Efferent connections of the centrum medianum of the cat thalamus revealed by autoradiography

1984 ◽  
Vol 16 (2) ◽  
pp. 186-191
Author(s):  
T. S. Sotnichenko ◽  
L. A. Istomina
Keyword(s):  
Efferent Connections ◽  
Centrum Medianum

Efferent connections of the substantia nigra in the cat

1965 ◽  
Vol 11 (4) ◽  
pp. 474-482 ◽  
Author(s):  
Adel Afifi ◽  
William W. Kaelber
Keyword(s):  
Substantia Nigra ◽  
Efferent Connections

scholarly journals Changes in Prefrontal Cortex–Thalamic Circuitry after Acoustic Trauma

Biomedicines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 77
Author(s):  
Kristin M. Barry ◽  
Donald Robertson ◽  
Wilhelmina H. A. M. Mulders
Keyword(s):  
Electrical Stimulation ◽  
Prefrontal Cortex ◽  
Auditory System ◽  
Acoustic Trauma ◽  
Neuron Activity ◽  
Compensatory Mechanism ◽  
Efferent Connections ◽  
Medial Geniculate ◽  
Central Auditory Pathways ◽  
Stimulation Of

In the adult auditory system, loss of input resulting from peripheral deafferentation is well known to lead to plasticity in the central nervous system, manifested as reorganization of cortical maps and altered activity throughout the central auditory pathways. The auditory system also has strong afferent and efferent connections with cortico-limbic circuitry including the prefrontal cortex and the question arises whether this circuitry is also affected by loss of peripheral input. Recent studies in our laboratory showed that PFC activation can modulate activity of the auditory thalamus or medial geniculate nucleus (MGN) in normal hearing rats. In addition, we have shown in rats that cochlear trauma resulted in altered spontaneous burst firing in MGN. However, whether the PFC influence on MGN is changed after cochlear trauma is unknown. We investigated the effects of electrical stimulation of PFC on single neuron activity in the MGN in anaesthetized Wistar rats 2 weeks after acoustic trauma or sham surgery. Electrical stimulation of PFC showed a variety of effects in MGN neurons both in sham and acoustic trauma groups but inhibitory responses were significantly larger in the acoustic trauma animals. These results suggest an alteration in functional connectivity between PFC and MGN after cochlear trauma. This change may be a compensatory mechanism increasing sensory gating after the development of altered spontaneous activity in MGN, to prevent altered activity reaching the cortex and conscious perception.

Afferent and efferent connections of the interpeduncular nucleus with special reference to circuits involving the habenula and raphe nuclei

2017 ◽  
Vol 525 (10) ◽  
pp. 2411-2442 ◽  
Author(s):  
Leandro B. Lima ◽  
Debora Bueno ◽  
Fernanda Leite ◽  
Stefani Souza ◽  
Luciano Gonçalves ◽  
...  
Keyword(s):  
Special Reference ◽  
Raphe Nuclei ◽  
Interpeduncular Nucleus ◽  
Efferent Connections ◽  
Raphé Nuclei

scholarly journals Efferent connections of the parvalbumin-positive (PV1) nucleus in the lateral hypothalamus of rodents

2013 ◽  
Vol 521 (14) ◽  
pp. 3133-3153 ◽  
Author(s):  
Marco R. Celio ◽  
Alexandre Babalian ◽  
Quan Hue Ha ◽  
Simone Eichenberger ◽  
Laurence Clément ◽  
...  
Keyword(s):  
Lateral Hypothalamus ◽  
Efferent Connections

Receptive-field properties and neuronal connectivity in striate and parastriate cortex of contour-deprived cats

1976 ◽  
Vol 39 (3) ◽  
pp. 613-630 ◽  
Author(s):  
W. Singer ◽  
F. Tretter
Keyword(s):  
Electrical Stimulation ◽  
Receptive Field ◽  
Visual Experience ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Connectivity Pattern ◽  
Area 18 ◽  
Efferent Connections ◽  
Receptive Field Properties ◽  
Areas 17 And 18

An attempt was made to relate the alterations of cortical receptive fields as they result from binocular visual deprivation to changes in afferent, intrinsic, and efferent connections of the striate and parastriate cortex. The experiments were performed in cats aged at least 1 jr with their eyelids sutured closed from birth.The results of the receptive-field analysis in A17 confirmed the reduction of light-responsive cells, the occasional incongruity of receptive-field properties in the two eyes, and to some extent also the loss of orientation and direction selectivity as reported previously. Other properties common to numerous deprived receptive fields were the lack of sharp inhibitory sidebands and the sometimes exceedingly large size of the receptive fields. Qualitatively as well as quantitatively, similar alterations were observed in area 18. A rather high percentage of cells in both areas had, however, preserved at least some orientation preference, and a few receptive fields had tuning properties comparable to those in normal cats. The ability of area 18 cells in normal cats to respond to much higher stimulus velocities than area 17 cells was not influenced by deprivation.The results obtained with electrical stimulation suggest two main deprivation effects: 1) A marked decrease in the safety factor of retinothalamic and thalamocortical transmission. 2) A clear decrease in efficiency of intracortical inhibition. But the electrical stimulation data also show that none of the basic principles of afferent, intrinsic, and efferent connectivity is lost or changed by deprivation. The conduction velocities in the subcortical afferents and the differentiation of the afferents to areas 17 and 18 into slow- and fast-conducting projection systems remain unaltered. Intrinsic excitatory connections remain functional; this is also true for the disynaptic inhibitory pathways activated preferentially by the fast-conducting thalamocortical projection. The laminar distribution of cells with monosynaptic versus polsynaptic excitatory connections is similar to that in normal cats. Neurons with corticofugal axons remain functionally connected and show the same connectivity pattern as those in normal cats. The nonspecific activation system from the mesencephalic reticular formation also remains functioning both at the thalamic and the cortical level.We conclude from these and several other observations that most, if not all, afferent, intrinsic, and efferent connections of areas 17 and 18 are specified from birth and depend only little on visual experience. This predetermined structural plan, however, allows for some freedom in the domain of orientation tuning, binocular correspondence, and retinotopy which is specified only when visual experience is possible.

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