Elsevier

Brain Research

Volume 301, Issue 1, 28 May 1984, Pages 39-45
Brain Research

Responses of prepositus hypoglossi neurons to optokinetic and vestibular stimulations in the rat

https://doi.org/10.1016/0006-8993(84)90400-1Get rights and content

Abstract

The responses of 47 nucleus prepositus hypoglossi neurons to vestibular optokinetic stimulations in the horizontal plane were recorded in immobilized, pigmented rats. During sinusoidal vestibular stimulation in the dark, type II (62%) and type I (38%) responses were recorded. In addition to the sinusoidal modulation of firing rate, units often showed fast rhythmic increases or decreases in firing (nystagmic modulation). The mean phase of the response relative acceleration measured at 0.025 and 0.2 Hz were 19 and 84 deg., respectively. Some units (25%) showed larger phase-lags. The sensitivities of unit responses at 0.025 and 0.2 Hz were 1.6 and 0.5 spikes × s−1/deg × s−2, respectively.

The responses of NPH neurons to binocular optokinetic stimulation were divided in 2 classes: (i) neurons with unidirectional responses (18%) were excited by stimuli moving towards the side of recording and showed no change in firing on oppositely directed stimulation; all of them showed a type II pattern during vestibular stimulation; (ii) bidirectional responses showed an increase in one direction and a decrease in firing for stimulation in the opposite direction. In every case the optokinetic responses were synergistic with the vestibular responses, which consisted of both type I and type II units.

On the basis of the directionality of their optokinetic response, the value of their time constants and the shape of their velocity tuning curves, it is suggested that unidirectional type II NPH neurons could serve as relays in the optokinetic pathways between NRTP (or PT) and vestibular neurons. Some other neurons, having time constants particularly long and different for the rising and falling of the response, probably serve other functions.

Reference (16)

There are more references available in the full text version of this article.

Cited by (40)

  • Resolving the active versus passive conundrum for head direction cells

    2014, Neuroscience
    Citation Excerpt :

    The firing rate sensitivity of NPH neurons at a constant head velocity generally decreases as the frequency, or number of changes in the direction of the head rotation, increases during smooth or low-frequency head movements. However, the NPH neurons display the opposite – increased firing rates with increasing rotational frequency when the head movements contain more perturbations, or are in a range of higher frequencies, which would be seen during locomotion (Lannou et al., 1984; Kaufman et al., 2000). There is currently little information about NPH neuron activity in relation to changes in rotational velocity for head movements of similar frequency (smooth vs. interrupted).

  • Nucleus prepositus

    2006, Progress in Brain Research
    Citation Excerpt :

    The visual inputs probably play an important prominent role in the transmission of visual optokinetic signals to vestibular neurons and VOR pathways (Cazin et al., 1982, 1984; Cheron et al., 1986; Kaneko, 1999). Detailed descriptions of the eye-movement-related responses of PH neurons have been provided in rodents (Lannou et al., 1984; Kaufman et al., 2000), cats (Lopez-Barneo et al., 1982; Escudero and Delgado-Garcia, 1988; Kitama et al., 1995), and primates (McFarland and Fuchs, 1992; Cullen et al., 1993; Sylvestre et al., 2003). The single-unit recordings were obtained usually from the rostral parts of the prepositus nucleus.

  • Does the vestibular system contribute to head direction cell activity in the rat?

    2002, Physiology and Behavior
    Citation Excerpt :

    Conventional neuroanatomical techniques have demonstrated a large input to LMN from the dorsal tegmental nucleus of Gudden (DTN) [26–28]. The DTN receives inputs from prepositus hypoglossi (PH) [26,29,30], a region of the caudal medulla adjacent to the vestibular nuclei that processes vestibular signals related to horizontal head velocity [31,32]. Thus, vestibular signals could potentially be transmitted from the vestibular nuclei to PH, and then to DTN, and then to HDC in LMN, ADN, and PoS.

View all citing articles on Scopus
View full text