“Unit 10: Neurobiology.” Online Textbook. Rediscovering Biology. Annenberg Learner. 2013. Web. 31 March 2014.
Neurobiology is a science that explores the brain works at the molecular level. The brain has three primary functions: “(1) take in sensory information, (2) process information between neurons, and (3) make outputs”. Neurons react to stimuli, similar to an exigence. The brain links the outside world and behavior. Neurons communicate rapidly via electrical and chemical communication. Neurons are supported by other cells, called glial cells. These cells perform important support tasks. Neurons are bipolar in that they have a body and extensions at one end and an axon at the end with synaptic terminals that send signals to the dendrites of an adjacent neuron. The neuron operates as a battery by changing voltage. The neuron has a negative voltage maintained by a pump that transfers sodium, potassium, and chloride ions. Proteins, made of amino acids, some charged, move when the voltage changes, causing channels to open and close, permitting ions to cross the membrane. when stimulated, the neuron charge will change causes channels to open allowing for a positive charge, and then potassium comes out and it becomes negative again. The action potential moves down the length of the neuron and maintains directional flow by back propagation. Myelin, a fatty outer layer of most neurons, protects the axon cells of neurons, allowing action potential to travel rapidly down the neuron, and this allows the action potential to travel from the brain to the base of the spinal cord in 1/100 of a second. Some degenerative diseases are caused by the lose of myelin.
Synapses, the meeting places in neurons, allow for communication between neurons. Signals transfer in only one direction across synapses. Synapses are chemical or electrical (gap junction). Electrical synapses are more rapid, but chemical are easier to modulate. Neurons only fire or do not fire-all or nothing. Whether it fires is determined by the number of inputs it receives as well as the nature of those input signals. A signal traveling through the brain may involve many neurons.
Neurotransmitters cause neurons to either fire or they inhibit firing by binding with receptor proteins (ionotropic or metabotropic) for as long as it remains in the synapse. When the signal is no longer needed, the neurotransmitter leaves the synapse by diffusion away, breakdown, and reuptake. The presynaptic neuron can store the neurotransmitter can use it again later. Psychoative drugs can be used to stimulate neurostranmitters for pleasurable experiences, but desensitization may occur over time. Memory involves electrical changes in the brain, specifically in the structure of the neurons. Memory requires postsynaptic neurons to continue firing at a high rate rather than resting. Memories required repeated stimulus of neurons form several sources. A repeated stimulus results in the activation of a circuit of neurons stimulated, which results in learning. Long-term-memory requires new proteins to be synthesized.
Scientist claims there are many kinds of memory that can be viewed in temporal terms: short-term and long-term or declarative (factual) or reflexive (learning by repetition). The hippocampus (which aids spatial learning and memory) as well as the nervous system are vital to memory formation. Neurodegenerative disorders can be combated by engaging in mental activity.
sensory neuron – the neurons that take in information from the environment
glial cell – support or glue cells in the brain that support neurons and perform tasks such as removing dead neurons and debris, releasing critical growth factors to neurons, and acting as insulating material for the neurons. Ions are carried through lipid cell membranes via gated (open or closed) channels.
membrane potential – the difference in voltage between the inside and outside of the neuron
resting potential – generally -0.07 volts, the voltage of a neuron at rest
voltage-gated channels – Ion channels on the cell membrane that will open or close depending upon the voltage.
action potenial – A nerve impulse, or an action potential, is a series of electrical responses that occur in the cell.
synapses – the meeting points between neurons that allow them to communicate at their meeting points
long-term potentiation – The phenomenon in which a neuron becomes more sensitive to stimuli after receiving synchronized stimuli.
How can we compare neurobiology and the activation of neural pathways to Bateson’s discussion of ecology?
Bateson claims that the mind is not capable of mapping entire territories, but only the differences in those territories, and then the mind creates maps of maps to process information. The mind receives information from these mappings (data or information). The mind then transforms the differences, and then the mind perceives the data resulting from transformations made by actions. Bateson says that human behavior involves total mental circuits, and that while the mind as a whole is a complete system, there are sub-systems with the mind that can be viewed as a mind; each step in hierarchy should be viewed as a system (466).
If we were to examine neurobiology in light of Bateson’s discussion, we can see that while a mental thought controlling the movement of the body seems to be the result of one large system, upon closer inspection in biology, the firing or inhibiting of firing of a single neuron is a sub-system within the larger system of the mind.
What can neurobiology tell us about network systems in general?
It seems that neurobiology is useful for understanding the complex ways in which minute actions by a node in a network can impact the entire development or operation of the network. If the synaptic signal is not strong enough, then the action neuron will not fire. It occurred to me while I was reading about the neural network that every node in the network makes a significant contribution to the action of the network. As I was trying to summarize the chapter, I felt that every element was important. According to Castells, in a network society, the space of flows is “the material support of simultaneous social practices communicated at a distance” and “involves the production, transmission, and processing of flows of information” (xxxii). Flow is incredibly important in neurobiology, and each step in the process of the firing or inhibited firing of a neuron is critical. In the same way, all elements involved in the space of flow, not just nodes that take action or produce, but those involved in transmission and processing of flows.
How is the brain like a computer network?
I was curious to find how others have articulated comparisons between computer networks and the brain and I came across this video that compares the internet to a child’s brain which is still in developing stages, rather than an adult brain that, in comparison to a child’s brain is in a stage of degeneration. According to the video the number of connections within each object is:
The internet: 100 trillion
Adult brain: 300 trillion
Child’s Brain: 1 quadrillion
The fact that every interaction a child has forms connections underscores the potential importance of interactions between every element in a network and in the context of the network.
Castells, Manuel. The Rise Of The Network Society. 2nd ed.Oxford; Malden, MA : Blackwell Publishers, 2010.
The preface of the 2010 edition of The Rise of the Network Society provides an interesting look back at the developments of networked society since the first edition of the text was published in 2000. Castells claims that a number of transformations in society (social, technological, economic, and cultural) have contributed to the network society. Castells uses crises in the early the early twenty-first century to illustrate the ways in which the economic, employment, communication, space and time, and human experience are impacted by the network society. While once society operated on a much more local scale, with national borders defining the bounds of society, the globalization of society has resulted in the blurring of such boundaries and the creation of a “global automaton” affecting the global economy that is resistant to attempts to control or regulate it. Labor is now divided into two categories: the talent and the generic worker, and wages have not kept pace with economic growth, contributing to the economic downturn. Internet and wireless communications have made society much more connected and communications much more immediate, as well as equal via horizontal communications. Rather than a society including virtual reality, the real has become virtual (xxix). Concepts of space and time have been turned on their heads. While we value immediacy, timeless time, while glacial time and biological time conflict with society’s valuation of timeless time. he ends the preface by claiming that research and theory on the network society must be accompanied by an ability to comprehend what is observed.
In the prologue, Castells explores some of the trends of the twentieth century that have led to this new society. Capitalism has been reshaped by the technological revolution; society has been reshaped by challenges to paternalism; humans have attempted to find identity in an increasingly fragmented world. Castells claims that all of these phenomena reshaping our society are related and that we can build a better world by observing, analyzing, and theorizing these trends. Castells explores the relationship between technology and society are the same concept, and the state throughout history has either stifled the development of technology or contributed to that development. According to Castells, the new social structure is manifested differently in different cultural structures (capitalism or statism), but informationalism has contributed to the restructuring of capitalism. Catsells claims that societies are shaped by a complex structure based on production (a complex process), experience, and power (founded on the state). Castells claims that the core foundation of a society is the “interaction between modes of production and modes of development” as the case with the rise of “informational capitalism,” but societies reacted differently to this new mode of society (18). Informational societies are capitalist, but they are very diverse as well, with diversity dependent on cultural/institutional expression.
mass self-communication – a new form of societal communication that is mass “because it reaches a potentially global audience through p2p networks and Internet connection” and it is multimodal because digitization of content and social software allow for reformatting of content in almost any form to be distributed in wireless networks (xxx).
space of contiguity – spaces of places (xxxi)
space of flows – “the material support of simultaneous social practices communicated at a distance” (xxxii).
timeless time – the kind of time occurring in a context when there is a systemic perturbation of sequential order (xli).
glacial time – slow motion time the human mind assigns to the evolution of the planet (xlii).
Theoretical Application: How can a network be both horizontal and vertical simultaneously? How can I apply it to La Leche League International’s network?
Castells claims that the information technology revolution has led to an increasing interaction between horizontal and vertical networks (xxx). He was speaking specifically about the interaction between mainstream media and interactive technologies such as blogs. Mainstream media, which is a top-down organization, has historically intended simply to pass on information without receiving feedback, while interactive technologies such as blogs and Twitter make it possible for the audience or consumer to provide feedback, which in turn may affect what the media outlet reports. According to Castells, horizontal networks often are focused on “communication built around people’s initiatives, interests, and desires” and they may involve cooperative projects (xxviii).
As I was reading the text, I realized that this simultaneous vertical and horizontal organization of the network resembles the way in which LLLI is organized. The organization prefers to promote the horizontal aspect of the organization offered by the mother-to-mother support groups, which require a shared interest in breastfeeding and cooperation of mothers, that are core to the organization. According to Nancy Mohrbacher and Sharon Knorr, mother-to-mother support groups provide informal support through vicarious experience, which increases a mother’s self-efficacy, while formal authoritative organizations make mothers lose self-confidence. Because LLLI leaders provide advice based on the organization’s core philosophy, and because LLLI manuals not only provide breastfeeding support but also strongly recommend an attachment parenting lifestyle that some mothers simply cannot live because they must work to provide for their families, some mothers may lose self-confidence as a parent because they are not capable of leading the lifestyle that the organization dictates.