# Roles of higher-order visual thalamus in state-dependent corticocortical communication

> **NIH NIH K99** · YALE UNIVERSITY · 2020 · $102,808

## Abstract

PROJECT SUMMARY
Normal sensory perception and motor control depend on dynamic functional interactions among different
regions of the neocortex. Dysfunction in these interactions can lead to devastating neurological and
neuropsychiatric disorders. While interactions among cortical areas are thought to be mediated primarily by
direct synaptic connections between cortical neurons (i.e. direct corticocortical connections), the thalamus may
also play a crucial role in these interactions. The thalamus is an obligatory relay for most sensory information
sent to the cortex, and the cortex sends massive feedback projections to thalamus, modulating sensory
throughput. Relay cells in higher-order thalamic nuclei receive especially strong corticothalamic synaptic
inputs from projection neurons in cortical layer 5, and these same thalamic relay cells also send strong
thalamocortical synaptic inputs to secondary/higher order cortex. Thus, in addition to monosynaptic
corticocortical connections, distinct cortical areas might also interact disynaptically via higher-order thalamus
(the “transthalamic corticocortical pathway”). Despite previous anatomical demonstrations, the functional role
of the transthalamic corticocortical pathway remains poorly understood. The primary goal of my proposal is to
investigate how higher-order visual thalamus (the lateral posterior nucleus, LP) mediates functional interactions
between primary (V1) and secondary (V2) visual cortex in awake, behaving mice, and how direct corticocortical
inputs are integrated with transthalamic corticocortical inputs in V2. These investigations will significantly
enhance our understanding of the thalamic contribution to dynamic cortical interactions and expand my training
in experimental and analytical techniques as I prepare for an independent investigator position. My research
proposal consists of three specific aims: 1) To study how the transthalamic interactions between V1 and V2
depend on arousal, 2) To determine how activity in the transthalamic pathway between V1 and V2 shapes
visual responses in V2 neurons, and 3) To investigate how synaptic inputs from direct corticocortical
projections and transthalamic corticocortical projections are integrated by V2 neurons, and what types of
information these two projections carry during active visually guided behavior. During the K99 phase, under
the guidance of Dr. Jessica Cardin and the support of my advisory committee (Drs. Michael Higley and Michael
Crair), I will become proficient in several techniques, including in vivo 2-photon calcium imaging of neuronal
populations and axon terminals and in vivo optogenetic manipulations. During the R00 phase and beyond, my
goal is to combine an array of techniques (from detailed study of synaptic transmission in vitro to large-scale
monitoring of neuronal activity in task-engaged animals) to study the dynamic interactions between various
cortical and thalamic pathways of the visual system, how these interactio...

## Key facts

- **NIH application ID:** 9986811
- **Project number:** 5K99EY030550-02
- **Recipient organization:** YALE UNIVERSITY
- **Principal Investigator:** Garrett Neske
- **Activity code:** K99 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $102,808
- **Award type:** 5
- **Project period:** 2019-09-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9986811

## Citation

> US National Institutes of Health, RePORTER application 9986811, Roles of higher-order visual thalamus in state-dependent corticocortical communication (5K99EY030550-02). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/9986811. Licensed CC0.

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