What happens in your brain when you shiver in the cold?

Updated

Cold signals travel through the thalamus to the somatosensory cortex, making you feel cold. The hypothalamus senses the drop in core temperature and sends signals via the brainstem to the spinal cord, triggering shivering.

Thalamus, Somatosensory Cortex, Hypothalamus, Brainstem, Spinal Cord lit up on the Brain Atlas 3D brain: what happens in your brain when you shiver in the cold
Figure. The brain regions that light up when you shiver in the cold, in order: Thalamus (sensory relay), then Somatosensory Cortex (feeling cold), then Hypothalamus (thermostat), then Brainstem (signal relay), then Spinal Cord (muscle activation).

Watch it light up on the 3D brain

Brain regions that light up

OrderRegionWhat it does here
1ThalamusCold signals from skin reach the thalamus, the brain's sensory switchboard.
2Somatosensory CortexYou consciously feel the cold as the somatosensory cortex processes the temperature signal.
3HypothalamusThe hypothalamus detects a drop in core body temperature and initiates the shivering response.
4BrainstemThe hypothalamus sends commands through the brainstem to the spinal cord.
5Spinal CordMotor neurons in the spinal cord fire rapidly, causing muscles to contract and relax quickly.

1. Thalamus: sensory relay

Step 1 of what happens in your brain when you shiver in the cold: Thalamus lit on the Brain Atlas 3D brain
Figure 1. Thalamus, sensory relay: Cold signals from skin reach the thalamus, the brain's sensory switchboard.

The thalamus receives input from peripheral thermoreceptors via the spinal cord and relays it to the somatosensory cortex. It acts as a gateway, filtering and directing sensory information to the appropriate cortical areas for conscious awareness.

2. Somatosensory Cortex: feeling cold

Step 2 of what happens in your brain when you shiver in the cold: Thalamus, Somatosensory Cortex lit on the Brain Atlas 3D brain
Figure 2. Somatosensory Cortex, feeling cold: You consciously feel the cold as the somatosensory cortex processes the temperature signal.

The primary somatosensory cortex, located in the postcentral gyrus, maps the body's surface and interprets the cold sensation. This conscious perception allows you to recognize the environmental chill and potentially seek warmth.

3. Hypothalamus: thermostat

Step 3 of what happens in your brain when you shiver in the cold: Thalamus, Somatosensory Cortex, Hypothalamus lit on the Brain Atlas 3D brain
Figure 3. Hypothalamus, thermostat: The hypothalamus detects a drop in core body temperature and initiates the shivering response.

The preoptic area of the hypothalamus contains warm-sensitive neurons that monitor blood temperature. When core temperature falls below the set point, it activates heat production mechanisms, including shivering, a key thermoregulatory reflex.

4. Brainstem: signal relay

Step 4 of what happens in your brain when you shiver in the cold: Thalamus, Somatosensory Cortex, Hypothalamus, Brainstem lit on the Brain Atlas 3D brain
Figure 4. Brainstem, signal relay: The hypothalamus sends commands through the brainstem to the spinal cord.

Descending pathways from the hypothalamus project to brainstem nuclei, such as the rostral ventromedial medulla, which then convey the shivering signal down the spinal cord. The brainstem acts as a relay station for involuntary motor commands.

5. Spinal Cord: muscle activation

Step 5 of what happens in your brain when you shiver in the cold: Thalamus, Somatosensory Cortex, Hypothalamus, Brainstem, Spinal Cord lit on the Brain Atlas 3D brain
Figure 5. Spinal Cord, muscle activation: Motor neurons in the spinal cord fire rapidly, causing muscles to contract and relax quickly.

Alpha motor neurons in the anterior horn of the spinal cord receive the shivering signal and activate skeletal muscles in a rhythmic pattern, typically at 10-20 Hz. These rapid contractions generate heat to raise core temperature, which is the essence of shivering.

Good to know

  • Shivering can increase metabolic heat production up to five times the resting rate.
  • The hypothalamus maintains a core temperature set point around 37°C (98.6°F).
  • Shivering is mediated by the same motor neurons used for voluntary movement, but activated by brainstem reflexes rather than cortical commands.

Shivering vs Sweating

In cold, the hypothalamus triggers shivering to produce heat; in heat, it triggers sweating and vasodilation to lose heat. Both are hypothalamic thermoregulatory responses but engage different effector pathways: shivering uses skeletal muscle via brainstem and spinal cord, while sweating uses autonomic nerves to sweat glands.

Test yourself

  1. Which brain region is considered the body's thermostat, primarily responsible for initiating shivering?

  2. Shivering involves rapid, involuntary muscle contractions. Which part of the nervous system directly activates the muscles?

  3. What is the role of the thalamus in the shivering response?

0 of 3 answered · 0 correct

Simplified: many regions work together at once, and this shows the main players in the order they act.