Sensory Integration Problems in AutismMay 24, 2009

Manuel F. Casanova, M.D.

Temple GrandinTemple 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 SystemsProperties 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 ColumnsOrientation 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 ControlsMinicolumns in Autism and Controls

Casanova et al., 2002

Gray Level Index OverlayGray Level Index Overlay

Casanova, 2007, in press

Rett Syndrome

Minicolumns in AutismMinicolumns in Autism

Shower Curtain of InhibitionShower 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 Predictability: Quantitative Sensory Testing in AutismTesting in Autism

Radial histogram of SI cortical → activity (Squirrel monkeys, n=5). Cortical activity measured as light absorbance.

←Spatial localization under two conditions of adapting stimulus duration.

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 AutismInhibitory Deficit in Autism

Casanova, 2006

Information (Neuronal Activity) and BackgroundInformation (Neuronal Activity) and Background

The Noisy Brain: Part 1The 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 2The 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 MinicolumnsInhibitory Surround of Minicolumns

Faraday’s lawFaraday’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 Precise Targeting of Specific Cortical Regions: Frameless StereotaxyRegions: Frameless Stereotaxy

Brainsight-Rogue Research, Inc

Diagnostic Characterization of Neural Circuitry: Modulation of Modulation of Activity in a Distributed NetworkActivity in a Distributed Network

Valero-Cabre et al., Exp Brain Res 2005, 2006

Gamma FrequenciesGamma Frequencies

Induced Gamma Frequency OscillationsInduced Gamma Frequency Oscillations