scholarly journals SPREAD OF DIRECTLY EVOKED RESPONSES IN THE CAT'S CEREBRAL CORTEX

1959 ◽  
Vol 42 (4) ◽  
pp. 761-777 ◽  
Author(s):  
V. B. Brooks ◽  
P. S. Enger
Keyword(s):  
Cerebral Cortex ◽  
Pyramidal Cells ◽  
Neuromuscular Blocking ◽  
Brain Circulation ◽  
Direct Stimulation ◽  
Synaptic Excitation ◽  
Excitatory State ◽  
Supramaximal Stimulation ◽  
The Brain ◽  
Stimulation Of

A study has been made of the electrical responses to direct stimulation of the exposed cerebral cortex of cats that had been immobilized with neuromuscular blocking drugs, and whose muscle and skin wounds had been locally anesthetized. The characteristics and spread of the first and second surface-negative responses are described. It was found that the first surface-negative response to weak stimuli decays linearly to zero at 3 to 6 mm. from the point of stimulation. Intermediate stimuli cause farther and non-linear spread: responses are re-initiated, or reinforced, at 6 to 10 mm.; and supramaximal stimulation produces reinforcement both at 5 and at 10 mm. The conduction velocity of these responses is uniform for linear spread (0.7 to 2.0 m./sec.), but reinforced responses occur 1 to 3 msec. earlier than would be expected for simple conduction. The phenomenon of re-initiation, or reinforcement, depends upon the excitatory state of the brain; circulation and previous stimulation are important factors. Connections outside the gyrus matter only in so far as they provide other sources of general excitation. It is concluded that two types of transmission: slow and fast, can lead to generation of similar surface-negative responses. The suggestion is made that the slowly conducted surface-negative potentials are due to direct or to synaptic excitation of pyramidal cells; while the responses with shortened latency are initiated synaptically on other pyramidal cells after fast conduction at about 10 m./sec. in tangential fibres.

scholarly journals К. Schaffer: Zur feineren Struktur der Hirnrinde und über funktionelle Bedeutung der Nervenzellenfortsätze. Arch. f. Mikrosk. Anatomie. XLVIIL 4 Heft. 1897. S. S. 550—572

2020 ◽  
Vol V (3) ◽  
pp. 167-169
Author(s):  
A. E. Smirnov
Keyword(s):  
Cerebral Cortex ◽  
Opposite Direction ◽  
Molecular Layer ◽  
Pyramidal Cells ◽  
Special Group ◽  
The Brain ◽  
Axial Cylinder

The author's research refers to the anterior cerebral cortex of a newborn dog. The author studies in detail the so-called tiny pyramidal cells, lying between the pluripolar cells of the molecular layer and the small (true) pyramidal cells. Already R. y Cajal drew attention to polygonal or core-shaped cells, the cells that lie behind the layer of the outermost cells (pluripolare Nervenzellen von R. y Cajal), but did not separate them into a special group, believing that these cells were gradually changing vid, go into the small pyramids, to which he numbered them. Schaffer separates these cells into a special group, calling it the layer of surface polymorphic cells. These cells have a dark variety of shapes (fusiform, oval, roundish, pear-shaped, polygonal) and lie in approximately four (4) rows. Dendrites go then, mainly, in two opposite directions (for fusiform cells), then they move radially in all directions (for round and polygonal cells). The number of dendrites is sometimes strikingly abundant. Dendrites going to the surface of the brain reach it, while dendrites of the opposite direction sometimes go down to the ammonium formations of the cerebral cortex. Special attention should be paid to the axial cylinder of the disassembled cells; on the basis of the features of this appendix, the author distinguishes 3 types of disassembled cells.

A unitary hypothesis of mind-brain interaction in the cerebral cortex

1990 ◽  
Vol 240 (1299) ◽  
pp. 433-451 ◽  
Keyword(s):  
Cerebral Cortex ◽  
Pyramidal Cells ◽  
Neuronal Structure ◽  
Mental Experience ◽  
Effective Selection ◽  
Global Nature ◽  
The Mind ◽  
Mental Events ◽  
Apical Dendrites ◽  
The Brain

A brief introduction to the brain-mind problem leads on to a survey of the neuronal structure of the cerebral cortex. It is proposed that the basic receptive units are the bundles or clusters of apical dendrites of the pyramidal cells of laminae V and III-II as described by Fleischhauer and Peters and their associates. There are up to 100 apical dendrites in these receptive units, named dendrons. Each dendron would have an input of up to 100000 spine synapses. There are about 40 million dendrons in the human cerebral cortex. A study of the influence of mental events on the brain leads to the hypothesis that all mental events, the whole of the World 2 of Popper, are composed of mental units, each carrying its own characteristic mental experience. It is further proposed that each mental unit, named psychon, is uniquely linked to a dendron. So the mind-brain problem reduces to the interaction between a dendron and its psychon for all the 40 million linked units. In my 1986 paper ( Proc. R. Soc. Lond . B 227, 411-428) on the mind-brain problem, there was developed the concept that the operation of the synaptic microsites involved displacement of particles so small that they were within range of the uncertainty principle of Heisenberg. The psychon-dendron interaction provides a much improved basis for effective selection by a process analogous to a quantal probability field. In the fully developed hypothesis psychons act on dendrons in the whole world of conscious experiences and dendrons act on psychons in all perceptions and memories. It is shown how these interactions involve no violation of the conservation laws. There are great potentialities of these unitary concepts, for example as an explanation of the global nature of a visual experience from moment to moment. It would seem that there can be psychons not linked to dendrons, but only to other psychons, creating what we may call a psychon world.

scholarly journals Mechanistic Insights in NeuroD Potentiation of Mineralocorticoid Receptor Signaling

2019 ◽  
Vol 20 (7) ◽  
pp. 1575 ◽  
Author(s):  
Lisa van Weert ◽  
Jacobus Buurstede ◽  
Hetty Sips ◽  
Isabel Mol ◽  
Tanvi Puri ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Mood Disorders ◽  
Chromatin Remodeling ◽  
Mineralocorticoid Receptor ◽  
Protective Factor ◽  
Specific Binding ◽  
Transcription Factor Family ◽  
Direct Stimulation ◽  
The Brain ◽  
Stimulation Of

Mineralocorticoid receptor (MR)-mediated signaling in the brain has been suggested as a protective factor in the development of psychopathology, in particular mood disorders. We recently identified genomic loci at which either MR or the closely related glucocorticoid receptor (GR) binds selectively, and found members of the NeuroD transcription factor family to be specifically associated with MR-bound DNA in the rat hippocampus. We show here using forebrain-specific MR knockout mice that GR binding to MR/GR joint target loci is not affected in any major way in the absence of MR. Neurod2 binding was also independent of MR binding. Moreover, functional comparison with MyoD family members indicates that it is the chromatin remodeling aspect of NeuroD, rather than its direct stimulation of transcription, that is responsible for potentiation of MR-mediated transcription. These findings suggest that NeuroD acts in a permissive way to enhance MR-mediated transcription, and they argue against competition for DNA binding as a mechanism of MR- over GR-specific binding.

scholarly journals Iron Deposition in the Brain Following the Ischemia in a Rat Model of Ischemic Tolerance

2004 ◽  
Vol 47 (4) ◽  
pp. 285-288 ◽  
Author(s):  
Viera Danielisová ◽  
Miroslava Némethová ◽  
Jozef Burda
Keyword(s):  
Cerebral Cortex ◽  
Frontal Cortex ◽  
Rat Model ◽  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Ischemic Tolerance ◽  
Iron Deposition ◽  
Sham Operation ◽  
Vessel Occlusion ◽  
The Brain

Preconditioning of the brain by short-term ischemia increases brain tolerance to the subsequent severer ischemia. In this study, we investigated iron deposition in the cerebral cortex and the ischemic tolerance in a rat model of cerebral ischemia. Forebrain ischemia was induced by four-vessel occlusion for 5 min as ischemic preconditioning. Two days after preconditioning or after the sham-operation, the second ischemia was induced for 20 min. Changes in the cerebral cortex were examined after 1 to 8 weeks of recirculation following 20 min ischemia with or without preconditioning using the iron histochemistry. Granular deposits of the iron were found in the cytoplasm of the pyramidal cells in the layers III and V of the frontal cortex after 1 week of recirculation. When the rats were exposed to 5 min ischemia 2 days before 20 min lasting ischemia, the deposition of iron in the cytoplasm of the pyramidal cells in layers III and V of the frontal cortex was significantly lower during all periods of reperfusion. Preconditioning 5 min ischemia followed by 2 days of reperfusion before 20 min ischemia also prevented degeneration of the pyramidal neurons in layers III and V of the frontal cortex.

scholarly journals Changes in subjective experience elicited by direct stimulation of the human orbitofrontal cortex

Neurology ◽  
2018 ◽  
Vol 91 (16) ◽  
pp. e1519-e1527 ◽  
Author(s):  
Kieran C. R. Fox ◽  
Jennifer Yih ◽  
Omri Raccah ◽  
Shrita L. Pendekanti ◽  
Lauren E. Limbach ◽  
...  
Keyword(s):  
Orbitofrontal Cortex ◽  
Subjective Experience ◽  
Focal Epilepsy ◽  
Causal Link ◽  
Direct Stimulation ◽  
Sensory Experiences ◽  
Neurosurgical Patients ◽  
Intracranial Electrodes ◽  
The Brain ◽  
Stimulation Of

ObjectiveWe applied direct cortical stimulation (DCS) to the orbitofrontal cortex (OFC) in neurosurgical patients implanted with intracranial electrodes to probe, with high anatomic precision, the causal link between the OFC and human subjective experience.MethodsWe administered 272 instances of DCS at 172 OFC sites in 22 patients with intractable focal epilepsy (from 2011 to 2017), none of whom had seizures originating from the OFC.ResultsOur observations revealed a rich variety of affective, olfactory, gustatory, and somatosensory changes in the subjective domain. Elicited experiences were largely neutral or negatively valenced (e.g., aversive smells and tastes, sadness, and anger). Evidence was found for preferential left lateralization of negatively valenced experiences and strong right lateralization of neutral effects. Moreover, most of the elicited effects were observed after stimulation of OFC tissue around the transverse orbital sulcus, and none were seen in the most anterior aspects of the OFC.ConclusionsOur study yielded 3 central findings: first, a dissociation between the “silent” anterior and nonsilent middle/posterior OFC where stimulation clearly elicits changes in subjective experience; second, evidence that the OFC might play a causal role in integrating affect and multimodal sensory experiences; and third, clear evidence for left lateralization of negatively valenced effects. Our findings provide important information for clinicians treating OFC injury or planning OFC resection and scientists seeking to understand the brain basis for the integration of sensation, cognition, and affect.

The Physiological Mechanisms of 2 Hz Electroacupuncture: A Study Using Blink and H Reflex

2002 ◽  
Vol 30 (02n03) ◽  
pp. 369-378 ◽  
Author(s):  
Ching-Liang Hsieh ◽  
Chin-Hsin Wu ◽  
Jaung-Geng Lin ◽  
Chuang-Chien Chiu ◽  
Mike Chen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Cerebral Cortex ◽  
Brain Stem ◽  
Blink Reflex ◽  
H Reflex ◽  
Physiological Mechanisms ◽  
Zusanli Acupoint ◽  
The Right ◽  
The Brain ◽  
Stimulation Of

Our previous studies have shown that the cerebral cortex modulates the physiological mechanisms of acupuncture. However, the role of the brain stem and spinal cord in acupuncture remains unclear. The present study investigated the action of the brain stem and spinal cord in acupuncture. A total of eight healthy adult volunteers were studied. Electrical stimulation of the supraorbital nerve in the supraorbital foramen was used to evoke the blink reflex. Electrical stimulation of the posterior tibial nerve in the right popliteal fossa was used to evoke the H reflex. Electroacupuncture (EA) of 2 Hz was applied to the Zusanli acupoint in the right or left leg. The area of the R1 and R2 components of the blink reflex, and the greatest H/M ratio and H-M interval of the H reflex were measured before EA, during EA and at various post-EA periods. These data were analyzed quantitatively by a computerized electromyographic examination system. The results indicate that EA did not change the R1 and ipsilateral R2 components of the blink reflex. EA depressed the contralateral R2 component of the blink reflex 10 minutes and 40 minutes after the start of EA, but not after 5 minutes. EA applied to the Zusanli acupoint did not change the H/M ratio or the H-M interval of the H reflex. The results of this study indicate that 2 Hz EA of the Zusanli acupoint does not change the R1 component of the blink reflex, and the H/M ratio and the H-M interval of the H reflex, suggesting that 2 Hz EA does not change the monosynaptic reflex in the brain stem and spinal cord in humans. We also found that EA at 2-Hz depressed the contralateral but not the ipsilateral R2 component of the blink reflex, suggesting that longer pathways, perhaps including the cerebral cortex, may play a role in the physiological mechanisms responsible for the effectiveness of acupuncture.

Analysis of association fiber system in piriform cortex with intracellular recording and staining techniques

1984 ◽  
Vol 51 (1) ◽  
pp. 90-112 ◽  
Author(s):  
L. B. Haberly ◽  
J. M. Bower
Keyword(s):  
Intracellular Recording ◽  
Piriform Cortex ◽  
Pyramidal Cells ◽  
Excitatory Postsynaptic Potential ◽  
Fiber System ◽  
Direct Stimulation ◽  
Postsynaptic Potential ◽  
Staining Techniques ◽  
Monosynaptic Epsp ◽  
Stimulation Of

The piriform cortex of the opossum has been studied with intracellular recording and staining techniques. The experiments were designed to investigate the association fiber system, but the results have also revealed new properties of the afferent fiber system from the olfactory bulb and the inhibitory systems within the piriform cortex. Following shock stimulation of the lateral olfactory tract (LOT), the response of pyramidal cells consists of an initial excitatory postsynaptic potential (EPSP) followed by a long-lasting inhibitory postsynaptic potential (IPSP). The LOT-evoked EPSP consists of two components: an initial monosynaptic followed by a disynaptic component. The monosynaptic EPSP can be isolated by the use of conditioning LOT shocks to block the IPSP and disynaptic EPSP. The disynaptic EPSP can be demonstrated by cutting LOT fibers at the surface of the cortex to eliminate the monosynaptic EPSP and by the use of bicuculline to block the IPSP. The latency of the IPSP is sufficiently brief so that the disynaptic EPSP is blocked at presumed intrasomatic recording sites unless these experimental manipulations are carried out. In all histologically verified pyramidal cells in both layers II and III in which the appropriate tests were carried out, both mono- and disynaptic EPSP components were present. It was concluded on the basis of anatomical considerations, however, that a small number of pyramidal cells would be expected to receive only a disynaptic EPSP. Evidence that the LOT-evoked disynaptic EPSP is mediated, at least in part, by association axons was provided by direct stimulation of these fibers in layer III and by demonstrating that the EPSP is present distal to cuts that sever LOT axons. Direct stimulation of association axons in layer III evokes both a monosynaptic EPSP and a disynaptic IPSP in pyramidal cells at similar latencies. This IPSP is indistinguishable in properties from that evoked by LOT stimulation. Indirect evidence indicates that it is mediated via both feedforward and feedback mechanisms. In most neurons the association fiber-evoked EPSP is masked by the IPSP in response to single deep shocks but can be demonstrated by blocking the IPSP with a preceding LOT shock or by application of bicuculline. Intracellular injection of horseradish peroxidase (HRP) revealed that pyramidal cell axons give rise to an extensive system of local collaterals with a large number of synaptic terminal-like swellings in layer III. It is postulated that these collaterals synapse on both pyramidal and nonpyramidal cells.(ABSTRACT TRUNCATED AT 400 WORDS)

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