J Cogn Neurosci ; 23(6): 1533-48, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20617893

RESUMEN

To investigate form-related activity in motion-sensitive cortical areas, we recorded cell responses to animate implied motion in macaque middle temporal (MT) and medial superior temporal (MST) cortex and investigated these areas using fMRI in humans. In the single-cell studies, we compared responses with static images of human or monkey figures walking or running left or right with responses to the same human and monkey figures standing or sitting still. We also investigated whether the view of the animate figure (facing left or right) that elicited the highest response was correlated with the preferred direction for moving random dot patterns. First, figures were presented inside the cell's receptive field. Subsequently, figures were presented at the fovea while a dynamic noise pattern was presented at the cell's receptive field location. The results show that MT neurons did not discriminate between figures on the basis of the implied motion content. Instead, response preferences for implied motion correlated with preferences for low-level visual features such as orientation and size. No correlation was found between the preferred view of figures implying motion and the preferred direction for moving random dot patterns. Similar findings were obtained in a smaller population of MST cortical neurons. Testing human MT+ responses with fMRI further corroborated the notion that low-level stimulus features might explain implied motion activation in human MT+. Together, these results suggest that prior human imaging studies demonstrating animate implied motion processing in area MT+ can be best explained by sensitivity for low-level features rather than sensitivity for the motion implied by animate figures.


Asunto(s)
Percepción de Movimiento/fisiología , Estimulación Luminosa/métodos , Tiempo de Reacción/fisiología , Lóbulo Temporal/fisiología , Adolescente , Adulto , Animales , Femenino , Humanos , Macaca mulatta , Masculino , Campos Visuales/fisiología , Adulto Joven
12.
Q J Exp Psychol (Hove) ; 62(11): 2081-104, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19557666

RESUMEN

This paper relates human perception to the functioning of cells in the temporal cortex that are engaged in high-level pattern processing. We review historical developments concerning (a) the functional organization of cells processing faces and (b) the selectivity for faces in cell responses. We then focus on (c) the comparison of perception and cell responses to images of faces presented in sequences of unrelated images. Specifically the paper concerns the cell function and perception in circumstances where meaningful patterns occur momentarily in the context of a naturally or unnaturally changing visual environment. Experience of visual sequences allows anticipation, yet one sensory stimulus also "masks" perception and neural processing of subsequent stimuli. To understand this paradox we compared cell responses in monkey temporal cortex to body images presented individually, in pairs and in action sequences. Responses to one image suppressed responses to similar images for approximately 500 ms. This suppression led to responses peaking 100 ms earlier to image sequences than to isolated images (e.g., during head rotation, face-selective activity peaks before the face confronts the observer). Thus forward masking has unrecognized benefits for perception because it can transform neuronal activity to make it predictive during natural change.


Asunto(s)
Mapeo Encefálico , Neuronas/fisiología , Lóbulo Temporal/citología , Visión Ocular/fisiología , Percepción Visual/fisiología , Animales , Diagnóstico por Imagen , Humanos , Modelos Neurológicos , Enmascaramiento Perceptual , Estimulación Luminosa/métodos , Psicofísica , Tiempo de Reacción/fisiología , Lóbulo Temporal/fisiología , Factores de Tiempo
13.
J Cogn Neurosci ; 21(9): 1806-20, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18855549

RESUMEN

Prolonged exposure to visual stimuli, or adaptation, often results in an adaptation "aftereffect" which can profoundly distort our perception of subsequent visual stimuli. This technique has been commonly used to investigate mechanisms underlying our perception of simple visual stimuli, and more recently, of static faces. We tested whether humans would adapt to movies of hands grasping and placing different weight objects. After adapting to hands grasping light or heavy objects, subsequently perceived objects appeared relatively heavier, or lighter, respectively. The aftereffects increased logarithmically with adaptation action repetition and decayed logarithmically with time. Adaptation aftereffects also indicated that perception of actions relies predominantly on view-dependent mechanisms. Adapting to one action significantly influenced the perception of the opposite action. These aftereffects can only be explained by adaptation of mechanisms that take into account the presence/absence of the object in the hand. We tested if evidence on action processing mechanisms obtained using visual adaptation techniques confirms underlying neural processing. We recorded monkey superior temporal sulcus (STS) single-cell responses to hand actions. Cells sensitive to grasping or placing typically responded well to the opposite action; cells also responded during different phases of the actions. Cell responses were sensitive to the view of the action and were dependent upon the presence of the object in the scene. We show here that action processing mechanisms established using visual adaptation parallel the neural mechanisms revealed during recording from monkey STS. Visual adaptation techniques can thus be usefully employed to investigate brain mechanisms underlying action perception.


Asunto(s)
Adaptación Fisiológica/fisiología , Efecto Tardío Figurativo/fisiología , Objetivos , Mano/fisiología , Desempeño Psicomotor/fisiología , Percepción Espacial/fisiología , Potenciales de Acción/fisiología , Adolescente , Adulto , Análisis de Varianza , Animales , Femenino , Fuerza de la Mano/fisiología , Humanos , Macaca mulatta , Masculino , Modelos Neurológicos , Neuronas/fisiología , Estimulación Luminosa/métodos , Psicofísica , Tiempo de Reacción , Factores de Tiempo , Corteza Visual/citología , Corteza Visual/fisiología , Adulto Joven
14.
Neural Comput ; 20(7): 1847-72, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18336081

RESUMEN

Neurons in the visual cortex receive a large amount of input from recurrent connections, yet the functional role of these connections remains unclear. Here we explore networks with strong recurrence in a computational model and show that short-term depression of the synapses in the recurrent loops implements an adaptive filter. This allows the visual system to respond reliably to deteriorated stimuli yet quickly to high-quality stimuli. For low-contrast stimuli, the model predicts long response latencies, whereas latencies are short for high-contrast stimuli. This is consistent with physiological data showing that in higher visual areas, latencies can increase more than 100 ms at low contrast compared to high contrast. Moreover, when presented with briefly flashed stimuli, the model predicts stereotypical responses that outlast the stimulus, again consistent with physiological findings. The adaptive properties of the model suggest that the abundant recurrent connections found in visual cortex serve to adapt the network's time constant in accordance with the stimulus and normalizes neuronal signals such that processing is as fast as possible while maintaining reliability.


Asunto(s)
Corteza Cerebral/fisiología , Modelos Neurológicos , Plasticidad Neuronal/fisiología , Corteza Visual/fisiología , Percepción Visual/fisiología , Potenciales de Acción , Algoritmos , Animales , Macaca mulatta , Microelectrodos , N-Metilaspartato/metabolismo , Vías Nerviosas/fisiología , Neuronas/fisiología , Dinámicas no Lineales , Estimulación Luminosa , Lóbulo Temporal/fisiología , Factores de Tiempo
15.
Prog Brain Res ; 154: 135-48, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-17010707

RESUMEN

We readily use the form of human figures to determine if they are moving. Human figures that have arms and legs outstretched (articulated) appear to be moving more than figures where the arms and legs are near the body (standing). We tested whether neurons in the macaque monkey superior temporal sulcus (STS), a region known to be involved in processing social stimuli, were sensitive to the degree of articulation of a static human figure. Additionally, we tested sensitivity to the same stimuli within forward and backward walking sequences. We found that 57% of cells that responded to the static image of a human figure was also sensitive to the degree of articulation of the figure. Some cells displayed selective responses for articulated postures, while others (in equal numbers) displayed selective responses for standing postures. Cells selective for static images of articulated figures were more likely to respond to movies of walking forwards than walking backwards. Cells selective for static images of standing figures were more likely to respond to movies of walking backwards than forwards. An association between form sensitivity and walking sensitivity could be consistent with an interpretation that cell responses to articulated figures act as an implied motion signal.


Asunto(s)
Movimiento (Física) , Neuronas/fisiología , Postura/fisiología , Lóbulo Temporal/citología , Vías Visuales/fisiología , Caminata/fisiología , Potenciales de Acción/fisiología , Análisis de Varianza , Animales , Mapeo Encefálico , Lateralidad Funcional , Macaca mulatta , Estimulación Luminosa/métodos , Lóbulo Temporal/fisiología , Vías Visuales/citología
16.
J Cogn Neurosci ; 17(3): 377-91, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15813999

RESUMEN

Processing of complex visual stimuli comprising facial movements, hand actions, and body movements is known to occur in the superior temporal sulcus (STS) of humans and nonhuman primates. The STS is also thought to play a role in the integration of multimodal sensory input. We investigated whether STS neurons coding the sight of actions also integrated the sound of those actions. For 23% of neurons responsive to the sight of an action, the sound of that action significantly modulated the visual response. The sound of the action increased or decreased the visually evoked response for an equal number of neurons. In the neurons whose visual response was increased by the addition of sound (but not those neurons whose responses were decreased), the audiovisual integration was dependent upon the sound of the action matching the sight of the action. These results suggest that neurons in the STS form multisensory representations of observed actions.


Asunto(s)
Percepción Auditiva/fisiología , Neuronas/fisiología , Lóbulo Temporal/citología , Percepción Visual/fisiología , Estimulación Acústica/métodos , Análisis de Varianza , Animales , Conducta Animal , Mapeo Encefálico , Recuento de Células , Potenciales Evocados Somatosensoriales/fisiología , Macaca mulatta , Estimulación Luminosa/métodos , Tiempo de Reacción/fisiología , Lóbulo Temporal/fisiología , Factores de Tiempo
17.
Prog Brain Res ; 144: 107-16, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-14650843

RESUMEN

We show that rapid serial visual presentation (RSVP) in combination with a progressive reduction of the stimulus set is an efficient method for describing the selectivity properties of high-level cortical neurons in single-cell electrophysiological recording experiments. Rapid presentation allows the experimental testing of a significantly larger number of stimuli, which can reduce the subjectivity of the results due to stimulus selection and the lack of sufficient control stimuli. We prove the reliability of the rapid presentation and stimulus reduction methods by repeated experiments and the comparison of different testing conditions. Our results from neurons in area STSa of the macaque temporal cortex provide a well-controlled confirmation for the existence of a population of cells that respond selectively to stimuli containing faces. View tuning properties measured using this method also confirmed earlier results. In addition, we found a population of cells that respond reliably to complex non-face stimuli, though their tuning properties are not obvious.


Asunto(s)
Cara , Neuronas/fisiología , Estimulación Luminosa/métodos , Corteza Visual/fisiología , Animales , Electrofisiología , Macaca mulatta , Reproducibilidad de los Resultados , Factores de Tiempo
18.
J Neurophysiol ; 90(2): 1245-56, 2003 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12904507

RESUMEN

The inferotemporal (IT) cortex of the monkey lies at the head of the ventral visual pathway and is known to mediate object recognition and discrimination. It is often assumed that color plays a minor role in the recognition of objects and faces because discrimination remains highly accurate with black-and-white images. Furthermore it has been suggested that for rapid presentation and reaction tasks, object classification may be based on a first wave of feedforward visual information, which is coarse and achromatic. The fine detail and color information follows later, allowing similar stimuli to be discriminated. To allow these theories to be tested, this study investigates whether the presence of color affects the response of IT neurons to complex stimuli, such as faces, and whether color information is delayed with respect to information about stimulus form in these cells. Color, achromatic, and false-color versions of effective stimuli were presented using a rapid serial visual presentation paradigm, and responses recorded from single cells in IT of the adult monkey. Achromatic images were found to evoke significantly reduced responses compared with color images in the majority of neurons (70%) tested. Differential activity for achromatic and colored stimuli was evident from response onset with no evidence to support the hypothesis that information about object color is delayed with respect to object form. A negative correlation (P < 0.01) was found between cell latency and color sensitivity, with the most color-sensitive cells tending to respond earliest. The results of this study suggest a strong role for color in familiar object recognition and provide no evidence to support the idea of a first wave of form processing in the ventral stream based on purely achromatic information.


Asunto(s)
Percepción de Color/fisiología , Percepción de Forma/fisiología , Neuronas/fisiología , Lóbulo Temporal/fisiología , Animales , Electrofisiología , Cara , Macaca mulatta , Masculino , Orientación/fisiología , Estimulación Luminosa , Percepción Visual/fisiología
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