Sensation and Perception

This page covers the topic of what makes our sensory experience possible.

Most people understand intuitively that there are five senses: sight, hearing, touch, smell, and taste.

Some might say there is a sixth sense, allowing dogs, for example, to detect ghosts.
Some might say there is a seventh sense, allowing you to "read" other people from a distance.
Many such claims can be debunked. For example, if dogs could really sense ghosts assumes that ghosts exist, and contrary to beliefs
there is really no physical or philosophical proof that ghosts have a place in our world. The proposition that ghosts exist place the human
in a world where he is not able to perceive "in-visible" beings, whose primary identity was also once human. Ghosts who somehow walk the physical earth still, assuming therefore that
ghosts maintain a material corporality in this world (i.e., a stage one conception of the "soul" as opposed to the favored view of the soul as a form, or
"blueprint"). Other beliefs are not so easily debunked. So how do we know what proposition is true, and what isn't?

Scientists include more than five senses in their categorization of human senses. In addition to those listed above, there are up to 7 senses in total: somatosensory (touch, temperature, pain and proprioception), kinesthetic (movement), and vestibular (orientation).

A list of cognitive techniques to improve retention that are evidence-based is listed next.

There are 7 systems to explore. Some important concepts attached to each are discussed next, along with the names of prominent researchers in the area and terms useful to know. Our brains, an organ, could be compared to a code compiler. This compiler receives input code in the form of high-level languages, that are interpreted by the compilator, verifying syntax and structure, seeking appropriate library codes to interpret some code, and finally, to translate all this high-level language into a machine assembly language which the computer will understand: binary. On a very simplified scale, our brains can be said to work in this way, too. Neurons fire following an action potential, or when the neuron is electrically and chemically excited enough past a default, negative-volt threshold. This causes the pre-synaptic neuron to release a neurotransmitter (a chemical molecule contained in a vesicule produced inside the neuron) into the synaptic cleft and to the post-synaptic neuron which is hanging around very close to it and waiting for its neurotransmitter input. The post-synaptic neuron has what are called receptors lined on the surface (these may be located on any part of the neuron, that is on the dendrites, soma, or axon).

These "voltage-gated" receptors act like gatekeepers or channels that are opened and closed depending on the electrical voltage (the movement of ions and their charge) inside the neuron and outside the neuron. Further physical laws interact with these receptors such as the law of diffusion, electromagnetism and the sodium-potassium ion pump. Different ions interact with these channels, and different channels exist: ion-gated sodium, potassium, chloride, calcium and proton channels. At this stage, we can see that our brains are similar to organic computers, using electricty, biochemistry and physics to function.

All these neurons in our brain have an all-or-nothing threshold which means that once the action potential is fired, the intensity of the action of potential is the same for each action potential, and it is much like turning a switch on and off, or in binary, it may be transduced as 1 and 0. The mechanism with which a neuron knows it has to fire is determined, in simplified terms, by spatial summation or temporal summation , meaning that a neuron takes the input of x amounts of excitatory potentials and sums the electrical voltage in terms of multiple simultaneous inputs, or it sums these potentials in terms of how frequent a signal is transmitted to the postsynaptic neuron's soma.

While these neurons may fire in a binary way, the way that our brain's systems interpret these outside world signals depend on the system used. It is a vast oversimplification (all of this is) to say that our brains are like compilers in a computer. The next level of explanation will involve describing the surface of what each sensory system does with these outside-world-transduced-to-bioelectrical signals according to its structure and potentialities.

The question is: How does our brain compile these sensory informations and interpret it in the brain? According to what does this code is verified as syntaxically correct? How are "error" inputs handled? How does these errors or leaky code affect our perception of reality? How is this related to the nature of illusions? Finally, beyond the perceptual illusions, may these tendencies be connected in any tangible way to cognitive illusions or thoughts that are not based on reality but rather to a "faulty" way of perceiving it?

There are dimensions of sensations, categorized along (a) quality, (b) intensity, (c) duration of the stimuli. For all these sensations we may say there are thresholds for them (Gustav Fechner and Weber). Fechner (the inventor of classic psychophysics techniques: methods of limits, adjustment and constant stimuli) pioneered the study of the interaction between senses and our experiences of them in his Elements of Psychophysics book, published in 1860/1966, along with Weber who contributed to the difference thresholds (Just Noticeable Difference or J.N.D.). These started the study of psychology on the whole because it provided methods that could be quantified and understood meaningfully.

The idiom "We See Better When We Spend Time in the Dark" takes a whole new meaning. Or at least, it can be understood both literally and figuratively now: As we stay longer in the dark our cells' receptive fields change and the threshold for stimulation decreases, allowing photoreceptors better suited to the dark (rods) to be stimulated and allowing us to see in the dark. We see at this point that our systems both have an object and function purpose, because there is an end to this adaptive transition: To let us see better in the dark. It is not random, but goal-directed!

Interesting, is it not? The figurative interpretation of this phenomenon is also meaningful: When God puts us in the "Waiting Room" as we undergo life trials, it often involves us "being in the dark" in our life. We don't know where our steps are leading us. We don't see where the way is. We don't recognize people around us, and worst of all, we don't see ourselves in the midst of it all. Yet just as our sensory system adapts and allows us to see better in the dark the longer we remain in it, so does our heart and mind transform and re-organizes emotional and logical information that best serves our purpose in the end. Notice that I abruptly dropped in God in the equation, because as we will see, and yet better, not see, it is impossible to exclude Jesus-Christ from both history, and any analysis of the world.

Neural pathway routes and their role in information transduction

Page last updated on 2018-10-09.