Biomedical subjects

J Devin McAuley

Publications and source records attributed to J Devin McAuley.

11 recordsLinked to original sources

PubMed2006

The time of our lives: life span development of timing and event tracking.

Life span developmental profiles were constructed for 305 participants (ages 4-95) for a battery of paced and unpaced perceptual-motor timing tasks that included synchronize-continue tapping at a wide range of target event rates. Two life span hypotheses, derived from an entrainment theory of timing and event tracking, were tested. A preferred period hypothesis predicted a monotonic slowing of a preferred rate (tempo) of event tracking across the life span. An entrainment region hypothesis predicted a quadratic profile in the range of event rates that produced effective timing across the life span; specifically, age-specific entrainment regions should be narrower in childhood and late adulthood than in midlife. Findings across tasks provide converging support for both hypotheses. Implications of these findings are discussed for understanding critical periods in development and age-related slowing of event timing.

Adolescent↗

PubMed2006

Effects of the NMDA receptor antagonist MK-801 on short-interval timing in rats.

Effects of MK-801, an N-methyl-D-aspartate antagonist, on short-interval timing were examined using the peak-interval (PI) and PI-gap procedures. Fisher 344 rats were given daily injections of 0.025 mg/kg, 0.05 mg/kg, and 0.2 mg/kg MK-801. The main results were (a) 0.2 mg/kg MK-801 produced an immediate overestimation of the criterion time; (b) MK-801 increased peak rate of responding; (c) 0.2 mg/kg MK-801 produced an increase in variability; (d) during the PI-gap procedure, a reset pattern was observed for all rats (MK-801 and saline). Results suggest that MK-801 has at least 2 effects. First, MK-801 interferes with short-interval timing by producing an overestimation of time and a nonscalar increase in variability. Second, MK-801 increases response rate, suggesting a decrease in response inhibition.

Animals↗

PubMed2006

Modeling the effects of the NMDA receptor antagonist MK-801 on timing in rats.

The NMDA receptor antagonist MK-801 produces different effects on timing tasks. In particular, MK-801 produces an underestimation of duration when animals are tested with the differential reinforcement of low rate of responding (DRL) schedule and an overestimation of duration when animals are tested with the peak-interval (PI) procedure. The goal of this study was to develop a model-based explanation for this discrepancy. Two computer simulations were conducted via an implementation of scalar expectancy theory (SET). In Simulation 1, SET was used to provide a quantitative account of PI timing data. Simulation 2 used parameter estimates from Simulation 1 to predict effects of MK-801 on the DRL task. DRL predictions provided a close match to previous empirical data. Results of the simulations suggest that differences in the literature are likely due to inherent differences between PI and DRL tasks, rather than fundamental differences in timing. Overall, the role of NMDA receptors in timing appears to be multifaceted, impacting perception, memory, and decision processes.

Animals↗

PubMed2005

Time judgments in global temporal contexts.

With three experiments, we examined the effects of global temporal context on time judgments as gauged by constant errors (CEs) and estimates of a preferred period (P). In Experiment 1, participants in seven different conditions listened to sequences of a given rate (with interonset intervals ranging from 200 to 800 msec) and judged the relative duration of a final (comparison) time interval. No P emerged. In Experiments 2 and 3, we embedded the same rates in different global (session) contexts that varied according to (1) mean session rate, (2) standard deviation, (3) range, and (4) number of different rates in a session. Evidence from CEs indicated that P varied primarily as a function of mean session rate and range of tempi. The best predictor of errors involved a measure termed relative range (RR = range/mean session rate). A general algorithm incorporating RR successfully predicts P, and the implications of this algorithm are discussed.

Humans↗

PubMed2005

Tempo sensitivity in isochronous tone sequences: the multiple-look model revisited.

Factors affecting tempo sensitivity in isochronous tone sequences were investigated in two experiments. Participants listened to tones in sequence conditions in which the number of time intervals in isochronous standard and comparison sequences was varied, and they were asked to judge the tempo of the comparison relative to the standard. When the duration of the standard interval was held constant, tempo sensitivity was affected by the number of comparison intervals, but not by the number of standard intervals. In contrast, when the duration of the standard interval was varied randomly from trial to trial, tempo sensitivity was affected by the number of intervals in both sequences. The present findings are discussed in the context of a generalized multiple-look model that posits independent contributions of both sequences to tempo sensitivity. Quantitative model fits suggest that the relative contribution of the number of the standard intervals to tempo thresholds depends on (1) the availability of a stable long-term referent for the standard tempo and (2) a priori knowledge about the number of standard intervals.

Auditory Perception↗

PubMed2004

Spontaneous fos expression in the suprachiasmatic nucleus of young and old mice.

The senescence-accelerated mouse (SAMP8) is an animal model of aging that displays an array of circadian rhythm disruptions as early as 7 months of age. The present study explored the physiological basis for age-related changes in circadian rhythms by measuring c-Fos immunostaining. Cellular activity in the SCN "core" and "shell" was examined for 2-, 7-, and 12-month-old SAMP8 at circadian times (CTs) 2 and 14. Consistent with previous studies in rats, we observed higher levels of cellular activity at CT2 than at CT14, and higher levels of activity in the "shell" than in the "core" of the SCN. However, there was no effect of age on the pattern of cellular activity in either the "core" or the "shell" of the SCN. These results are discussed in the context of current research on spontaneous and light-induced c-Fos expression in the SCN of rodents.

Age Factors↗

PubMed2004

Play it again: did this melody occur more frequently or was it heard more recently? The role of stimulus familiarity in episodic recognition of music.

Episodic recognition of novel and familiar melodies was examined by asking participants to make judgments about the recency and frequency of presentation of melodies over the course of two days of testing. For novel melodies, recency judgments were poor and participants often confused the number of presentations of a melody with its day of presentation; melodies heard frequently were judged as have been heard more recently than they actually were. For familiar melodies, recency judgments were much more accurate and the number of presentations of a melody helped rather than hindered performance. Frequency judgments were generally more accurate than recency judgments and did not demonstrate the same interaction with musical familiarity. Overall, these findings suggest that (1) episodic recognition of novel melodies is based more on a generalized "feeling of familiarity" than on a specific episodic memory, (2) frequency information contributes more strongly to this generalized memory than recency information, and (3) the formation of an episodic memory for a melody depends either on the overall familiarity of the stimulus or the availability of a verbal label.

Adolescent↗

PubMed2004

Circadian rhythms in SAMP8: a longitudinal study of the effects of age and experience.

Age-related effects on circadian rhythms include reductions of rhythm amplitude, alterations in re-entrainment, and increased fragmentation. Currently, the pattern of these changes across an individuals' lifespan is unknown. The present study used a cross-sequential experimental design to determine the pattern of circadian rhythm changes, identify predictors of later circadian rhythm disruption, and assess the effect of prior run-wheel experience on circadian rhythms. Run-wheel activity was assessed in senescence-accelerated mice (SAMP8) at 2, 7, and 12 months of age. Age-related changes included decrease of run-wheel activity, decrease in circadian rhythm amplitude, increase in proportion of light activity, and increase in split activity rhythms. Proportion of light activity at 2 months was a good predictor of circadian rhythm disruption at 7 months. Run-wheel experience increased overall activity and decreased proportion of light activity, but did not alter rhythm amplitude or period. These results demonstrate that aging produces several patterns of circadian rhythm changes, describe predictive measures of future rhythm disruptions, and suggest an intervention to reduce circadian rhythm disruptions.

Aging↗

PubMed2003

Modeling effects of rhythmic context on perceived duration: a comparison of interval and entrainment approaches to short-interval timing.

Relative merits of interval and entrainment conceptions of the internal clock were assessed within a common theoretical framework by 4 time-judgment experiments. The timing of tone onsets marking the beginning and ending of standard and comparison time intervals relative to a context rhythm were manipulated: onsets were on time, early, or late relative to the implied rhythm, and 2 distinct accuracy patterns emerged. A quadratic ending profile indicated best performance when the standard ended on time and worst performance when it was early or late, whereas a flat beginning profile (Experiments 1-3) indicated uniform performance for the 3 expectancy conditions. Only in Experiment 4, in which deviations from expected onset times were large, did significant effects of beginning times appear in time-discrimination thresholds and points of subjective equality. Findings are discussed in the context of theoretical assumptions about clock resetting, the representation of time, and independence of successive time intervals.

Humans↗

PubMedDate not supplied

Age-related disruptions in circadian timing: evidence for "split" activity rhythms in the SAMP8.

In the senescence-accelerated mouse of the P8 line (SAMP8), age-related changes in circadian timing include a decrease in amplitude of the rhythm, a slower rate of re-entrainment following a phase advance, and a longer free-running period (tau). The present study extends previous research by investigating possible split activity rhythms in the SAMP8. Running wheel activity was examined in 2-, 7-, and 12-month SAMP8. Consistent with previous research, rhythms of older SAMP8 were decreased in amplitude and showed high levels of activity during the light phase of the light-dark cycle. Contrary to previous reports, lengthening of tau in constant darkness was not observed. Additionally, activity rhythms were "split" in older SAMP8, demonstrated by 1) the appearance of a secondary peak in the periodogram at approximately half the value of tau and 2) the perceptual classification of actograms by naïve observers. This result differs from previous studies in hamsters demonstrating an age-related decrease in the incidence of rhythm splitting. Overall, the present findings provide further evidence for age-related disruption of circadian timing in SAMP8.

Aging↗

PubMedDate not supplied

Age-related changes in the spontaneous motor rhythms of the senescence-accelerated mouse (SAMP8).

The present study examined the effect of age on the spontaneous motor rhythms of mice during wheel running. The spontaneous motor tempo (SMT) of wheel running was measured for the P8 strain of the senescence-accelerated mouse (SAMP8) by recording the sequence of time intervals (measured in milliseconds) for successive revolutions ofa run-wheel over the course of 16 days. Analyses of the distribution of interrevolution intervals of 2-, 7-, and 12-month-old SAMP8 revealed an age-related slowing of wheel running and a corresponding increase in variability consistent with Weber's law. All three age groups also demonstrated a practice effect over the course of testing best described by a power law. These findings provide evidence of age-related changes in the spontaneous motor rhythms of the SAMP8 that occur as early as 7 months of age. The results are consistent with age-related changes in human subjects and suggest that spontaneous wheel-running behavior in rodents may be a good model for studying SMT.

Aging↗