Two-point discrimination is defined as the distance at which two stimuli are perceived as separate.

Two-point discrimination is defined as the distance at which two stimuli are perceived as separate.

• A. The size of the receptive field
• B. The distance at which two stimuli are perceived as separate
• C. The speed of conduction
• D. The threshold for pain

Answer: (B)

Two-point discrimination measures tactile spatial acuity: it is the smallest distance between two simultaneous skin stimuli that the brain can perceive as two distinct points. This threshold reflects how densely the skin is innervated and how the somatosensory cortex represents that skin area. Areas with small receptive fields and many receptors, like the fingertips, have low two-point thresholds and can distinguish points that are very close. Conversely, regions with larger receptive fields, such as the back, have higher thresholds and cannot separate nearby points as well. This concept is separate from the speed of nerve conduction, which influences timing and reaction speed, and from the pain threshold, which concerns the intensity needed to feel pain rather than spatial separation.

Two-point discrimination measures tactile spatial acuity: it is the smallest distance between two simultaneous skin stimuli that the brain can perceive as two distinct points. This threshold reflects how densely the skin is innervated and how the somatosensory cortex represents that skin area. Areas with small receptive fields and many receptors, like the fingertips, have low two-point thresholds and can distinguish points that are very close. Conversely, regions with larger receptive fields, such as the back, have higher thresholds and cannot separate nearby points as well. This concept is separate from the speed of nerve conduction, which influences timing and reaction speed, and from the pain threshold, which concerns the intensity needed to feel pain rather than spatial separation.