**Part 1**

**Amnestic Disorders** 

**1** 

*Brazil* 

**Neuroimaging in Dementia and** 

**Other Amnestic Disorders** 

Leonardo Caixeta1, Bruno Galafassi Ghini2

*2Centro de Diagnóstico por Imagem, Goiânia-GO,* 

*1Psychiatric Cognitive Unit of the Hospital das Clínicas* 

*3Radiology Clinic – Universidade Federal de São Paulo, SP, 4Psychotraumatology Clinic - Hospital Perola Byington, SP,* 

Neuroimaging has revolutionized the field of cognitive neuroscience. Early studies of brainbehavior relationships relied on a precise neurological examination as the basis for hypothesizing the site of brain damage that was responsible for a given behavioral syndrome. Episodic amnesia, for example, clearly implicated the hippocampus as the site of

Clinicopathological correlations were the earliest means of obtaining precise data on the site of damage causing a specific neurobehavioral syndrome (D'Esposito & Wills, 2000). In 1861, Paul Broca's observations of nonfluent aphasia in the setting of left inferior frontal gyrus damage cemented the belief that this brain region was critical for speech output (Broca, 1861). The advent of structural brain imaging more than 100 years after Broca's observations, first with computed tomography (CT) and later with magnetic resonance imaging (MRI), paved the way for more precise anatomical localization of the cognitive deficits that are

Anatomical analyses of Broca's aphasia using structural neuroimaging (Naeser et al., 1989, Dronkers, 1996, Alexander et al., 1990) have more precisely determined that damage restricted to the inferior frontal gyrus causes only a transient aphasia, with recovery within weeks to months. Instead, damage to deep white matter and insular cortex causes persistent nonfluency. Noninvasive, structural neuroimaging provides the remarkable power to detail anatomical pathology in every stroke patient without re-lying upon the infrequently obtained autopsy. Neuroimaging is a powerful tool for creative exploration of the epidemiology, diagnostic sensitivity, progression and therapeutic efficacy in many brain diseases featured by memory impairment (Apostolova & Thompson, 2008). Some consider modern functional neuroimaging methods as useful tools to establish similarities and differences between different forms of amnesias with respect to their brain correlates, while others consider them adequate for constituting groups of patients in a research perspective, but still out of reach

**1. Introduction** 

recent memory abilities.

manifest after brain injury.

for the practitioner (Celsis, 2000).

and Julio F. P. Peres, PsyD, PhD.3,4

*of the Federal University of Goiás,* 
