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Physiology and Cognitive Science

Physiology is one of the many sources of cognitive science. As in other behavioral sciences, the role of physiology is mainly to explain the mechanisms underlying what is observed. Because of the definition of cognitive science, physiological explanations are mainly useful when they explain cognition. In other words, it is not the physiology itself that is of interest to the cognitive scientist. Rather, it is what physiology can do to explain cognition that is of interest. Vision, for example, is not of interest because it exists and can be studied. No, the usefulness of vision lies in how it aids and abets cognition. What problems does vision solve? What are vision's limits? How do other sense systems compare to vision? How do other living species and constructed machines use vision? These are interesting (and difficult) questions for cognitive scientists.

Another area of interest for cognitive science emanating from physiology is the discovery of evolved "design principles" which can then be applied to constructed devices (i.e., robots). Some of those principles are discussed below. Note that because wheels have never evolved in animals then a natural categorization ensues. Wheeled devices are, by definition, constructed.

Physiological Issues

What is Physiology? See URL below:

• http://info.abdn.ac.uk/~phy050/nphysiol.htm#defn

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Index and Graphics

• The Human Brain Pictures
  • Left Side
  • Right Side
  • Anterior
  • Inferior
  • Superior
• Lobes of the Brain (local link)
  • Frontal
  • Parietal
  • Occipital
  • Temporal
  • All lobes together
• Parts of the Brain: Location and Function (local link)
• Neurons (local link)
• Bilateral Symmetry
  • Need for forward locomotion
  • Symmetry Online
  • Radial vs. bilateral
• Biological Design Principles (from Braitenberg's Vehicles)
• Robot Design Principles (lego robots)
• Thinking Biologically for Robots
• Robot Pictures
• Legged robots
  • tinbug
  • ROACH
  • RIHMO
  • 6-legged service robot
• Swimming robot
• Hopping robot
• Aerial robots
  • Aerial robotics competition rules
  • Freewing products
• Other competitions (undersea, ground, and aerial)

Frontal Lobe: The frontal lobe is the most anterior section. It is located right under the forehead.

• Functions:
  • It determines how we know what we are doing in our environment (Consciousness).
  • It determines how we initiate activity in response to our environment.
  • Judgments we make about what occurs in our daily activities.
  • Controls our emotional response.
  • Controls our expressive language.
  • Assigns meaning to the words we choose.
  • Involves word associations.
  • Memory for habits and motor activities

Parietal Lobe: The parietal lobe is located near the back and top of the head.

• Functions:
  • The parietal lobe contains the location for visual attention.
  • The parietal lobe contains the location for touch perception.
  • Goal directed voluntary movements.
  • Manipulation of objects.
  • Integration of different senses that allows for understanding a single concept.

Occipital Lobe: The occipital lobe is the most posterior. It is located at the back of the head.

• Functions:
  • Vision
  • Visual Fields

Temporal Lobe: The temporal lobe is located at the side of the head and above the ears.

• Functions:
  • The temporal lobe is responsible for the hearing abilities.
  • Memory acquisition
  • Some visual perceptions
  • Categorization of subjects Top of page

Another Lobe picture

Parts of the Brain

Brain Stem: The brain stem is made up of the medulla, the midbrain, and the pons.

1. Medulla:

• Location: The medulla is the continuation of the spinal cord. It contains all the ascending and descending fiber tracts interconnecting the brain and the spinal cord. A majority of the cranial nerves enter and leave the brain from the medulla.
• Function: Several vital autonomic nuclei concerned with respiration, heart action, and gastrointestinal function are in the medulla. Controls our breathing blood pressure and heart rhythms.

1. Pons:

• Location: The pons is the upward continuation of the brain stem. It contains ascending and descending fiber tracts and many additional nuclei.
• Function: The pons plays a major role in feeding behavior and in facial expressions. It also helps in controlling our breathing, blood pressure, and heart rhythms.

1. Midbrain:

• Location: The midbrain is the most anterior continuation of the brain stem that still maintains the basic tubular structure of the spinal cord.
• Function: The top portion of the midbrain contains nuclei important for the visual and auditory systems. The bottom portion of the midbrain contains nuclei for the cranial nerves that control eye movement and the lower portions of the brain. A large nucleus called the red nucleus is found here, as is a collection of dark, heavily pigmented cells, the substania nigra. These structures are involved in movement.

Cerebellum:

• Location: The cerebellum overlies the pons.
• Function: The cerebellum sends motor fibers to the thalamus, brain stem, and several other structures. Although it is probably involved in a number of other functions as well, the cerebellum is primarily concerned with the regulation of motor coordination. Removal of the cerebellum produces a characteristic set of symptoms of jerky, uncoordinated movement. The cerebellum also appears to play an important role in learning. The cerebellum fine tunes our motor activity or movement.

Thalamus:

• Location: The thalamus is located towards the anterior and dorsal side of the midbrain.
• Function: The thalamus is the final relay station for the major sensory systems that project to the cerebral cortex: the visual, auditory, and somatic sensory systems. It plays a role in pain sensation, attention, and alertness.

Hypothalamus:

• Location: The hypothalamus is the lower portion of the cerebrum at the junction of the midbrain and the thalamus.
• Function: The hypothalamus interconnects regions of the brain. It secretes hormones that control the pituitary glands which are responsible for physical growth, fight or flight reactions, sexual responses and many other physical expressions of mental states. The hypothalamus is sometimes called the "mastery control system."

Hippocampus:

• Location: The hippocampus is found between the corpus callosum and the temporal lobe.
• Function: The hippocampus provides the structure of the limbic system. It also is involved in the learning and memorization processes.

Basal Ganglia:

• Location: The basal ganglia is surrounds the thalamus, is enclosed by the cerebral cortex and cerebral white matter.
• Function: The basal ganglia forms the major part of the extrapyramidal motor system.

Cerebral Cortex:

• Location: The cerebral cortex is the brain's outer covering of cells.
• Function: The cerebral cortex is responsible for visual, auditory and skin -to-brain information. It is also responsible for the control of movements. Top of page

Location and Functions

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Neurons

Anatomy:

• Dendrites
• Cell Body
• Axons
• Myelin
• Synapse

Dendrites:

• The dendrites are all of the fibrous extensions of the cell body except the axon and are what give the neuron its characteristic shape. Dendrites range in number and size and serve to extend the receptive surface of the neuron. Dendrites receive information through synaptic connection from the proceeding neuron.

Cell Body:

• The cell body is that part of the neuron containing the nucleus, cell membrane and contributing organelles, such as the endoplasmic reticulum (for secreting substances), Golgi apparatus (for packaging secretions), and the mitochondria (for energy).

Axon:

• The axon conducts information from the neuron cell body to the synaptic terminals in order to trigger synaptic transmission. It also transports chemical substances from the cell body to the synaptic terminals and back from the synaptic terminals to the cell body.

Myelin:

• Myelin is a fatty sheath of insulation that covers larger axons. The myelin is formed by glial cells, but NOT ALL NEURONS HAVE MYELIN.

Synapse:

• The synapses are points of functional contact between axon terminals and other cells. There are two types, the chemical synapse and the electrical synapse.

Functions:

• First, ACH is produced by the brain and transmitted to the dendrites of a neuron. The synapses of the dendrites receive the ACH message.
• The message is then transferred through the dendrites to the cell body and from the cell body down the axon to the synaptic terminals.
• Next, synaptic vessicles are signaled to shoot the neuron's chemicals to the next neurons dendrites. Once this message has been received by the neighboring neuron, the original chemicals are shot back from the neighbor neuron to the original neuron.
• The chemicals then return to a storage pool where they will await the next message to be sent.
• This procedure will continue from one neuron to another until the message reaches its designated place. Top of page

Other sites of interest

Neuropsychology Central (huge site, music, movies, index to many, many neuropsychology sites)

Physiology Falk Library Resources (U. of Pittsburgh Library site)

Other Physiology Departments (U. of Toronto site)

Neurosciences Atlas Page (U. of Oklahoma site, virtual "dissection" of human brain)

Neuroanatomy and Neuropathology on the Internet (Very large index site, from Hungary)

Dr. Charles Long University of Memphis-Neuropsychology (Course materials-physio. psych and others)

Neurobiology Links (small but eclectic index site)

Neuroanatomy and Physiology (complete descriptions and graphics, large site)

Neuron (journal)

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Summary

By now you should see that like much in cognitive science, physiology serves as a source for several reasons. Physiology serves as a model for real systems (animals) in real environments (the world). Physiology also serves as the basis for design principles for the human creation of analogous machines. Such work is primitive still, at least when compared to animals. In the future, not only will simple physiology be a model for cognitive science, but complex neurophysiology will too. Already, such efforts have begun. Minsky and Papert's old experiments with perceptrons are on example. Another is Braitenberg's conjectures about Vehicles. The new emphasis on neural net computing is still another example. Such efforts will likely continue in the future.