Temporal lobe

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Temporal lobe
Lobes of the human brain (temporal lobe is shown in green)
Superficial middle cerebral vein[1]: 16 
  • Inferior anastomotic vein[2]
    • Identifiers
    Latinlobus temporalis
    MeSHD013702
    NeuroNames125
    NeuroLex IDbirnlex_1160
    TA98A14.1.09.136
    TA25488
    FMA61825
    Anatomical terms of neuroanatomy]

    The temporal lobe is one of the four

    lateral fissure on both cerebral hemispheres of the mammalian brain.[3]

    The temporal lobe is involved in processing sensory input into derived meanings for the appropriate retention of

    language comprehension, and emotion association.[4]
    : 21  Temporal refers to the head's temples.

    Structure

    The

    Declarative (denotative) or explicit memory is conscious memory divided into semantic memory (facts) and episodic memory (events).[4]: 194  Medial temporal lobe structures that are critical for long-term memory include the hippocampus, along with the surrounding hippocampal region consisting of the perirhinal, parahippocampal, and entorhinal neocortical regions.[4]: 196  The hippocampus is critical for memory formation, and the surrounding medial temporal cortex is currently theorized to be critical for memory storage.[4]: 21  The prefrontal and visual cortices are also involved in explicit memory.[4]
    : 21 

    Research has shown that lesions in the hippocampus of monkeys results in limited impairment of function, whereas extensive lesions that include the hippocampus and the medial temporal cortex result in severe impairment.[5]

    Function

    Visual memories

    The temporal lobe communicates with the hippocampus and plays a key role in the formation of explicit long-term memory modulated by the amygdala.[4]: 349 

    Processing sensory input

    Auditory
    Adjacent areas in the superior, posterior, and lateral parts of the temporal lobes are involved in high-level auditory processing. The temporal lobe is involved in primary
    primary auditory cortex.[6] The primary auditory cortex receives sensory information from the ears and secondary areas process the information into meaningful units such as speech and words.[6] The superior temporal gyrus includes an area (within the lateral fissure) where auditory signals from the cochlea first reach the cerebral cortex and are processed by the primary auditory cortex in the left temporal lobe.[citation needed
    ]
    Visual
    The areas associated with vision in the temporal lobe interpret the meaning of visual stimuli and establish
    ventral stream for visual processing are involved in object perception and recognition.[6]
    Animation showing the position of the human left temporal lobe

    Language recognition

    The temporal lobe holds the

    primary auditory cortex, which is important for the processing of semantics in both language and vision in humans. Wernicke's area, which spans the region between temporal and parietal lobes, plays a key role (in tandem with Broca's area in the frontal lobe) in language comprehension,[7] whether spoken language or signed language. FMRI imaging shows these portions of the brain are activated by signed or spoken languages.[8][9] These areas of the brain are active in children's language acquisition[10] whether accessed via hearing a spoken language, watching a signed language, or via hand-over-hand tactile versions of a signed language[11]

    The functions of the left temporal lobe are not limited to low-level perception but extend to comprehension, naming, and verbal memory.[12]

    New memories

    See also: Emotion and memory

    The medial temporal lobes (near the

    declarative long term memory.[4]: 194–199  The medial temporal lobes include the hippocampi, which are essential for memory storage, therefore damage to this area can result in impairment in new memory formation leading to permanent or temporary anterograde amnesia.[4]
    : 194–199 

    Clinical significance

    Unilateral temporal lesion

    Dominant hemisphere

    Non-dominant hemisphere

    • Impaired non-verbal memory
    • Impaired musical skills

    Bitemporal lesions (additional features)

    Damage

    Individuals who suffer from medial temporal lobe damage have a difficult time recalling visual stimuli. This neurotransmission deficit is not due to lacking perception of visual stimuli, but rather to the inability to interpret what is perceived.[13] The most common symptom of inferior temporal lobe damage is visual agnosia, which involves impairment in the identification of familiar objects. Another less common type of inferior temporal lobe damage is prosopagnosia which is an impairment in the recognition of faces and distinction of unique individual facial features.[14]

    Damage specifically to the anterior portion of the left temporal lobe can cause savant syndrome.[15]

    Disorders

    Pick's disease, also known as frontotemporal amnesia, is caused by atrophy of the frontotemporal lobe.[16] Emotional symptoms include mood changes, which the patient may be unaware of, including poor attention span and aggressive behavior towards themselves or others. Language symptoms include loss of speech, inability to read or write, loss of vocabulary and overall degeneration of motor ability.[17]

    Temporal lobe epilepsy is a chronic neurological condition characterized by recurrent seizures; symptoms include a variety of sensory (visual, auditory, olfactory, and gustation) hallucinations, as well as an inability to process semantic and episodic memories.[18]

    Schizophrenia is a severe psychotic disorder characterized by severe disorientation. Its most explicit symptom is the perception of external voices in the form of auditory hallucinations. The cause of such hallucinations has been attributed to deficits in the left temporal lobe, specifically within the primary auditory cortex.[19] Decreased gray matter, among other cellular deficits, contribute to spontaneous neural activity that affects the primary auditory cortex as if it were experiencing acoustic auditory input. The misrepresentation of speech in the auditory cortex results in the perception of external voices in the form of auditory hallucinations in schizophrenic patients.[20] Structural and functional MRI techniques have accounted for this neural activity by testing affected and non-affected individuals with external auditory stimuli.[19]

    See also

    References

    1. ^
      ISBN 9781588903990
      .
    2. ISBN 9780865776982
      .
    3. ^ "Temporal Lobe". Langbrain. Rice University. Retrieved 2 January 2011.
    4. ^ a b c d e f g h Smith; Kosslyn (2007). Cognitive Psychology: Mind and Brain. New Jersey: Prentice Hall. pp. 21, 194–199, 349.
    5. PMID 15217334
      .
    6. ^
      ISBN 9781429237192.[page needed
      ]
    7. S2CID 6199399
      .
    8. ^ Richardson, Michael W. "Does the Brain Process Sign Language and Spoken Language Differently?". www.brainfacts.org. Retrieved 2020-12-14.
    9. PMID 17602162
      .
    10. ^ "Language Learning Through the Eye and Ear Webcast". clerccenter.gallaudet.edu. Archived from the original on 2020-12-05. Retrieved 2020-12-16.
    11. ^ Humphries, Tom; et al. (April 2012). "Language Acquisition for Deaf Children: Reducing the Harms of Zero Tolerance to the Use of Alternative Approaches". Harm Reduction Journal. 9(1):16 – via Research Gate.
    12. ^ Ruiz Mitjana, Laura (6 September 2019). "Lóbulo temporal: anatomía, funciones y características" [Temporal lobe: anatomy, functions and characteristics]. MedSalud (in Spanish).
    13. ^ Pertzov, Y., Miller, T. D., Gorgoraptis, N., Caine, D., Schott, J. M., Butler, C., & Husain, M. (2013). "Binding deficits in memory following medial temporal lobe damage in patients with voltage-gated potassium channel complex antibody-associated limbic encephalitis". Brain: A Journal of Neurology, 136(8), 2474–2485.
    14. ^ Mizuno, T., & Takeda, K. (2009). "The symptomatology of frontal and temporal lobe damages". Brain And Nerve = Shinkei Kenkyū No Shinpo, 61(11), 1209–1218.
    15. PMID 19528017
      .
    16. PMID 22411252
      .
    17. S2CID 23749655
      .
    18. doi:10.1037/neu0000029
    19. ^
      doi:10.3389/neuro.01.001.2009
      .
    20. doi:10.1016/j.bbr.2015.08.009
      .

    External links

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