摘要:

Chicks with dorsal midIine hyperstriatal lesions (DMHA) were trained to prefer red to yellow food before being presented with a choice from a plain floor (experiment 1) or a pebble-encrusted floor (experiment 2). On both tests DMHAs showed a relatively stable pattern of choice compared to controls. In experiment 1, controls decreased their intake of non-preferred yellow food on day 1, but this sharply increased on subsequent tests. In experiment 2, controls increased the number of pebbles pecked, and thus, the length of a run of pecks on non-preferred food changed with respect to DMHAs. Chicks with more lateral lesions gave patterns distinct from controls and DMHAs showing an initial disruption of the trained preference. The choice of chicks with more ventral or posterior lesions could not be distinguished from controls. The lack of lability of the trained feeding behaviour of DMHA-lesioned chicks is interpreted as consistent with the suggestion that the DMHA may have functions which are similar to the ''hippocampus'' of mammals.

ISSN:0006-8977    

DOI:10.1159/000123801

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

A single electrode was implanted in each of ten cats at a point in the ventral midbrain from which nonaffective biting attack on a rat could be elicited by electrical stimulation. A lesion was then made which was just large enough to eliminate the elicitation of attack at suprathreshold intensities from that electrode. After post-lesion survival times of 3–14 days the cats were sacrificed, and the degeneration resulting from the lesions was followed with the use of modified Nauta silver stains. Four additional cats were used as anatomic controls. Degenerating fibers were observed to descend bilaterally through the midbrain, pontine, and medullary tegmentum to the vicinity of the principal sensory and motor nuclei of the trigeminal nerve. There was, in addition, evidence of degenerating terminals within the nucleus of the facial nerve and the spinal nucleus of the trigeminal nerve. Of particular note was the observation that the degenerating fibers in the region of the nucleus of the spinal tract of the trigeminal nerve terminated in glomeruli in the rostral portion of the nucleus. Degenerating fibers ascending from the lesion were found to course along the medial forebrain bundle into the hypothalamus and the midline thalamus in a pattern very similar to that previously demonstrated after lesions of biting attack sites in the hypothalamus. The role that the neural pathways associated with ventral midbrain attack sites might play in the mediation of behavior patterns which are elicited during attack stimulation was discussed and it was concluded that the demonstrated neural pathway could provide a cogent explanation for some of the properties of centrally elicited attack behavio

ISSN:0006-8977    

DOI:10.1159/000123802

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Among living hominoids, skull asymmetry tends to characterize only those possessing lateralized brains. Asymmetry in casts of skulls of fossil hominids suggests that Neanderthal man and Homo erectus possessed lateralized brains.

ISSN:0006-8977    

DOI:10.1159/000123803

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Parts of the rails neocortex were mapped for sites where electrical stimulation, square waves at 10/sec, will suppress a bar-press response for food. Effective sites were found in the frontal pole and over most of the frontal dorsolateral cortex. Within these regions the strongest inhibitory influences were at sites in the frontal pole and adjacent frontal cortex, and at sites along the midline. These data generally agree with results of previous cortical ablation studies, but they suggest that inhibitory processes are more widespread in the dorsolateral cortex than these studies indicated.

ISSN:0006-8977    

DOI:10.1159/000123804

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

To study the somatosensory input to the inferior colliculus, lesions were made in the dorsal column nuclei of the hedgehog, tree shrew, slow loris, marmoset and African green monkey, and spinal cord of the hedgehog, tree shrew and slow loris. The degenerating fibers were stained with silver impregnation methods. The dorsal column system projects primarily to an area lateral to the central nucleus of the inferior colliculus, whereas the spinotectal projection is primarily to the medial region in the hedgehog and medial and dorsal regions in the tree shrew and slow loris. Both fiber systems are quantitatively quite constant in the various species. It is apparent from published data on a variety of mammals that the central nucleus is primarily part of the auditory system in which the intercollicular area is involved only indirectly via projections from the central nucleus and auditory cortex. In nonmammalian vertebrates, the data available suggest that there is a comparable area in the mesencephalon that is involved with somatosensory as well as auditory sensation. Since low frequency stimulation, generally characterized as vibration, stimulates both modalities, the intercollicular area may be the input side of a mechanism for alerting the animal to vibratory stimuli.

ISSN:0006-8977    

DOI:10.1159/000123805

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

The direct projections of the spinal cord onto the cerebellar cortex were traced using the Nauta method following the placement of cervical or thoracic spinal cord hemisections in six brush-tailed possums. Degenerating fibres reached the cerebellum via typically placed dorsal and ventral spinocerebellar tracts. Although complete differentiation of the terminations of ventral and dorsal tracts was not possible, it was found that the dorsal tract terminates mainly in the ipsilateral anterior lobe vermis and in the pyramis and paraflocculus of the ipsilateral posterior lobe. The ventral tract ends almost entirely in the anterior lobe with the majority of fibres terminating contralateral to the side of the hemisection. Within the anterior lobe, degenerating fibres were distributed fairly symmetrically about the midline in five sagittal rows. Three such rows were found in the posterior lobe. The relatively small number of rows in the anterior lobe (five) may be a characteristic feature of marsupials when compared with eutherian mammals.

ISSN:0006-8977    

DOI:10.1159/000123806

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Arousal induced by tail pinching results in stimulus-bound feeding, licking and gnawing in male rats during the aphagic and adipsic phase that follows electrolytic damage to the lateral hypothalamus (LH). Such stimulus-bound behavior is very similar to electrically induced stimulus-bound behavior. Furthermore, brain-damaged animals during tail pinch-induced drinking trials are responsive to the sensory properties of the test liquid. Chocolate milk is consumed but tap water is actively rejected. Tail pinch to sham-operated control rats failed to induce such behavior; instead, it induced rage behavior towards the hand that pinched the tail. The results support the conclusion that rats with LH lesions require an arousing stimulus for feeding but that the same externally applied arousing stimulus enhances active rejection of tap water.

ISSN:0006-8977    

DOI:10.1159/000123807

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Electrical stimulation of the midbrain call areas was used to drive medullary neurons. Their activity was recorded with fine (25 µm) wire electrodes that allowed the nearer ones to be resolved as units. Syringeal (hypoglossal) motor-neurons were identified by antidromic activation. Various units were turned on, speeded, slowed, stopped, or caused to fire in repetitive bursts. All units that were antidromically activated by hypoglossal stimulation fired in repetitive bursts with a rhythm which closely resembled that of calling. Many other units also fired in this bursting pattern, and the large majority of them were found at the obex or caudal to it despite extensive search rostrally. The nature of likely inputs to the medullary call neurons is discussed

ISSN:0006-8977    

DOI:10.1159/000123808

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

A species of prosimian (bush baby, Galago senegalensis) was tested on delayed-alternation and spatial-reversal learning before and after ablation of prefrontal cortex. The results show that normal performance on the two behavioral tasks depend on different subdivisions of the MD-prefrontal system. Delayed alternation is disrupted by prefrontal lesions which cause degeneration in the lateral division of MD while spatial-reversal learning is disrupted by lesions causing degeneration of the medial division of MD. Therefore, the bush baby prefrontal system can be subdivided either on behavioral or anatomical grounds into at least two chief parts. Because of several similarities in the MD-prefrontal system of bush baby and monkey despite their remote common ancestry, it can be concluded that the differentiation of the MD-prefrontal system into distinct divisions and the involvement of this system in delayed alternation and spatial reversal are features probably as old as the order Primates itself. It can be further concluded that the further evolution of the anthropoid variety of prefrontal system beyond this common primate stage probably depended on selective pressure on abilities other than those measured here.

ISSN:0006-8977    

DOI:10.1159/000123809

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

The bullfrog amphibian papilla, which has been identified as the peripheral source of two of the three types of auditory axon in that animal, is shown to have a continual distribution of receptor types based on surface topography, but a dichotomy of types based on the adjacent tectorium and its apparent mechanical linkage to the receptors and their supporting cells and a second dichotomy based on receptor polarization patterns. Each dichotomy divides the receptors into two approximately equal populations and thus might correspond to the previously observed division of primary axons into two frequency-response types.

ISSN:0006-8977    

DOI:10.1159/000123810

出版商:S. Karger AG    

年代:1976

数据来源: Karger