Inferior+Temporal+Lobe

the Inferior Temporal Lobe appears to be involved in the highest level of visual integration containing highly developed neurons which seem to be the end station of a hierarchical system which mediates the perception and recognition of specific and particular shapes and forms The anterior-inferior temporal lobes can be loosely defined as auditory cortex, although neurons in this vicinity receive visual as well as somesthetic input.. Hence, the inferior temporal lobes responds to auditory as well as emotionally and visually significant stimuli.

Connections
The processing of complex auditory, visual and emotional stimuli is probably a function of it being a derivative of the amygdala & visual cortex.
 * Projections from:** extensive (upper visual field) projections from the optic radiations, highly processed input from the visual association areas in the occipital lobes of both cerebral hemispheres (via the corpus callosum), and fibers from the superior colliculus via the pulvinar.



Functions: VISUAL CAPABILITIES & FORM RECOGNITION
-Specialized for receiving, analyzing, discriminating, recognizing and recalling complex visual information -Involved in attention and visually guided behavior -Recollection and learning of visual discriminations -Memory for objects and spatial locations

Lesions/Damage
- loss of the ability to recognize faces (prosopagnosia) -Severe disturbances involving visual discrimination learning and retention -Difficulty performing visual closure and recognizing incomplete figural stimuli (different shapes and patterns and objects which differ in regard to size or color)

Laterality
 * Right:** impaired visual discriminations when presented with fragmented concentric circle patterns or overlapping nonsense shapes -skills which are also related to visual closure and gestalt formation. Lobectomies showed impaired ability to remember and recognize toys and their location
 * Left:**



Cells sensitive to:
-Direction of stimulus movement -Color -Contrast -Size -Shape -Orientation -Perception of three dimensional objects -Supramodal analysis of information already processed in the association areas

Notes: A single neuron can respond to a combination of these features and many will fire selectively in response to particular shapes and faces

FORM & FACIAL RECOGNITION
In addition to the optic radiations, there is a pathway (the ventral stream) beginning in the primary visual cortex which passes through areas 18 and 19 and terminates in the ITL. As information is passed from the primary to these association areas various features important in the identification of specific objects become progressively and hiarchically analyzed and increasingly complex associations are formed.

Some neurons have been found to become particularly excited when presented with two dimensional patterns or three dimensional objects such as hands, brushes, and in particular, faces A variety of different feature detectors are found and the majority probably act collectively so as code and assemble a particular shape, including the formation of gestalts and thus "visual closure" in which a partial stimulus can be recognized as a face vs. a rabbit Some cells are responsive to particular facial orientations, such as a profile, some respond to only parts of the face, such as eyes or a mouth, whereas others respond only to the entire face; i.e. a correctly organized facial gestalt. Also neurons which will fire even to a scrambled face, so long as all the features are present. Some cells respond preferentially to familiar faces, to the faces of certain individuals, to specific emotions conveyed via the face, and the direction of the face including the direction of gaze--especially cells within the amygdala. **Left Amygdala:** discriminates the direction of another person's gaze **Right amygdala:** activated while making eye-to-eye contact. Can determine if someone is looking at them, or looking at someone else, if the facial expression conveys threat, and if there is a hand moving toward or away from the subject or another person.

-Especially equipped for determining social signals and to read the emotions conveyed facially between two people. These same capacities were originally mediated by the olfactory system which in turn gave rise to the amygdala and promoted its differentiation and thus the development of the temporal lobe.

Bilateral removal of the anterior inferior temporal lobe (thus amygdala & parts of the hippocampus): "psychic blindness," and will pick up and smell and taste whatever object captures their attention. In other words, being deprived of an amygdala that can process, visually, social and emotional signals, the amygdalectomized patient/primate reverts back to those behaviors typical of creatures that rely on smell.