Candidate for the Degree Of Ph.D. in Physiological Optics

Candidate for the Degree Of Ph.D. in Physiological Optics
Gender and Ovarian Hormone Effects on the Relative Contribution of Chromaticity to Brightness Brian K. Foutch Candidate for the Degree Of Ph.D. in Physiological Optics June 7th, 2007

Acknowledgements COMMITTEE: Dr. Carol Peck (Advisor) Dr. Carl Bassi
Dr. George Taylor Dr. W. Gary Bachman TECHNICAL SUPPORT: Michael Howe and Janice White OPTOMETRY (“3rd Floor”) STAFF: Maria Ahrens, Tammy Jones, Lis Ellerbusch Irene Ericson FAMILY: J.P. and Charlotte Foutch; Jim, Lori, Mark Ron and Joyce Redd; John Redd Becky

Properties of Light Light Luminance Chromaticity Saturation BRIGHTNESS
COLOR Hue

Models of Color Vision From Lee, B. (2004) CEO L M R R L M L M S S
3 cone photoreceptor types: SWS (“blue”) nm MWS (“green”) nm LWS (“red”) nm Trichromatic Theory - Young (1802): red, green, violet nerve fibers - Maxwell (1856): any color = a*BLUE + b*GREEN + c*RED From Lee, B. (2004) CEO

Models of Color Vision Color opponent theory
What about certain combinations of colors?  ?   ? - Hering theorized two color-opponent channels (R/G and B/Y)

Models of Color Vision What about after images? Afterimage Image

} Zone model } R G L-M Four “primary” colors S-(L+M) B Y L+M
Achromatic luminance Three cone photoreceptors types Combined in second “zone” or stage Perception of two color-opponent channels and one non-opponent luminance channel

Retinal Anatomy From Lee, B. (2004) CEO L M Rods [L or M] L M S-cones
Magnocellular - ACHROMATIC - FAST - LARGE - LOW RESOLUTION - GLOBAL (“Bird’s eye”) Parvocellular RED/GREEN - SLOWEST - SMALL - HIGH RESOLUTION - LOCAL (DETAILS) Koniocellular BLUE/YELLOW VARIABLE From Lee, B. (2004) CEO

Are there gender differences in parallel processing?
Kramer et al., 1996 Iijima et al., 2001 BOYS referred to overall shape. GIRLS referred to smaller elements. BOYS were more global (“bird’s eye”). FREE DRAWINGS GIRLS were more detailed, used more color.

Are there gender differences in parallel processing?
Differences in Color Processing (Bimler et al., 2004) Males: more weight on “lightness” LIGHTNESS Y G DS-15 Caps R B Females: more weight on R/G axis D-15 Caps

STUDY 1: Dominant Eye Study (2005)
RESULTS Stimulus Type Parvo Magno 300 100 50 10 1 Male Female “MAGNO” 30 cycle/sec drift * “PARVO” Stationary, foveal * Women more sensitive than men (p = 0.05) Foutch BK and Bassi CJ, 2005; Foutch BK and Fletcher T, 2006

STUDY 2: Saturation Study (2005)
COLOR COLOR +/- WHITE RESULTS: Females > males (p < 0.05) across colors and at each color LIMITATIONS: Test stimuli were not narrowband - Need optics set-up to find achromatic interval Foutch and Peck, 2005

Photometric methods Heterochromatic Flicker Photometry (HFP) 20 Hz
Flicker is too fast (20 Hz) to involve color channels.

STUDY 3: HFP Age and Gender Study (2006)
wavelength 676 650 620 600 589 580 568 560 550 540 532 520 510 500 480 450 420 Mean rel efficiency 1.20 1.00 0.80 0.60 0.40 0.20 0.00 male female Gender No gender difference Foutch and Peck, 2006

Direct Brightness Matching (DBM)
Measures both chromatic and achromatic systems

Contributions to Brightness
Total output from DBM R G B Y Chromatic contribution to brightness = DBM/HFP Achromatic output from HFP

HYPOTHESES: Gender differences?
Women are more sensitive to chromatic contribution (DBM/HFP) - Higher DBM/HFP ratios for females

Why are women more sensitive?
VARIOUS POSSIBILITIES STEROID SEX HORMONES - Receptors for estrogens and progesterone present in human retina - Ovarian hormones: -- Estrogens (excitatory): - augment glutamate and inhibits GABA synthesis -- Progesterone (inhibitory): - antagonizes estrogens by increasing sensitivity of brain to GABA and  reply to glutamate

Menstrual Cycle OVULATION LUTEAL Progesterone Estrogen MENSTRUAL

HYPOTHESES: Hormone Analysis
Chromatic contribution (DBM/HFP) positively correlates with estrogen/progesterone ratio

Methods SUBJECTS: 31 Total (18 females, 13 males) recruited at UMSL
Ages 18-45 Normal color vision GENETICS OF COLOR VISION: MALES: XY FEMALES: XX Recessive sex linked trait SEX LINKED  carried on X RECESSIVE  will not be expressed if normal X present

Methods SUBJECTS: 31 Total (18 females, 13 males) recruited at UMSL
Ages 18-45 Normal color vision GENETICS OF COLOR VISION: MEN: XY  normal X’Y  color defective WOMEN: XX  normal X’X’ color defective XX’  carriers: should be normal, but not always  3 potential subjects excluded

Methods SUBJECTS: FEMALES:
31 Total (18 females, 13 males) recruited at UMSL Ages 18-45 Normal color vision Normal or corrected visual acuity (20/25) No neurological/psychological disorders FEMALES: Were asked to consent to “post card” tracking of cycle 16 consented, placed in Group II; 2 in Group I Were asked about contraceptive devices may use, but not to avoid menses

Overview HORMONE ANALYSIS GENDER ANALYSIS

Each session Adapted to low light levels (~0.5 cd/m2) for 5 minutes
HFP and DBM for each of the following wavelengths: 450(blue) 520(green) 560 (yellow-green) 580(yellow) 650(red)

Apparatus NB Filter Controller Optical chopper Intensity controller
(computer interfaced)

HFP Benefits Experimental procedure: 3 trials at each wavelength 30 sec adaptation between each wavelength State the benefits to your audience for taking this action: Benefit #1 Benefit #2 Benefit #3 HFP performed for all five stimuli (including 560 nm) at each session.

DBM Benefits Experimental procedure: 3 trials at each wavelength 30 sec adaptation between each wavelength State the benefits to your audience for taking this action: Benefit #1 Benefit #2 Benefit #3 DBM performed for all five stimuli (including 560 nm) at each session.

Data Reduction % Transmission = radiance of stimulus required to match
maximum measurable radiance of stimulus

Data Reduction: HFP “Raw” HFP = 1 / % transmission HFP Measures
Will be used as denominator of DBM/HFP Will be analyzed separately

Data Reduction: DBM “Raw” DBM = 1 / % transmission DBM Measures
Will be used as numerator of DBM/HFP Will be analyzed separately

DBM/HFP ratio = chromatic contribution to brightness

Hormone Measurement Saliva testing
Measures bioavailable hormones; ~1/100 serum levels Each sample was collected at home on the morning of each session. - All samples were analyzed by ZRT labs within 30 days as recommended - assayed for E2 and Pg - several samples had immeasurable Pg levels (only one Pg “profile”)

Hormone Collection Hormone Evaluation R S Samples Arrived: 08/24/2006 Samples Collected: A 08/18/06 08:00 AM Date Closed: 08/27/2006 24-1-lu Gender: Female Client Phone: Menopausal Status: Pre-Menopausal Age: Hormone Test In Range Range Estradiol (saliva) 1.0 pg/ml Synthetic Estrogen (HRT, Birth control pill) Progesterone (saliva) pg/ml Synthetic progestins (HRT, Birth control pill) Ratio: E2/Pg (saliva) 0.04 High Values stored in database with HFP and DBM values (Optimal: when E pg/ml) Current Hormone Therapies: oral BC-OrthoTricyclen (Pharm-Dosage Unknown) (12 hrs Last used)

Analysis Gender analysis: Hormone analysis: ANOVA of DBM/HFP
Contraceptive use Hormone analysis: Correlations of DBM/HFP with E2/Pg, E2, Pg Menstrual cycle phase

Analysis Gender analysis: Hormone analysis: ANOVA of DBM/HFP
Contraceptive use Hormone analysis: Correlations of DBM/HFP with E2/Pg, E2, Pg Menstrual cycle phase All analyses repeated for HFP and DBM measures

Gender Comparison ** * ** ** ** p<0.01, * p<0.05
Error bars: ± 95% CI ** * ** ** ** p<0.01, * p<0.05

Gender Comparison of HFP, DBM
- There were no significant gender differences in HFP or DBM measures.

Results: E2, Pg measures Progesterone Estradiol Day of Menstrual Cycle
25 20 15 10 5 Day of Menstrual Cycle 1.00 0.80 0.60 0.40 0.20 0.00 -0.20 -0.40 Hormone level (pg/ml) 100 80 60 40 -20 contraceptive users non contraceptive users

Results: E2, Pg measures } F = 5.23, p = 0.03 p > 0.05 { Non-users
Luteal Ovulation Menstrual 0.80 0.60 0.40 0.20 0.00 -0.20 -0.40 Mean Hormone level (pg/ml) 80.00 60.00 40.00 20.00 -20.00 Estradiol Progesterone } F = 5.23, p = 0.03 p > {

Comparisons by Contraceptive Use
* * p < 0.05 Contraceptive users actually had higher DBM measures at 560 nm (F = 7.03, p = 0.02), which accounted for 41% of the variance.

Summary Results: Gender Analysis
1. Higher DBM/HFP ratios for females - Across wavelengths - At 450, 520, 580 and 650 nm 2. No gender differences in HFP or DBM measures Effects of contraceptive use - No significant effect across wavelengths - Contraceptive users had higher DBM measures at 560 nm

DBM/HFP Ratios vs. Hormone Levels
Correlations were low and none were statistically significant.

There was a trend at 650 nm.

450 nm 1.00 520 nm 560 nm 580 nm R = 0.14, p = 0.09 650 nm 0.10 0.00 -0.10 -0.02 -0.015 -0.01 -0.005 0.00 0.005 0.01 Estradiol/Progesterone Ratio

DBM/HFP Ratios Across the Menstrual Cycle
Non contraceptive users Contraceptive users 1.00 Mean DBM/HFP Ratio 0.1 0.0 -0.01 450 560 650 520 580 Follicular Phase Luteal Phase Follicular Phase Luteal Phase Error bars: +/ SE

DBM/HFP Ratios @ 650 nm Across the Menstrual Cycle
DBM/HFP Ratios at 650 nm non contraceptive users 1.00 contraceptive users } Mean Difference: (F = 9.36, p < 0.01) Luteal phase: Non-users > users Mean DBM/HFP Ratio 0.10 Contraceptive users: Luteal < Follicular Contraceptive users: Follicular > Luteal 0.00 -0.10 Error bars: 95% CI Follicular Phase Luteal Phase Overall, menstrual phase and contraceptive use combined to predict a significant proportion of the variance (R2 = 0.30) in DBM/HFP ratios (F = 5.51, p = 0.003).

HFP Measures vs. Hormones
0.01 0.005 0.00 -0.005 -0.01 -0.015 -0.02 0.10 -0.10 -1.00 Estradiol/Progesterone Ratio HFP MEASURES There were no significant relationships.

DBM Measures vs. Hormones
1.00 0.80 0.60 0.40 0.20 650: R = 0.71 650: R = 0.40 0.00 -0.02 -0.015 -0.01 -0.005 0.00 0.005 0.01 0.0 20. 40 60 80 100 Progesterone (pg/ml) Estradiol/Progesterone Ratio Significant positive correlations at 650 nm.

HFP measures across the Menstrual Cycle
Luteal Phase Follicular Phase Mean HFP 0.0 -0.2 -0.4 -0.6 -0.8 -1.0 -1.2 Contraceptive users Non-contraceptive users Error bars: +/ SE HFP MEASURES

HFP @ 450 nm across the Menstrual Cycle
Non-contraceptive users Contraceptive users Non-contraceptive users had higher HFP measures than contraceptive users at 450 nm (F = 4.18, p = 0.05).

DBM Measures across the Menstrual Cycle
Luteal Phase Follicular Phase Mean DBM 1.0 0.8 0.6 0.4 0.2 0.0 Contraceptive users Non contraceptive users Error bars: +/ SE DBM MEASURES 650nm higher for non-contraceptive users

Summary Results: Hormone Analysis
No significant correlations of DBM/HFP with E2/Pg - Trend at 650 nm: R = 0.14, p = 0.09 DBM at 650 nm - Positive correlations with E2/Pg (R = 0.40) and Pg (R = 0.71) Trends across menstrual cycle - DBM/HFP Ratios and DBM Measures -- Higher for non-contraceptive users at 650 nm - HFP Measures -- Higher for non-contraceptive users at 450 nm

MECHANISMS? EXPERIENTIAL EFFECTS INNATE DIFFERENCES
- There is evidence that boys/girls are treated differently; may provide different “experiences” - Art students have different color preferences than other students  developed?  become art students because of better appreciation of colors? INNATE DIFFERENCES - Is it just genetic? (i.e. XX condition) - Organizational effects of hormones  In free drawings, girls with excess androgen exposure (CAH) behave like boys Could test DBM/HFP in: -- Difference sex twins -- Women exposed to androgenic hormones prenatally  CAH girls vs. unaffected girls

Possible mechanisms VARIOUS POSSIBILITIES: - Pupil size - Iris color
- Corneal & refractive error - Macular pigment - Measured in each subject - Can not account for these findings

Possible mechanisms Photoreceptors
- Presence of estrogen receptors in pre-menopausal women - No known gender differences in retinal organization - Carriers of color defective vision? -- Unlikely in present subjects - Hormone & Cyclical effects at 650 nm: -- Temperature effects > 590 nm (deVries, 1949) -- Changes in cell “environment” (Knowles, 1980) -- Blood flow (Toker et al., 2003; Eisner and Samples, 2003)

Possible mechanisms Thalamus dLGN of thalamus
- more R-G spectrally opponent cells in female monkeys - humans?

Possible mechanisms Visual cortex dLGN V1 & V2 - P and M break down
- did not isolate function

Extensions: Vision Science: Clinical practice: Other applications:
Gender needs to be considered in all vision research Clinical practice: nm higher in non-contraceptive users - might relate to macular pigment measures - blue-on-yellow visual field testing Other applications: Detectability of chromatic signals Workspace/workplace design

Summary Females have higher chromatic contribution
to brightness than males. While hormone effects at 650 nm agree with previous findings on LWS mechanisms, hormones had limited effects across wavelengths.

THANK YOU QUESTIONS?

“Loose ends” Budget Third channel optics/instruments : $2600
Programming and hardware : $ 700 Subject costs = 30 subj x 10 hrs each x $10 /hr : $3000 _____________________________________ TOTAL : $6300

“Loose ends” Timeline Formal defense of this proposal: Mar 2006
Final IRB submitted: Apr 2006 Data collection: May 2006 – Jan 2007 Dissertation completion: Jun 2007 Dissertation defense: Jun/Jul 2007

OUTLINE INTRODUCTION Light and Models of Vision (GOAL = develop stimuli used in experiment) Gender Differences General, Ocular/Visual, Color Vision Photometric Methods Hypotheses METHODS Subjects Scheduling Experimental measures Hormone collection DBM and HFP measures

OUTLINE (cont’d) RESULTS
Analysis I – DBM/HFP Ratios, HFP, and DBM measures by: Gender Contraceptive use Analysis II – DBM/HFP Ratios, HFP, and DBM measures vs.: Hormone levels Menstrual cycle phase DISCUSSION Variability in measures Effects through the visual system (i.e. anterior segment  visual cortex) Other effects Applications to vision science/clinical practice Conclusions

“Personal Experience”
Foutch and Bassi, 2004 -- Females more sensitive to “parvo” stimulus; no “magno” difference Modeling Luminous Efficiency (2005) -- Crawford found no difference; LOW reference luminance (~10-6 cd/m2) -- Used 3.43 cd/m2 reference luminance; no overall gender difference Gender Color Contrast Study (2005) -- females had higher thresholds for all colored stimuli (B,Cy,G,Y,O,R,V) -- female > male variability for B and Y stimuli

My work so far… Dominant Eye Study (2004)
-- females more sensitive to “parvo” stimulus; no significant “magno” difference No diff in contrast/RT to SF - Solberg and Brown (2002) Perceptual and Motor Skills 94 (3, Pt. 1): Modeling Luminous Efficiency (2005) -- Crawford found no difference; LOW reference luminance (~10-6 cd/m2) -- Used 3.68 cd/m2 reference luminance; no gender difference Gender Color Contrast Study (2005) -- females had higher thresholds for all colored stimuli (B,Cy,G,Y,O,R,V) -- female > male variability for B and Y stimuli

Gender Color Contrast (2005)
DESIGN: • 19 females / 18 males; yo; normal Ishihara and D-15 • “contrast” thresholds measured for 7 colored stimuli • measure was related to saturation power of stimuli PREDICTIONS: • Females would be more sensitive to RED and GREEN RESULTS: • Females had higher thresholds (tolerated more white) in all except for blue and magenta stimuli; female variance higher for “primary” hues; identical to result of Nichols EL (1885) Journal of Science XXX: 37-41 Foutch B and Peck C (2005) Gender Differences in Color Contrast Thresholds OVS E-abstract 82

For green and red Green: F = 10.90, p < 0.001
Red: F = 6.24, p =0.014

Bonferroni Correction
Cyan: F = 8.55, p < 0.01 Yellow: F = 13.21, p < 0.001 Orange: F = 13.58, p < 0.001 Magenta: F = 5.45, p =0.02 Blue: F = 7.49, p < 0.01

Differences in variation?
Note the  in variance for 1° Hues (and yellow) B G Y R

Proposed Question I propose investigating a potential gender difference in chromatic processing. I will compare between genders the DBM/HFP ratios, which represent a measure of chromatic contribution to brightness. In addition, I propose to attribute the predicted gender difference to estrogen/progesterone ratio changes during menstrual cycle. PREDICTIONS: 1. DBM/HFP (females) > DBM/HFP (males) for B, G, Y, and R 2. DBM/HFP order (within females): ovulatory > menstrual > mid-luteal

Visual Sensation Model
Chromaticity RODS SENSATION LWS MWS SWS Lightness Walls (1955) AJO

Methods Three channel optical view system
Ref luminance of 3.8 cd-m2 ; ensures reliable cone contributions to both achromatic and chromatic systems (Lee, 1999) while in recommended range for accurate HFP readings (deVries, 1947) Ss rrr ttttt ff Ff r rssdkkj sslkldkfjslkj INPUT OUTPUT

Heterochromatic Flicker Photometry (HFP)
Benefits 520 nm State the benefits to your audience for taking this action: Benefit #1 Benefit #2 Benefit #3

Experimental sessions
Each subject will complete 4 sessions 1 practice session + 3 “real” sessions The real sessions will be scheduled: Male sessions: at least one week apart Female sessions: 1. during days 1-7 of cycle (EST = 1, PROG = 1) 2. during days of cycle (EST = 3, PROG = 2) 3. during days of cycle (EST = 2, PROG = 3) - females may complete sessions during different months - PI will not be aware of cycle (subject will; effect = ?) - however, each session must be complete

Were Graham and Hsia correct?
DBM/HFP Ratios - As predicted by Graham and Hsia (1969), DBM/HFP and saturation are very similar

Possible Mechanisms DOPAMINE - Color Effects:
- Neurotransmitter involved in retinal processing; Feigenspan (2000) - Color Effects: -- Only blue cone pathway affected; Haug et al. (1995) -- L-Dopa improved B/Y and R/G color discrimination; Bűttner et al. (1994) - Sex Differences? -- Bold fMRI study found sex differences in primary visual cortex response to photopic stimulation with blue light (not with red); Cowan et al. (2000)

Gender Differences in Luminous Efficiency
ABSOLUTE THRESHOLD - Crawford (1948) found no gender difference using very LOW reference luminance LUMINOUS EFFICIENCY USING HIGHER LUMINANCE - Post-hoc analysis of Harrington et al. no gender difference in HBM or HFP - Foutch and Peck (2006) found no gender difference using achromatic flicker - No studies found implicating total brightness or achromatic difference IF GENDER DIFFERENCE, MUST BE IN CHROMATIC MECHANISM

Retinal Anatomy From Lee, B. (2004) CEO L M Rods [L or M] L M S-cones
R-G cells: - small, slow - high spatial B-Y cells: - lowest spatial Achromatic cells: - large, fast - low spatial From Lee, B. (2004) CEO

Retina (Ganglion cells)
Visual Pathway Retina (Ganglion cells) dLGN of thalamus Visual cortex “Higher” areas M cells P cells M pathway P pathway Dorsal Stream Ventral Stream

Photometric methods Heterochromatic Flicker Photometry (HFP) THEORY:
- Each color stimulus is modulated temporally (~20 Hz) against a reference white stimulus. TASK: Observer adjusts intensity of color until the flicker disappears or is minimized.

What about color channels?
Direct brightness matching (DBM) THEORY: - Narrowband (color) and reference (white) hemicircles are directly compared. This technique is more intuitive, but more difficult to make reliable matches. TASK: - Observer adjusts intensity of color until the brightness is the same as the white stimulus.

Data Reduction Will be used as numerator of DBM/HFP
Will be analyzed separately

Why implicate menstrual cycle?
CYCLICAL CHANGES - Visual thresholds found to be cyclical; Diamond et al. (1972) -- OVULATION < MENSTRUAL - Color fields constricted during menstrual phase; Finkelstein (1887) -  Green and yellow sensitivity during late luteal phase -- where E2/Pg ratio is the lowest; Lorenzetti (1926) - Greater variance in female group vs. males; Foutch and Peck (2005)

“Loose End”: Factor Analysis
Chromatic Contribution To Brightness 450 nm All subjects 50% 520 nm 560 nm Males 580 nm 20% Females 650 nm Second factor for females (red-green)

Other Effects: Learning: Mood:
“In short, our brains are what we teach them to be given their genetically defined templates.” Jones (1998) Mood: Fluctuations in mood, affect, and behavior (Moos et al., 1969) Slade and Jenner (1980): Poor performance on very difficult perception tasks correlate with mood (present task?) Guttridge (1996): Mood not a covariate of SAP VF performance

Analysis I: Gender Comparison
Between-subjects effects of gender on experimental measures DBM/HFP RATIO HFP DBM Wavelength F p η2 ALL *15.4 <0.01 0.36 0.32 0.58 0.02 1.27 0.27 0.04 450 *9.51 0.25 0.11 0.75 0.01 0.98 0.34 0.05 520 *14.8 0.35 0.07 0.80 0.00 3.35 0.08 0.15 560 2.44 0.13 0.60 0.45 0.03 0.38 0.55 580 *12.3 0.31 0.51 0.87 650 *5.95 0.18 0.91 1.78 0.20 0.09 * p < 0.05

Analysis I: Contraceptive Use
- Due to differences in progesterone levels and different actions of exogenous progestin and naturally occurring progesterone, analyzed contraceptive and non-contraceptive users separately. DBM/HFP RATIO HFP DBM Wavelength F p η2 ALL 0.04 0.84 0.00 1.05 0.37 0.11 2.49 0.15 0.20 450 0.85 3.72 0.08 0.27 3.11 0.24 520 0.36 0.56 0.03 0.46 0.51 0.61 0.45 0.06 560 0.88 0.69 0.42 0.07 *7.03 0.02 0.41 580 0.14 0.72 0.01 0.57 0.67 650 1.16 0.30 0.59 0.53 * p < 0.05

Analysis I: Gender Comparison
Between-subjects effects of gender on experimental measures DBM/HFP RATIO HFP DBM Wavelength F p η2 ALL *15.4 <0.01 0.36 0.32 0.58 0.02 1.27 0.27 0.04 450 *9.51 0.25 0.11 0.75 0.01 0.98 0.34 0.05 520 *14.8 0.35 0.07 0.80 0.00 3.35 0.08 0.15 560 2.44 0.13 0.60 0.45 0.03 0.38 0.55 580 *12.3 0.31 0.51 0.87 650 *5.95 0.18 0.91 1.78 0.20 0.09 * p < 0.05

Analysis II: DBM/HFP Ratios vs. Hormone Levels

Analysis II: HFP vs. Hormone Levels
HFP MEASURES Non-contraceptive users Contraceptive users 0.00 -0.10 560: R2 = 0.26 580: R2 = 0.49 -1.00 -0.02 -0.015 -0.01 -0.005 0.00 0.005 0.01 -0.02 -0.015 -0.01 -0.005 0.00 0.005 0.01 Estrogen/Progesterone Ratio

HFP measures regressed onto hormone levels and contraceptive use MEASURE OVERALL MODEL PREDICTOR COEFF t p F p R2 HFP 580 6.42 0.00 0.68 CONSTANT -0.13 -4.29 E2 0.81 5.57 PG 0.002 3.23 0.01 E2*PG -0.02 -4.85 CONT 0.11 2.08 0.05 CONT*E2 -0.43 -4.24 CONT*PG -0.004 -2.21

0.10 -0.10 -1.00 Contraceptive users Non-contraceptive users 0.60 0.40 0.20 0.00 -0.20 -0.40 PG > MEDIAN PG < MEDIAN HFP measures had ZERO dependence on E2 when Pg was below median. Estrogen Estrogen

Analysis II: DBM vs. Hormone Levels
DBM measures regressed onto hormone levels and contraceptive use MEASURE OVERALL MODEL PREDICTOR COEFF t p F p R2 DBM 580 CONT*E2*PG *0.61 2.67 0.01 DBM 650 13.70 <0.001 0.27 CONSTANT 14.77 0.00 E2 2.95 PG *0.58 3.72 CONT*PG *-0.49 -3.26 * - standardized coefficient; no predictive value to regression equation

Discussion VISUAL SYSTEM OTHER EFFECTS APPLICATIONS CONCLUSIONS

Introduction LIGHT AND PERCEPTION GENDER DIFFERENCES
PHOTOMETRIC METHODS HYPOTHESES

1.00 0.10 -0.10 Contraceptive users Non-contraceptive users 0.60 0.40 0.20 0.00 -0.20 -0.40 PG ABOVE MEDIAN PG BELOW MEDIAN Estrogen (pg/ml) DBM/HFP Ratios 580: R2=0.45 Interaction of contraceptive use and PG levels

Visual System Visual cortex (Area V4) DORSAL STREAM
V4: Possible cyclical effects VENTRAL STREAM

Other CNS structures Prefrontal Cortex:
- Higher metabolite concentrations in prefrontal cortex of females (Grachev and Apkarian, 2000)

Other CNS structures FRONTAL Hippocampus: OCCIPITAL
Increase in number of dendritic spines demonstrated in the presence of estrogen OCCIPITAL

- There is evidence that children are
Other Effects: Experiential effects? - There is evidence that children are treated differently depending on gender

STUDY 3: HFP Age and Gender Study (2006)
GENDER: AGE: No gender difference <20 yo ≠ yo = 60+ yo Gender Age Group 1.20 1.20 <20 yrs female 21-49 yrs male 1.00 >60 yrs 1.00 0.80 0.80 0.60 Mean rel efficiency 0.60 Mean rel efficiency 0.40 0.40 0.20 0.20 0.00 Error bars: 95% CI 0.00 -0.20 420 450 480 500 510 520 532 540 550 560 568 580 589 600 620 650 676 420 450 480 500 510 520 532 540 550 560 568 580 589 600 620 650 676 wavelength wavelength Foutch and Peck, 2006

HFP Age and Gender Study (2006)
CONCLUSIONS: 1. No achromatic gender difference 2. Large individual differences in children Typical HFP of ~10 year olds - magnocellular immaturity? Foutch and Peck, 2006

Candidate for the Degree Of Ph.D. in Physiological Optics

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