By this stage, your baby can use his senses and recognize the sensations of light, pressure, pain, and temperature. Sound is thought to be the first sense to develop, although taste buds are at least present on the tongue from as early as 10 weeks. Nerves carrying the sensations of pain, temperature, and light touch from your baby's body reach his spinal cord and then travel to the hypothalamus, which lies in the center of the brain. This then sends signals to another part of your baby's brain so that the stimuli can be recognized and also evoke an emotional response. Many, but not all, of these nerves require insulation around them to conduct signals effectively. Known as myelin sheaths, these do not develop until much later, after 29 weeks in the spine and 37 weeks in the brain.
Painful stimuli result in a reflex action (such as pulling your hand away from a hot object). Reflexes don't have to involve the brain and for these sensations to be recognized at a conscious level, rather than as a simple reflex, the nerves need to connect the hypothalamus to the gray matter in the brain. These connections are thought to function after 26 weeks of pregnancy, but it may be 34 weeks before their electrical activity can be clearly seen on an electroencephalogram (EEG).