Heterogeneity of ventral tegmental area neurons: Single-unit recording and iontophoresis in awake, unrestrained rats

Using spectral analysis and in vivo single-unit recording in rats, the present study revealed a pronounced slow oscillation (SO) in the firing activity of about half the dopamine (DA) neurons recorded in the ventral tegmental area. DA neurons in this group tended to fire repetitive spike clusters, making them appear to be rhythmic bursting cells. However, only some of these burst-like events met the traditional “80/160 ms” burst criteria entirely. The observation that the SO could be found in nonbursting DA cells, occurred at frequencies different from those of bursts, and persisted after bursts were digitally removed from spike trains further supports the suggestion that the SO is different from the traditionally defined bursting. Interspike intervals (ISIs) had been thought to be bimodally distributed in bursting DA neurons. This study found that some nonbursting DA cells also had a bimodal ISI distribution and a significant number of bursting cells did not. In the majority of cells where less than half the spikes occurred in bursts, a bimodal ISI distribution was highly predictive of the presence of the SO. Results further showed that the generation of the SO required forebrain inputs to DA neurons but not the adrenergic α1 receptor activation responsible for psychostimulant-induced increases in the SO. Taken together, these results suggest that the SO is distinct from the traditionally defined bursting and represents a major firing pattern of DA neurons in the ventral tegmental area.

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Faculty Opinions recommendation of In vivo visualization of single-unit recording sites using MRI-detectable elgiloy deposit marking.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.9957958.10693054 ◽

2011 ◽

Author(s):

Wolf Singer ◽

Sean Lee

Keyword(s):

Single Unit ◽

Single Unit Recording ◽

Unit Recording

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

Molecular Pain ◽

10.1177/1744806920927852 ◽

2020 ◽

Vol 16 ◽

pp. 174480692092785 ◽

Cited By ~ 1

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.

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