The Other Side of Dr. Xeno's Brain

Various and strange ideas, stories and images from me, Dr. Xeno. Mostly related to my current obsession - cycling for life!

Thursday, November 19, 2009

Growing a brain, inside a body (week 9)







Humans change - they grow, develop and mature. Lots of ways to look at this; measure is quantitatively, view it qualitatively or consider it's transformative nature. However, it clearly rests upon a biological entity (the human itself). It is fascinating, because it is us and those around us. (
Growth, development and maturation definitions; p. 15, Barry Bogin, Patterns of Human Growth)

Human development (biology) Wikipedia.org article with mega-hypertext
Especially note the stages/phases of physical growth. Alternatively, consider simply the age of the organism. Age often reveals the stage of development and/or functional capacity. But individual variability can be great.
Seen a fetus lately?
Motor Milestones
Brain Growth
Major Events in Neural Development
Important terms, semi-chronological: proliferation (increase in number), migration (movement/organization), connection (preliminary and ongoing), pruning (normal early death of neurons not forming significant/useful connections), mylenation (temporal lobes not until ages 2-4, frontal lobes not until late 20s).


The only way to pack the incredible human cortex into our skulls is to fold it in upon itself - this is what gives the cortex is wrinkled look. This allows greater surface area in a smaller volume. The sulci are valleys and the gyri are the bumps or hills. Tracking the development of the folding process may give us an early indication of abnormal brain growth & development. See the brief report in the NCRR Reporter.
See this link for some physical growth charts by the WHO.

Marilyn Diamond (UC Berkeley), Godmother of lifelong cortical plasticity - or brain enrichment. Studied enriched environments effects on rat brain, behavior, health. Amazing stuff.
Response of the brain to enrichment (1997).


Thursday, November 12, 2009

Emotion, Integration and States of Conciousness

How Ya Feelin'?! (Week 9 is fine)


The above are the classic and universal expressions associated with the basic human emotions. Many thanks for Paul Ekman and his socio-emotional-behavioral research team.

Wikipedia says, "Paul Ekman is a Psychologist who has been the pioneer in the study of emotions and their relation to facial expressions. He is considered one of the 100 most eminent psychologists of the twentieth century. Ekman takes an evolutionary perspective, in that the development of human traits and states over time is the background to his research." Ekman found that facial expressions of emotion are not culturally determined but are universal to all human cultures and suggesting they are biological in origin (innate?). Ekman also discovered microexpressions which are a brief facial expression that last less than a quarter of a second. In his research called the Diogenes Project, Paul Ekman found that these tiny movements often can expose lying (seen "Lie To ME" on TV?). Paul Ekman is also the founder of The Facial Action Coding System (FACS) which details the exact muscular-physical expressions of emotions which is useful to psychologists and animators.

So, how ya feelin'?

Much of emotion is communicated non-verbally - both it's expression and perception. Expressed emotion is 'affect', while experiencing emotion is 'mood'. Different mood states involve different patterns of activation in both physical and cognitive domains. "Flat affect" indicates a lack of emotional expression. May be on purpose (like a poker face) or reflect low mood/low energy (like in major depressive episodes). Adding emotion (or meaning) to our spoken language is known as "prosody." This aspect of langauage, and emotional processing in general seems to be one of the strengths of the right hemisphere. However, there are known structures and pathways specializing in emotion and I will name only the amygdala; a limbic structure, sub-cortical (diencephalon) with some tight connections with memory structures such as the hippocampus.

"Feeling" or "feelings" is another problematic term - it is probably more accurate to use sensation(s), perception(s), or emotion(s). My point is picky I suppose, but just clarify what exactly it is that you are "feeling" - it's a verb - so, "I am feeling angry" suits me fine; so does, "I am feeling something poke me". Emotional processing is just another example of information processing; on the other hand, some have argued that ALL information processing IS emotional. Kenneth Dodge suggests that, "emotion is the energy that drives, organizes, amplifies and attenuates cognitive activity."

Most theories of emotion include common themes: emotion involves complex layers of processes that are in constant interaction with the environment. Emotional processing involves BOTH cognitive AND physical process.

Basic Phases of Emotion
Initial Orientation
Appraisal
Arousal

Organizing Emotions
Differential and Categorical - most simple category is the emotional valence. (positive vs. negative)
Primary Emotions - more highly categorized, and yet, basic emotions such as: sadness, fear, joy, anger, disgust or surprise.

Development of emotional maturity is largely about regulating emotional responsiveness.

Integration

One of the mind-brain's key features is it's ability to interconnect a range of processes within it's present time frame as well as interconnecting activities and content across time. We experience this as 'spatiotemporal integration.' Much brain tissue and activity is about this type of 'association' of information rather than specific or direct sensory or motor processing (side note on association cortex). Lack of integration leads to a lack of cohesiveness in our mental/cognitive worlds/experiences. While specific (modular) cognitive activities can lead to or disrupt integrative experience, holistic (molar) operations such as language, consciousness, emotional processing (or powerful retrieval experiences) are more likely to set the tone for integration or cohesive mental experience. When successful, this is a seamless, tacit process. That is, we are unaware of all the sub-processing and patterns of activation, we experience it as a whole. Our consciousness.

What needs to be integrated?
1. Various cognitive activities (content and process); orientation, attention, sensation-perception, visuospatial function, cognitive mapping, memory function, language processing, prosody, emotion, planning and other executive functions. AND basic body control/monitoring.
2. Various levels of brain functions (triune brain; vertical integration in columns)
3. Hemispheres of the brain (lateral integration; corpus callosum)

Evidence/pathways to integration
1. Self - sense of self may result from the recursive nature of ALL neural processing. It's always happening to YOUR neural pathways and the activity shifts always resemble to ones before and after closely. It's a placeholder, or perhaps a canvas, or a major landmark by which to measure and compare all experience.

2. Theory of mind - requires some meta-cogition and meta-memory. What we know about our own cognitive/memory function. Building a theory of mind requires that we have the ability to place ourselves in their position and imagine what they would hear/feel/etc.

3. Response flexibility - consider alternative responses and select the best suited response set. Opposite is 'stimulus bound' behavior. This may be ultimate executive function. Intelligence? Problem solving?

4. Narrative - sequential descriptions of people and events that condense numerous experiences in generalizations and contrasting stories. Narrative process attempts to make meaning of the world and one's own mind on it's various states.

What is lack of integration?
Disintegration? Lack of cohesive experience; incoherent. Lack of the above 4 items? Some terms for lack of various functions:
Dementia
Amentia
Amnesia
Aphasia
Agnosia
Apraxia
Psychopathological dissociation - shizophrenia (split or broken mind) vs. multiple personality disorder.

Can result from structural or functional brain problems or simply psychogenic states with no know organic cause.

State(s) of consciousness
OVERALL pattern of mind-brain activation; includes, but more than simply being conscious or unconscious or "the subconscious" mind. These states are fluctuating, however, any pattern of activation is likely to recur; and a recurring pattern of activation may become a persisting TRAIT rather than simply a state. The state reflects both the type of processing going on (or degrees of various processes) AND the content being processed. Many things can affect the overall pattern of activation; keep in mind you have some control over this. SO, be mindful over whatever pattern of activation you allow - because it will recur or possibly even persist and may not go away (or at least not easily).

Thursday, November 05, 2009

Brain Damage, Neurodegeneration and Dementia, Oh My!

Week 8?/Chapter 8 (plus Dementia Max PowerPoint slides)

Non-cortical (sub-cortical?) conditions:
A lot of these are predominantly movement/motor disorders with or without cognitive impairment. ALS (Lou Gherig's Disease) is exclusively motor and is not discussed here.

Multiple sclerosis (MS) - demyelinating disease (auto-immune disorder?)
  • wide ranges of symptoms depending on central (including cortex) or peripheral
  • relapsing-remitting or chronic progressive form; even CP form can begin as RR
  • variable signs & symptoms as well as clinical course
  • limb weakness, ataxia, sensory loss, etc.
Parkinson's Disease:
Parkinson (1817) described the syndome, also known as "paralysis agitans". Destruction of substantia nigra of the basal ganglia and presence of Lewy bodies; subcortical/nonvoluntary motor control, smoothing. Parkisonism is similar signs & symptoms but from another cause.
  • Parkinson's shuffle - stooped, small steps, straight-lines, etc.
  • slow, including speech (and hyphonic)
  • rigid, cogwheeling, TREMO at rest
  • cognition? depends, at the very least, it is also slowed
  • responds to dopamine therapy (l-dopa)
Huntington's Disease/Chorea:
writhing, genetic. More rare. Basal ganglia also, but striatum. Personality and cognitive changes.

Profound brain injury, coma, locked in syndrome.

DEMENTIA?

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Thursday, October 29, 2009

Language

Week 6, Chapter 7: Language


Catscan image credit, John norseen, George Washington University. Reveals differential patterns of functional brain activation. Shown are neural activation patterns associated with four different operations within the realm of verbal processing. Shown is the left hemisphere and most people are left hemisphere dominant for language processing.
Hearing words show temporal cortex activation (location of auditory cortex); seeing words shows occipital cortex activation (visual cortex); speaking words shows frontal (motor cortex); and generating words shows prefrontal cortex activation (uhhhh.... executive functions, coming up with new ideas, response flexibility, following rules).


Conceptual reminder/review:

LOCALIZATION of Function: specific regions (locations) of the brain have specific functions. Damage to that region leads to impairment or loss of specific functions. In the absence of damage, individuals with varying degrees of efficiency and/or interconnnectivity in that region may show varying degrees of proficiency in it's specific function. Taken to an extreme, this concept suggests MODULARITY wherein independent modules of the mind-brain perform specific and unique processing on particular forms of information.

DISTRIBUTION of Function: any function or process of the mind-brain will involve multiple regions (either nuclei or pathways) distributed throughout the nervous system. Therefore, the location is not as important as the overall mass action of the brain. Taken a bit to an extreme suggests the concept of EQUIPOTENTIALITY wherein any brain region can be organized or re-organized to perform any task.

Varieties of APHASIA (language disorder):
1. Broca's aphasia - motor, nonfluent, expressive
2. Wernicke's aphasia - sensory, receptive
3. Conduction aphasia - central
4. Anomic aphasia - anomia, naming items
5. Transcortical motor aphasia
6. Transcortical sensory aphasia

Anatomy; p. 139
Congnitive processes; p. 147

Thursday, October 22, 2009

Parietal and Occipital Lobes

Week 5: Parietal Lobes (Chap 5) and Occipital Lobes (Chap 6)

Parietal Lobes (Chap 5)

Anatomical items: anterior and posterior regions

1. anterior region - foreward most/anterior border is the posterior central sulcus/gyrus
  • primary somatosensory cortex (sensory strip)
  • secondary somatosensory cortex
  • tactile perception
  • body sense
2. posterior region - no clear/hard borders
  • ALL tertiary cortex
  • spatial orientation/spatial neglect
  • some cases of visual agnosia
  • APRAXIA; disorder of practical/purposeful/intentional motor behavior
  • cross-modal integration/language (PTO, remember?)

Occipital Lobes (Chap 6) - the visual perception lobes
  • primary - basic visual functions
  • secondary - visual perceptual functions
  • tertiary - higher order perception and inter-sensory integration (PTO, remember?)

Tuesday, October 20, 2009

Temporal Lobes

Week 4/Chapter 4: The Temporal Lobes (and memory)

Anatomical considerations:
Temporal lobe is like a peninsula, or the thumb in the hand brain
Lateral portion - outer surface; neocortex = new cortex (thumb nail side)
Mesial portion - inner or middle surface; paleocortex = old cortex (thumb pad side)
Medial temporal lobe - deep structures, not actually 'sub'cortical, because it is like a cortical roll up. Basically, the hippocampus.

7 Functions of the temporal lobes? (see p. 92 for list, and chapter for details)
Heavily involved in memory and perceptual processes.

1. Audition; primary, secondary and tertiary auditory cortical zones in temporal lobe
2. Vision (chap 6 also, Occipital Lobes)
3. Language (chap 7 also)
4. Attention
5. Cross-modal integration
6. Memory - see Memory Max powerpoint at Bb
7. Personality

Cases studies in amnestic disorders involving temporal lobes. The "Hollywood Amnesia" syndrome is usually unrealistic.

Monday, October 05, 2009

Frontal Lobes


Week 3/Chapter 3: terms and topics for the frontal lobes

Executive functions?
Personality? Humanness?
Intelligence? Methodological issues: comparing lesions; quantitative (IQ, Category Test) versus qualitative changes (abstract and concrete thought).

Specific functions and the FOUR divisions of the frontal lobe
  1. Motor and premotor cortex
  2. Prefrontal cortex
  3. Broca's area
  4. Orbital cortex or orbital-frontal region