The hyperpallium (formerly called the hyperstriatum or the wulst) is the destination for lemnothalamic projections in

birds Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

. The projections as well as the granular cells at the destination of the lemnothalamic projections to the hyperpallium are similar in morphology,

electrophysiology Electrophysiology (from Greek , ''ēlektron'', "amber" etymology of "electron"">Electron#Etymology">etymology of "electron" , ''physis'', "nature, origin"; and , '' -logia'') is the branch of physiology that studies the electrical properties of b ...

retinotopic Retinotopy (from Greek τόπος, place) is the mapping of visual input from the retina to neurons, particularly those neurons within the visual stream. For clarity, 'retinotopy' can be replaced with 'retinal mapping', and 'retinotopic' with 'r ...

organization, and columnar organization to the

striate cortex The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and ...

in mammals. These avian granular cells are thought to have evolved independently in birds, as they do not appear in

reptiles Reptiles, as most commonly defined are the animals in the Class (biology), class Reptilia ( ), a paraphyletic grouping comprising all sauropsid, sauropsids except birds. Living reptiles comprise turtles, crocodilians, Squamata, squamates (lizar ...

. The projections originate in the dorsal

lateral geniculate nucleus In neuroanatomy, the lateral geniculate nucleus (LGN; also called the lateral geniculate body or lateral geniculate complex) is a structure in the thalamus and a key component of the mammalian visual pathway. It is a small, ovoid, ventral projec ...

and target three layers in the hyperpallium: the hyperpallium intercalatum, the hyperpallium densocellularis, and the nucleus interstitialis hyperpalii apicalis, with the densest projections being to the later two layers. The

efferent Efferent may refer to: Anatomical structures Meaning 'conveying away from a center': *Efferent arterioles, conveying blood away from the Bowman's capsule in the kidney *Efferent nerve fiber, carries nerve impulses away from the central nervous sy ...

s of the telencephalic components of the lemnothalamic pathway project to the

optic tectum In neuroanatomy, the superior colliculus () is a structure lying on the roof of the mammalian midbrain. In non-mammalian vertebrates, the homologous structure is known as the optic tectum, or optic lobe. The adjective form ''tectal'' is commonly ...

(equivalent to the superior colliculus), the lemnothalamic visual nucleus, as well as other optic tract targets. The hyperpallium is observed to be large and well developed in raptors such as

eagles Eagle is the common name for many large birds of prey of the family Accipitridae. Eagles belong to several groups of genera, some of which are closely related. Most of the 68 species of eagle are from Eurasia and Africa. Outside this area, just ...

hawks Hawks are birds of prey of the family Accipitridae. They are widely distributed and are found on all continents except Antarctica. * The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks and others. This subfamily a ...

, and

owls Owls are birds from the Order (biology), order Strigiformes (), which includes over 200 species of mostly Solitary animal, solitary and Nocturnal animal, nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vi ...

References

{{reflist Bird neuroanatomy Brain