Role of the Cerebellar Posterior Interpositus Nucleus in Saccades I. Effect of Temporary Lesions

2000 ◽  
Vol 84 (3) ◽  
pp. 1289-1302 ◽  
Author(s):  
Farrel R. Robinson
Keyword(s):  
Neural Activity ◽  
Single Unit ◽  
Single Unit Recording ◽  
Unit Recording ◽  
Interpositus Nucleus ◽  
Before And After

The ventrolateral corner of the cerebellar posterior interpositus nucleus (VPIN) contains many neurons that respond during saccades. To characterize the VPIN contribution to saccades, I located this area in three monkeys with single-unit recording and injected the GABAA agonist muscimol among saccade-related neurons there to reduce or eliminate neural activity. I compared the size, direction, velocity, and duration of saccades recorded before and after a unilateral injection in all three monkeys. In two of three monkeys, I also examined saccades after bilateral injection. After unilateral VPIN inactivation, upward saccades were abnormally large (avg. across all 3 monkeys = 112% of normal) and downward saccades were abnormally small (avg. across all 3 monkeys = 94% of normal). In the two monkeys tested, bilateral inactivation increased these abnormalities. Upward saccades went from 111% of normal size in these two monkeys after unilateral inactivation to 120% after bilateral inactivation; downward saccades went from 97 to 86%. VPIN inactivation caused changes in saccade gain and did not add of a constant offset to saccades. (The 1 exception was upward saccades in 1 monkey in which both gain and offset changed.) Neither uni- nor bilateral VPIN inactivation consistently affected the size of horizontal saccades (uni- avg. = 101% normal; bi- avg. = 97% normal). In two of the three monkeys, saccades to horizontal targets angled significantly upward after VPIN inactivation (uni- avg. = 3.6° above normal, bi- avg. = 10.3° above normal). The velocities of horizontal saccades were not strongly affected, but downward saccades exhibited abnormally low peak velocities and long durations. Upward velocities were inconsistently changed. I interpret these results to mean that the activity of some VPIN neurons helps drive the eyes downward and the activity of others helps drive the eyes upward. The downward drive outweighs the upward drive. The net effect of VPIN inactivation is to deprive all saccades of a downward component and to slow downward saccades.

Responses of sagittally aligned Purkinje cells during perturbed locomotion: synchronous activation of climbing fiber inputs

1992 ◽  
Vol 68 (2) ◽  
pp. 570-580 ◽  
Author(s):  
J. S. Lou ◽  
J. R. Bloedel
Keyword(s):  
Purkinje Cells ◽  
Single Unit ◽  
Climbing Fiber ◽  
Single Unit Recording ◽  
Step Cycle ◽  
Unit Recording ◽  
Recording Technique ◽  
Afferent System ◽  
Fixed Array

1. These experiments were performed to test the hypothesis that climbing fiber inputs to sagittally aligned Purkinje cells located in a single folium are activated synchronously in response to a perturbation of the step cycle that interrupts the trajectory of the ipsilateral forelimb. 2. The experiments were performed in acutely decerebrate ferrets capable of walking spontaneously on a moving treadmill. A multiple single-unit recording technique was employed utilizing a fixed array of five sagittally oriented electrodes with electrode tips approximately 200 microns apart. 3. The extent to which the climbing fiber inputs to the recorded Purkinje cells were activated synchronously by the perturbation was calculated for individual trials by determining the synchrony index, a measure of the fraction of the cells responding to each perturbation. 4. The data indicate that there was a statistically significant increase in the synchronous activation of climbing fiber inputs at times immediately after the perturbation. No comparable complex spike modulation was found at the same phase of the unperturbed step cycle. 5. The specific combinations of climbing fiber inputs to neighboring Purkinje cells activated by successive perturbations varied from trial to trial. 6. The implications of these observations are discussed in the context of the nature of the inputs encoded by climbing fiber activation and the role of this afferent system in cerebellar cortical information processing.

scholarly journals Pressure-clamped single-fiber recording technique: A new recording method for studying sensory receptors

2020 ◽  
Vol 16 ◽  
pp. 174480692092785 ◽  
Author(s):  
Mayumi Sonekatsu ◽  
Hiroshi Yamada ◽  
Jianguo G Gu
Keyword(s):  
Nerve Fiber ◽  
Single Unit ◽  
Single Fiber ◽  
Single Unit Recording ◽  
Sensory Receptors ◽  
Unit Recording ◽  
Recording Technique ◽  
C Fibers ◽  
Recording Method ◽  
Single Nerve

An electrophysiological technique that can record nerve impulses from a single nerve fiber is indispensable for studying modality-specific sensory receptors such as low threshold mechanoreceptors, thermal receptors, and nociceptors. The teased-fiber single-unit recording technique has long been used to resolve impulses that are likely to be from a single nerve fiber. The teased-fiber single-unit recording technique involves tedious nerve separation procedures, causes nerve fiber impairment, and is not a true single-fiber recording method. In the present study, we describe a new and true single-fiber recording technique, the pressure-clamped single-fiber recording method. We have applied this recording technique to mouse whisker hair follicle preparations with attached whisker afferents as well as to skin-nerve preparations made from mouse hindpaw skin and saphenous nerves. This new approach can record impulses from rapidly adapting mechanoreceptors (RA), slowly adapting type 1 mechanoreceptors (SA1), and slowly adapting type 2 mechanoreceptors (SA2) in these tissue preparations. We have also applied the pressure-clamped single-fiber recordings to record impulses on Aβ-fibers, Aδ-fibers, and C-fibers. The pressure-clamped single-fiber recording technique provides a new tool for sensory physiology and pain research.

On the search for the vocal pattern generator. A single-unit recording study

Neuroreport ◽  
2000 ◽  
Vol 11 (9) ◽  
pp. 2031-2034 ◽  
Author(s):  
Frank Düsterhöft ◽  
Udo Häusler ◽  
Uwe Jürgens
Keyword(s):  
Single Unit ◽  
Pattern Generator ◽  
Single Unit Recording ◽  
Unit Recording
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