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Neuronanotechnology to Cure Criminality and Mental Illness. July 20, 2006—Terasem Annual Workshop on Geoethical Nanotechnology, Lincoln, Vermont. Nancy J. Woolf, Ph.D. Department of Psychology University of California, Los Angeles, CA n woolf@ucla.edu.

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july 20 2006 terasem annual workshop on geoethical nanotechnology lincoln vermont

Neuronanotechnology to Cure Criminality and Mental Illness

July 20, 2006—Terasem Annual Workshop on Geoethical Nanotechnology, Lincoln, Vermont

Nancy J. Woolf, Ph.D.

Department of Psychology

University of California, Los Angeles, CA

nwoolf@ucla.edu

in order to elucidate potential cures a physically detailed model of mind is needed
In Order to Elucidate Potential Cures a Physically Detailed Model of Mind is Needed
  • Neural networks are part of the solution.
  • Biomolecular and biophysical approaches offer the most complete description of mind, but are in the early stages of development.
  • One biomolecule of interest is the microtubule.
current approach
Current Approach
  • Define the mind as a unique interwoven collection of thoughts.
  • Understand the biomolecular and biophysical nature of an individual thought.
  • Apply neuronanotechnology to find cures to mental illness.
thoughts are stored in memory
Thoughts are stored in memory.

Leading to the question: How is memory stored?

arguments for subsynaptic storage of memory
Arguments for Subsynaptic Storage of Memory
  • Synapses (many on dendrite spines) are transiently plastic; most return to baseline.
  • Dendrites continue to grow as intellect grows.
  • Microtubule matrices inside dendrites determine synaptic strength because they control transport and local protein translation.
  • Microtubules store information via patterns of microtubule-associated proteins (e.g., MAP2); these patterns are determined by tubulin isotypes. But how does this translate into a mental state?
what happens inside neurons when animals learn
What happens inside neurons when animals learn?

(e.g. What happens when animals perform tasks such as fear conditioning, avoidance, and spatial navigation?)

map2 and tubulin are reorganized with memory tasks

MAP2 and Tubulin Are Reorganized with Memory Tasks

Fear conditioning increases the breakdown of MAP2 and tubulin and also alters the phosphorylation state (Woolf et al., 1999; Woolf, 1998; Woolf et al., 1994).

Knockout studies show MAP2 is essential to fear conditioning (Khuchua et al., 2003).

Passive avoidance affects the distribution of MAP2-rich modules of cortex (Van der Zee et al., 1994).

Spatial and working memory are enhanced by overexpression of kinesin (Wong et al., 2002).

slide8

Woolf et al., 1999

Naïve Control Tone-Shock Paired Tone-Shock Unpaired

Increased MAP2 immunostaining in hippocampal CA1 pyramidal cells is due to increased breakdown of these proteins (confirmed by immunoblotting).

slide10
During learning, there is activation of…
  • acetylcholine and glutamate terminals, therebyaffecting neurotransmitter release.
  • actin filaments,microtubules, and MAPs, thereby affecting their conductive signaling properties.

Woolf, 2006

neurons have the largest variety of tubulin isotypes why
Neurons Have the Largest Variety of Tubulin Isotypes: Why?
  • The tubulin dimer consists of a and b subunits.
  • bI-tubulin is present in all cells.
  • The rarer bII-, bIII-, bIVa- and bVII-tubulin isotypes are found in brain.
  • Semi-periodic distribution of rare b-tubulin isotypes individualizes each neuronal microtubule. This enables the storage of specific information along the microtubule.
slide12

Microtubules are universal cables when dephosphorylated (with MAP2 densities hidden).

Specific information is amplified upon phosphorylation (with MAP2 density-contours revealed).

bipolar disorder an opportunity for neuronanotechnology
Bipolar Disorder: An Opportunity for Neuronanotechnology
  • Bipolar disorder is an affective disorder that afflicts as many as 4% of the population.
  • Bipolar disorder is characterized by dramatic changes in mood (e.g., shifts between depression and mania or hypomania, or mixed states).
bipolar disorder related changes in cingulate cortex orbitofrontal cortex hippocampus and amygdala
Bipolar Disorder-Related Changes in Cingulate Cortex, Orbitofrontal Cortex, Hippocampus and Amygdala
  • Decreased activity in cingulate cortex and increased activity in orbitofrontal cortex of bipolar subjects and their siblings during a sadness task (Kruger et al., 2006).
  • Increased activity in amygdala and decreased activity in orbitofrontal cortex with mania during a facial response task (Altshuler et al., 2005).
bipolar disorder associated with tubulin and map2 deficiencies
Bipolar Disorder Associated with Tubulin and MAP2 Deficiencies
  • b-Tubulin is decreased in the anterior cingulate cortex of bipolar patients (Beasley et al., 2006).
  • MAP2 mRNA levels are decreased in the hippocampus (MacDonald et al., 2006).
mood stabilizers used to treat bipolar disorder affect maps
Mood Stabilizers Used to Treat Bipolar Disorder Affect MAPs
  • Lithium, valproate, and carbamazepine inhibit glycogen synthase kinase-3 (GSK3), which phosphorylates the two MAPs: tau and MAP2 (Williams et al., 2004; Grimes & Jope, 2001).
  • By this mechanism, these mood stabilizers alter microtubule dynamics.
meta analyses of genetic studies on bipolar disorder
Meta-Analyses of Genetic Studies on Bipolar Disorder

Genomic loci identified for bipolar disorder(e.g., Hayden & Nurnberger, 2006; Cheng et al., 2006; Segundo et al., 2003) overlap with loci for human tubulin proteins (Entrez Gene,NIH):

  • bIIA-, bIIB-, and bIIC-tubulin, bIII-and bVI-tubulin
  • proteins similar to aII-tubulin, b-chain-tubulin, bI-tubulin, bIV-tubulin, and bV-tubulin
  • pseudogenes for bIVQ-tubulin, bII-tubulin, and bV-tubulin, and bIV-tubulin polypeptide.
slide19

In bipolar disorder, thoughts speed up (as in mania) or slow down (as in depression) possibly due to altered MAP2-binding dynamics as dictated by the tubulin isotypes expressed.

a novel treatment for bipolar disorder is needed
A Novel Treatment for Bipolar Disorder Is Needed
  • Certain individuals do not respond to mood stabilizers, and while polytherapy is common, this can be self-limiting because of drug interactions.
  • Bipolar disorder affects approximately 12 million Americans and exhibits co-morbidities with substance abuse and criminality, thereby raising sociobiological issues and ethical concerns.
increased incidence of substance abuse and criminality in bipolar disorder
Increased Incidence of Substance Abuse and Criminality in Bipolar Disorder
  • Fifty-three percent of female and 79 percent of male rapid-cycling bipolar subjects with co-morbid substance abuse report having been charged with a crime (Friedman et al., 2005).
  • Many mentally ill end up incarcerated.(In 1939,Lionel Penrose noted a consistent inverse relationship between the prison population and the number of inhabitants in mental hospitals at any point in time.)
electromagnetic treatments can be effective for affective disorders
Electromagnetic Treatments Can Be Effective for Affective Disorders
  • Repetitive Transcranial Magnetic Stimulation (rTMS) delivered to the frontal cortex at 1 – 20 Hz decreases symptoms of unipolar depression and bipolar disorder (Isenberg et al., 2005;Michael & Erfurth, 2004; Dolberg et al., 2002;Kozel & George, 2002).
  • There is a laterality effect: Right cortical stimulation treats mania and left cortical stimulation treats depression (Li et al., 2004; Sakkas et al., 2003).
slide23

Electromagnetic treatments are potentially beneficial, but there is no theoretical basis for how they work, thereby limiting our ability to make these treatments any better.

Redefining electromagnetic treatments in terms of how they affect microtubule signaling and how they correct abnormal signaling patterns will enable significant improvements.

microtubules respond to electromagnetic waves
Microtubules Respond to Electromagnetic Waves
  • Second-harmonic generation microscopy indicates that microtubules are one of a few endogenous structures that show intense doubling of laser excitation in the 760 – 880 nm range (Dombeck et al., 2003; Campagnola et al., 2002).
  • Individual microtubules respond to near infrared waves by destabilizing and moving towards the source (Albrecht-Buehler, 1998; Albrecht-Buehler, 2005).
steps to develop treatments that normalize neuronal activity via stimulation of microtubules
Steps to Develop Treatments That Normalize Neuronal Activity Via Stimulation of Microtubules
  • Identify normal and abnormal collective patterns of conductive signaling among microtubules.
  • Use electromagnetic principles such as constructive and destructive interference to train normal conductive signaling and inhibit aberrant conductive signaling.
slide26

Moreover, since microtubules are both structurally plastic and capable of long-term storage, permanent functional adaptation may be possible. (i.e., This approach may lead to a long-lasting cure for affective disorders.)

future directions
Future Directions
  • Research at the subcellular level: Studies on individual microtubules and their conductive signaling properties.
  • Research at the clinical level: Measuring abnormal activity associated with mental disorders and associated co-morbidities, as these relate to microtubule signaling.
  • Long-term goal: Retrain microtubule networks in neurons to behave adaptively.