Human performance

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Describe the location and Functions of the lateral occipital cortex (LOC), the fusiform face area (FFA) And the estrastriate body area (EAB).

The Lateral occipital complex (LOC) is a large region of the ventral stream of the Visual association cortex, and appears to respond to a wide variety of objects And shapes. // The fusiform face area (FFA) is located in the ventral stream, On the anterior fusiform gyrus. It recognizes facial features, but also the Activity of this region can be affected by previously learned information. // The Extraestriate body area (EBA) is located in the ventral stream posterior to the FFA and partly overlaps it. This region is specifically activated by Photographs, silhouettes, or stick drawings of human bodies or body parts and Not by control stimuli such as photographs or drawings of tools, scrambled Silhouettes, or scrambled stick drawings of human bodies.

Represent the main somatosensory pathways And describe their properties.

Path of the posterior cord-medial lemniscus: path that is dedicated to the touch. It Has much temporal resolution and has more spatial resolution than pain.

1. The ascending limb of the Aα enters the posterior ipsilateral cord of The spinal cord (rapid transmission by myelinated fibers temporal resolution).

2. The posterior cords convey information About the tactile sensation (and the position of the extremities) towards the Brain.

3. The axons of the posterior cord Terminate in the nuclei of the posterior cord (between medulla and bulb).

It is a fast and direct route that leads Information from the skin to the brain without synapses intervening. At that Point, the information is still preserved ipsilaterally, that is, the tactile Information from the left side of the brain is represented in the neurons of The left cord nuclei. Once past that point the path is decusa and the sensory System of one side deals with the sensations originated in the opposite side of The body (decusación of the nucleus).

4. The axons of the nucleus go to the Medial leminiscus. This ascends to the VP nucleus of the thalamus and from There to the primary somatosensory cortex (S1), in the postcentral gyrus.

The information is altered each time it Passes through a group of synapses in the brain. As it increases, the spatial Resolution of the tactile information increases, thanks to the mechanisms of Lateral inhibition by limiting the extent of the excitation.

Trigeminal nerve pathway: The somatic sensation of the face comes mainly from The large trigeminal nerves (V cranial nerve) that enter the brain through the Bridge. There are two trigeminal nerves, one on each side, and each is divided Into three peripheral nerves that innervate the face. Additional sensations of The skin surrounding the ears, nasal region and pharynx depend on other cranial Nerves: facial (VII), glossopharyngeal (IX), and vagus (X).

1. Thick sensory axons of the trigeminal Nerve carry tactile information of the mechanoreceptors of the skin.

2. Synapse with 2nd order sensory neurons In the ipsilateral trigeminal nucleus.

3. Axons leaving the trigeminal nucleus Decussate and project toward the medial portion of the VP nucleus of the Thalamus.

4. From there the information is Retransmitted to the somatosensory cortex.

Represent and describe the neural circuits Involved in the three components of pain.

1. Sensory component (pure Perception of the intensity of painful stimulus): pathways from the spinal cord To ventral posterolateral thalamus and to the primary and secondary Somatosensory cortex.

2. Immediate emotional Consequences of pain: appears to be mediated by pathways that reach the Anterior cingulate cortex (ACC) and the insular cortex.

Several studies have found That painful stimuli activate the insular cortex and the ACC. In addition, Electrical stimulation of the insular cortex caused reports of painful burning And stinging sensations.

Damage to this region Decreases people’s emotional response to pain: They continue to feel the pain But do not seem to recognize that it is harmful. They do not withdraw from pain Or the threat of pain.

3. Long-term emotional Implications of chronic pain: appears to be mediated by pathways that reach the Prefrontal cortex. Damage to the prefrontal cortex impairs people’s ability to Make plans for the future and to recognize the personal significance of Situations in which they are involved. Along with the general lack of insight, People with prefrontal damage tend not to be concerned with the implications of Chronic conditions including chronic pain—for their future.

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