In some neural structures (for instance, SC, pulvinar
, posterior parietal cortex), it was observed an enhancement of the response to a visual stimulus flashed in the receptive field of a neuron when the stimulus became relevant to the animal (see Colby, 1991; Wurtz et al.
There is evidence that diffuse injury disrupts neural pathways or networks that serve attention, such as the parietal lobe, thalamic structures, superior colliculus, pulvinar
, dorso-lateral frontal cortex, and anterior cingulus.
Researchers examining vision also find brain centers that control what they call "the flashlight of attention." David Lee Robinson of the National Eye Institute in Bethesda, Md., reports that cells in the brain area called the pulvinar
thalamic nucleus respond more strongly when an animal has been trained to pay attention to the visual stimulus than when it is not paying attention.
Only one significant cluster (67 voxels; Talairach coordinates of best voxel: [11, -25, 2]) was found which included the ventral posterior lateral nucleus, the pulvinar
, and the medial dorsal nucleus, located in the right thalamus; HR swimmers showed stronger net connections between the thalamus and the whole brain when compared to those in the LR (Figures 1(d) and 1(e)).
sign was present on the T2-weighted images in 5 of the 10 cases.
sign (30), cortical ribboning (31), or other findings suggestive of human prion disease have not been identified.
This pathway impacts on pupil function as well as sending fibres to the pulvinar
(posterior thalamus) where it is relayed to the parietal cortex, bypassing the occipital cortex.
In addition, recognition provoked differentially localized increases in the pulvinar
, posterior hippocampus, and prefrontal cortex.
A characteristic high signal in the posterior thalamus on T2- and diffusion-weighted magnetic resonance imaging (the "pulvinar
sign") is demonstrated in >75% of vCJD patients, and in the appropriate clinical context, is highly indicative of a vCJD diagnosis (7).
Asbjornsen, "Auditory neglect after right frontal lobe and right pulvinar
thalamic lesions," Brain and Language, vol.
Medical evaluations at the National Prion Clinic included an electroencephalogram (EEG), which revealed a normal alpharhythm, and magnetic resonance imaging (MRI) studies, which revealed signal abnormalities in the pulvinar
and metathalamus region that were suggestive of vCJD.