NEUR3002 SAQs injuries Flashcards
explain the concept of somatotopic organisation
Somatotopic organization refers to the spatial arrangement of neurons within a sensory or motor area of the brain that corresponds to the arrangement of body parts in the periphery.
Spatial Mapping: Neurons are arranged in the brain in a way that reflects the orderly arrangement of body parts, such as the hands, feet, or other body regions.
Sensory and Motor Areas: This concept is particularly relevant in sensory and motor areas of the brain, where specific regions are devoted to processing sensory information or controlling movements related to specific body parts.
Topographic Representation: The somatotopic map allows the brain to process and interpret sensory information or coordinate movements in an organized and efficient manner.
Examples: The primary somatosensory cortex and motor cortex are classic examples of areas with somatotopic organization, where adjacent regions represent adjacent body parts.
In summary, somatotopic organization is the systematic arrangement of neurons in the brain that mirrors the spatial arrangement of body parts, facilitating sensory perception and motor control.
Distinguish the functional and anatomical features of the ascending systems that
mediate fine (discriminative) touch
Ascending Systems for Fine (Discriminative) Touch:
Functional Features:
Fine touch is mediated by the dorsal column-medial lemniscus pathway.
It conveys precise touch and proprioceptive information, enabling discrimination of texture, shape, and position of objects.
Allows accurate localization and identification of tactile stimuli.
Anatomical Features:
Fine touch signals are transmitted by large, myelinated Aβ fibers.
Primary afferents synapse in the dorsal column nuclei in the medulla.
Second-order neurons cross over and ascend in the medial lemniscus to reach the ventral posterolateral nucleus (VPL) of the thalamus.
From the thalamus, information is projected to the primary somatosensory cortex.
Distinguish the functional and anatomical features of the ascending systems that
mediate crude (pain, temperature, itch, sensual) touch
Ascending Systems for Crude (Pain, Temperature, Itch, Sensual) Touch:
Functional Features:
Crude touch includes pain, temperature, itch, and non-discriminative touch.
Mediated by the spinothalamic tract, it provides general awareness of potentially harmful or uncomfortable stimuli.
Anatomical Features:
Signals are carried by small, thinly myelinated Aδ fibers and unmyelinated C fibers.
Primary afferents synapse in the dorsal horn of the spinal cord.
Second-order neurons decussate and ascend in the spinothalamic tract to reach the ventral posterolateral nucleus (VPL) of the thalamus.
From the thalamus, signals are relayed to various sensory cortices, including the primary somatosensory cortex.
Distinguish the functional and anatomical features of the ascending systems that
mediate fine (discriminative) versus crude (pain, temperature, itch, sensual) touch
In summary, the ascending systems for fine touch and crude touch have distinct functional and anatomical features. Fine touch is characterized by precise discrimination and is transmitted through the dorsal column-medial lemniscus pathway, while crude touch encompasses various non-discriminative sensations and is conveyed via the spinothalamic tract.
What are the central targets involved in bodily perception
Central Targets in Bodily Perception:
Somatosensory Cortex: This brain region processes tactile information such as touch, pressure, temperature, and pain from the body. It contributes to our cognitive understanding of bodily sensations.
Insular Cortex: The insula integrates sensory input with emotional and cognitive processes. It plays a key role in self-awareness, interoception, and emotional responses linked to bodily states.
Anterior Cingulate Cortex (ACC): The ACC is involved in monitoring and regulating emotional and cognitive responses to bodily sensations. It aids in attention, pain perception, and emotional regulation.
Amygdala: This almond-shaped structure processes emotions, including fear and anxiety, which can be triggered by bodily sensations. It links bodily experiences to emotional reactions.
How does bodily perception Relating to Cognitive, Emotional, and Adaptive Responses:
Cognitive Responses: The somatosensory and insular cortices contribute to our cognitive awareness of bodily sensations, helping us recognize touch, temperature, and pain. The ACC also guides our cognitive attention to these sensations and regulates responses.
Emotional Responses: The insular cortex and amygdala connect bodily sensations to emotional experiences. The insula integrates bodily signals with emotional context, while the amygdala contributes to emotional reactions like fear in response to bodily changes.
Adaptive Responses: These central targets collectively help in adaptive responses. The somatosensory cortex aids in quick reactions to potential threats. The insula enables us to perceive internal bodily states, helping us make adaptive choices for well-being. The ACC and amygdala facilitate appropriate responses to pain and emotional challenges, enhancing our overall adaptability.
What is referred pain
Phenomenon: Referred pain is when pain is perceived in an area of the body that is different from the actual source of the pain. For example, during a heart attack, pain may be felt in the left arm or jaw.
Structural Basis: Referred pain occurs due to the convergence of sensory neurons from different body areas onto the same neurons in the spinal cord and brain. This convergence confuses the brain’s interpretation of the pain’s origin, leading to a perceived location different from the actual source.
What is phantom limb
Phenomenon: Phantom limb sensation is the perception of sensations, including pain, in a limb that has been amputated. Individuals may feel itching, pain, or movement in the absent limb.
Structural Basis: After amputation, the brain’s sensory and motor regions that previously represented the limb can remain active. The neighboring brain areas “remap” and invade the space previously dedicated to the missing limb, causing sensory input to be misinterpreted as coming from the absent limb.
what is the Anterolateral system
The anterolateral system is a neural pathway responsible for transmitting pain, temperature, and crude touch sensations from the body to the brain. It consists of a network of nerve fibers that ascend through the spinal cord and synapse at various levels before reaching the thalamus and somatosensory cortex.
what is the principle pathway for sensation from head and face
The trigeminal nerve (CN V), which originates from the pons
What does the largest roots of the trigeminal nerve contain?
Sensory fibres that connect to the trigeminal ganglion
What does the smallest roots of the trigeminal nerve contain?
motor fibres (muscles of mastication [jaw movement / chewing)
What doe The ophthalmic branch of the trigeminal nerve (V1) carry
sensory information from the orbit, cornea, bridge of the
nose, scalp & forehead
What does The maxillary branch of the trigeminal nerve (V2) carry
sensory information from between the lateral corners of
the eye and mouth
What does The mandibular branch of the trigeminal nerve (V3) carries
sensory information from the lower and mandibular part of
the face. (Note: V3 also carries motor fibres [e.g. muscles
of mastication])
