scholarly journals FIELD POTENTIALS PRODUCED BY THE PARALLEL FIBRE STIMULATION IN THE CEREBELLAR CORTEX

1969 ◽  
Vol 19 (1) ◽  
pp. 80-94 ◽  
Author(s):  
K. SASAKI ◽  
T. SHIMONO ◽  
S. KAWAGUCHI ◽  
Y. YONEDA
Keyword(s):  
Cerebellar Cortex ◽  
Field Potentials ◽  
Parallel Fibre

Nitric oxide contributes to functional hyperemia in cerebellar cortex

1995 ◽  
Vol 268 (5) ◽  
pp. R1153-R1162 ◽  
Author(s):  
C. Iadecola ◽  
J. Li ◽  
T. J. Ebner ◽  
X. Xu
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Catalytic Activity ◽  
Cerebellar Cortex ◽  
Ex Vivo ◽  
Molecular Layer ◽  
Nerve Fibers ◽  
Functional Hyperemia ◽  
Field Potentials ◽  
Doppler Flowmetry

We used the parallel fibers (PF) system of the cerebellar cortex as a model to investigate the role of nitric oxide (NO) in the increases in blood flow elicited by neural activation. Rats were anesthetized with halothane and ventilated. The vermis was exposed, and the site was superfused with Ringer (37 degrees C; pH 7.3-7.4). PF were stimulated electrically (100 muA; 30 Hz), and the associated changes in cerebellar cortex blood flow (BFcrb) were monitored by laser-Doppler flowmetry. The field potentials evoked by PF stimulation were recorded using microelectrodes. During Ringer superfusion (n = 7), PF stimulation increased BFcrb (+ 52 +/- 4%). Topical application of the NO synthase (NOS) inhibitor N omega-nitro-L-arginine (L-NNA; 0.1-1 mM) attenuated the increases in BFcrb dose dependently and by 50 +/- 4% at 1 mM (n = 9; P < 0.001; analysis of variance and Tukey's test). L-NNA (1 mM) inhibited NOS catalytic activity, assessed ex vivo using the citrulline assay, by 95 +/- 9% (P < 0.001). L-NNA did not influence the field potentials evoked by PF stimulation. D-NNA (1 mM; n = 6), the inactive stereoisomer of nitroarginine, did not attenuate the BFcrb response (P > 0.05). Methylene blue (1 mM; n = 7) reduced the response by 41 +/- 9% (P < 0.01) without affecting NOS catalytic activity (P < 0.05). The increases in BFcrb were not affected by lesioning the NOS-containing nerve fibers innervating cerebral vessels, indicating that these nerves are not the source of NO. Thus the increases in BFcrb elicited by activation of PF are, in part, mediated by NO produced in the molecular layer during neural activity. The results indicated that NO participates in the coupling of function activity to blood flow and support the hypothesis that NO is one of the mediators responsible for functional hyperemia in the central nervous system.

Local and Propagated Vascular Responses Evoked by Focal Synaptic Activity in Cerebellar Cortex

1997 ◽  
Vol 78 (2) ◽  
pp. 651-659 ◽  
Author(s):  
Costantino Iadecola ◽  
Guang Yang ◽  
Timothy J. Ebner ◽  
Gang Chen
Keyword(s):  
Cerebellar Cortex ◽  
Synaptic Activity ◽  
Field Potentials ◽  
Vascular Changes ◽  
Vasoactive Agents ◽  
Doppler Flowmetry ◽  
Vascular Responses ◽  
Cranial Window ◽  
Synaptic Release ◽  
Horizontal Beam

Iadecola, Costantino, Guang Yang, Timothy J. Ebner, and Gang Chen. Local and propagated vascular responses evoked by focal synaptic activity in cerebellar cortex. J. Neurophysiol. 78: 651–659, 1997. We investigated the local and remote vascular changes evoked by activation of the cerebellar parallel fibers (PFs). The PFs were stimulated (25–150 μA, 30 Hz) in halothane-anesthetized rats equipped with a cranial window. The changes in arteriolar and venular diameter produced by PF stimulation were measured with the use of a videomicroscopy system. Cerebellar blood flow (BFcrb) was monitored by laser Doppler flowmetry and the field potentials evoked by PF stimulation were recorded with the use of microelectrodes. PF stimulation increased the diameter of local arterioles (+26 ± 1%, mean ± SE) in the activated folium ( n = 10, P < 0.05). The vasodilation was greatest in smaller arterioles (16.5 ± 0.8 μm), was graded with the intensity of stimulation, and was less marked than the vasodilation produced by hypercapnia in comparably sized vessels (+58 ± 5%, CO2 pressure = 50–60 mmHg, n = 8). In addition, the vasodilation was greatest along the horizontal beam of activated PFs and was reduced in arterioles located away from the stimulated site in a rostrocaudal direction. The increases in vascular diameter were associated with increases in BFcrb in the activated area (+55 ± 4%, n = 5). PF stimulation increased vascular diameter (+10 ± 0.5%, n = 10) also in larger arterioles (30–40 μm) located in the folium adjacent to that in which the PFs were stimulated. Higher-order branches of these arterioles supplied the activated area. No field potentials were evoked by PF stimulation in the area where these upstream vessels were located. The data suggest that increased synaptic activity in the PF system produces a “local” hemodynamic response mediated by synaptic release of vasoactive agents and a “remote” response that is propagated to upstream arterioles from vessels residing in the activated folium. These propagated vascular responses are important in the coordination of segmental vascular resistance that is required to increase flow effectively during functional brain hyperemia.

Localization in the Cerebellar Hemisphere of Climbing-Fiber Responses Evoked from the Trigeminal Nerve in the Cat

1974 ◽  
Vol 52 (6) ◽  
pp. 1147-1153 ◽  
Author(s):  
T. S. Miles ◽  
J. D. Cooke ◽  
M. Wiesendanger
Keyword(s):  
Purkinje Cells ◽  
Cerebellar Cortex ◽  
Anterior Lobe ◽  
Cerebellar Hemisphere ◽  
Projection Area ◽  
Field Potentials ◽  
Facial Skin ◽  
Almost All ◽  
Climbing Fiber Responses ◽  
Stimulation Of

The area of cerebellar cortex to which climbing fibers (CF) project from trigeminal cutaneous afferents has been established in pentobarbital-anesthetized cats. This area is centered upon the ipsilateral lobule HVI, with some overlap onto adjoining folia of the anterior lobe (lobule V) and onto crus Ia of lobule HVIIA. At almost all points within the projection area, CF field potentials of various amplitudes could be elicited by stimulation of more than one trigeminal branch. Hence the general somatotopic arrangement was a complex pattern of inputs converging onto many points from spatially related areas of facial skin. Convergence from more than one nerve was also seen on 32 of 47 single Purkinje cells.

scholarly journals The Shape of Data: a Theory of the Representation of Information in the Cerebellar Cortex

2021 ◽  
Author(s):  
Mike Gilbert
Keyword(s):  
Cerebellar Cortex ◽  
Cell Group ◽  
Parallel Fibre ◽  
Circuit Input ◽  
Minimum Number ◽  
Fine Control ◽  
Group A ◽  
Rate Coding ◽  
Functional Equivalent ◽  
Mossy Fibres

AbstractThis paper presents a model of rate coding in the cerebellar cortex. The pathway of input to output of the cerebellum forms an anatomically repeating, functionally modular network, whose basic wiring is preserved across vertebrate taxa. Each network is bisected centrally by a functionally defined cell group, a microzone, which forms part of the cerebellar circuit. Input to a network may be from tens of thousands of concurrently active mossy fibres. The model claims to quantify the conversion of input rates into the code received by a microzone. Recoding on entry converts input rates into an internal code which is homogenised in the functional equivalent of an imaginary plane, occupied by the centrally positioned microzone. Homogenised means the code exists in any random sample of parallel fibre signals over a minimum number. The nature of the code and the regimented architecture of the cerebellar cortex mean that the threshold can be represented by space so that the threshold can be met by the physical dimensions of the Purkinje cell dendritic arbour and planar interneuron networks. As a result, the whole population of a microzone receives the same code. This is part of a mechanism which orchestrates functionally indivisible behaviour of the cerebellar circuit and is necessary for coordinated control of the output cells of the circuit. In this model, fine control of Purkinje cells is by input rates to the system and not by learning so that it is in conflict with the for-years-dominant supervised learning model.

Direct and relayed projection of periodontal receptor afferents to the cerebellum in the ferret

1987 ◽  
Vol 231 (1263) ◽  
pp. 199-216 ◽  
Keyword(s):  
Cerebellar Cortex ◽  
Evidence Based ◽  
Field Potentials ◽  
Muscle Spindle Afferents ◽  
Latency Analysis ◽  
Jaw Muscle ◽  
To Come ◽  
Periodontal Afferent ◽  
Mossy Fibres ◽  
Stimulation Of

Field potentials in the cerebellar cortex of the ferret have been studied in response to stimulation of alveolar, muscular and cutaneous branches of the trigeminal nerve. Responses from the alveolar nerves are unusual in their very short latency. Evidence based on latency analysis, frequency following and comparison with other well-known inputs supports the view that the earliest field potentials are due to direct, unrelayed afferents, which terminate as mossy fibres. There is, in addition, a monosynaptically relayed afferent path via mossy fibres. The alveolar nerve afferents concerned with the direct projection are shown to come from periodontal mechanoreceptors and not from cutaneous receptors. No such connections are found from jaw-muscle spindle afferents. The direct and relayed periodontal pathways are both ipsilateral and crossed. They terminate in the cerebellar cortex in the parvermal region of lobules IV, V and VI. The functional significance of the direct periodontal afferent projection is considered particularly in the light of parallels with the vestibular system, which also has direct and relayed cerebellar projections.

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