Brodmann area 19
From Freepedia
Brodmann area 19, or BA19, is part of the occipital lobe cortex in the human brain. Along with area 18, it comprises the extrastriate (or peristriate) cortex. In normally-sighted humans, extrastriate cortex is a visual association area, with feature-extracting, shape recognition, attentional, and multimodal integrating functions.
What does it do?
Area 19 is a histologically delineated band anterolaterally abutting visual area 18. Single-cell electrophysiological recordings from area 19 in the cat suggest sensitivity to motion-delineated forms; recordings from primates have yielded varying results, indicating that this area may be a heterogeneous collection of visual areas, with multiple incomplete representations of the visual scene.
In humans, this band putatively contains regions of the visual areas designated V3, V4 and V6 in the primate. Functional magnetic resonance imaging shows some degree of retinotopic mapping. The area has reciprocal connections with areas 17 and 18, as well as posterior parietal association areas.
Area 19 has been noted to receive inputs from the lateral geniculate nucleus via the pulvinar, and may contribute to the phenomenon of blindsight. In patients blind from a young age, the area has been found to be activated by somatosensory stimuli.
Because of these findings, it is thought that area 19 is the differentiation point of the two visual streams, of the 'what' and 'where' visual pathways. The dorsal region may contain motion-sensitive neurones, and ventral areas may be specialised for object recognition.
See also
References
- Hyvarinen, J., Carlson, Y. and Hyvarinen, L. (1981) Early visual deprivation alters modality of neuronal responses in area 19 of monkey cortex, Neurosci. Lett. 26, 239–243
- Theories of visual cortex organization in primates: areas of the third level, Prog Brain Res. 1996;112:213-21
