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Biomedical subjects

I Lott

Publications and source records attributed to I Lott.

5 recordsLinked to original sources
PubMed1992

Regional cerebral glucose metabolism and attention in adults with a history of childhood autism.

Sixteen high-functioning adults with a history of childhood autism and 26 normal control subjects underwent [18F]fluoro-2-deoxyglucose positron-emission tomography to assess regional cerebral glucose metabolic rate (GMR). Autistic patients had a left > right anterior rectal gyrus asymmetry, as opposed to the normal right > left asymmetry in that region. Patients also showed low GMR in the left posterior putamen and high GMR in the right posterior calcarine cortex. Brain regions with GMR > 3 SD from the normal mean were more prevalent in patients than in control subjects. This variable pattern of abnormal activity is consistent with heterogeneous neurophysiological etiology; group differences in striatum and cortex may represent a final common pathway.

Adolescent↗
PubMed1991

Olfactory classical conditioning in neonates.

One-day-old, awake infants underwent an olfactory classical conditioning procedure to assess associative learning within the olfactory system of newborns. Experimental infants received ten 30-second pairings of a novel olfactory conditioned stimulus (a citrus odor of neutral value) and tactile stimulation provided by stroking as the reinforcing unconditioned stimulus (a stimulus with positive properties). Control babies received only the odor, only the stroking, or the stroking followed by the odor presentation. The next day, all infants, in either the awake or sleep state, were given five 30-second presentations of the odor. Results were analyzed from video tapes scored by an observer unaware of the infants' training condition. The results indicate that only those infants who received the forward pairings of the odor and stroking exhibited conditioned responding (head turning toward the odor) to the citrus odor. The performance of the conditioned response was not affected by the state of the baby during testing, because both awake and sleeping infants exhibited conditioned responses. Furthermore, the expression of the conditioned response was odor specific; a novel floral odor presented during testing did not elicit conditioned responses in the experimental babies. These results suggest that complex associative olfactory learning is seen in newborns within the first 48 hours of life. These baseline findings may serve as normative data against which observation from neonates at risk for neurological sequelae may be compared.

Conditioning, Classical↗
PubMed1987

Effects of isotretinoin on the behavior of neural crest cells in vitro.

Isotretinoin (13-cis-retinoic acid), an anti-acne medication, has been found to cause severe birth defects which affect the craniofacial elements, ear, heart, thymus, and central nervous system. Many of these structures receive contributions from the cranial neural crest. Here, we examine the possibility that these teratogenic effects are due to disturbances in neural crest development. Cranial and trunk neural crest explant cultures were exposed to different concentrations of isotretinoin and the cell morphology was monitored at daily intervals. Treated neural crest cells often became rounded or spindle shaped, separated from their neighbors, and frequently detached from the substrate or clumped together. In contrast, neural tube cells and cardiac fibroblasts were relatively unaffected by the drug. These results suggest that isotretinoin selectively affects neural crest cells by decreasing their cell-substratum adhesion.

Animals↗