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Thalamus

About: Thalamus is a research topic. Over the lifetime, 9087 publications have been published within this topic receiving 563833 citations. The topic is also known as: thalamencephalon & Tálamo dorsal.


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Journal ArticleDOI
TL;DR: In this paper, it was shown that reticular activation is associated with the activation of the reticular formation of the brain stem, and that reticulus activation can be induced by low frequency stimulation of the diffuse thalamic projection system, rather than intra-cortical spread following the arrival of afferent impulses at the sensory receiving areas of the cortex.

4,014 citations

Journal ArticleDOI
TL;DR: The OMPFC appears to function as a sensory-visceromotor link, especially for eating, which appears to be critical for the guidance of reward-related behavior and for setting of mood.
Abstract: This paper reviews architectonic subdivisions and connections of the orbital and medial prefrontal cortex (OMPFC) in rats, monkeys and humans. Cortico-cortical connections provide the basis for recognition of 'medial' and 'orbital' networks within the OMPFC. These networks also have distinct connections with structures in other parts of the brain. The orbital network receives sensory inputs from several modalities, including olfaction, taste, visceral afferents, somatic sensation and vision, which appear to be especially related to food or eating. In contrast, the medial network provides the major cortical output to visceromotor structures in the hypothalamus and brainstem. The two networks have distinct connections with areas of the striatum and mediodorsal thalamus. In particular, projections to the nucleus accumbens and the adjacent ventromedial caudate and putamen arise predominantly from the medial network. Both networks also have extensive connections with limbic structures. Based on these and other observations, the OMPFC appears to function as a sensory-visceromotor link, especially for eating. This linkage appears to be critical for the guidance of reward-related behavior and for setting of mood. Imaging and histological observations on human brains indicate that clinical depressive disorders are associated with specific functional and cellular changes in the OMPFC, including activity and volume changes, and specific changes in the number of glial cells.

2,522 citations

Journal ArticleDOI
TL;DR: The results demonstrate that local neuronal populations in the visual cortex engage in stimulus-specific synchronous oscillations resulting from an intracortical mechanism, and may provide a general mechanism by which activity patterns in spatially separate regions of the cortex are temporally coordinated.
Abstract: In areas 17 and 18 of the cat visual cortex the firing probability of neurons, in response to the presentation of optimally aligned light bars within their receptive field, oscillates with a peak frequency near 40 Hz. The neuronal firing pattern is tightly correlated with the phase and amplitude of an oscillatory local field potential recorded through the same electrode. The amplitude of the local field-potential oscillations are maximal in response to stimuli that match the orientation and direction preference of the local cluster of neurons. Single and multiunit recordings from the dorsal lateral geniculate nucleus of the thalamus showed no evidence of oscillations of the neuronal firing probability in the range of 20-70 Hz. The results demonstrate that local neuronal populations in the visual cortex engage in stimulus-specific synchronous oscillations resulting from an intracortical mechanism. The oscillatory responses may provide a general mechanism by which activity patterns in spatially separate regions of the cortex are temporally coordinated.

2,404 citations

Journal ArticleDOI
03 Jun 1988-Science
TL;DR: Fos immunohistochemistry provides a cellular method to label polysynaptically activated neurons and thereby map functional pathways in response to polysynaptic activation.
Abstract: The proto-oncogene c-fos is expressed in neurons in response to direct stimulation by growth factors and neurotransmitters. In order to determine whether the c-fos protein (Fos) and Fos-related proteins can be induced in response to polysynaptic activation, rat hindlimb motor/sensory cortex was stimulated electrically and Fos expression examined immunohistochemically. Three hours after the onset of stimulation, focal nuclear Fos staining was seen in motor and sensory thalamus, pontine nuclei, globus pallidus, and cerebellum. Moreover, 24-hour water deprivation resulted in Fos expression in paraventricular and supraoptic nuclei. Fos immunohistochemistry therefore provides a cellular method to label polysynaptically activated neurons and thereby map functional pathways.

1,962 citations

Journal ArticleDOI
TL;DR: The differential projections from the dorsal raphe and median raphe nuclei of the midbrain were autoradiographically traced in the rat brain after 3H‐proline micro‐injections to identify six ascending fiber tracts.
Abstract: The differential projections from the dorsal raphe and median raphe nuclei of the midbrain were autoradiographically traced in the rat brain after 3H-proline micro-injections. Six ascending fiber tracts were identified, the dorsal raphe nucleus being the sole source of four tracts and sharing one with the median raphe nucleus. The tracts can be classified as those lying within the medial forebrain bundle (dorsal raphe forebrain tract and the median raphe forebrain tract) and those lying entirely outside (dorsal raphe arcuate tract, dorsal raphe periventricular tract, dorsal raphe cortical tract, and raphe medial tract). The dorsal raphe forebrain tract lies in the ventrolateral aspect of the medial forebrain bundle (MFB) and projects mainly to lateral forebrain areas (e.g., basal ganglion, amygdala, and the pyriform cortex). The median raphe forebrain tract lies in the ventromedial aspect of the MFB and projects to medial forebrain areas (e.g., cingulate cortex, medial septum, and hippocampus). The dorsal raphe cortical tract lies ventrolaterally to the medial longitudinal fasciculus and projects to the caudate-putamen and the parieto-temporal cortex. The dorsal raphe periventricular tract lies immediately below the midbrain aqueduct and projects rostrally to the periventricular region of the thalamus and hypothalamus. The dorsal raphe arcuate tract curves laterally from the dorsal raphe nucleus to reach the ventrolateral edge of the midbrain and projects to ventrolateral geniculate body nuclei and the hypothalamic suprachiasmatic nuclei. Finally, the raphe medial tract receives fibers from both the median and dorsal raphe nuclei and runs ventrally between the fasciculus retroflexus and projects to the interpeduncular nucleus and the midline mammillary body. Further studies were done to test whether the fiber tracts travelling in the MFB contained 5-HT. Unilateral (left) injections of 5,7-dihydroxytryptamine (5 μgm/400 nl) 18 days before midbrain raphe microinjections of 3H-proline produced a reduction in the grain concentrations in all the ascending fibers within the MFB. Furthermore, pharmacological and behavioural evidence was obtained to show that the 5-HT system had been unilaterally damaged; these animals displayed preferential ipsilateral turning in a rotameter which was strongly reversed to contralateral turning after 5-hydroxytryptophan administration. The results show that DR and MR nuclei have numerous ascending projections whose axons contain the transmitter 5-HT. The results agree with the neuroanatomical distribution of the 5-HT system previously determined biochemically, histochemically, and neurophysiologically. The midbrain serotonin system seems to be organized by a series of fiber pathways. The fast transport rate in these fibers was found to be about 108 mm/day.

1,895 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023423
20221,001
2021268
2020229
2019224
2018178