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Neurons in the monkey pulvinar react extremely fast to visually perceived faces (50ms).

According to Johnson and Morton, there are two visual pathways for face detection: the primary cortical pathway and one through SC and pulvinar.

The cortical pathway is called CONLEARN and is theorized to be plastic, whereas the sub-cortical pathway is called CONSPEC and is thought to be fixed and genetically predisposed to detect conspecific faces.

Masking visual face stimuli can evoke responses in sc, pulvinar, and amygdala.

The right amygdala responded differently to masked than to unmasked stimuli, while the left did not in Morris et al.'s experiments.

A possible ascending pathway from SC to visual cortex through the pulvinar nuclei (pulvinar) may be responsible for the effect of SC activity on visual processing in the cortex.

Regions lesions of which can induce visuospatial neglect include

  • the parietal lobe, in particular the inferior part,
  • temporo-parietal junction,
  • the anterior cingulate cortex,
  • basal ganglia,
  • thalamus,
  • the pulvinar nucleus.

There is a disynaptic connection from SC to the dorsal stream visual cortex, probably through the pulvinar.

The subcortical visual pathway which may drive face detection and orienting towards faces in newborns hypothesized by Johnson also includes amygdala and pulvinar.

According to the hypothesis expressed by Johnson, amygdala, pulvinar, and SC together form a sub-cortical pathway which detects faces, initiates orienting movements towards faces, and activates cortical regions.

This implies that this pathway may be important for the development of the `social brain', as Johnson puts it.

The pulvinar receives direct retinal input.

There seems to be an ascending pathway from superficial SC to the medial temporal area (MT) through the pulvinar nuclei (inferior pulvinar).

Berman and Wurtz found neurons in the pulvinar nuclei which received input from SC and sent output to MT.

Pulvinar neurons project to the SC.

Pulvinar neurons receive input from the MT.

There seem to be few, if any, neurons in the pulvinar which receive input from and project to neurons in the same region of MT.

Pulvinar neurons seem to receive input and project to different layers in visual cortex:

They receive input from layer 5 and project to layers one and three.

Connectivity between pulvinar and MT is similar to connectivity between pulvinar and visual cortex.