H2020Индивидуална стипендия2017–2020

Thalamic Circuits · Circuit analysis of thalamic visual processing and its modulation by long-range projections

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2017-09-01 → 2020-04-01
Финансиране от ЕС: 175 420 €
Участници: 1
Схема: MSCA-IF-EF-ST

Линиите свързват координатора с партньорите.

Накратко на български

Невронните вериги в таламуса обработват визуалната информация от ретината, като се влияят от вниманието и състоянието на организма. Разбирането им помага при разработването на визуални протези и изясняването на механизмите при шизофрения.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Circuit analysis of thalamic visual processing and its modulation by long-range projections

The thalamus, a region located deep inside the brain, is a major communication hub for sensory information propagating to cortex and consciousness. One of the thalamic nuclei, the dorsal lateral geniculate nucleus (dLGN), is often referred to as the visual “relay” nucleus, even though it not only relays visual information, but is the first brain region in which visual information coming from the retina and traveling towards visual cortex is integrated and modified. Yet, how exactly information is modified at this stage is not fully understood. In addition to retinal information, the dLGN integrates top-down information and is modulated by behavioral state, arousal, and attention. Recent studies have shown that attentional modulation of visual processing is mediated by an interplay between inhibition and excitation in the dLGN. Inhibition in the dLGN is provided by a local population of inhibitory interneurons, as well as inputs from inhibitory neurons located in the thalamic reticular nucleus (TRN). Understanding visual information processing in the dLGN is of great clinical relevance. In patients with retinal or optic nerve damage, the dLGN is largely preserved, and therefore thalamic visual prostheses could, by stimulating dLGN neurons, potentially mimic the no longer available visual information. Moreover, schizophrenic patients show abnormalities in early visual processing and deficits in visual attention. The TRN has been implicated with these clinical symptoms of schizophrenia, and a possible role of the dLGN is debated. A better understanding of the neuronal circuits underlying function and malfunction of early visual processing would be needed to approach an understanding of the neurobiological disease mechanisms. The aim of “Thalamic Circuits” was to describe the neuronal circuits underlying early-stage thalamic visual processing in the mouse dLGN and its modulation by long-range projections. For gaining a deeper biophysical understanding of information processing in the LGN and the basic rules of signal integration in LGN neurons, two methods needed to be established: deep brain monosynaptic rabies tracing (to resolve functional connectivity with monosynaptic resolution in vivo) and deep 2-photon calcium imaging (to achieve in vivo recordings of both cellular activity and subcellular signals). Applying these methods, we find that dLGN interneurons play an unexpectedly complex role for information processing.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

The thalamus, whose anatomical history goes back two millenia, has long been recognized as the master relay for sensory information propagating to cortex and consciousness. Yet, it is indisputable that thalamic nuclei are much more than simple relays but integrate different sensory modalities, bottom-up as well as top-down information. One elementary form of top-down modulation is attention, which selectively enhances behaviorally relevant information. Attentional modulation occurs already at the thalamus by, yet, unresolved circuit mechanisms. My research specifically aims at (1) exploring circuits for long-range, top-down modulation of thalamic visual processing, (2) dissecting the circuitry underlying attentional modulation, and (3) understanding basic rules of thalamic information processing. I will pursuit these three aims using an innovative combination of monosynaptic retrograde rabies tracing, optogenetics and deep 2-photon calcium imaging. My experiments will focus on the lateral geniculate nucleus (LGN), which is the main connection between the optic nerve and the visual cortex, as well as on the thalamic reticular nucleus (TRN), which provides major inhibitory input to LGN and has previously been implicated in attentional regulation. Notably, TRN deficits have been suggested to contribute to the clinical symptoms of schizophrenia. By rabies tracing, I will target channelrhodopsin to monosynaptic long-range inputs to the visual thalamus. By GRIN-lens assisted 2-photon imaging I will quantify visual responses and search for signatures of attentional modulation that can be induced by optogenetic stimulation of specific inputs. This approach will allow me to quantify attentional modulation of thalamic information-processing by specific long-range inputs, to dissect the underlying circuitry mechanisms and to contribute to a better understanding of thalamic computational power as well as its vulnerabilities.

Оригинален текст от CORDIS (на английски).

Участници

FRIEDRICH MIESCHER INSTITUTE FOR BIOMEDICAL RESEARCH FONDATION · BASELКоординаторШвейцария