# The Role of Thalamus in Cortical Function and Tactile Perception

> **NIH NIH F31** · UNIVERSITY OF CHICAGO · 2022 · $46,752

## Abstract

Project Summary
In most mammals, the dorsal thalamus is considered to be a relay station for sensory signals propagating from
periphery to cortex. Indeed, first order (FO) nuclei receive their input from the periphery (e.g. retinal input to the
lateral geniculate nucleus or LGN) and send their principal output to cortex. By volume, however, the majority of
the thalamus in primates consists of higher-order (HO) nuclei, defined as receiving their principal input from
cortex. Despite their dominance in the thalamus, the function of HO nuclei has yet to be conclusively elucidated.
One hypothesis is that HO nuclei play a key role in the communication between cortical fields given their patterns
of interconnectivity with cortex. These transthalamic corticocortical circuits are commonly paralleled by direct
corticocortical connections between the same two cortical areas. The nature and function of the signals carried
by HO nuclei remain largely unknown. The goal of the proposed experiments in macaque monkeys is to
determine if and how it shapes neuronal responses in primary and higher order cortical areas, and establish its
role in touch-mediated behaviors. To this end, we will study the response properties of sHO neurons while
animals perform one of two tasks – a discrimination task that relies heavily on higher order cortical processing
and a detection task that does not. Then, we will assess the consequences of silencing the sHO nucleus both
on the responses of neurons in different cortical fields and on the animal’s behavior.
INTELLECTUAL MERIT. The expansion of the neocortex is the hallmark of human evolution, endowing us with
language, fine motor control, and increased cognitive capacity. With the relative expansion of the neocortex,
primary sensory nuclei of the thalamus have remained relatively stable in size while higher order (HO) thalamic
nuclei have expanded. We hypothesize that this relative expansion is closely associated with the expansion of
cortex because the function of these nuclei is to mediate communication between different cortical fields. The
role of this transthalamic circuit remains largely unknown, a gap we will begin to fill.
BROADER IMPACT. In addition to their contribution to basic science, the results will also have important clinical
implications. Indeed, many cognitive defects have been associated with HO thalamic relays. For instance,
schizophrenia presents a noteworthy thalamic pathology based on MRI and postmortem anatomy: HO nuclei
(e.g., the mediodorsal nucleus and Pulvinar) are shrunken with neuronal loss but FO nuclei appear normal.
Schizophrenia may thus disrupt transthalamic circuits, among other effects and the cognitive defects in
schizophrenia may be at least partly related to pathology in the transthalamic system. Generally speaking, this
new hypothesis of FO and HO thalamic relays may prove a useful hypothetical framework against which to
consider thalamic deficits in various clinical conditions.

## Key facts

- **NIH application ID:** 10437628
- **Project number:** 5F31NS124322-02
- **Recipient organization:** UNIVERSITY OF CHICAGO
- **Principal Investigator:** Natalya Shelchkova
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $46,752
- **Award type:** 5
- **Project period:** 2021-07-01 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10437628

## Citation

> US National Institutes of Health, RePORTER application 10437628, The Role of Thalamus in Cortical Function and Tactile Perception (5F31NS124322-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10437628. Licensed CC0.

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