 Okay. Hi there. Today we're going to be talking about the general senses. As a reminder, general senses include touch, pressure, pain, temperature, proprioception which is your body's position in space, itch, tickle, and vibration. These differ from special senses because you can sense the general senses from most parts of the body. For example, if you want to tell the temperature of a particular liquid you can put your finger, your toe, you can also tell temperature with your forehead which is very different than the special sense of sight you can only see with your eye. Sorry mom, not the back of the head. So general senses are very different from special senses and today's lecture we're going to focus just on the general senses. So in talking about general senses the first step of sensation is activating a receptor. Each receptor is for a specific modality. Modality is each of the general senses that we have previously listed. So you have a receptor for temperature, you have a receptor for pain which is different than the receptors for proprioception, etc. These receptors come in two varieties. They either specialize cells on their own or they are part of the sensory neuron. So two different types. Once you stimulate that receptor with a stimulus regardless of what variety it is that information will then be passed on to your sensory neuron. That sensory neuron I've shown in green travels up through the spinal nerve into the posterior root. The cell body or soma for that neuron is located in the dorsal root ganglion back here in the back. The neuron continues to synapse in the posterior gray horn of the spinal cord. As a reminder words that go together can be seen here in green. Sensory information travels up the afferent pathway through the posterior dorsal root via a unipolar neuron. So when you see these words, these are words that go together in reference to general senses. So that's kind of your clue. This first neuron here will synapse in the posterior gray horn with another neuron that will carry the information up the spinal cord. Once it gets to the medulla it's going to decussate which is crossover. So if it was carried up the right side it crosses over to the left and continues on to end in the thalamus. So you see this little v here that's the axon terminals that's where it ends. Another neuron will then pick up the information and carry it to the appropriate place in the primary somatosensory cortex. So it's kind of like passing the information along. The receptor passes it to the neuron in green, who passes it to blue and then passes it to red. So that eventually it ends up in the primary somatosensory cortex. There are specific names given to these neurons and it's really self-explanatory. The first neuron that carries the information is called the first-order neuron. So our green neuron is the first order. It's the first one that carries the information. It passes it on to the blue. That's the second neuron that carries the information so we call it the second order and then passes it on to the red. That's our third order. Third one to carry the information. So remember, regardless of the modality, once it's passed into that first-order neuron, the first passes it to the second, the second on to the third, and then eventually it's going to find its final resting place up in the primary somatosensory cortex.