Psych M119L: Agnosias, Brain Imaging Techniques, and Attentional Networks

Vocabulary flashcards covering agnosias, brain lesion sites, neuroimaging techniques, attentional networks, and commissures from the Psych M119L lecture material.

Visual Object Agnosia

Loss of ability to visually identify object and function; caused by damage to the left hemisphere at the intersection of the parietal and temporal lobes.

Finger Agnosia

Loss of knowledge of the meaning of individual fingers; caused by damage to the angular gyrus in the parietal lobe of the left hemisphere.

Autotopagnosia

Disorder in knowledge of body schema; caused by damage to the parietal lobe in the left hemisphere.

Color Agnosia

Loss of knowledge of the meaning of colors; caused by damage to the lingual gyrus (bottom region including occipital and temporal lobes) in the left hemisphere.

Simultanagnosia

Loss of understanding of pictorial scene; caused by damage to the left hemisphere at the intersection of the parietal and temporal lobes.

Topographical Agnosia

Loss of knowledge of previously known routes; caused by damage to the retrosplenial cortex (parietal lobe) in the right hemisphere.

Spatial Agnosia

Loss of knowledge of relationships between objects, resulting in being unable to build a 3D structure from looking at a diagram or model; caused by damage to the parieto-occipital junction in the right hemisphere.

Anosognosia

Denial of illness; caused by damage to the parietal lobe in the right hemisphere.

Prosopagnosia

Loss of ability to recognize people by faces alone; caused by damage to the fusiform gyrus (bottom of occipital and temporal lobes) in the right hemisphere.

Tactile Agnosia / Astereognosis

Loss of ability to recognize objects by touch alone; caused by damage to the left or right parietal lobe and right frontal lobe.

Mirror Agnosia

Loss of ability to recognize an object by its reflection; caused by damage to the left or right parietal lobe and right frontal lobe.

Phonagnosia

Loss of ability to recognize people by their voice; caused by damage to the medial temporal lobe, and can be congenital.

Agnosia for Environmental Sounds

Loss of ability to recognize environmental sounds; caused by damage to the left, right, or both temporal lobes.

Gustatory Agnosia

Loss of knowledge of tasting (cognition); caused by damage to the left or right temporal lobe.

Post Mortem Brain Tissue

An examination method that shows structural anomalies, arteries, veins, lesions, and tumors.

X-Rays: Conventional Radiography

Imaging technique that shows structural anomalies, lesions, and tumors.

Angiography

Imaging method used to show vascular anomalies.

Computed Axial Tomography (CT)

An advanced form of X-ray where a beam of X-ray is rotated through $180^\top$ to provide images on a computer screen of digital slices through the brain.

Magnetic Resonance Imaging (MRI)

An imaging technique where a patient's head is surrounded by a magnetic field and radio waves directed at the skull/brain interfere with hydrogen ($\text{H}$) inside the brain; the change in orientation of $\text{H}$ causes a local magnetic field detected by magnetic detectors around the head.

Diffusion Tensor Imaging (DTI)

A technique based on detection of how water diffuses along the length of nerve fibers; shows changes in diseases and reveals white matter.

Positron Emission Tomography (PET)

Imaging technique that shows active brain regions by injecting radioactive (inert) glucose into the blood to be taken up by currently active neurons; decaying radioactive material emits positrons detected by a scanner.

Functional Magnetic Resonance (fMRI)

Technique exposing the brain to several magnetic fields to measure oxygen uptake in blood while performing a task; the amount of oxygen indicates brain activity demanded by neural activity.

Trans Electric Stimulation (TES)

Method directing weak electrical current at the brain to rapidly change magnetic fields and deactivate receiving regions; by stimulating cortical points and recording deactivation responses, maps of functional brain areas are obtained.

DAN (Dorsal Attentional Network)

A bilaterally represented network extending from the intra-parietal sulcus (superior parietal lobule) to the frontal eye fields (dorsolateral PFC) that functions in spatial orienting in goal-directed behavior when selecting relevant stimuli.

VAN (Ventral Attentional Network)

A network extending from the inferior parietal lobule and posterior parietal temporal junction to the ventral frontal cortex (inferior, middle frontal gyri) that functions in automatically detecting unexpected but behaviorally relevant/salient events; mostly lateralized to the right hemisphere.

Somatoparaphrenia

An extreme condition of anosognosia where hemi-neglect must also be present, characterized by extreme hatred towards a limb on the left half of the body and usually paralysis on the left half of the body.

Alcalculia

Inability to do math; caused by damage to the angular gyrus.

3 Major Commissures

The three major fiber tracts connecting the cerebral hemispheres: Corpus Callosum, Anterior Commissure, and Hippocampal Commissure.