Predictive encoding of moving target trajectory by neurons in the parabigeminal nucleus.

Intercepting momentarily invisible moving objects requires internally generated estimations of target trajectory. We demonstrate here that the parabigeminal nucleus (PBN) encodes such estimations, combining sensory representations of target location, extrapolated positions of briefly obscured targets, and eye position information. Cui and Malpeli (Cui H, Malpeli JG.

Contrast sensitivity of cats and humans in scotopic and mesopic conditions.

Human contrast sensitivity in low scotopic conditions is regulated according to the deVries-Rose law. Previous cat behavioral data, as well as cat and mice electrophysiological data, have not confirmed this relationship. To resolve this discrepancy at the behavioral level, we compared sensitivity in dim light for cats and humans in parallel experiments using the same visual stimuli and similar behavioral paradigms.

Dim-light sensitivity of cells in the awake cat's lateral geniculate and medial interlaminar nuclei: a correlation with behavior.

Contrast thresholds of cells in the dorsal lateral geniculate (LGNd) and medial interlaminar (MIN) nuclei of awake cats were measured for scotopic and mesopic vision with drifting sine gratings (1/8, 2, and 4 cycles/deg [cpd]; 4-Hz temporal frequency). Thresholds for mean firing rate (F0) and temporally modulated responses (F1) were derived with receiver-operating-characteristic analyses and compared with behavioral measures recently reported by Kang and colleagues. Behavioral sensitivity was predicted by the neural responses of the most sensitive combinations of cell class and response mode: Y-cell F1 responses for 1/8 cpd, X-cell F1 responses for 2 cpd, and Y-cell F0 responses for 4 cpd.

Behavioral calibration of eye movement recording systems using moving targets.

Equipment used to measure eye movements must generally be calibrated to the individual subject. Some methods of measuring eye position are quite non-linear, requiring that the system's output be linearized. We describe an approach of behavioral calibration and linearization that utilizes tracking of moving targets.

Activity in the parabigeminal nucleus during eye movements directed at moving and stationary targets.

The parabigeminal nucleus (PBN) is a small satellite of the superior colliculus located on the edge of the midbrain. To identify activity related to visuomotor behavior, we recorded from PBN cells in cats trained to fixate moving and stationary targets. Cats tracked moving targets primarily with small catch-up saccades, and for target speeds of 2-6 degrees /s, they did so with sufficient accuracy to keep targets within 2.