Editing Head injury (section)

=== Location of brain damage predicts symptoms ===
Symptoms of brain injuries can also be influenced by the location of the injury and as a result, impairments are specific to the part of the brain affected. Lesion size is correlated with severity, recovery, and comprehension.<ref>{{Cite web |title=Traumatic brain injury - Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/traumatic-brain-injury/symptoms-causes/syc-20378557 |access-date=2023-06-08 |website=Mayo Clinic |language=en}}</ref> Brain injuries often create impairment or [[disability]] that can vary greatly in severity.

Studies show there is a correlation between brain lesion and language, speech, and category-specific disorders. Wernicke's aphasia is associated with [[Anomic aphasia|anomia]], unknowingly making up words ([[neologisms]]), and problems with comprehension. The symptoms of Wernicke's aphasia are caused by damage to the posterior section of the [[superior temporal gyrus]].<ref>{{Cite web|url=https://dnalc.cshl.edu/|title=CSHL DNA Learning Center|website=dnalc.cshl.edu}}</ref><ref>{{cite book | doi=10.1007/978-0-387-79948-3_935 | chapter=Wernicke–Lichtheim Model of Aphasia | title=Encyclopedia of Clinical Neuropsychology | date=2011 | last1=Hux | first1=Karen | pages=2702–2703 | isbn=978-0-387-79947-6 }}</ref>

Damage to the [[Broca's area]] typically produces symptoms like omitting functional words ([[agrammatism]]), sound production changes, [[dyslexia]], [[dysgraphia]], and problems with comprehension and production. Broca's aphasia is indicative of damage to the posterior inferior frontal gyrus of the brain.<ref>{{Cite journal|last=Kean|first=Mary Louise | name-list-style = vanc | date = October 2003 |title=Syntactic deficits in aphasia: Was Wernicke right after all? |journal=Brain and Language|volume=87|issue=1|pages=27–28|doi=10.1016/s0093-934x(03)00180-9 |s2cid=54407724 }}</ref>

An impairment following damage to a region of the brain does not necessarily imply that the damaged area is wholly responsible for the cognitive process which is impaired, however. For example, in [[pure alexia]], the ability to read is destroyed by a lesion damaging both the left visual field and the connection between the right visual field and the language areas (Broca's area and Wernicke's area). However, this does not mean someone with pure alexia is incapable of comprehending speech—merely that there is no connection between their working visual cortex and language areas—as is demonstrated by the fact that pure alexics can still write, speak, and even transcribe letters without understanding their meaning.<ref>{{Cite journal|last=Wilkes|first=Kathleen V. | name-list-style = vanc |date= October 1980 |title=More Brain Lesions |journal=Philosophy|volume=55|issue=214|pages=455–470|doi=10.1017/s0031819100049482 |s2cid=170723313 }}</ref> Lesions to the [[fusiform gyrus]] often result in [[prosopagnosia]], the inability to distinguish faces and other complex objects from each other.<ref>{{cite journal | vauthors = Corrow SL, Dalrymple KA, Barton JJ | title = Prosopagnosia: current perspectives |journal = Eye and Brain| publisher = Eye Brain | date = 26 September 2016 |volume = 8|pages = 165–175|doi = 10.2147/EB.S92838| pmid = 28539812|pmc = 5398751 | doi-access = free }}</ref>{{medical citation needed|date=November 2017}}<ref>{{Cite web |title=Prosopagnosia |url=https://www.ninds.nih.gov/health-information/disorders/prosopagnosia |access-date=2023-06-08 |website=National Institute of Neurological Disorders and Stroke |language=en}}</ref> Lesions in the [[amygdala]] would eliminate the enhanced activation seen in occipital and fusiform visual areas in response to fear with the area intact. Amygdala lesions change the functional pattern of activation to emotional stimuli in regions that are distant from the amygdala.<ref>{{Cite journal |last1=Diano |first1=Matteo |last2=Tamietto |first2=Marco |last3=Celeghin |first3=Alessia |last4=Weiskrantz |first4=Lawrence |last5=Tatu |first5=Mona-Karina |last6=Bagnis |first6=Arianna |last7=Duca |first7=Sergio |last8=Geminiani |first8=Giuliano |last9=Cauda |first9=Franco |last10=Costa |first10=Tommaso |date=2017-03-27 |title=Dynamic Changes in Amygdala Psychophysiological Connectivity Reveal Distinct Neural Networks for Facial Expressions of Basic Emotions |journal=Scientific Reports |language=en |volume=7 |issue=1 |pages=45260 |doi=10.1038/srep45260 |pmid=28345642 |issn=2045-2322|pmc=5366904 |bibcode=2017NatSR...745260D }}</ref>

Other lesions to the [[visual cortex]] have different effects depending on the location of the damage. Lesions to [[Visual cortex|V1]], for example, can cause [[blindsight]] in different areas of the brain depending on the size of the lesion and location relative to the [[calcarine fissure]].<ref>{{Cite journal|last=Celesia|first=Gastone G. | name-list-style = vanc | date = January 2010 |title=Visual Perception and Awareness |journal=Journal of Psychophysiology|volume=24|issue=2|pages=62–67|doi=10.1027/0269-8803/a000014 }}</ref> Lesions to [[Visual cortex|V4]] can cause [[color-blindness]],<ref>{{cite journal | vauthors = Jaeger W, Krastel H, Braun S | title = [Cerebral achromatopsia (symptoms, course, differential diagnosis and strategy of the study). I] | language = de | journal = Klinische Monatsblätter für Augenheilkunde | volume = 193 | issue = 6 | pages = 627–34 | date = December 1988 | pmid = 3265459 | doi = 10.1055/s-2008-1050309 | s2cid = 260195187 }}</ref> and bilateral lesions to [[Visual cortex|MT/V5]] can cause the loss of the ability to perceive motion.<ref>{{Cite journal |last1=Bridge |first1=Holly |last2=Hicks |first2=Stephen L. |last3=Xie |first3=Jingyi |last4=Okell |first4=Thomas W. |last5=Mannan |first5=Sabira |last6=Alexander |first6=Iona |last7=Cowey |first7=Alan |last8=Kennard |first8=Christopher |date=2010-12-01 |title=Visual activation of extra-striate cortex in the absence of V1 activation |journal=Neuropsychologia |language=en |volume=48 |issue=14 |pages=4148–4154 |doi=10.1016/j.neuropsychologia.2010.10.022 |pmid=20974160 |issn=0028-3932|pmc=2998000 }}</ref> Lesions to the [[parietal lobes]] may result in [[agnosia]], an inability to recognize complex objects, smells, or shapes, or [[amorphosynthesis]], a loss of perception on the opposite side of the body.