Neurobiology and Behavior, Week 12

When I think about the topic of sleep and what goes on during the stages it is very interesting. I often times joke around when asked to wake up early stating, "i can't wake up that early, I'll be in my REM cycle." After learning about the different stages of sleep and dreaming it has become more interesting when looking at insomniacs and narcoleptics. What is going on in their brains?

Also I find it interesting how people can often change their sleep pattern. This is observed in college students as well as people who work night shifts. I have an older cousin who works night shifts and the idea that this could be doing damage to her brain and functionality is pretty scary. Is their no way to successfully change your sleep pattern and be okay?

Hey everyone,

I found this really cool article in the New Yorker that talks about cosmetic neurology, especially with stimulants (e.g. Adderall and Ritalin) at colleges (i.e the ivies).

http://www.newyorker.com/reporting/2009/04/27/090427fa_fact_talbot?currentPage=all

They quote a HC alum, Chatterjee at Penn, too.

The idea that the picture in our heads is not located in a particular place in our brains, but is the rather the result of patterns of activity across the neocortex makes sense. The act of seeing involves a host of different neuronal signals that then require either conscious, or subconscious (or both) interpretation. Upon reaching the fovea, the image must be determined and isolated from several photoreceptor cells (cones and rods). This act alone involves multiple cortical visual areas within the neocortex, which takes this sequence of information and allows the brain to generate the picture in our heads. This sequence of neural networks, that begins with the retina, made me wonder about the existence of other types of vision.

            In this sense, I do not mean to refer to the types of vision that result from structural defects in the eyes (such as myopia (shortsightedness), hyperopia (farsightedness) and astigmatism ( a misshaped, asymmetrical lens)). Rather, I’m curious about how the brain is able to precisely locate and distinguish one’s “objectivity” in reference to our environment. In my experiences with roller hockey, for example, it seems to me that players use three main types of vision; identification, association and peripheral.  Identification provides the picture that allows one to determine the context and content of the environment. For example, this picture allows a hockey player to identify the puck from the floor. Subsequently, association with past experience allows the brain to take the picture produced by identification to locate the object with in the environment (depth perception, i.e. how close is the puck to the boards?) and thereby, allow for the generation of a proper response. Finally, peripheral vision provides a hockey player with yet another picture, which provides information about one’s immediate surroundings.

            Since this picture from our head is the result of a distributive system, do these types of vision correspond to different regions in the brain? Moreover, how many types of vision do we actually possess with in our neocortex? 

Professor Grostein asked in class why we sleep. Although his question was really asking for what causes us to sleep, I nevertheless thought about why it is important to sleep. His question immediatley reminded me of a sement on 60 Minutes that aired about a year ago called The Science of Sleep (link provided below). The exact answer on why it is important to sleep is still unclear. From an evolutionary standpoint, sleep seems counterproductive. When we plunge into a world of unconsciousness, we are left vulnerable to our surroundings. This suggests that the service sleep provides is far more important than being aware at all times. We can try to evade it, but we all know (perhaps through first hand experience) that lack of sleep comes with serious repercussions. Of the many studies featured on the 60 Minutes segment, one in particular has definitly resonated with me. This particular experiment tested the effects of sleep deprivation on emotional response. A control group that had received a full night’s rest was shown a series of increasingly disturbing images of blood, gore, mutilation, etc. The same procedure was followed for a group of sleep deprived subjects. Brain MRI scans of the control group showed constant and controlled activity in the imigdula, the emotional center of the brain. MRI scans of the experimental group, however, displayed hyperactive brain responses indicating a lack of control in processing information and then in generating an emotional response. Furthermore, scans of the frontal lobe, the region of the brain responsible for cognition, showed a pattern of activity among the experimental group that was similar to that found in patients with severe mental illness such as Schizophrenia. Is it possible that a lack of sleep can somehow interrupt connections between/among regions of the brain?

Although the exact cause of Schizophernia is still under investigation, studies such as the Hollow Mask Illusion Test suggest that the illness is caused, at least in part, by a disconnectivity between or among different regions of the brain. The Hollow Mask Illusion Test reveals that the spatial recognition and visual processing centers of the brain are not communicating in Schizophrenic patients and in the aforementioned mood study, these patients also exhibited such disconnectivity between the emotional and congnitive centers of the brain. 

If processing information such as seeing requires the coordination between or among various regions of the brain, does this "checks and balances" system also apply to emotional responses? In my studies of Modern Art history, I have come across the Freudian theories concerning the id, the ego, and the superego. The belief is that the id is the emotional or irrational part of the mind located deep within the subconcious. The superego, on the other hand, is the moral and perfectionist part of the mind located in the consciousness and arising from societal conditioning. Both the demands of the id and the superego can at times be unrealistic therefore the mind requires the ego to mediate between the two--to find a way to get what the subconcious wants in a reasonable manner. In relating Freud's theories to neurobiology, could the id be seen as a lack of connectivity between/among various parts of the brain, the superego as too much communication of these regions, and the ego as the coordination of these parts? Would Schizophrenic patients have an overactive id?

The Science of Sleep 

Our talk about whether or not sleep is beneficial reminded me of a section of Jonah Lehrer's Proust Was a Neuroscientist. The book has received a lot of criticism for the leaps Lehrer makes between science and the arts, but I think Lehrer's aims apply well to what we are doing in this course. 

Lehrer talks about the role of sleep in the process of neurogenesis, which is the process of creating new neurons in the brain. Neurogenesis is a newly accepted observation among neuroscientists because it overrides the popularly held notion that our brains are fixed. Lehrer notes that neurogenesis is encouraged by sleep and suggests that our brains are a little different each time we wake up. 

Interestingly, neurogenesis studies that have been done have observed that neurogenesis is strongly linked to a positive mood. Neurogenesis, and the activities that promote it (learning, exposure to new things, sleeping), do the same work as an anti-depressent.

Sleeping too much versus not sleeping enough can profoundly effect a persons mood, which ultimately effects who they are as a person.  Why do we get grumpy when we are tired?  Conversely, why do people who are depressed sleep all the time? 

I wonder why mood is so dependent on so many factors in order to form one emotion. It seems that mood is variable based on how you yourself want to feel, what medicines or other substances you are on, and your environment. Why would this be? I know we discussed this and decided that it allows you to see things from a new perspective but, what evolutionary value could that have? If you look at a tree when your happy versus when you are angry it is still the same tree.

Also, I wonder if we can discuss what happens with more extreme mood changes like severe depression or mania. Is it solely based on chemical alterations in the brain or is there and I-function/ environmental element to the creation of these problems?