The Extraction of Frequency-Specific Information from Electrical Stimulation of the Medial Geniculate Body

1973 ◽  
Author(s):  
Frederick W. Mis ◽  
John W. Moore
Keyword(s):  
Electrical Stimulation ◽  
Medial Geniculate Body ◽  
Specific Information ◽  
Medial Geniculate ◽  
Stimulation Of

Corticofugal Projection Inhibits the Auditory Thalamus Through the Thalamic Reticular Nucleus

2008 ◽  
Vol 99 (6) ◽  
pp. 2938-2945 ◽  
Author(s):  
Zhuo Zhang ◽  
Chun-Hua Liu ◽  
Yan-Qin Yu ◽  
Kenji Fujimoto ◽  
Ying-Shing Chan ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Medial Geniculate Body ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Inhibitory Effects ◽  
Inhibitory Pathway ◽  
Inhibitory Postsynaptic Potentials ◽  
Medial Geniculate ◽  
Inferior Colliculi ◽  
Stimulation Of

Electrical stimulation of the auditory cortex (AC) causes both facilitatory and inhibitory effects on the medial geniculate body (MGB). The purpose of this study was to identify the corticofugal inhibitory pathway to the MGB. We assessed two potential circuits: 1) the cortico-colliculo-thalamic circuit and 2) cortico-reticulo-thalamic one. We compared intracellular responses of MGB neurons to electrical stimulation of the AC following bilateral ablation of the inferior colliculi (IC) or thalamic reticular nucleus (TRN) in anesthetized guinea pigs. Cortical stimulation with intact TRN could cause strong inhibitory effects on the MGB neurons. The corticofugal inhibition remained effective after bilateral IC ablation, but it was minimized after the TRN was lesioned with kainic acid. Synchronized TRN neuronal activity and MGB inhibitory postsynaptic potentials (IPSPs) were observed with multiple recordings. The results suggest that corticofugal inhibition traverses the corticoreticulothalamic pathway, indicating that the colliculi-geniculate inhibitory pathway is probably only for feedforward inhibition.

The functional anatomy of middle-latency auditory evoked potentials: thalamocortical connections

1992 ◽  
Vol 68 (2) ◽  
pp. 425-431 ◽  
Author(s):  
S. Di ◽  
D. S. Barth
Keyword(s):  
Electrical Stimulation ◽  
Auditory Cortex ◽  
Evoked Potentials ◽  
Linear Combination ◽  
Evoked Potential ◽  
Medial Geniculate Body ◽  
Cortex Area ◽  
Medial Geniculate ◽  
Potential Complex ◽  
Stimulation Of

1. An 8 x 8-channel microelectrode array was used to map epicortical field potentials from a 4.375 x 4.375-mm2 area in the right parietotemporal neocortex of four rats. Potentials were evoked with bilaterally presented click stimuli and with electrical stimulation of the ventral and dorsal divisions of the medial geniculate body. 2. Epicortical responses to click stimuli replicated earlier findings. The responses consisted of a positive-negative biphasic waveform (P1a and N1) in the region of primary auditory cortex (area 41) and a positive monophasic waveform (P1b) in the region of secondary auditory cortex (area 36). Two potential patterns, one at the latency of the N1 and the other at the latency of the P1b, were used to represent activation of cells within areas 41 and 36. A linear combination of these patterns was sufficient to explain from 90 to 94% of the variance of the evoked potential complex at all latencies. 3. In the same animals, epicortical responses to electrical stimulation of the ventral and dorsal divisions of the medial geniculate body were also localized to areas 41 and 36, respectively. A linear combination of potential patterns from these separate stimulation conditions was sufficient to explain from 80 to 93% of the variance of the original click-evoked potential complex at all latencies. 4. These data provide functional evidence for anatomically defined topographical thalamocortical projections to primary and secondary auditory cortex. They suggest that short-latency cortical evoked potentials (10-60 ms poststimulus) are dominated by parallel thalamocortical activation of areas 41 and 36.

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.

AN ASCENDING PATHWAY FOR RELEASE OF PROLACTIN IN THE BRAIN OF THE RABBIT

1969 ◽  
Vol 45 (1) ◽  
pp. 111-120 ◽  
Author(s):  
J. S. TINDAL ◽  
G. S. KNAGGS
Keyword(s):  
Electrical Stimulation ◽  
Medial Geniculate Body ◽  
Posterior Hypothalamus ◽  
Implanted Electrodes ◽  
Oxytocin Release ◽  
Central Grey Matter ◽  
Medial Geniculate ◽  
Monopolar Electrodes ◽  
Milk Ejection Reflex ◽  
The Brain

SUMMARY Rabbits in pentobarbitone anaesthesia were implanted bilaterally with a pair of monopolar electrodes in the brainstem. Approximately 10 days after the operation, pseudopregnancy was induced by i.v. injection of human chorionic gonadotrophin, and 1 week later the rabbits received electrical stimulation with square-wave pulses through the implanted electrodes for two periods of 30 min. daily for 11 days. At autopsy on the following day the mammary glands were inspected for occurrence of lactogenesis and sites of electrode tips in the brain were determined histologically. Lactogenesis, indicating release of prolactin, occurred when electrical stimulation had been applied to sites in the lateral mesencephalic tegmentum and further forward in a region medio-ventral to the medial geniculate body. Passing rostrally, the pathway moved medially and then forwards in association with the extreme rostral central grey matter, and was traced as far forward as the posterior hypothalamus where sites were found close to, but not involving, the mammillo-thalamic tracts. When compared with our previous studies on the afferent path of the milk-ejection reflex in this species, the ascending path for release of both oxytocin and prolactin appears to be the same in the mesencephalon. However, whereas the ascending path for oxytocin release bifurcates on each side into dorsal and ventral paths which reunite in the posterior hypothalamus, that for prolactin release appears to follow only the dorsal path, since stimulation of the subthalamus, through which the ventral path passes, was ineffective. It is proposed that the pathway traced in the present study represents the mesencephalic and posterior diencephalic route by which impulses initiated by the suckling stimulus attain the hypothalamus to evoke release of prolactin from the adenohypophysis.

Stimulation-mapping of the upper human auditory pathway

1973 ◽  
Vol 38 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Ronald R. Tasker ◽  
L. W. Organ
Keyword(s):  
Electrical Stimulation ◽  
Auditory Cortex ◽  
Brain Stem ◽  
Inferior Colliculus ◽  
Primary Auditory Cortex ◽  
Auditory Pathway ◽  
Association Cortex ◽  
Content Type ◽  
Medial Geniculate ◽  
Stimulation Of

✓ Auditory hallucinations were produced by electrical stimulation of the human upper brain stem during stereotaxic operations. The responses were confined to stimulation of the inferior colliculus, brachium of the inferior colliculus, medial geniculate body, and auditory radiations. Anatomical confirmation of an auditory site was obtained in one patient. The hallucination produced was a low-pitched nonspecific auditory “paresthesia” independent of the structure stimulated, the conditions of stimulation, or sonotopic factors. The effect was identical to that reported from stimulating the primary auditory cortex, and virtually all responses were contralateral. These observations have led to the following generalizations concerning electrical stimulation of the somesthetic, auditory, vestibular, and visual pathways within the human brain stem: the hallucination induced in each is the response to comparable conditions of stimulation, is nonspecific, independent of stimulation site, confined to the primary pathway concerned, chiefly contralateral, and identical to that induced by stimulating the corresponding primary auditory cortex. No sensory responses are found in the brain stem corresponding to those from the sensory association cortex.

scholarly journals Inhibition of Experimental Tinnitus With High Frequency Stimulation of the Rat Medial Geniculate Body

2018 ◽  
Vol 22 (4) ◽  
pp. 416-424 ◽  
Author(s):  
Gusta van Zwieten ◽  
Marcus L. F. Janssen ◽  
Jasper V. Smit ◽  
A. Miranda L. Janssen ◽  
Milaine Roet ◽  
...  
Keyword(s):  
High Frequency ◽  
Medial Geniculate Body ◽  
High Frequency Stimulation ◽  
Medial Geniculate ◽  
Frequency Stimulation ◽  
Stimulation Of
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