Middle+Temporal+Lobe

THE 'VISUAL" MIDDLE INFERIOR TEMPORAL LOBE
The middle temporal lobe, (MTL) appears to be functionaly lateralized. right MTL: visual and non-verbal auditory functioning, visual responsiveness left MTL: auditory-linguistic capabilities. both: visually responsive neurons

this is considered speculative due to relatively few published studies of the effects of lesions or the functional capabilities of the middle temporal lobes in humans

Connections
Has connections with areas concerned with visual and visual attentional capabilities - **projections from:** striate cortex, area 17 and the association area 18 **projects to:** MTL of the opposite hemisphere via the corpus callosum, ipsilaterally to areas 17, 18, 19, the inferior temporal and the parietal-occipital cortex and maintains interconnections with the pulvinar, superior colliculus and pontine nuclei of the brainstem.

Functions
appears to provide visual guidance in regard to interactional object and body movement. -Analysis of the flow of movement -Local direction and speed -Relative distances of objects

**neurons sensitive to:** speed/direction of movement, motion, orientation, width, and disparity

Not particular sensitive to the form of a stimulus--most preferring narrow stimuli

A large number of cells have binocular capabilities and respond to stimuli from either or both eyes - significantly involved in stereoscopic vision & determining distance.

Although not specialized for perception of form per se, via the combined analysis of width, orientation, speed and direction of movement these cells can process visual stimuli in a three-dimensional fashion, particularly in regard to trajectory, depth and position, i.e. if an object is near or far, approaching or withdrawing.

These neurons (in conjunction with area 7 cells) are important in guiding the movements of the body as well as the individuals limbs toward the object

The MTL maintains extensive interconnections with the inferior region and thus with limbic nuclei. It is probably via these connections that objects or conspecies of motivational significance can be discerned and attended to. That is, not only is the speed, movement, distance, etc. of a stimulus determined, but its emotional attributes (e.g. should it be feared, chased, eaten). Moreover, not just written words, but object recognition occurs in this area (in conjunction with the inferior temporal lobe), such that if injured, patients may suffer from agnosia, i.e. an inability to recognize visual images.

project into: auditory association area, frontal convexity, and orbital region

Left inferior-middle posterior temporal lobe (Brodmann's area 37) located between the visual cortex and the anterior temporal cortex. Activated during a variety of language tasks, including reading and object and letter naming Reading of concrete and abstract words activates the left posterior basal temporal lobe and the left frontal operculum

Lesions/Damage
middle temporal lobe: -Word finding difficulty -possible aphasic abnormalities -Confrontive naming deficits -Abnormalities in the maintanance of temporal order and sequence -Verbal memory impairments -Reading and naming deficits (phonological alexia) patients with developmental dyslexia have been found to have abnormalities in this area

Notes:
Left temporal lobe activity increases as word length increases. Hence, with injuries in this area, including the basal temporal lobe, patients may have difficulty recalling word lists or order of word presentation, such that the longer the list, the greater the difficulty. Hence, if a list of four words were read, the patient cannot repeat the correct order even after repeated presentations, although individuals words may be recalled correctly.

In general, the more posterior: visual aspects of perception and language, including reading and object naming (left posterior basal temporal lobe is a convergence zone for visual, auditory, and tactile information) <span style="font-family: 'Times New Roman',serif;">-may show alexia as well as visual and tactile anomia if this area is injured

<span style="font-family: 'Times New Roman',serif;">right basal temporal lobe: more concerned with non-verbal visual functioning.

HALLUCINATIONS

 * Tumors:** middle temporal lobe auditory and visual hallucinations, dreamy states, and alterations in emotional functioning--particularly as the lesion encroaches on the inferior regions.
 * Electrical stimulation:** initiates the development of complex hallucinations and alterations in consciousness.