Temporal lobe

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Temporal lobe
Lobes of the human brain (temporal lobe is shown in green)
Gray730.png
Section of brain showing upper surface of temporal lobe.
Details
Part of Cerebrum
Artery
Vein
Identifiers
Latin lobus temporalis
MeSH D013702
NeuroNames 125
NeuroLex ID birnlex_1160
TA98 A14.1.09.136
TA2 5488
FMA 61825
Anatomical terms of neuroanatomy

The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. [3]

Contents

The temporal lobe is involved in processing sensory input into derived meanings for the appropriate retention of visual memory, language comprehension, and emotion association. [4] : 21 Temporal refers to the head's temples.

Structure

The temporal lobe consists of structures that are vital for declarative or long-term memory. 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 auditory perception, such as hearing, and holds the 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 object recognition.[ citation needed ] The ventral part of the temporal cortices appears to be involved in high-level visual processing of complex stimuli such as faces (fusiform gyrus) and scenes (parahippocampal gyrus).[ citation needed ] Anterior parts of this ventral stream for visual processing are involved in object perception and recognition. [6]
Animation showing the position of the human left temporal lobe Temporal lobe animation.gif
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

The medial temporal lobes (near the sagittal plane) are thought to be involved in encoding 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

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

Related Research Articles

<span class="mw-page-title-main">Language center</span> Speech processing areas of the brain

In neuroscience and psychology, the term language center refers collectively to the areas of the brain which serve a particular function for speech processing and production. Language is a core system that gives humans the capacity to solve difficult problems and provides them with a unique type of social interaction. Language allows individuals to attribute symbols to specific concepts, and utilize them through sentences and phrases that follow proper grammatical rules. Finally, speech is the mechanism by which language is orally expressed.

<span class="mw-page-title-main">Parietal lobe</span> Part of the brain responsible for sensory input and some language processing

The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus.

<span class="mw-page-title-main">Cerebrum</span> Large part of the brain containing the cerebral cortex

The cerebrum, telencephalon or endbrain is the largest part of the brain containing the cerebral cortex, as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In the human brain, the cerebrum is the uppermost region of the central nervous system. The cerebrum develops prenatally from the forebrain (prosencephalon). In mammals, the dorsal telencephalon, or pallium, develops into the cerebral cortex, and the ventral telencephalon, or subpallium, becomes the basal ganglia. The cerebrum is also divided into approximately symmetric left and right cerebral hemispheres.

<span class="mw-page-title-main">Wernicke's area</span> Speech comprehension region in the dominant hemisphere of the hominid brain

Wernicke's area, also called Wernicke's speech area, is one of the two parts of the cerebral cortex that are linked to speech, the other being Broca's area. It is involved in the comprehension of written and spoken language, in contrast to Broca's area, which is primarily involved in the production of language. It is traditionally thought to reside in Brodmann area 22, which is located in the superior temporal gyrus in the dominant cerebral hemisphere, which is the left hemisphere in about 95% of right-handed individuals and 70% of left-handed individuals.

Amusia is a musical disorder that appears mainly as a defect in processing pitch but also encompasses musical memory and recognition. Two main classifications of amusia exist: acquired amusia, which occurs as a result of brain damage, and congenital amusia, which results from a music-processing anomaly present since birth.

<span class="mw-page-title-main">Language processing in the brain</span> How humans use words to communicate

In psycholinguistics, language processing refers to the way humans use words to communicate ideas and feelings, and how such communications are processed and understood. Language processing is considered to be a uniquely human ability that is not produced with the same grammatical understanding or systematicity in even human's closest primate relatives.

Semantic dementia (SD), also known as semantic variant primary progressive aphasia (svPPA), is a progressive neurodegenerative disorder characterized by loss of semantic memory in both the verbal and non-verbal domains. However, the most common presenting symptoms are in the verbal domain. Semantic dementia is a disorder of semantic memory that causes patients to lose the ability to match words or images to their meanings. However, it is fairly rare for patients with semantic dementia to develop category specific impairments, though there have been documented cases of it occurring. Typically, a more generalized semantic impairment results from dimmed semantic representations in the brain.

<span class="mw-page-title-main">Lobes of the brain</span> Parts of the cerebrum

The lobes of the brain are the major identifiable zones of the human cerebral cortex, and they comprise the surface of each hemisphere of the cerebrum. The two hemispheres are roughly symmetrical in structure, and are connected by the corpus callosum. They traditionally have been divided into four lobes, but are today considered as having six lobes each. The lobes are large areas that are anatomically distinguishable, and are also functionally distinct to some degree. Each lobe of the brain has numerous ridges, or gyri, and furrows, the sulci that constitute further subzones of the cortex. The expression "lobes of the brain" usually refers only to those of the cerebrum, not to the distinct areas of the cerebellum.

The two-streams hypothesis is a model of the neural processing of vision as well as hearing. The hypothesis, given its initial characterisation in a paper by David Milner and Melvyn A. Goodale in 1992, argues that humans possess two distinct visual systems. Recently there seems to be evidence of two distinct auditory systems as well. As visual information exits the occipital lobe, and as sound leaves the phonological network, it follows two main pathways, or "streams". The ventral stream leads to the temporal lobe, which is involved with object and visual identification and recognition. The dorsal stream leads to the parietal lobe, which is involved with processing the object's spatial location relative to the viewer and with speech repetition.

Auditory verbal agnosia (AVA), also known as pure word deafness, is the inability to comprehend speech. Individuals with this disorder lose the ability to understand language, repeat words, and write from dictation. Some patients with AVA describe hearing spoken language as meaningless noise, often as though the person speaking was doing so in a foreign language. However, spontaneous speaking, reading, and writing are preserved. The maintenance of the ability to process non-speech auditory information, including music, also remains relatively more intact than spoken language comprehension. Individuals who exhibit pure word deafness are also still able to recognize non-verbal sounds. The ability to interpret language via lip reading, hand gestures, and context clues is preserved as well. Sometimes, this agnosia is preceded by cortical deafness; however, this is not always the case. Researchers have documented that in most patients exhibiting auditory verbal agnosia, the discrimination of consonants is more difficult than that of vowels, but as with most neurological disorders, there is variation among patients.

<span class="mw-page-title-main">Inferior temporal gyrus</span> One of three gyri of the temporal lobe of the brain

The inferior temporal gyrus is one of three gyri of the temporal lobe and is located below the middle temporal gyrus, connected behind with the inferior occipital gyrus; it also extends around the infero-lateral border on to the inferior surface of the temporal lobe, where it is limited by the inferior sulcus. This region is one of the higher levels of the ventral stream of visual processing, associated with the representation of objects, places, faces, and colors. It may also be involved in face perception, and in the recognition of numbers and words.

<span class="mw-page-title-main">Lingual gyrus</span> Gyrus of the occipital lobe of the brain

The lingual gyrus, also known as the medialoccipitotemporal gyrus, is a brain structure that is linked to processing vision, especially related to letters. It is thought to also play a role in analysis of logical conditions and encoding visual memories. It is named after its shape, which is somewhat similar to a tongue. Contrary to the name, the region has little to do with speech.

The perirhinal cortex is a cortical region in the medial temporal lobe that is made up of Brodmann areas 35 and 36. It receives highly processed sensory information from all sensory regions, and is generally accepted to be an important region for memory. It is bordered caudally by postrhinal cortex or parahippocampal cortex and ventrally and medially by entorhinal cortex.

Auditory agnosia is a form of agnosia that manifests itself primarily in the inability to recognize or differentiate between sounds. It is not a defect of the ear or "hearing", but rather a neurological inability of the brain to process sound meaning. While auditory agnosia impairs the understanding of sounds, other abilities such as reading, writing, and speaking are not hindered. It is caused by bilateral damage to the anterior superior temporal gyrus, which is part of the auditory pathway responsible for sound recognition, the auditory "what" pathway.

The neuroanatomy of memory encompasses a wide variety of anatomical structures in the brain.

Recognition memory, a subcategory of explicit memory, is the ability to recognize previously encountered events, objects, or people. When the previously experienced event is reexperienced, this environmental content is matched to stored memory representations, eliciting matching signals. As first established by psychology experiments in the 1970s, recognition memory for pictures is quite remarkable: humans can remember thousands of images at high accuracy after seeing each only once and only for a few seconds.

<span class="mw-page-title-main">Superior temporal sulcus</span> Part of the brains temporal lobe

In the human brain, the superior temporal sulcus (STS) is the sulcus separating the superior temporal gyrus from the middle temporal gyrus in the temporal lobe of the brain. A sulcus is a deep groove that curves into the largest part of the brain, the cerebrum, and a gyrus is a ridge that curves outward of the cerebrum.

Phonagnosia is a type of agnosia, or loss of knowledge, that involves a disturbance in the recognition of familiar voices and the impairment of voice discrimination abilities in which the affected individual does not suffer from comprehension deficits. Phonagnosia is an auditory agnosia, an acquired auditory processing disorder resulting from brain damage, other auditory agnosias include cortical deafness and auditory verbal agnosia also known as pure word deafness.

<span class="mw-page-title-main">Sign language in the brain</span>

Sign language refers to any natural language which uses visual gestures produced by the hands and body language to express meaning. The brain's left side is the dominant side utilized for producing and understanding sign language, just as it is for speech. In 1861, Paul Broca studied patients with the ability to understand spoken languages but the inability to produce them. The damaged area was named Broca's area, and located in the left hemisphere’s inferior frontal gyrus. Soon after, in 1874, Carl Wernicke studied patients with the reverse deficits: patients could produce spoken language, but could not comprehend it. The damaged area was named Wernicke's area, and is located in the left hemisphere’s posterior superior temporal gyrus.

<span class="mw-page-title-main">Auditosensory cortex</span>

Auditosensory cortex is the part of the auditory system that is associated with the sense of hearing in humans. It occupies the bilateral primary auditory cortex in the temporal lobe of the mammalian brain. The term is used to describe Brodmann area 42 together with the transverse temporal gyri of Heschl. The auditosensory cortex takes part in the reception and processing of auditory nerve impulses, which passes sound information from the thalamus to the brain. Abnormalities in this region are responsible for many disorders in auditory abilities, such as congenital deafness, true cortical deafness, primary progressive aphasia and auditory hallucination.

References

  1. 1 2 3 Starr, Philip A.; Barbaro, Nicholas M.; Larson, Paul S. (30 November 2008). Neurosurgical Operative Atlas: Functional Neurosurgery. Thieme. pp. 16, 26. ISBN   9781588903990.
  2. ↑ Sekhar, Laligam N.; de Oliveira, Evandro (1999). Cranial Microsurgery: Approaches and Techniques. Thieme. p. 432. ISBN   9780865776982.
  3. ↑ "Temporal Lobe". Langbrain. Rice University. Retrieved 2 January 2011.
  4. 1 2 3 4 5 6 7 8 Smith; Kosslyn (2007). Cognitive Psychology: Mind and Brain. New Jersey: Prentice Hall. pp. 21, 194–199, 349.
  5. ↑ Squire, LR; Stark, CE; Clark, RE (2004). "The medial temporal lobe" (PDF). Annual Review of Neuroscience. 27: 279–306. doi:10.1146/annurev.neuro.27.070203.144130. PMID   15217334.
  6. 1 2 3 Schacter, Daniel L.; Gilbert, Daniel T.; Wegner, Daniel M. (2010). Psychology (2nd ed.). New York: Worth Publishers. ISBN   9781429237192.[ page needed ]
  7. ↑ Hickok, Gregory; Poeppel, David (May 2007). "The Cortical Organization of Speech Processing". Nature Reviews Neuroscience. 8 (5): 393–402. doi:10.1038/nrn2113. PMID   17431404. S2CID   6199399.
  8. ↑ Richardson, Michael W. "Does the Brain Process Sign Language and Spoken Language Differently?". www.brainfacts.org. Retrieved 2020-12-14.
  9. ↑ Campbell, Ruth; et al. (29 June 2007). "Sign Language and the Brain: A Review". The Journal of Deaf Studies and Deaf Education. 13 (1 [Winter 2008]): 3–20. doi: 10.1093/deafed/enm035 . 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. ↑ Treffert, D. A. (2009). "The savant syndrome: An extraordinary condition. A synopsis: Past, present, future". Philosophical Transactions of the Royal Society B: Biological Sciences. 364 (1522): 1351–1357. doi:10.1098/rstb.2008.0326. PMC   2677584 . PMID   19528017.
  16. ↑ Takeda, N.; Kishimoto, Y.; Yokota, O. (2012). "Pick's Disease". Neurodegenerative Diseases. Advances in Experimental Medicine and Biology. Vol. 724. pp. 300–316. doi:10.1007/978-1-4614-0653-2_23. ISBN   978-1-4614-0652-5. PMID   22411252.
  17. ↑ Yokota, O.; Tsuchiya, K.; Arai, T.; Yagishita, S.; Matsubara, O.; Mochizuki, A.; Akiyama, H. (2009). "Clinicopathological characterization of Pick's disease versus frontotemporal lobar degeneration with ubiquitin/TDP-43-positive inclusions". Acta Neuropathologica. 117 (4): 429–444. doi:10.1007/s00401-009-0493-4. PMID   19194716. S2CID   23749655.
  18. ↑ Lah, S., & Smith, M. (2013). "Semantic and Episodic Memory in Children With Temporal Lobe Epilepsy: Do They Relate to Literacy Skills?". Neuropsychology doi : 10.1037/neu0000029
  19. 1 2 Hugdahl K, Løberg E-M, Nygård M. "Left Temporal Lobe Structural and Functional Abnormality Underlying Auditory Hallucinations in Schizophrenia". Frontiers in Neuroscience. 2009;3(1):34–45. doi : 10.3389/neuro.01.001.2009.
  20. ↑ Ikuta T, DeRosse P, Argyelan M, et al. "Subcortical Modulation in Auditory Processing and Auditory Hallucinations". Behavioural brain research. 2015;295:78–81. doi : 10.1016/j.bbr.2015.08.009.
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