Reading and Dyslexia

Important to remember that reading is a cultural phenomena. Not all cultures developed reading in the same way which raises issues concerning the next cognitive disorder. Chatterjee presented a case where an subject learned to read a second language in adolescence to the point where the second language dominated while the primary language regressed! (Something that does not normally happen where a dominant language is learned early, second languages are harder at this time.)

ImageThe difference revolved around the way different languages are acquired (grapheme or phoneme) which influence abilities to obtain the language particularly English, since the language has so many irregular words, require whole word exception.

This example lead to a discussion of developmental dyslexia which inhabits 5% population of school age children. SES is not thought to be causally related but does require both the need to combine eye and ear (rapid auditory processing and lexical command) and . However, biological indicators of the problem might include the magnocellular decrease (neurons involved fast switching) and abnormal cortical folding.

[Unfortunately the lack of etiology with dyslexia has prompted quick fix responses (computer programs) which actually are not as important than more difficult, highly related work with a tutor.]

What was overlooked in the illustration presented was that the adolescent could not read irregular words (English) where the adolescent could read Spanish which has all regular words. The desire to speak the second language did include adolescent behavior but the etiology was primarily around dyslexic ability to read another language at a level that was greater than anticipated (the subject could read Dantes in Spanish!).

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Pathologies of Cognition

ImageAfternoon presentation focuses on pathologies of cognition with Dr. Anjan Chatterjee. Session opened with definitions for dementia and Alzheimer disease. One indicator is patient/relative ratio rule of thumb (when patient concerned but not relative then depression, when relative concerned but not patient, Alzheimer). Still the overall these areas are provide one of the most emotional social issues today. Dementia is a major problem: 10% of people over the age of 65 or 5.1 million cases in the United States with 16 million expected by 2040. Currently dementia costs 148 billion/year caring for patients with dementia. It is important to remember that age is a major risk factor

–65-69  –  2%
–70-74  –  4%
–74-79  –  8%
–80-85  –  16%
–over 85  –  40%
•Over 85 – (with this age group the fastest growing segment of the population)
Alzheimer entails loss of cognition (repeating oneself within an hour) decrease in activities of daily living (caring for oneself) and personality changes. The neurological reasoning entails two phenomenon: Amyloid Plaques and Neurofibrillary Tangles (disagreement over which most important)Image
•Amyloid Plaques (Ab) includes the extracellular accumulation of Ab  (fragment of the amyloid precursor protein). Abnormal processing of APP critical to pathophysiology of Alzheimer’s disease.
•Neurofibrillary Tangles define Intracellular, paired helical structures composed of hyperphosphorylated tau. The tangles correlate well with disease severity and neuronal death.
The reason “why” these occur and contribute to Alzheimer remains unknown but their overall impact result in brain shrinkage over time.
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While some disorders from last week seem to be associated with specific areas of the brain it is amazing how some disorders involve several brain functions. For instance Schizophrenia involves a number of areas with generally less neural activity in schizophrenic subjects in the Amygdala, Parahippocampal gyrus, Fusiform gyrus, Right superior frontal gyrus… alll leading to a disruption of “an integrated social cognitive network”

Structural brain analysis in Autism reveal Greater volume in the total brain, including the cerebellum, caudate nucleus (area correlated with degree of repetitive movements, the
Caudate is involved in higher order motor control). The disparate regions seem less well organized with inefficient connections, poor integration. Also there appears to be reduced volume in the corpus callosum.

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Functionally autistic brain displayd ecreased activity in regions recruited during social cognition (e.g., thinking about others’ emotional states): the Ventromedial PFC and Amygdala. In addition reduction in the Fusiform “face area” so that faces processed more like non-face objects.

Gilihand noted that there is some struggle with brain and diagnosis (adolescents is a cultural construct while HIV a physical disease). So can we take DSM description and predict brain construction? Can bosses or insurance providers require workers to take fMRI to “diagnose” conditions? Probably not at this point. For instance Amygdala and PFC affected in all disorders reviewed this morning so it is hard to find sufficient resolution on fMRI since most other studies have been studied “on average” so “specific” diagnoses would be very difficult.

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Social and Affective Disorders and Neuroscience

ImageStarting a new day with Clinical Psychologist Dr. Seth Gillihan.The focus will be on the Neuroscience in Social and Affective Disorders. After reviewing the disorders I suspect the neuroscience will be particularly fascinating in regards to OCD, PTSD, etc. Gilihan’s goals include the following

•Review reliable brain correlates of major classes of social and affective disorders
•Review diagnostic criteria for these disorders
•Provide tools for making sense of studies in these areas

ImageThe presentations will push us into practical issues beginning with the issue of anxiety via fMRI studies. Amygdala studies note that most actions exist between between emotional and social dynamics (emotional expressions seem keyed to social awareness at times).   Not surprising that studies around anxiety might begin with Amygdala activityGilihan notes that we need metanalyses across studies to better understand how specific studies converse with each other. What is noted is that both amygdala and insula both were involved in activation in anxiety states like PTSD but also reduced activity in the Pre Frontal Cortext where executive control exists.

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Emotion and the Brain

A long but beneficial day studying emotion and the brain. Dr. Joseph Kable  provided three lectures that started with the basics of neural correlates to emotion (regions involved),  the nature of motivation including specific issues involved in addiction, the place of decision making in emotion, and the role of empathy both with social interactions and moral decision making (which include both judgement and empathy). There were just too many insights for summary, and some of the material had to be condensed with an extensive discussion over methodology (n0t surprising with a group this size). Still, a lot of important material introduced. Rather than cover everything I am just going to touch on a few highlights that might intersect with popular ideas.

One preliminary, Kable defined emotion as a “discrete response to an external or internal event involving a synchronized:

  • expression
  • bodily response
  • subjective experience or feeling
  • evaluation and appraisal
  • action tendencies”

Kable notes psychologists prefer to use terms like intensity and valence (toward positive or negative) rather than terms like “joy” or “love” since the more technical terms provide better control for the sake of  comparison (so joy becomes an intense positive emotion and fear an intense negative emotion).

One surprise to me is that the historically used idea of the limbic system is losing favor in neuroscience with greater interest in researching the Dopamine/Reward correlation and the Amygdala/Fear correlation.

One caution is that neuroscience is always using comparative frameworks so one traditional study involved standard behavior reward (Pavlov).

Dopamine seems to be active both when an animal receives an unexpected reward but later appears when the animal “anticipates” the reward (we are talking milliseconds) and drops rapidly if the reward does not appear. However the study tested the difference between receiving or not receiving the reward (anticipatory set not the issue). Dopamine is not encoding the presence of the reward but encoding a reward prediction error (what you got versus what you expected to get). However, the overall study proves helpful  since it helps us understand learning through “trial and error” based on the number of tstwe do not get it correct). This simple study opens up a neurochemical basis for the most basic form of learning.

Similarly studies on fear (see the work of Joesph LeDoux) provide a basic learning theory. Think of the fact animals “freeze” at the sight of a dangerous snake or when a sound emits a dangerous shock.

Amygdala is one place where all information occurs in brain to address this phenomenon: lateral nucleus has ability to gather both sound and shock while central nucleus to mediate freezing, blood pressure, and hormones. Also fear studies contribute to the idea “cells that fire together also wire together.” The concept is called long term potentiation (LTP) where continued synaptic firing between two neurons (axon to dendrite) “strengthen” the connection between the two neurons (via amplification: the strength of the response is greater to the firing). This provides a synaptic basis for learning as well (LeDoux says we are “synaptic selves”).

Later in the day we moved beyond these basic categories to discuss judgment and emotion. It is important that controlling emotion is not just the Prefrontal Cortext “shutting down” the seat of emotions (amygdala) but actually activates the subcortical striatum

(which has densest number of dompamanergic receptors) so that the PFC (seat of executive function) actually “biases” flow of activation in other areas of the brain based on the representation of what the rules are in the PFC. So PFC is not directly controlling but modulating stimulus/response. A question rose whether to call the brain’s executive function a Modulator? Mediator? perhaps Moderator is best term. Raises question whether a better metaphor for brain activity might be harmonics rather than hydraulics… something to reflect on later.

When engaged in empathy or social decision making Kable noted we have to begin with a theory of the mind (great example is the following movie Heider-Simmel Demonstration where we ascribe intention to actions (even if just objects).

Empathy seems to involve the same areas of the brain where we directly feel pain and pleasure (so seeing someone in pain lights up the same parts of the brain as experiencing pain, but also just telling someone of a painful event!)

When it comes to social interaction and moral decisions, we seem to employ both decision making processes (theory of mind area) and empathetic pathways in many “personal” decisions. Need to end this post. Much more to say but a good day to “digest” in the coming weeks.

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New Classrooms Can Change Children’s Brains

New Classrooms Can Change Children’s Brains

Yesterday’s opening presentation over Executive Function caused this article title to jump out at me. Have not read it yet but seems to be indicative of how popular science is using the material in regards to education (same edition also has digital dating). 

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Great presentations

A day of great presentations as well as visits to the labs. Morning lectures by Wolk focused more on role and contribution of technology and raised the possibilities of Deep Brain Stimulation in the future (including possibly with Alzheimers) but more work need to be done.

What was new to me was the role of Transcranial Direct Current Stimulation (tDCS) which uses very low doses of current (9 volt) across cranial portions of the brain. These mechanisms are much smaller and can be used longer and may actually have some impact on plasticity. Overall this methodology proves cheaper and smaller design may leads to greater portability. With this much easier technology we may see claims in the use of the instrument that cannot be verified in the near future, apparently they are for sale on market which might lead to commercialization and unfounded claims…but still a hopeful future.

Martha Farah presented an intro to cognitive neuroscience that incorporated aspects of perception, memory (particularly the role of episodic memory and semantic memory) and closed the day with executive functions. A lot of survey material but well done (learned a lot).

She spent a lot of time on long term memory, the biological bases of different memory problems (where she has provided strong research as well) and the possibilities of how executive function oversees parallel processes in the brain.

Tons of info so just one note: Farah noted that semantic memory (knowing data) is always derived from episodic memory (narrative or lived memory) via the hippocampus. This simple observation raises a real question how much “data” we can teach that does not include some level of contextualization and opportunity to process the same information over time in real world settings. Worth a discussion in class in the future.

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