Sensory gating is often considered an automatic and involuntary first step in the attentional process and, in adults and children diminished sensory gating ability is associated with neurocognitive and behavioral problems in attention. (Hutchinson 2013)
Sensory gating of auditory input
Diminished auditory sensory gating is linked to both internalizing and externalizing disorders in children.
P50 sensory gating utilizes an auditory evoked potential paradigm to measure inhibitory processes in the brain. In the P50 sensory gating paradigm, auditory evoked potentials to two successive auditory stimuli, in this case 2 “clicks” are compared. Most healthy adults show an attenuated response to the second stimulus reflecting the robust ability of the brain to decrease response to irrelevant repetitive stimuli (Hutchinson 2015)
Recently, P50 sensory gating has been described in early infancy with stable performance from infancy to 4 years of age (Gillow, Hunter, & Ross, 2010). Both presumed genetic risk factors—such as having a parent with a psychotic illness—and environmental risk factors—such as prenatal exposure to maternal anxiety, maternal nicotine use, or maternal illicit substance use— are well-established larger effect size risk factors of later attention-drive behavioral impairment. Each of these risk factors is associated with impaired infant P50 sensory gating, with effects identifiable in even relatively small samples (Hunter et al., 2012; Hunter, Kisley, McCarthy, Freedman, & Ross, 2011).
A study by Hutchinson (2015) demonstrated that infants with diminished sensory gating deficit ranked higher, at 40 months of age, on parent-reported problems in attention and anxiety/depression, in the overall externalizing symptoms domain, and in DSM-IV (APA, 1994)-oriented scales of anxiety disorders and ADHDs. Infants with diminished sensory gating were later higher rated for oppositional defiant symptoms, although the difference did not reach statistical significance.
Sensory gating during movement
Sensory inputs are initiated from peripheral receptor and transmitted through the spinal cord via thalamus to cortex, and sensory information could be regulated at each of these different levels during behavior.
Movement could activate peripheral sensory receptors that activate neurons along the somatosensory pathway, however sensory information is commonly suppressed during movement and even during observation of movement (Song 2015, Voisin et al., 2011).
Movement related sensory gating can occur at spinal, brainstem, and thalamic levels and is stronger during active movement than passive movement (Song 2015)
Marlinski et al (2012) used single neuron extracellular recordings in cats performing simple locomotion on a flat surface as well as complex visually guided stepping along a horizontal ladder. They found that the activity of neurons in the motor compartment of the reticular nucleus of thalamus (RE) was profoundly modulated in the rhythm of strides, strongly differed between cells with receptive fields on different segments of the limb, and varied depending on the complexity of the locomotion task.
"The reticular nucleus of thalamus (RE) consists of GABA-ergic neurons that receive inputs from axonal collaterals of both thalamic neurons projecting to the cortex, and of neurons of cortical layer VI projecting to the thalamus (rev. in Jones 2007). RE neurons project back to the dorsal thalamic nuclei inhibiting them. Thus, the RE provides feedback inhibition of ascending thalamo-cortical signals and feedforward inhibition of descending cortico-thalamic signals." ( Malinski et al 2012)
Sensory processing of olfactory inputs
Increased olfactory sensitivity as well as an increase in olfactory bulb volume had been found in ADHD. A study by Lonenzo et al (2016) showed thtat there were no group differences in sensitivity towards a trigeminal stimulus, but compared to healthy controls, the fPIR in ADHD was more positively coupled with structures belonging to the salience network during olfactory and, to a lesser extent, during trigeminal stimulation.
Bibliography
Hutchison, A. K., Hunter, S. K., Wagner, B. D., Calvin, E. a, Zerbe, G. O., & Ross, R. G. (2013). Diminished Infant P50 Sensory Gating Predicts Increased 40-Month-Old Attention, Anxiety/Depression, and Externalizing Symptoms. Journal of Attention Disorders, (X). doi:10.1177/1087054713488824
Lorenzen A, Scholz-Hehn D, Wiesner CD, Wolff S, Bergmann TO, van Eimeren T, Lentfer L, Baving L, Prehn-Kristensen A. Chemosensory processing in children with attention-deficit/hyperactivity disorder. J Psychiatr Res. 2016 Feb 13;76:121-127. doi: 10.1016/j.jpsychires.2016.02.007. [Epub ahead of print] Abstract
Marlinski V., Sirota M. G., Beloozerova I. N. (2012). Differential gating of thalamocortical signals by reticular nucleus of thalamus during locomotion. J. Neurosci. 32, 15823–15836. 10.1523/JNEUROSCI.0782-12.2012
Song, W., & Francis, J. T. (2015). Gating of tactile information through gamma band during passive arm movement in awake primates. Frontiers in Neural Circuits, 9, 64. http://doi.org/10.3389/fncir.2015.00064
