Perusing Psychology

Posted by Jared Tanner on October 2nd, 2008 in brain, neuroanatomy, neuroscience, psychology

The human brain is a wondrous thing. It is the single most complex organ on the planet. It sits atop the spinal cord. Gazing upon the brain, one sees four main distinct areas - two roughly symmetrical hemispheres, a cerebellum stuck up underneath the posterior part of the brain, and a brainstem sticking out and down from the middle of the brain. Each cerebral hemisphere is divided into four visible lobes: frontal, temporal, parietal, and occipital. The frontal lobes jut out at nearly a 90 degree angle from the spinal cord and are the largest part of the human brain. The temporal lobes stick out the sides of the brain, like thumbs pointing forward at the side of a fist. The parietal lobes are harder to distinguish. They are just posterior to the frontal lobes and dorsal to (above) the temporal lobes. The occipital lobes are at the very back of the brain, like a caboose on a train.

The outside of the brain is covered with a series of bumps and grooves. The bumps are called gyri (sing. gyrus) whereas the grooves are called sulci (sing. sulcus). This outside part of the brain is filled with tiny cell bodies of neurons, the main functional cell of the brain. Some people estimate that there are 100 billion neurons in the central nervous system (brain + spinal cord). This outer layer of the brain is called the cortex (which means “bark”). The cortex is only about 5mm thick, or about the thickness of a stack of 50 sheets of copy paper, yet it is responsible for much of the processing of information in the brain.

At room temperature the brain is the consistency of warm cream cheese. If removed from the skull and placed on a table, it would flatten and widen out a bit, like jello that is warming up. The brain is encased in a series of protective sheaths called meninges. The outermost encasing is called the dura mater (L. “tough mother”), which is thick and tough and is attached to the skull. The next layer in is softer. It is called the arachnoid layer; it adheres to the brain. Just underneath this layer is where cerebrospinal fluid (CSF) flows. This fluid is produced in holes in the middle of the brain called ventricles. CSF helps cushion the brain as well as remove waste products from the brain. Underneath this is a very thin and fine layer called the pia mater (L. “soft mother”), which adheres directly to the cortex and is difficult or impossible to remove without damaging the cortex. These three layers of meninges serve to protect the brain.

The brain can be roughly split into three functional areas, each one more “advanced” than the previous. The brainstem (and midbrain), which includes such structures as the medulla, pons, and thalamus, activates and regulates the general arousal of the cortex. Damage to the brainstem often results in coma or death. The next rough functional area is the posterior portion of the brain (parietal and occipital lobes and portions of the temporal lobes). This area is heavily involved in sensory processing - touch, vision, hearing. It sends information to other parts of the brain largely through the midbrain structures. The last functional area includes the frontal lobes. This area can regulate all other parts of the brain but is essential for goal-setting, behavior inhibition, motor movements, and language. The frontal lobes are the most advanced area of the brain and arguably the most important for human functioning - for what makes us human. In summary the three areas roughly are responsible for:

1. Overall arousal and regulation
2. Sensory input
3. Output, control, and planning

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Posted by Jared Tanner on October 2nd, 2008 in neuroscience

I’m working on finding a new look for my site. It will be going through revisions over the next few days as I get everything situated. Please forgive any bumps in the process.

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Posted by Jared Tanner on September 25th, 2008 in clinical psychology, psychology

When writing or talking about medical patients or therapy clients, it is helpful to describe their presentation. You cover things such as appearance and grooming, mood, openness, language, and thought process. How a client looks can reveal a lot about their lives, stressors, and their overall cognitive functioning. How open they are with you as a doctor or therapist is also important to note. Sometimes people are reticent to talk about themselves (which is very understandable) and very distrustful in general. Some people also don’t know how to talk about themselves, so they don’t.

The language people use also reveals their underlying cognitive functioning. Tangential language, disjointed speech, and slowed speech, for example can mean different things - a thought disorder, depression, acquired brain injury, and so forth. Related to language is a person’s thought process; this is apparent from their language but also in how they describe their problems or their lives.

When discussing mood, there are three general terms doctors use. The first is euphoric - extremely happy. Sometimes it is appropriate for people to exhibit this emotion but it can also be a sign of mania, especially if the positive mood was not seemingly triggered by anything. The next term for a mood state is euthymic, meaning normal, slightly positive mood. This is the mood that most people exhibit most of the time. It is neither positive nor negative (again, with a slight positive lean). The last descriptor for mood is dysthymic, which means depressed or having negative affect.

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Posted by Jared Tanner on September 16th, 2008 in neuroscience, philosophy, psychology, science

I’m going to preface my post by stating that the following post was written to help me think through the relationship between neuroscience and therapy. As such, it is a philosophical journey through some of my thoughts and is not even necessarily what I really believe because I’m still working on discovering what I believe. Thought processes like this are one way I try to keep some of my beliefs about psychology and neuroscience balanced. If I start leaning too strongly one way, I’ll start looking for things that disconfirm those beliefs and see what I discover. It’s a bit of playing the Devil’s Advocate with myself and a bit of philosophizing. Some of my friends and I used to do things like this in junior high and high school - having philosophical discussions where we discussed things and even tried to argue for things that we didn’t necessarily believe (e.g., classic topics such as supposing that this world and universe really aren’t real but are just reflections of reality. Again, that’s not something I believe but we would speculate). What does this all have to do with psychology and neuroscience?

The brain is what drew me to psychology initially. However, I vowed I would never go into clinical psychology because I didn’t think I would like therapy or dealing with people’s problems. Over time I discovered neuropsychology. Most neuropsychologists are clinical psychologists so in order or me to be a neuropsychologist, I had to be trained as a clinical psychologist. There are many things I enjoy about clinical psychology but therapy is not one of those things. Granted, most neuropsychologists do not actually do therapy, but we have to be trained in it. I enjoy talking with people in sessions but I haven’t been that impressed with therapy as a whole so far. Maybe that’s just because I haven’t exactly found the particular type of therapeutic method that really “clicks” with me. Cognitive-behavioral therapy is fine but so much of actual therapy in practice is just plain common sense. However, not everyone has a lot of common sense so they need some training in it. Part of me recognizes the validity of therapy but another part of me struggles with it. Now on to my main article.

The more I study the brain and the more exposure I have to therapy (giving, not receiving), the more biased towards the brain I become. What I mean is that we continue to discover more about the brain and as we discover more, the more behavior we can explain based on biology or neurophysiology and the less important I think therapy is. I’ve written about this topic in the past but wanted to briefly revisit it. This is somewhat of a second chapter to that post. Before I continue I wanted to expose one of my biases; I believe humans have free will. Even though some of my beliefs about the brain could be seen as mechanistic and deterministic, I do not believe that a strongly-biological foundation for behavior rules out free will. You can still assume biological foundations without assuming determinism. If, for example, you have a monistic set of assumptions that incorporates both mind - “nonmaterial” - and body - “material” - in one. [I have quotes around nonmaterial and material because mind is not necessarily nonmaterial and body is not necessarily material, well at least philosophically speaking]. Monism is a similar idea to a unified field theory (e.g., Grand Unified Theory) or the Theory of Everything for which some theoretical physicists are searching. That’s not what I’m going to write about and if it didn’t make sense, then don’t worry about it (I discussed this topic in a couple different posts: here {I linked to that post previously} and here). To summarize, I view behavior through a strong biological bias but I do not assume determinism.

As I said earlier, the more I learn about the brain and behavior (through research and observation), the more I lean towards neuroscience and away from “traditional psychology.” However, I still appreciate the psychosocial aspects of behavior; the nature versus nurture dispute will never be resolved because both are important. The environment is important  - all external stimuli are important - but the problem with downplaying biology is that it is the medium of behavior. What I mean is, everything we think, sense, perceive, or do is translated and transmitted through the firing of neurons. This means that all abnormal behavior, which is what psychologists often are interested in, originates in a neuron or related cell. Whether or not the cause of that behavior was internal or external is irrelevant. All events and stimuli are translated into patterns of neuronal firings.

This is why I think that understanding the biology of the brain is the best way to understand a person’s behavior. However, because we have an imperfect understanding of the biology of the brain, we have an imperfect understand of the biological foundations of behavior. This means that until we have a perfect understanding, we cannot ignore the psychosocial aspects of behavior; even with a perfect understand we couldn’t either because even if we understand the “translation” process we may not understand the origin of what needs to be translated. This is where traditional talk therapy can be most beneficial. However, I still believe less and less that talk therapy is the best solution for dealing with many psychological issues. Over time as we discover more and more about the brain, therapy will become even less important.

That is a fairly radical position to take as a student of clinical psychology - it’s more in line with psychiatry, or rather, I believe it’s more in line with neuroscience. I’m not saying that therapy is useless, I’m just saying that as we gain a more perfect understanding of the brain and how various chemicals interact in the brain, we will have less need for people to help others by “talking” through their problems. The better we understand the physiology of the brain, the more natural our pharmaceuticals will be. In other words, it will be easier to mimic and create normal brain functioning. Of course, many will ask, “What is normal?” That’s a good question.

Some may argue that with depression, for example, many people will have negative image and self-evaluations, which can lead to depression. That is true but it’s the classic chicken and egg question. Which came first? Did the negative thoughts cause the depression or did the person experiencing negative thoughts have a biological predisposition to those thoughts and depression? In other words, it is possible that biology originally led to the negative thoughts and not vice versa. This is all speculation but I think there is increasing evidence for this view.

The big problem with my point though is that at some point, it does become a deterministic system in that it’s possible that we could medicate away people’s free will. This is an unacceptable outcome. There would be a lot of power with this knowledge and many opportunities for abuse. That’s an ethical discussion for a later time.

To summarize, I think that as we (speaking in the collective) gain a more perfect understanding of the brain (and even individual differences in the brain) we will be better able to eradicate and prevent many or most psychological disorders. We could potentially stop schizophrenia through genetic engineering or other modifications. Again, I’m not addressing whether or not we should but I believe we will have the ability to at some point. This is why, at the moment I lean more towards neuroscience than I do psychotherapy. Of course, tomorrow I could [I won't] write a post that completely contradicts this one. As I said, this is a process. I think it’s important to argue both sides of the issue.

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Posted by Jared Tanner on September 6th, 2008 in neuropsychology, websites

A few days ago I wrote another post for Brain Blogger about some of the issues people who have been diagnosed with epilepsy face.

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Posted by Jared Tanner on September 5th, 2008 in brain, cognition, hippocampus, learning, memory, neuroscience

Today in Science a team of scientists (Hagar Gelbard-Sagiv, Roy Mukamel, Michal Harel, Rafael Malach, and  Itzhak Fried) at the Weizmann Institute of Science in Israel, UCLA, and Tel Aviv University published their research where they directly recorded via implanted electrodes the firing of hippocampus neurons during learning and free recall. This represents the first time in humans this has been done. Here’s the abstract from Science:

The emergence of memory, a trace of things past, into human consciousness is one of the greatest mysteries of the human mind. Whereas the neuronal basis of recognition memory can be probed experimentally in human and nonhuman primates, the study of free recall requires that the mind declare the occurrence of a recalled memory (an event intrinsic to the organism and invisible to an observer). Here, we report the activity of single neurons in the human hippocampus and surrounding areas when subjects first view television episodes consisting of audiovisual sequences and again later when they freely recall these episodes. A subset of these neurons exhibited selective firing, which often persisted throughout and following specific episodes for as long as 12 seconds. Verbal reports of memories of these specific episodes at the time of free recall were preceded by selective reactivation of the same hippocampal and entorhinal cortex neurons. We suggest that this reactivation is an internally generated neuronal correlate of the subjective experience of spontaneous emergence of human recollection. (Published Online September 4, 2008; Science DOI: 10.1126/science.1164685)

The New York Times also has an article about the research.

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Posted by Jared Tanner on September 2nd, 2008 in neuroanatomy

I’ll be writing some basic neuroanatomy posts over the coming months (I started with my previous post about the corticospinal tract). I recently finished an intense neuroanatomy course where I learned how much I love basic neuroanatomy. It’s exciting to look at a brain or brain slices and try to figure out what and where different structures are.

In the early 1900s Korbinian Brodmann studied the cytoarchitecture (organization of the cortical layers of neurons) of human and non-human brains. His work was painstaking and thorough. He created a topographic map of the cortex containing 52 (50 in humans) different areas. In my class we were not required to learn all of Brodmann’s cortical areas but had to learn some of the major ones. Brodmann’s Areas (BA) 3,1, and 2 compose the primary somatosensory area of the brain. BA 4 is the primary motor cortex. BA 5 is somatosensory association cortex just posterior to BA 3,1,2. BA 6 is pre-motor cortex, which connects directly to BA 4. BA 7 is more somatosensory association cortex that lies just posterior to BA 5. BA 8 is the frontal eye fields, which among other things is responsible for initiating horizontal eye saccades (i.e., quick movement to the left or right). BA 17 is the primary visual cortex, a credit card sized area that lies both dorsal and ventral to the calcarine fissure in the occipital lobe. This area processes most of the basic visual information. BAs 18 and 19 are visual association cortices. BA 22 is Wernicke’s Area, which is involved in the comprehension of language and is in the dorsal-posterior temporal lobe on the border between the temporal and parietal lobes. BAs 41 and 42 are the primary auditory cortex, which processes auditory information from the cochlea; this lies on the transverse temporal gyrus in the dorsal part of the temporal lobes (it is hidden from view unless the cortex around the Sylvian Fissure is pulled away). BAs 44 & 45 are Broca’s area, which is involved in the production of language and is in the lateral frontal lobes.

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Posted by Jared Tanner on September 1st, 2008 in neuroanatomy

The corticospinal tract is a descending motor pathway originating in the Primary Motor Cortex (Brodmann’s area 4) and terminating at various levels in the ventral horn of the spinal cord. The corticospinal tract descends through the posterior limb of the internal capsule then down through the cerebral peduncles into the brainstem. In the brainstem the corticospinal tract remains in the ventral portion, passing through the pyramids on its way down. In the caudal brainstem (just above where the spinal cord starts) 90% of the the corticospinal tract decussates (crosses) to the contralateral (opposite) side and continues down through the dorsolateral spinal cord. This portion controls limb movements. The remaining 10% remains in the ventral spinal cord and is largely responsible for bilateral axial (trunk) movement. From the dorsolateral spinal cord, the axon (that started in the cortex) enters the ventral horn of the spinal cord at the appropriate level (e.g., cervical for arms or lumbar for legs) then exits through the ventral root to terminate on the appropriate muscles.

Through this tract, the cortex controls much of the movement of the body; as such, it’s vitally important for our functioning. Damage to the tract results in an upper motor neuron disorder, with paresis (weakness instead of complete paralysis) and the Babinski reflex fairly common symptoms. Soon after damage, a patient might have flaccid paralysis though with little to no movement of the affected limb(s). As the body starts to recover slightly, spastic paralysis usually sets in with jerky, often uncontrolled limb movements. The corticospinal tract is one of the largest pathways in the central nervous system; it’s one of the most important for motor functioning as well.

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Posted by Jared Tanner on August 29th, 2008 in philosophy, science

I wrote this response to someone who questioned the assertion I made (on a different website) that science is not impartial. Let me know what you think.

I don’t really have room or time to get into a philosophical discussion; this is a discussion that takes months to talk about. As a note, I’m not just making things up, I’ve studied epistemology in college. One of the philosophical foundations of science (science is all based on philosophy, which is one reason in the U.S. all science doctorates are PhDs - Doctor of Philosophy) is empiricism. I’ll quote from Wikipedia because in this case it is accurate.

“Empiricism is one of several competing views about how we know things, part of the branch of philosophy called epistemology, or “theory of knowledge”. Empiricism emphasizes the role of experience and evidence, especially sensory perception, in the formation of ideas, while discounting the notion of innate ideas.”

“In the philosophy of science, empiricism emphasizes those aspects of scientific knowledge that are closely related to evidence, especially as discovered in experiments. It is a fundamental part of the scientific method that all hypotheses and theories must be tested against observations of the natural world, rather than resting solely on a priori reasoning, intuition, or revelation. Hence, science is considered to be methodologically empirical in nature.”

There are other competing philosophies to empiricism. Rationalism is one of those; although in our day some ideas of rationalism are combined with empiricism. Materialism (all entities are matter and reducible to smaller entities, e.g., atoms) is another foundation for most science.

Because modern science is based on specific philosophies with specific assumptions (e.g., that all is matter) it cannot be completely impartial because science (forgive the anthropomorphism) inherently disregards anything that is not based on its same assumptions and philosophies (e.g., religion). Science has one particular view of the world and states that everything else is false, or at least unknowable. That’s not impartial - that’s bias. That’s like Americans saying “Our world view is the only correct world view.” Now, maybe it is true but that does not make it less biased. Everything and everyone have biases, even the philosophies that form the foundation for science.

As I said, this is some pretty deep philosophy. People have been arguing over this for thousands of years and will be for thousands more.

One last example. We tend to believe that mathematics is perfect and unbiased. Kurt Godel showed that it isn’t. Now, not everyone agrees with his ideas but he convincingly showed that most math is flawed, or at least incomplete. Math does not equal science but most science is founded on mathematical principles.

I answered your question, hopefully without coming across as a troll. As I said in my original post, I’m not trying to discredit science (science is my job) but blindly accepting that science is perfect and completely unbiased and the only way to knowledge is demonstrating as much faith in science as many do in religion.”

After a reply back that expressed complete disbelief (that also insulted my intelligence) here’s my final response:

“I did not say that philosophy and science are the same, I just said that science is based on specific philosophies. As I said, it’s some pretty heavy stuff that most people (rightly) don’t care about. Again, I didn’t say philosophy and science are the same. The relationship (and this isn’t a perfect example) is more like philosophy:science::arithmetic:calculus.”

Am I completely off base here? I haven’t had extensive epistemology but I’ve had a fair amount. I remember in one of my classes that some people just didn’t get it. They were very bright people, it’s just that philosophy requires a different way of thinking (not better, just different). It takes practice; I just happened to start having serious philosophical discussions with friends pretty early on in school.

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Posted by Jared Tanner on May 24th, 2008 in neuroscience

I wrote another post called Neuroscience: Psychotherapy’s Executioner? for BrainBlogger.com. You can read it here.

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