Biomedical subjects

T Pinilla

Publications and source records attributed to T Pinilla.

5 recordsLinked to original sources

PubMed2001

Attentional shifts between surfaces: effects on detection and early brain potentials.

Two consecutive events transforming the same illusory surface in transparent motion (brief changes in direction) can be discriminated with ease, but a prolonged interference ( approximately 500 ms) on the discrimination of the second event arises when different surfaces are concerned [Valdes-Sosa, M., Cobo, A., & Pinilla, T. (2000). Attention to object files defined by transparent motion. Journal of Experimental Psychology: Human Perception and Performance, 26(2), 488-505]. Here we further characterise this phenomenon and compare it to the attentional blink AB [Shapiro, K.L., Raymond, J.E., & Arnell, K.M. (1994). Attention to visual pattern information produces the attentional blink in RSVP. Journal of Experimental Psychology: Human Perception and Performance, 20, 357-371]. Similar to the AB, reduced sensitivity (d') was found in the two-surface condition. However, the two-surface cost was associated with a reduced N1 brain response in contrast to reports for AB [Vogel, E.K., Luck, S.J., & Shapiro, K. (1998). Electrophysiological evidence for a postperceptual locus of suppression during the attentional blink. Journal of Experimental Psychology: Human Perception and Performance, 24(6), 1656-1674]. The results from this study indicate that the two-surface cost corresponds to competitive effects in early vision. Reasons for the discrepancy with the AB study are considered.

Adult↗

PubMed2000

Attention to object files defined by transparent motion.

Two interspersed and differently colored sets of dots were rotated in opposite directions and were perceived as superimposed transparent surfaces. Probes consisting of brief changes in dot motion direction were reported. Two probes affecting the same surface were discriminated accurately. The 2nd probe was discriminated poorly if it affected a surface different from the 1st and if the time between probes was less than 600 ms. This reflects a difficulty in switching attention rapidly between surfaces. Spatial proximity increased the interference. Controls were incompatible with traditional spatial mechanisms (2- or 3-dimensional) or with simple sensory filters. Instead, probes were apparently selected by object files. The interference is not simply due to an inability to process 2 objects at once but requires close spatial proximity of incompatible motion signals.

Adult↗

PubMed1998

Transparent motion and object-based attention.

The difficulty in processing two stimuli at once increases with their separation. Therefore to demonstrate constraints in dividing attention between objects, the effects of their spatial separation must be controlled. Duncan used superimposed objects to achieve this, and showed that judging two attributes is more accurate if they concern one object than if they concern two objects (Duncan, J. 1984. Journal of Experimental Psychology: General, 113, 501-517). However, critics claim that differences in the spatial or spatial-frequency extent of attention exist between these conditions. We studied transparent motion defined by two sets of differently colored dots that were interspersed in the same region of space, and matched in spatial and spatial frequency properties. Each set moved in a distinct and randomly chosen direction. We found that simultaneous judgments of speed and direction were more accurate when they concerned only one set than when they concerned different sets. Furthermore, appraisal of the directions taken by two sets of dots is more difficult than judging direction for only one set, a difficulty that increases for briefer motion. We conclude that perceptual grouping by common fate exerted a more powerful constraint than spatial proximity, a result consistent with object-based attention. Evidence that this type of object-based attention operates at early stages of vision is examined.

Adult↗

PubMed1998

Switching attention without shifting the spotlight object-based attentional modulation of brain potentials.

Although psychophysical evidence for object-based attention has been reported, corresponding studies with event-related potentials (ERPs) are scarce. Here subjects were presented with perceptual fields containing two superimposed objects (transparent surfaces generated by two sets of dots in rigid rotation around fixation, each set of a different color and direction of motion) or only one object (the same dots but either at rest or all rotating in the same direction). Brief (150-msec) rectilinear displacements affected either of the sets at random ISIs of 350 to 550 msec. Attention was directed to one set of dots, guided by color, in order to discriminate the direction of their displacement. Motion-onset ERPs elicited by these displacements were compared for attended and unattended dots. When the perceptual field consisted of two objects, strong suppression of P1 and N1 was obtained in the ERPs associated with the unattended object. No suppression was found with the field containing a single object, although an enhanced selection negativity was found in ERPs associated with attended dots (selected by color). Since the two objects occupied the same region of visual space, the suppression of P1/N1 cannot be explained by the space-based mechanisms but is consistent with object-based attentional selection at early stages of vision. The results highlight the role of perceptual organizations in enabling alternative attentional mechanisms.

Adult↗

PubMed1993

Help me make it through the night: behavioral entrainment of breast-fed infants' sleep patterns.

The study objective was to investigate whether exclusively breast-fed infants could be taught to sleep through the night (defined from 12:00 AM to 5:00 AM) during the first 8 weeks of life. The design was short-term longitudinal, from the last trimester of pregnancy until the eighth week after birth. Twenty-six first-time parents and their newborn were randomly assigned to treatment and control groups (13 in each group). Treatment parents were instructed to offer a "focal feed" (between 10 PM and 12 AM) to their infants every night, to gradually lengthen intervals between middle-of-the-night feeds by carrying out alternative caretaking behaviors (eg, reswaddling, diapering, walking), and to maximize environmental differences between day and nighttime. All parents kept 72-hour diaries of their infants' feeding and sleeping patterns every week from birth to 8 weeks of age and rated their infants' temperament at birth and at 8 weeks. By 3 weeks, treatment infants showed significantly longer sleep episodes at night. By 8 weeks 100% of treatment infants were sleeping through the night compared to 23% of control infants. Treatment infants were feeding less frequently at night but compensated for the relatively long nighttime interval without a feed by consuming more milk in the early morning. Milk intake for 24-hour periods did not differ between groups. Treatment infants were rated as more predictable on Bates' Infant Characteristics Questionnaire. It is concluded that parents can have a powerful influence on the development of their infants' sleep patterns. Frequent night waking in breast-fed infants often results in early termination of lactation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Psychological↗