Results and Discussion

The most prominent finding was a highly significant reduction in GMV in the left primary visual (LV-1) and visual association cortices (LV-2) (Brodmann's Area [BA] 17 to 18; Talairach's coordinates x = -27 through 14, y = -90 through 86, z = -10 through 1; p < 0.0001, corrected cluster level; Fig. 2.1) (also see color insert). Compared with healthy control subjects, a 14.1% lower average GMV was observed in

B

1

i H

J

r ■■

■ J

figure 2.1. Differences in gray matter volume between abuse and control subjects. Significantly lower gray matter densities in abuse subjects were observed in the left visual cortex. Crosshairs placed at x = -14, y = -90, z = -1 (left lingual gyrus). Color scale (0-5) represents t values.

these regions for the abuse subjects. Within these areas, a strong correlation existed between visual memory and GMV of BA 17 (r = 0.68, p < 0.00001; x = 10, y = -91, z = -5; Fig. 2.2; Tables 2.1-2.3) (also see color insert). The MAS subscale with the strongest correlation to BA 17 GMV was visual recognition (r = 0.65, p < 0.00005; Talairach's coordinates x = 9, y = -90, z = -4). A significant correlation was also seen between GMV of BA 17 and an overall index of short-term memory (r = 0.46, p < .005; Talairach's coordinates x = 19, y = -101, z = -8). Within the occipital region, verbal memory correlated with GMV of BA 19 (r = 0.43, p < 0.01; Talairach's coordinates x = 45, y = -75, z = 0).

figure 2.2. Correlations between brain volume and visual memory in the left primary visual cortex ( LV-1). Crosshairs placed at x = -3, y = -90, z = -3 (left lingual gyrus). The color scale (0-6) indicates t values.

table 2.1. Correlations Between Visually Based Memory Assessment Scale (MAS) Subtests and Left Visual Cortex Among All Subjects (N = 37)

Talairach Coordinates

MAS Subtest

P

r

x

y

z

t value

Region

Visual memory

0.005

0.45

-3

-90

-3

5.26

Left lingual gyrus

Visual span

0.027

0.36

-23

-93

-13

2.79

Left lingual gyrus

Visual reproduction

0.096

0.28

-19

-87

-7

5.42

Left lingual gyrus

Visual recognition

0.005

0.45

-3

-90

-3

4.19

Left lingual gyrus

Visual recognition

0.034

0.35

-14

-88

-1

1.81

Left lingual gyrus

(delayed recall)

Verbal memory

0.004

0.47

-41

-89

3

4.07

Left middle

(controlling for

occipital gyrus

visual memory)

The findings of reduced GMV in brain areas known to process visual stimuli are intriguing, especially in light of the fact that the reductions are correlated with visual memory—visual recognition in particular—but not verbal memory. We interpret these data as evidence to support the table 2.2. Correlations Between Visually Based Memory Assessment Scale (MAS) Subtests and Left Visual Cortex in Abuse Subjects (N = 23)

Talairach Coordinates

MAS Subtest

P

r

x

y

z

t value

Region

Visual memory

0.24

0.25

-3

-90

-3

5.26

Left lingual gyrus

Visual span

0.87

0.04

-23

-93

-13

2.79

Left lingual gyrus

Visual reproduction

0.26

0.24

-19

-87

-7

5.42

Left lingual gyrus

Visual recognition

0.25

0.25

-3

-90

-3

4.19

Left lingual gyrus

Visual recognition

0.43

0.17

-14

-88

-1

1.81

Left lingual gyrus

(delayed recall)

Verbal memory

0.005

0.58

-41

-89

3

4.07

Left middle

(controlling for

occipital gyrus

visual memory)

table 2.3. Correlations Between Visually Based Memory Assessment Scale (MAS) Subtests and Left Visual Cortex in Control Subjects (N = 14)

Talairach Coordinates

MAS Subtest

P

r

x

y

z

t value

Region

Visual memory

0.0003

0.82

-3

-90

-3

5.26

Left lingual gyrus

Visual span

0.02

0.61

-23

-93

-13

2.79

Left lingual gyrus

Visual reproduction

0.01

0.66

-19

-87

-7

5.42

Left lingual gyrus

Visual recognition

0.0001

0.85

-3

-90

-3

4.19

Left lingual gyrus

Visual recognition

0.03

0.57

-14

-88

-1

1.81

Left lingual gyrus

(delayed recall)

Verbal memory

0.005

0.58

-41

-89

3

4.07

Left middle

(controlling for

occipital gyrus

visual memory)

proposition that disparate forms of CA can differentially influence the sensorium and its associated neurobiology. Thus, one prediction is that if the abuse that was experienced involved substantial visual perception, then perhaps those brain systems subserving visual information and processing were maladaptively impacted. Given that the neural substrates of visual perception overlap those of visual memory (e.g., occipital, inferior temporal, and parietal cortices; Slotnick, 2004), the possibility that visual stimuli perceived as external stressors (e.g., a child literally seeing an abuser perpetrating the abusive act[s]) could have adverse effects on the developing visual system seems plausible.

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