The Cambridge Declaration on Consciousness-On this day of July 7, 2012, a prominent international group of cognitive neuroscientists, neuropharmacologists, neurophysiologists, neuroanatomists and computational neuroscientistsgathered at The University of Cambridge to reassess the neurobiological substrates of conscious experience and related behaviors in human and non-human animals.-They are proclaiming their support for the idea that animals are conscious and aware to the degree that humans are— a list of animals that includes all mammals, birds, and even the octopus. But will this make us stop treating these animals in totally inhumane ways? Blindsight-‘Blindsight’ - Weiskrantz, 1986-Visual capacities in scotoma - D.B. had headaches from the age of 14 eventually relieved by removing part of visual cortex… leaving scotoma-Weiskrantz called in to check his vision found he could ‘guess’ the orientation of a stick, point to a target, reach for a outstretched hand-He could ‘see’ things he was not aware of!Visual Spatial Neglect-Caused by damage to the Parietal Lobe-Impairs ability to attend to the side of space that is opposite of the damaged hemisphere-The vision is normal, but the attention is impaired.-For example, a patient only eats food from the same side of plate as damage.Biological rhythm types
-Circadian oAny rhythmic change that continues at close to a 24-hour cycle in the absence of 24-hour cuesbody temperaturecortisol secretionsleep and wakefulnessoInfradian – occurs less than once a dayoUltradian – occurs more than once a dayoIn the absence of time cues, the cycle period will become somewhat longer than 24 hours-Circalunar – menstruation; circannual – migration of birds/hibernation at winter/weight gain in winter/ SAD because of less lightExamples of Human Circadian RhythmsFunctionTypical Circadian RhythmPeak mental alertness and memory functionstwo peaks: around 9 AM and 9 PMLowest body temperatureabout 36.2: around 3 to 4 AM Highest body temperatureabout 37.2: around 5 to 6 PMPeak physical strengthtwo peaks: around 11 AM and 7 PMPeak hearing, visual, taste, and smell sensitivitytwo peaks: around 3 AM and 6 PMLowest sensitivity to painaround 3 to 5 PMPeak sensitivity to painaround 3 to 5 AMPeak degree of sleepiness two peaks: around 3 AM and 3 pmPeak melatonin hormone in blood between 1 and 3 AMIsolation studies-Jurgen Aschoff in Germany-Isolation experiments. Subjects placed in an underground bunker and allowed to turn lights on or off when they wanted.
-Aschoff tracked their sleep-wake cycles, body temperature, and other physiological and behavioral variables. -He concluded that humans have endogenous circadian cycles. -Isolation studies: Typically, humans show freerunning rhythms with periods ~ 25 hr-Siffre (1972) -– speleologist -– lived in a cave for 7 months -– no time cues-– mentally lost 25 days!Conclusion: We have internal clocks but we also need time cues (light) to reset them. Zeitgebers – time cues, external or environmental cues to entrain biological rhythms