When do infants know about objects?
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Awareness↗
Biomedical subjects
B Hood
Publications and source records attributed to B Hood.
Is visual search really like foraging?
The visual-search paradigm provides a controlled and easy to implement experimental situation in which to study the search process. However, little work has been carried out in humans to investigate the extent to which traditional visual-search tasks are similar to more general search or foraging. Here we report results from a task in which search involves walking around a room and leaning down to inspect individual locations. Consistent with more traditional search tasks, search time increases linearly with display size, and the target-present to target-absent search slope is 1:2. However, although rechecking of locations did occur, compared to more traditional search it was relatively rare, suggesting an increased role for memory.
Adult↗
An incremental approach to a Web-based computerized medical record.
Acceptance of an electronic medical record within physician practices is a challenge that the Everett Clinic and the Wenatchee Valley Clinic in Washington State have chosen to approach incrementally. These two independent clinics, with 180 physicians each, joined forces in 1995 to form an information service organization, CliniTech Information Resources, to consolidate operation of their practice management and lab systems. With that done, in 1997 they asked CliniTech to come up with a solution to give physicians online access to clinical data in a way that didn't interrupt their work-flow or decrease their productivity--not a small order. The first HTML application was On Line Transcription, for viewing chart notes and radiology reports. Next, the On Line Patient Profile was developed to replace the face sheet. On Line Lab Results followed as a way to view results from the clinics' internal and reference lab systems. A single user interface was created in 2000 to link these components to the physician's schedule and clinical references. The new computerized medical record (CMR) has been embraced by the clinics' physicians (currently at 70 percent usage) and will continue to grow with additional results and images. Electronic signature capabilities for transcription and results are also slated for 2001 and will be the first change to how the physician practices.
Clinical Laboratory Information Systems↗
Two intact executive capacities in children with autism: implications for the core executive dysfunctions in the disorder.
Many studies have shown that children with autism perform at a much lower level than control subjects on tests of executive functioning, defined as tasks requiring subjects to hold information in mind while suppressing a prepotent response. These tasks have invariably required subjects to (a) follow arbitrary and novel rules and (b) make a nonverbal response. We report that when one of these features is absent, children with autism are not impaired relative to controls. They perform at a similar level to normally developing children on the "tubes" task (containing no arbitrary and novel rules) and on the day/night task (in which the output is verbal). Results are consistent, at least, with the hypothesis that children with autism are challenged by executive tasks because they are unlikely to encode rules in a verbal form.
Adolescent↗
Eikenella corrodens phase variation involves a posttranslational event in pilus formation.
The human pathogen Eikenella corrodens synthesizes type IV pili and exhibits a phase variation involving the irreversible transition from piliated to nonpiliated variants. On solid medium, piliated variants form small (S-phase), corroding colonies whereas nonpiliated variants form large (L-phase), noncorroding colonies. We are studying the molecular basis of this phase variation in the clinical isolate E. corrodens VA1. A genomic fragment encoding the major type IV pilin was cloned from the S-phase variant of strain VA1. Sequence analysis of the fragment revealed four tandemly arranged potential open reading frames (ORFs), designated pilA1, pilA2, pilB, and hagA. Both pilA1 and pilA2 predict a type IV pilin. The protein predicted by pilB shares sequence identity with the Dichelobacter nodosus FimB fimbrial assembly protein. The protein predicted by hagA resembles a hemagglutinin. The region containing these four ORFs was designated the pilA locus. DNA hybridization and sequence analysis showed that the pilA locus of an L-phase variant of strain VA1 was identical to that of the S-phase variant. An abundant pilA1 transcript initiating upstream of pilA1 and terminating at a predicted hairpin structure between pilA1 and pilA2 was detected by several assays, as was a less abundant read-through transcript encompassing pilA1, pilA2, and pilB. Transcription from the pilA locus was nearly indistinguishable between S- and L-phase variants. Electron microscopy and immunochemical analysis showed that S-phase variants synthesize, export, and assemble pilin into pili. In contrast, L-phase variants synthesize pilin but do not export and assemble it into pili. These data suggest that a posttranslational event, possibly involving an alteration in pilin export and assembly, is responsible for phase variation in E. corrodens.
Bacterial Proteins↗
Metamemory in narcolepsy.
People with narcolepsy consistently report diminished memory function attributable to the disorder, however, objective evaluations of memory performance in this clinical group remain inconclusive. Previous evaluations of these subjective experiences have been primarily anecdotal with subjects required to provide global assessments of their memory function. The present study aimed to evaluate subjective assessments of memory dysfunction more extensively comparing responses by narcoleptics, subjects experiencing excessive daytime sleepiness, and controls, on the Metamemory in Adulthood (MIA) questionnaire. The results of the study indicate that subjects with narcolepsy have lower self efficacy for memory performance than either of the comparison groups, despite there being no significant difference between groups in relation to knowledge based aspects of memory functioning. This lowered self efficacy in narcolepsy is expressed through increased anxiety about memory function, decreased evaluations of memory capacity and increased perceptions of memory decline in relation to the comparison groups. It is argued that the negative cognitive self evaluations of narcoleptics potentially arise as a consequence of global psychosocial adjustment difficulties.
Adult↗
Sleepiness and performance in narcolepsy.
Previous attempts to investigate the relationship between sleepiness and performance for subjects with narcolepsy have been limited by both the ability of narcoleptic subjects to contain their sleepiness for brief testing periods and the potential lack of sensitivity of routine performance tasks to sleepiness induced changes. The present study developed a research protocol which allowed subjects with narcolepsy to express states of sleepiness and non sleepiness and to then compare the performance of subjects with narcolepsy to age, gender and IQ matched controls on tasks evaluating automatic, attentional and complex cognitive functioning. The results indicated that at high arousal subjects with narcolepsy performed as well as controls on automatic tasks suggesting that the capacity to perform for narcolepsy subjects is not restricted by physiological factors but is secondary to the effects of sleepiness. Comparison of both the within subject effects for narcolepsy subjects of the transition between high and low arousal states, and the between subject effects of low arousal for narcolepsy subjects compared to controls indicate that complex cognitive tasks are the most sensitive to arousal fluctuation. This study provides support for the subjective experiences of subjects with narcolepsy of diminished cognitive function associated with the disorder.
Adult↗
Bovine tuberculosis in a free-ranging mule deer (Odocoileus hemionus) from Montana.
A survey of 41 mule deer (Odocoileus hemionus) and three white-tailed deer (O. virginianus) for bovine tuberculosis was conducted on a Montana (USA) cattle ranch from 2 November 1993 through January 1994. Gross and microscopic lesions typical of tuberculosis were present in tonsil and lymph nodes of the head, thorax, and abdomen of one adult female mule deer. Additionally, a single microgranuloma considered morphologically suggestive of tuberculosis was present in one lymph node of the head of a second mule deer. Mycobacterial isolates from lymph nodes of the head and thorax of the first deer were identified as Mycobacterium bovis.
Animals↗
Possible blindsight in infants lacking one cerebral hemisphere.
Patients with damage to the striate cortex have a subjectively blind region of the visual field, but may still be able to detect and localize targets within this region. But the relative roles in this 'blindsight' of subcortical neural systems, and of pathways to extra-striate visual areas, have been uncertain. Here we report results on two infants in whom one cerebral hemisphere, including both striate and extra-striate visual cortex, needed surgical removal in their first year. Single conspicuous targets in the half-field contralateral to the lesion could elicit fixations, implying detection and orienting by a subcortical system. In contrast, binocular optokinetic nystagmus (OKN), for which a subcortical pathway has often been thought adequate, showed a marked asymmetry. In normal neonates, fixation shifts and OKN have both been taken to reflect subcortical control; our results are consistent with subcortical control for fixation but not for OKN.
Brain↗
Orientation selectivity in infancy: behavioural evidence for temporal sensitivity.
One-month-old infants were tested with a habituation-recovery paradigm to determine whether they could discriminate phase-shifting grating patterns that switched between two orientations, three or eight times a second, from grating patterns that only shifted in phase. The infants were found to discriminate patterns switching orientation at the lower temporal rate of 3 reversals s-1, but not 8 reversals s-1. This finding supports the idea that orientation-selective mechanisms improve in their temporal sensitivity during early infancy. Where they can be compared, the results from behavioural and electrophysiological studies agree as to the course of this development.
Child↗
Changes in infants' ability to switch visual attention in the first three months of life.
The abilities of 1-month-old and 3-month-old infants to shift their gaze from a central target to a peripheral target were compared in four experiments. In experiment 1 targets matched in mean luminance to the background were presented to infants in the periphery at varying levels of contrast. The contrast thresholds for target detection were found to be significantly different for 1-month-olds compared with 3-month-olds. With targets set close to these contrast thresholds, correct refixations and the latency for shifting attention were examined in experiment 2. Two conditions were used: a peripheral target was presented against a homogeneous background (noncompetition); and in the second condition, the patterned target appeared at one of two lighter peripheral windows set against a darker background (competition). Although there was no difference between the two age groups in the latency for shifting visual attention, 1-month-olds were found to make more directional errors in the competition condition. The competition effect of two potential targets on latencies was examined in experiment 3. In the competition condition, two identical peripheral patterned targets were presented to the infants. The 3-month-olds refixated more quickly to one of the double targets in the competition condition than to a single peripheral target, whereas 1-month-olds were slowed down by a double target display. Finally, in experiment 4 the ability of the infants to process and disengage from a central stimulus and to refixate towards a similar peripheral target was examined. This type of competition disrupted both the direction of the first eye movement and the latency to shift attention in both age groups. However, the effect was significantly greater for the 1-month-olds. Taken together, the results of these experiments demonstrate the greater disruption of fixation-shift behaviour in 1-month-olds compared with 3-month-olds when competing visual stimuli are used. This developmental change is explained in terms of maturation of executive cortical orienting systems over the first months of life.
Age Factors↗
[Serum cholesterol, serum triglyceride, alcohol, myocardial infarction and death (1): Increased serum GT is strongly related to alcohol-induced diseases].
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Alcoholism↗
[Serum cholesterol, serum triglyceride, alcohol, myocardial infarction and death (2): necessary to pay attention to serum GT in assessment of risks of myocardial infarction and death].
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Adult↗
Sensory visual loss and cognitive deficits in the selective attentional system of normal infants and neurologically impaired children.
The ability of infants to shift their gaze laterally from a central target (fixation shift) was investigated in normal one- and three-month-old infants in two visual tasks; competition (central fixating stimulus remained visible while peripheral target was presented) and non-competition (central fixating stimulus replaced by peripheral target). The younger infants were significantly more disrupted by the competition condition, in terms of latency to refixate and direction of first eye movement. An immature attention system is proposed to explain this affect. In addition, visually evoked potentials in response to comparable stimuli were easier to elicit in older infants, suggesting that the one-month-olds possessed more immature sensory and perceptual visual systems, as well as poorer neural systems for controlling selective attention. Both techniques have been applied to a group of neurologically impaired children, and the results indicate that the tests may be useful in distinguishing sensory loss from attentional impairments in these patients.
Anisometropia↗
Effects of a competitive inhibitor (mevinolin) of 3-hydroxy-3-methylglutaryl coenzyme A reductase on human and bovine endothelial cells, fibroblasts and smooth muscle cells in vitro.
Mevinolin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity, is a potent inhibitor of cholesterol synthesis. We have tested the effects of mevinolin on cell replication (3H-thymidine incorporation), prostacyclin production (6-keto-PGF1 alpha) and cell death (51Cr release) in cell cultures (human umbilical vein endothelial cells, bovine endothelial cells, human fibroblasts and bovine smooth muscle cells). Mevinolin concentrations ranging from 0.05 mumol/l (reported therapeutic concentration) to 20 mumol/l were used. In human endothelial cells the replication was reduced by 11% at a concentration of 2.0 mumol/l (P less than 0.01). In fibroblasts and smooth muscle cells the reduction was significant already at 0.1 mumol/l (10%, P less than 0.01). The prostacyclin production was reduced in endothelial cells at 1.0 mumol/l (19%, P less than 0.01) and in smooth muscle cells at 2.0 mumol/l (15%, P less than 0.05). At 20 mumol/l both cell replication and prostacyclin production was markedly reduced by about 40% in all cell types. No effects on 51Cr release or trypan blue staining was seen at any concentration. It is concluded that mevinolin has an effect on DNA synthesis and prostacyclin production on the tested cell types in vitro. These effects were, however, observed only at concentrations higher than those recommended for therapeutical use.
Animals↗
Development of orientation discrimination in infancy.
It has previously been found by us, with a visual evoked potential (VEP) measure, that orientation discrimination of dynamic patterns in infants can be demonstrated from around 6 weeks after birth. Experiments are reported in which orientation discrimination was measured behaviourally, in two infant control habituation procedures, with both dynamic and static patterns. When dynamic patterns identical to those in our previous VEP studies were used, the first positive evidence of orientation discrimination was found at around 6 weeks postnatally. The time course of both the VEP and the behavioural measures was similar. However, with static patterns, evidence of orientation discrimination by newborns was found if the infants were allowed to compare the habituated and novel orientations in a paired simultaneous comparison after habituation, but was not found when the habituated and novel stimulus were presented sequentially. The positive evidence of orientation discrimination in newborns supports the hypothesis that some form of orientationally tuned detectors can be used for discrimination of static patterns at birth. However, some developmental change over several weeks seems to be required before a positive electrophysiological VEP response can be measured for dynamic patterns changing in orientation.
Child Development↗
Vulnerability factors in the transition to university: self-reported mobility history and sex differences as factors in psychological disturbance.
A study was conducted on the psychological reaction to the transition to university in 198 first year residential students. Female subjects had higher levels of psychological disturbance and cognitive failure. Thirty-one per cent of the subjects reported experiencing homesickness. These subjects had higher levels of psychological disturbance and cognitive failure than non-homesick subjects. There were no sex differences in homesickness reporting. The non-homesick group were found to be more likely to have been away from home before either to attend boarding school or to take holidays. This suggests either that selective aspects of previous mobility experience are beneficial or that self-selection factors operate in that those who do not feel distress at leaving home are more likely to acquire mobility experience.
Adolescent↗
[3H]noradrenaline efflux from platelets and synaptosomes of ethanol-treated rats.
Platelets have the ability to take up, store and release biogenic amines and have therefore been used as models for neurons in studies of neuropsychiatric disorders and hypertension. We have studied the spontaneous efflux of [3H]noradrenaline from platelets and synaptosomes of rats chronically treated with ethanol. Male control rats had a more rapid [3H]noradrenaline efflux both from synaptosomes and platelets than female control rats. Ethanol treatment increased efflux in female rats, again both in platelets and synaptosomes. These results suggest that a parallelism exists in noradrenaline release between synaptosomes and platelets, both basal and in situations which stimulate the release.
Animals↗