Sensory Integration Problems in Autism

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Sensory Integration Problems in Autism May 24, 2009 Manuel F. Casanova, M.D.
Temple Grandin
• In an interview with Temple Grandin (2008) when asked where the federal government should spend their research money, she answered: “…I would spend it on…really figuring out what causes all the sensory problems. I realize it’s not the core deficit in autism, but it something that makes it extremely difficult for persons with autism to function.”
Properties of Systems
A system has: 1) properties that are emergent, if not intrinsically found in any of its parts, 2) phase transitions; the capacity to change from one defined state to another at a critical juncture, and 3) a high degree of internal interdependence.
Orientation Preference of Columns
Proposed emergent properties: Thresholding, amplification, derivative functions, feature convergence, distribution functions, coincidence detection, pattern generation, etc. Mountcastle, 1998.
Minicolumns in Autism and Controls
Casanova et al., 2002
Gray Level Index Overlay
Casanova, 2007, in press
Rett Syndrome
Minicolumns in Autism
Shower Curtain of Inhibition
Minicolumnar activity patterns generated by Favorov and Kelly (1994) in response to spatially defined patterns in a shape of letters H and U.
Predictability: Quantitative Sensory Testing in Autism
←Spatial localization under two conditions of adapting stimulus duration.
Radial histogram of SI cortical → activity (Squirrel monkeys, n=5). Cortical activity measured as light absorbance.
Minicolumnar activity patterns generated by Favorov and Kelly (1994) in response to spatially defined patterns in a shape of letters H and U.
Inhibitory Deficit in Autism
Casanova, 2006
Information (Neuronal Activity) and Background
The Noisy Brain: Part 1
• 1) “What researchers found was that in fact stimulus overload is devastating to the brain’s- to the self’s- capacity to maintain itself. Entirely normal people who are severely overloaded, especially by unpredictable and uncontrollable stimuli, can show impaired functioning, raised physiological stress, internal chaos. Impulsive actions, and a “lower level of adaptation: to life’s challenges.” • 2) “Because research shows that prolonged states of sensory overload (or noise) are actually traumatizing, we can conclude that patients suffering from severe mental disorders are actually being traumatized by their own brains.”
Ratey JJ. Shadow Syndromes, page 29, 1997
The Noisy Brain: Part 2
• 1) “Noise affects this top level, causing a person afflicted to fall back to a more primitive, “lower” level of brain functioning that corresponds to the social strategies of the adolescent or child. (Or lower still…where we respond reflexively instead of thoughtfully.” • 2) “Finally, beyond both of these difficulties, intense physiological arousal also impairs reasoning ability, a phenomenon psychiatrists describe as becoming concrete. Once we have become concrete, we take things at face value; we are no longer responding to the subtle clues and subtext of social interactions…But what happens when people become concrete is that they have no way of gauging the depth, the possible subtexts, of any particular exchange.”
Ratey JJ. Shadow Syndromes, page 29, 1997
Inhibitory Surround of Minicolumns
Faraday’s law
Any change in the magnetic environment of a conductor will cause a voltage to be induced in that conductor.
Precise Targeting of Specific Cortical Regions: Frameless Stereotaxy
Brainsight-Rogue Research, Inc
Diagnostic Characterization of Neural Circuitry: Modulation of Activity in a Distributed Network
Valero-Cabre et al., Exp Brain Res 2005, 2006
Gamma Frequencies
Induced Gamma Frequency Oscillations