Superior colliculi control activity of the rostromedial tegmental nucleus in a lateralized manner - an optogenetic study in the rat

• Autorzy: Pradel K. , Blasiak T.
• Języki publikacji: EN

Abstrakty

EN

INTRODUCTION: Midbrain dopaminergic (DA) neuronal functioning is related to controlling the animal’s orienting and movement towardssalient and/orrewarding stimuli present in the environment. The firing of DA neurons is controlled by various brain regions; however, the main sensory-related innervation is brought by the ipsilateral superior colliculus (SC). Tract tracing experiments suggest that the SC also projects to the contralateral rostromedial tegmental nucleus (RMTg) – the main inhibitory input to DA neurons. Since the orientation of the animal is a manifestation of the imbalance between the left and right DA systems, it is likely that the above-described circuit might explain the lateralization of the motivational/motor behaviours toward the object located on one side of the animal. AIM(S): The aim of this study is to describe the physiology and anatomy of the SC‑RMTg circuit. METHOD(S): Electrophysiological experiments combined with optogenetics were performed to investigate the circuit. The SC of Sprague‑Dawley rats was bilaterally injected with viral vectors containing Channelrhodopsin-2 (ChR2) and yellow fluorescent protein (eYFP) genes. After ChR2 (blue light‑sensitive cation channel) expression, in vivo electrophysiological recordings were performed. RMTg neurons were recorded using 32-channel silicon probes, while either ipsi- or contralateral SC was optogenetically stimulated with laser blue light (473 nm). After each experiment, expression of eYFP and optical fiber location in the SC, as well as, the location of the silicon probe within the RMTg, was histologically verified. RESULTS: Obtained results revealed that stimulation of the contralateral SC was more efficient in increasing firing of the RMTg neurons, as opposed to ipsilateral SC stimulation. Additionally, ipsilateral SC stimulation was more efficient in inhibiting the firing of the RMTg neurons than contralateral SC stimulation. CONCLUSIONS: Such brain wiring might have strong implications for the lateralisation of motivational/locomotor behaviours.

• Wydawca: -
• Czasopismo: Acta Neurobiologiae Experimentalis
• Rocznik: 2019
• Tom: 79
• Numer: Suppl.1
• Opis fizyczny: p.LXXXVI

Twórcy

autor

Pradel K.

• Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland

autor

Blasiak T.

• Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland