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Biomedical subjects

H J Jerison

Publications and source records attributed to H J Jerison.

At least 19 recordsLinked to original sources
PubMed1985

Animal intelligence as encephalization.

There is no consensus on the nature of animal intelligence despite a century of research, though recent work on cognitive capacities of dolphins and great apes seems to be on one right track. The most precise quantitative analyses have been of relative brain size, or structural encephalization, undertaken to find biological correlates of mind in animals. Encephalization and its evolution are remarkably orderly, and if the idea of intelligence were unknown it would have to be invented to explain encephalization. The scientific question is: what behaviour or dimensions of behaviour evolved when encephalization evolved? The answer: the relatively unusual behaviours that require increased neural information processing capacity, beyond that attributable to differences among species in body size. In this perspective, the different behaviours that depend on augmented processing capacity in different species are evidence of different intelligences (in the plural) that have evolved.

Adaptation, Biological↗
PubMed1982

Visual evoked potentials (VEP) recorded from the hippocampus of the chronically-implanted unanesthetized hedgehog.

Visual evoked potentials (VEPs) were recorded from the dorsal hippocampus of chronically-implanted unanesthetized European hedgehogs (Erinaceus europaeus). The hippocampal VEP is less complex in appearance than the VEP recorded from the visual cortex. It consists of several distinct, reliably reproducible peaks and one distinct afterpotential (AP). The ease of recording and the reliability of the elicited electrophysiological responses recommended this primitive placental insectivore for use in comparative electrophysiological and psychophysiological studies.

Animals↗
PubMed1980

Photically evoked potentials and afterpotentials recorded from the visual cortex of the unanesthetized hedgehog.

Evoked potentials to visual stimuli (VEP) were recorded from the visual cortex of the unanesthetized hedgehog (Erinaceus europaeus), a primitive placental mammal with relatively little differentiation of cortex and thalamus. The VEPs consisted of several distinct positive and negative voltage deflections. Reproducibility of the response was high, as indicated from the small intrasession and intersession response variability. Rhythmic afterpotentials (AP), previously reported for higher mammals, were readily elicited. They had a lower frequency (3/sec) than APs observed in other mammals. The use of the hedgehog in electrophysiological and psychophysiological research is suggested because data obtained from this primitive placental mammal may shed light on CNS functions of higher mammals, as well as mammalian forms 'lower' on the evolutionary scale.

Animals↗
PubMed1980

Auditory evoked brain potentials as a function of interstimulus interval in adults with Down's syndrome.

Auditory-evoked potentials (AEP) to repeated binaural tone pips of several interstimulus intervals (ISIs) greater than or equal to 1 s were recorded from the vertex of young adults with Down's syndrome (DS; trisomy 21) and normal young adults. The following results were obtained: (1) AEP amplitudes, as well as one latency measure, of both experimental groups increased with the lengthening of ISI. (2) AEP peak latencies of the DS group were longer than AEP peak latencies of the normal group for all the ISIs employed. (3) AEP amplitudes of the DS group tended to be larger than AEP amplitudes of the normal group. These findings are discussed in relationship to issues of attention.

Acoustic Stimulation↗
PubMed1979

Effects of rate of repetitive stimulus presentation on the visual evoked brain potentials of young adults with Down's syndrome.

Visual evoked brain potentials (VEP) to repeated stimuli of several interstimulus intervals (ISI) were recorded from young adults with Down's syndrome (DS). The following results were obtained: (i) An ISI effect previously observed in normals: VEP amplitudes increased with increase in ISI; some ISI effect on latency was also observed; (ii) VEP amplitudes of DS subjects were larger than VEP amplitudes of normals; (iii) VEP peak latencies of DS subjects were longer than VEP peak latencies obtained from normals; (iv) ISI had a more pronounced effect on VEP amplitudes of DS than normal subjects. These results are discussed with respect to CNS differences and issues of attention and information processing.

Adult↗
PubMed1977

The theory of encephalization.

The theory of encephalization is developed from elementary dimensional requirements for the construction of a brain of given size. The basic assumption in the theory is that most of the brain in vertebrates is constructed as a series of mappings repeated at various levels. Encephalization is seen as a composite of an amplification factor for the repeated mappings (identical with the encephalization quotient EQ) and a factor associated with "added" tissue. The latter may be viewed as tissue that corresponds to new functions. The relation of the theory to allometric analysis is a relationship of theory to empirical estimation of "expected" brain size at a given body size. But body size is not fundamental to the theory. It is merely one of several possible sources of a measure of the area of a basic mapping, as it were, which is then subject to the amplification factor. Issues in the use of encephalization to assess behavioral capacities are reviewed briefly, as are the neurobiological correlates of encephalization and brain size.

Animals↗
PubMed1970

Brain evolution: new light on old principles.

The fossil evidence on the evolution of brains and bodies in mammals shows that there has been a progressive increase in relative brain size accompanied by and correlated with increased diversity among species in relative brain size. Small-brained species have also evolved, but more large-brained species have appeared in successive epochs.

Animals↗