Subdivisions and Functions of the Parietal Lobes

Comprehensive vocabulary flashcards covering parietal lobe anatomy, functional subdivisions, somatoperceptual disorders, somatosensory agnosias, Bálint's syndrome, and contralateral neglect symptoms.

Anterior zone (parietal lobe)

The somatosensory cortex comprising Brodmann's areas 1, 2, 3, and 43, responsible for processing somatic sensations and perceptions.

Posterior zone (parietal lobe)

The posterior parietal cortex region that integrates visual and somatosensory information for spatial function, movement, and mental imagery such as mental object rotation.

Parietal area PG

A posterior parietal cytoarchitectonic area described in von Economo's maps that is polymodal, asymmetrical, and larger in the right hemisphere of humans.

Postcentral gyrus

A parietal lobe gyrus that contains Brodmann's cytoarchitectonic areas 1, 2, and 3, corresponding to the primary somatosensory cortex.

Superior parietal lobule

A parietal region that includes Brodmann's areas 5 and 7.

Parietal operculum

A cortical structure of the anterior parietal zone containing Brodmann's area 43.

Inferior parietal lobule

A parietal region composed of the supramarginal gyrus (Brodmann's area 40) and the angular gyrus (Brodmann's area 39).

Allocentric navigation

Spatial navigation that relies on cues and information from the external visual environment to navigate space.

Egocentric navigation

Person-centered spatial navigation that uses one's own body as a frame of reference.

Astereognosis

A somatoperceptual disorder of tactile perception characterized by the inability to recognize the nature or identity of an object by touch.

Simultaneous extinction

A failure to report a stimulus applied to one side of the body when two stimuli are applied simultaneously to opposite sides; associated with damage to secondary cortex areas PE and PF.

Numb touch (blind touch)

A condition resulting from large lesions in areas PE, PF, and partially PG, wherein a patient cannot consciously feel touch or sensory stimuli yet can accurately report the location of the touch.

Asomatognosia

A somatosensory agnosia involving the loss of sense of one's own body, most commonly affecting the left side of the body.

Anosognosia

A form of asomatognosia characterized by the unawareness or explicit denial of one's own illness or deficit.

Anosodiaphoria

A condition in which a patient acknowledges a neurological deficit or illness but displays complete indifference or absence of emotional response toward it.

Asymbolia for pain

The absence of normal sensory and behavioral reactions to painful stimuli, such as the withdrawal reflex.

Autopagnosia

An inability to localize and name body parts or maintain internal knowledge of one's limbs, typically resulting from lesions in the left parietal cortex.

Finger agnosia

A specific manifestation of autopagnosia where a patient cannot identify, distinguish, or name individual fingers.

Bálint's syndrome

A neurological condition caused by bilateral posterior parietal damage characterized by inability to voluntarily fixate gaze on visual stimuli, simultanagnosia, and optic ataxia.

Simultanagnosia

A visual symptom (seen in Bálint's syndrome) characterized as neglect of objects, where attention directed toward one object prevents perception of all others.

Optic ataxia

A severe deficit in reaching and grasping under visual guidance despite intact vision and motor ability, common in superior parietal region (PE) lesions, while non-visually guided actions remain intact.

Contralateral neglect

A disorder most commonly following right inferior parietal lesions (such as the intraparietal sulcus and angular gyrus) characterized by neglect of visual, auditory, and somesthetic stimulation on the side opposite the lesion.

Constructional apraxia

An impairment in combining blocks to form designs or performing visuospatial construction tasks such as drawing and cutting.

Topographic disability

An inability to draw maps or mentally recall spatial layouts and routes from memory.

Allesthesia

A recovery phase in contralateral neglect during which patients begin responding to stimuli on the neglected side as if they were presented on the unlesioned side of the body or space.

Neglect paralexia

A reading deficit associated with neglect where patients read only the right half of compound words (e.g., reading 'COW BOY' as 'BOY' or 'DESK TOP' as 'TOP').

Neglect paragraphia

A writing disturbance in which patients write on only one half of a page or make errors concentrated on the contralesional side when typing.

Personal neglect

A form of hemispatial neglect where an individual fails to attend to one side of their own body, such as shaving or grooming only one half of the face.