Visual Memory Research
The Genesis of Mnemonic Visual Systems 
Recurrent Dynamics in Excitable Media

Topic D8: The Blind Spots of Mariotte

The locations of the optic nerve heads can be identified as asymmetric positive/negative entoptic phenomena. The impletion mechanisms of these "scotomata" as described (Pearce, Arch. Ophthal. Vol. 79 May, 1968) relate to cortical functions; similar mechanisms also erase the momentary perceptions of the pre-retinal vascular shadows.
These intra-ocular vascular retinotopic images are "object-derived"; hence are cognitively transparent to the exogenic, homotopic images as both images are transmitted along the same on-line pathways.  But the complex illusory images which are generated by neural processes in the higher visual pathways and derived from "percepts in storage," engrams, dreams, and the hypnagogic images are generally not transparent with external images.
The subjective recognition of entopic structures is useful in the evaluation and scaling of other less familiar entoptic visual phenomena.

  

 With  both eyes closed- but-  lit , (an umbral view)  the locations of the optic nerve heads can be identified by manually  occluding  alternate  eyes , thus manifesting  asymmetric positive  entoptic phenomena. The impletion mechanisms of these "scotomata" as described (Pearce  I Arc. Oph.  1968)  relate to cortical functions; similar mechanisms also erase the momentary perceptions of the pre-retinal vascular shadows.   These images can  act as landmarks and as scalar references for  other entopic phenomena
    The intra-ocular retinotopic images are "object-derived", hence are cognitively transparent to the exogenic, homotopic images as both images are transmitted along the same on-line pathways.    But the complex illusory images which are generated by neural processes in the higher visual pathways and derived from "percepts in storage," engrams, from dreams and hypnagogic images are generally not transparent with external images.