Chronic Neurophysiological Effects of Repeated Head Trauma in Retired Australian Male Sport Athletes.

This study investigated the somatosensory and corticomotor physiology of retired contact sport athletes with a history of repeated concussion/subconcussion head trauma. Retired male athletes with a history of playing contact sports and repeated head trauma ( = 122) were divided into two groups: those who expressed concerns regarding their mental and cognitive health ("symptomatic": = 83), and those who did not express any ongoing concerns ("asymptomatic": = 39). Both groups were compared to age-matched male controls ( = 50) with no history of concussions or participation in contact sports, an absence of self-reported cognitive, or mood impairments.

Perceptual metrics of individuals with autism provide evidence for disinhibition.

Adults with autism exhibit inhibitory deficits that are often manifested in behavioral modifications, such as repetitive behaviors, and/or sensory hyper-responsiveness. If such behaviors are the result of a generalized deficiency in inhibitory neurotransmission, then it stands to reason that deficits involving localized cortical-cortical interactions--such as in sensory discrimination tasks--could be detected and quantified. This study exemplifies a newly developed method for quantifying sensory testing metrics.

Vibrotactile adaptation enhances spatial localization.

A two-interval forced choice tracking procedure was used to evaluate the effects of a pre-exposure to vibrotactile stimulation ("adaptation") on the capacity of human subjects to spatially localize a subsequent tactile stimulus. A 25 Hz flutter adapting stimulus was presented at a randomly selected position within a 20 mm linear array oriented transversely on the hand dorsum. Two flutter stimuli delivered subsequently were applied to different sites along the linear array; one to the same locus that received the adapting stimulation (the "standard" stimulus), the other to a distant site (the "test" stimulus).

Stimulus-evoked modulation of sensorimotor pyramidal neuron EPSPs.

Sensory cortical neurons display substantial receptive field dynamics during and after persistent sensory drive. Because a cell's response properties are determined by the inputs it receives, receptive field dynamics are likely to involve changes in the relative efficacy of different inputs to the cell. To test this hypothesis, we have investigated if brief repetitive stimulus drive in vitro alters the efficacy of two types of corticocortical inputs to layer V pyramidal cells.