The Power of (In)Attention
Attention greatly enhances our perception of whatever is the object of attention, but at some cost to the ability to notice other stimuli. While pursuing a suspect, police officer Kenny Conley ran right past two other police beating an undercover officer whom the other two had mistaken for the suspect. Conley reported that he did not see the beating; he was convicted of perjury and obstruction of justice and sentenced to 34 months in jail (later overturned on appeal).
Video and computer simulations have indicated that attention to one aspect of a scene can prevent subjects from noticing an event that would seem too compelling to miss, but researchers at Union College in New York decided to see whether this could happen in real life. They had a total of 94 subjects pursue a confederate of the experimenter over a predetermined path around the campus; along the way the subject passed three other confederates involved in a staged fight. In the first experiment, done at night, only 35% noticed the fight. When the experiment was done during the day, detection rose to 72%. But if the subject was asked to count the number of times the pursued confederate touched his head, the rate dropped to 56%; and if the task was to keep track of how many times the confederate touched his head with his left hand and with his right hand, the subject noticed the fight only 42% of the time. i-Perception, Vol 2, 150-153. (This video used to study "inattentional blindness" is worth seeing!)
More Evidence for Neuronal Replay During Sleep
According to your text (p 477), replay during slow wave sleep (SWS) of neural activity that occurred during learning appears to strengthen memory. A group of German and Swiss researchers had volunteers learn the locations of matching pairs of cards while being presented with an odor. Half of the subjects remained awake, while half slept for 40 minutes. During this intervening period, some of the subjects in both groups were presented the odor again, in an attempt to invoke memory recall. Presenting the odor to subjects while they were awake interfered with later task recall, compared to the other waking subjects; this may seem surprising, but is consistent with what we know about reconsolidation. On the other hand, sleeping subjects who experienced the odor during SWS did better than the subjects who did not experience the odor during sleep. This research is significant because, unlike previous correlational studies, it manipulated recall–and presumably neural replay—during sleep. Nature Neuroscience, Vol 14, 381-386.
Consciousness as an Interactive Network
Many theorists now believe that consciousness involves a widely-distributed neuronal network; diminished consciousness is accompanied by decreased communication over this network. In an experimental test of these observations, a team of European researchers used EEG to track communication between temporal cortex and frontal cortex during stimulation with an auditory tone. The tone activated the temporal cortex in minimally conscious patients and patients in a vegetative state, as well as in non-patients. Occasionally the tone's frequency would vary, and the "surprise" effect of the change resulted in the temporal cortex sending a message to the frontal cortex. In the non-patients and minimally conscious patients, the frontal cortex then communicated back to the temporal cortex. But in the vegetative patients, this feedback was absent, providing additional support for the network view of consciousness. Science, Vol 332, 858-862.