Biomedical subjects

H M Reid

Publications and source records attributed to H M Reid.

22 records · Page 2Linked to original sources

PubMed1977

Concurrent schedules: a quantitative relation between changeover behavior and its consequences.

Data from several published experiments on concurrent variable-interval schedules were analyzed with respect to the effects of changeover delay on the time spent responding on a schedule before changing to an alternate schedule: i.e., the interchangeover time. Interchangeover time increases as the duration of the changeover delay increases, and the present analysis shows that a power function describes the relation. The power relation applied in spite of numerous differences in the experiments: different variable-interval schedules for the concurrent pairs; equal or unequal reinforcement rates for the schedules of the concurrent pairs; different durations of the changeover delay; response-dependent or response-independent reinforcers; pigeons or rats as subjects; different reinforcers. A power function also described the data in experiments where the changeover incurred a timeout, where a fixed ratio was required to changeover, and also when asymmetrical changeover delays were used.

Journal Article↗

PubMedDate not supplied

Evidence for anomalous lateralization across domain in ADHD children as well as adults identified with the Wender Utah rating scale.

Two studies assessed the relation between ADHD symptomatology and correlates of cerebral dominance. In the first, laterality was examined in school children (N=57), 28 with ADHD. Parental reports of greater attentional symptoms were related to non-righthandedness, but teacher reports were related to anomalous laterality of foot, ear and eye, as well as hand. This suggests that the previously reported association between ADHD and non-righthandedness may not be unique, but instead indicative of a more general condition of anomalous lateralization. This possibility was examined in study two, in which 234 undergraduates were assessed. As expected, the 26 adults identified by the Wender Utah Rating Scale (WURS) as retrospectively reporting more ADHD characteristics were found to be generally male. Also, in a replication of study one, enhanced WURS scores were associated with anomalous lateralization beyond handedness. In this case, ADHD characteristics were associated with a shift away from a right bias for hand, foot, and ear, but not eye. Factor analysis of the extensive Steenhuis and Bryden handedness questionnaire was then undertaken to determine whether all aspects of handedness, or only a subset, are associated with ADHD. The factor analysis indicated that the retrospective reports of ADHD characteristics were associated with only two of the three dimensions. Though limitations such as the gender composition of the groups in study one tempers the conclusions, the results of both studies support previous findings that ADHD is associated with anomalous laterality, but also indicate that non-righthandedness is not an adequate characterization of this relationship.

Adult↗

PubMedDate not supplied

Monaural audiogenic seizures: evidence for control by parallel processes.

SJL/J mice were binaurally sensitized and monaurally tested for susceptibility to sound-induced seizure. Most control subjects exhibited the expected biphasic pattern of running. In mice in the experimental groups, the acoustic stimulation was interrupted for less than 20 s at the conclusion of the initial burst of running. During this quiet period, the side of the blocked ear was reversed for some mice. These mice had an independent biphasic seizure when acoustic stimulation was reintroduced, indicating that the biphasic seizure progression characteristic of monaural testing is the result of a lateralized process. We conclude that the locus of this process is probably at the level of the inferior colliculus (IC).

Acoustic Stimulation↗

PubMedDate not supplied

Recovery of susceptibility to audiogenic seizure in mice.

The applicability of the auditory fatigue and anoxia hypotheses for the refractory period observed after sound-induced seizure was examined in SJL/J mice. Duration of auditory stimulation was varied independent of attainment of clonic seizure activity by use of an acoustic interruption technique. Duration of the recovery period affected the pattern of preconvulsive running. Furthermore, the motor asymmetries exhibited during clonus remained consistent across tests. Because duration of acoustic stimulation and attainment of clonus did not affect recovery rate, we conclude that neither the auditory fatigue nor the anoxia hypothesis provides a complete account for the refractory period after audiogenic seizure. We suggest that an inhibitory process, activated before clonus occurs and perhaps linked to depletion of excitatory amino acids in the inferior colliculus, may also be involved.

Acoustic Stimulation↗