摘要:

We have previously derived a hypothetical tree of the lines of mammalian descent, based upon a comprehensive numerical taxonomic cross-analysis of primitive and derived states of 15 brain traits in 38 representative species. In this communication we use this tree to describe the probable sequence of changes that have taken place in phylogenetic history. 2 characters proved to be multiply convergent, occurring in parallel in several disparate lines of descent. The remaining 9 characters each appeared in ancestors of one or another of the lineages and characterize related progeny.

ISSN:0006-8977    

DOI:10.1159/000121314

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Continuing with a plan for overall testing of the timing and sequencing of brain processes, further testing techniques are introduced for probing a normal adult's short-term central processes, especially those which are employed in reading a short digit span. The tests are administered by means of a personal computer and can provide information on the individual subject's characteristic sequencing and timing of particular central processes. In a subject whose first language is read from left to right, the presented tests reported in this paper can reveal an interesting asymmetry. A temporal display of digits in the right visual field is correctly perceived more readily than in the left. Conversely, a brief, spatial display of digits in the left visual field is correctly reported more often than in the right. It is suggested, therefore, that there are individuals whose left hemisphere is superior in handling a temporal sequence of digits while the right hemisphere is superior in handling a spatial display of digits.

ISSN:0006-8977    

DOI:10.1159/000121315

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

The corticocortical connections and receptive field properties of primary or striate visual cortex of the brushtailed possum, Trichosurus vulpecula, have been examined. In this Australian marsupial species primary visual cortex has connections with four other visual areas in the occipital lobe. In these adjacent visual areas fibers from striate cortex terminate mainly in layers 3 and 4 and in some cases also in layers 1 and 2. In all four areas return connections to striate cortex originate predominantly in layers 2 and 3, and to a much lesser extent in layers 5 and 6. Interhemispheric connections of striate cortex are limited to the boundary of striate and peristriate cortex. In addition to its cortical connections, striate cortex makes reciprocal connections with the claustrum. Most neurons in striate cortex are highly binocular. Of our sample of 113 visually responsive neurons, only 30% were orientation selective. On the basis of these observations we have compared striate cortex of the marsupial brushtailed possum with striate cortices of the American marsupial opossum and those of placental mammals.

ISSN:0006-8977    

DOI:10.1159/000121316

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Experimental data which have suggested the probability of connections between the cerebellum and hypothalamus are reviewed. Early studies relied mainly on physiological methods and, in general, concluded that such connections were multisynaptic being relayed via an undetermined number of synapses in the bulbar reticular formation. Recent studies, using horseradish peroxidase techniques, have identified direct connections between cerebellar nuclei and the hypothalamus and between several regions of hypothalamus and the cerebellar cortex. It is proposed that the cerebellum, by way of direct nucleo-hypothalamic projections and the resultant descending hypothalamic projections to visceral centers, has a variety of specific circuits through which it can directly influence autonomic centers. It is further noted that autonomic centers, as exemplified by hypothalamo-cerebellar projections, may have equally specific feedback loops to cerebellar cortex. Direct cerebello-hypothalamic projections and the subsequent diffuse pathways from hypothalamus into a number of forebrain areas may represent circuits responsible for the affective responses seen as a result of cerebellar ablation and/or stimulation.

ISSN:0006-8977    

DOI:10.1159/000121317

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Experimental data which have suggested the probability of connections between the cerebellum and hypothalamus are reviewed. Early studies relied mainly on physiological methods and, in general, concluded that such connections were multisynaptic being relayed via an undetermined number of synapses in the bulbar reticular formation. Recent studies, using horseradish peroxidase techniques, have identified direct connections between cerebellar nuclei and the hypothalamus and between several regions of hypothalamus and the cerebellar cortex. It is proposed that the cerebellum, by way of direct nucleo-hypothalamic projections and the resultant descending hypothalamic projections to visceral centers, has a variety of specific circuits through which it can directly influence autonomic centers. It is further noted that autonomic centers, as exemplified by hypothalamo-cerebellar projections, may have equally specific feedback loops to cerebellar cortex. Direct cerebello-hypothalamic projections and the subsequent diffuse pathways from hypothalamus into a number of forebrain areas may represent circuits responsible for the affective responses seen as a result of cerebellar ablation and/or stimulation.

ISSN:0006-8977    

DOI:10.1159/000315995

出版商:S. Karger AG    

年代:1984

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000121318

出版商:S. Karger AG    

年代:1984

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000121319

出版商:S. Karger AG    

年代:1984

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000121320

出版商:S. Karger AG    

年代:1984

数据来源: Karger