![Image](https://www.worldsupporter.org/sites/default/files/styles/medium/public/tips_suggestions/wereldbol_summaries_joho_single_boek_1_150x190px.png?itok=rEljlfYL)
How does the somatosensory system work?
Tactile information is processed by the somatosensory system. Somatosensory information is derived from different receptors in the skin, muscles and joints that transmit information about different basic sensory modalities. Such as gnostic touch (pressure, vibrations), proprioception (contains information about the position and movement of the body), pain and sensitivity to hot and cold, and affective touch. There are two systems responsible for converting somatosensory input to the brain:
- The medial lemniscal system. This system is concerned with gnostic touch and proprioception.
- The spinothalamic channel. This channel mediates pain, thermal and affective tactile information.
Input is then forwarded to the primary somatosensory cortex (S-I), also known as somatosensitive bark. This is located in the parietal lobe. The somatosensory cortex contains somatotopic maps of the contralateral side of the body. When the somatosensory cortex is damaged, limitations can be seen in processing the physical and elemental characteristics of tactile stimuli. Higher order somatosensory processes involve more widely distributed networks, including the secondary somatosensory cortex (S-II). These processes include deriving the characteristics of an object, recognising an object and body perception-related processes.
What are primary somatosensory disorders?
Primary tactile disorders consist of an inability to detect basic somatosensory aspects, including limited sensitivity to pressure on the skin, reduced spatial acuity, loss of vibration, and limitations in proprioception. These disorders often result from damage to the contralateral primary somatosensory cortex, thalamus or subcortical ascending to the somatosensory pathways. The deficits may relate to only a somatosensory submodality, while the others remain entirely intact. Primary tactile disorders can lead to higher order problems, such as the inability to recognise objects based on touch. However, higher order tactile disorders can also be present in the absence of primary elemental deficits.
Which higher order tactile disorders can we distinguish?
Discrimination against haptic features. Haptic features include texture, substance, size, shape, weight and hardness of a stimulus. There are two categories related to the micro and macrogeometric properties of an object. Texture, density and thermal properties are considered to be microgeometric aspects. Size and shape are considered as macro geometric aspects. It is still unclear whether the two functions are also segregated at the neuroanatomical level.
Tactile apraxia. This is a deviation that occurs with actions related to the active sense of touch. This is not specific to the use of objects, but has to do with any action using the hand as a sensing means. These are problems in matching the hand movements with the characteristics of an object under certain circumstances. Tactile apraxia is often related to damage to the superior posterior parietal areas.
Tactile agnosia. This concerns the inability to recognise an object by touch.
Tactile aphasia. Tactile aphasia occurs when a person is unable to name an object based on touch (but can name the object when perceived through another modality). The patient is also able to visually depict and categorise the object based on meaning, indicating that semantic knowledge about the object is available to the patient.
What are body-related disorders?
Information about our body is based on the integration of visual, proprioceptive and tactile input. A distinction is made between body image and body scheme. The body image concerns a conscious perceptual identification of body characteristics. It is more visually based and is influenced by existing knowledge of body structure and semantics. The body scheme concerns the position of body parts in space for directing action. It is mainly based on tactile input and proprioceptive information and is continuously updated as our body moves and changes. Body representation disorders can include features of both types.
What are structural body representation disorders?
Structural body representation concerns the knowledge about the composition and shape of body parts. This is essential for forming body awareness. Here are some examples of disorders related to structural body representation and body awareness:
In autotopagnosia, patients are unable to pinpoint their own body parts on a visual schedule. In heterotopagnosia, patients are unable to identify the body parts of another. These disorders are associated with mid-temporal and parietal leasies in the dominant hemisphere.
Patients with asomatognosia experience that a body part is no longer there. In somatoparaphrenia, the patient experiences asomatognosia with extensive delusions, misidentifications and fabrications about the affected body part.
The phantom limb phenomenon concerns the persistent experience of the postural and motor aspects of a limb after the physical loss of that limb.
Samenvattingen per artikel bij het vak Neuropsychologische diagnostiek UU 20/21
Samenvattingen per artikel bij het vak Neuropsychologische diagnostiek UU 20/21
- 1 of 2158
- next ›
JoHo can really use your help! Check out the various student jobs here that match your studies, improve your competencies, strengthen your CV and contribute to a more tolerant world
Online access to all summaries, study notes en practice exams
- Check out: Register with JoHo WorldSupporter: starting page (EN)
- Check out: Aanmelden bij JoHo WorldSupporter - startpagina (NL)
How and why would you use WorldSupporter.org for your summaries and study assistance?
- For free use of many of the summaries and study aids provided or collected by your fellow students.
- For free use of many of the lecture and study group notes, exam questions and practice questions.
- For use of all exclusive summaries and study assistance for those who are member with JoHo WorldSupporter with online access
- For compiling your own materials and contributions with relevant study help
- For sharing and finding relevant and interesting summaries, documents, notes, blogs, tips, videos, discussions, activities, recipes, side jobs and more.
Using and finding summaries, study notes en practice exams on JoHo WorldSupporter
There are several ways to navigate the large amount of summaries, study notes en practice exams on JoHo WorldSupporter.
- Use the menu above every page to go to one of the main starting pages
- Starting pages: for some fields of study and some university curricula editors have created (start) magazines where customised selections of summaries are put together to smoothen navigation. When you have found a magazine of your likings, add that page to your favorites so you can easily go to that starting point directly from your profile during future visits. Below you will find some start magazines per field of study
- Use the topics and taxonomy terms
- The topics and taxonomy of the study and working fields gives you insight in the amount of summaries that are tagged by authors on specific subjects. This type of navigation can help find summaries that you could have missed when just using the search tools. Tags are organised per field of study and per study institution. Note: not all content is tagged thoroughly, so when this approach doesn't give the results you were looking for, please check the search tool as back up
- Check or follow your (study) organizations:
- by checking or using your study organizations you are likely to discover all relevant study materials.
- this option is only available trough partner organizations
- Check or follow authors or other WorldSupporters
- by following individual users, authors you are likely to discover more relevant study materials.
- Use the Search tools
- 'Quick & Easy'- not very elegant but the fastest way to find a specific summary of a book or study assistance with a specific course or subject.
- The search tool is also available at the bottom of most pages
Do you want to share your summaries with JoHo WorldSupporter and its visitors?
- Check out: Why and how to add a WorldSupporter contributions
- JoHo members: JoHo WorldSupporter members can share content directly and have access to all content: Join JoHo and become a JoHo member
- Non-members: When you are not a member you do not have full access, but if you want to share your own content with others you can fill out the contact form
Quicklinks to fields of study for summaries and study assistance
Field of study
- All studies for summaries, study assistance and working fields
- Communication & Media sciences
- Corporate & Organizational Sciences
- Cultural Studies & Humanities
- Economy & Economical sciences
- Education & Pedagogic Sciences
- Health & Medical Sciences
- IT & Exact sciences
- Law & Justice
- Nature & Environmental Sciences
- Psychology & Behavioral Sciences
- Public Administration & Social Sciences
- Science & Research
- Technical Sciences
Add new contribution