Table 2.

α 4YFP intensities in various brain regions

	Saline	Nicotine	Nicotine, % of saline	p value	Area-based measurements (μm2)
					Saline (6 mice)	Nicotine (6 mice)
Superior colliculus	195 ± 20	262 ± 21	134 ± 12	0.027	11 × 105	12 × 105
Medial habenula	669 ± 55	749 ± 24	112 ± 4	NS	1.7 × 105	1.6 × 105
Fasciculus retroflexus	599 ± 86	673 ± 41	112 ± 7	NS	2.8 × 105	1.8 × 105
Interpeduncular nucleus	1216 ± 71	984 ± 38	81 ± 3	0.01	3.0 × 105	2.3 × 105
Perforant path	287 ± 8	555 ± 7	194 ± 2	<0.001	5.2 × 105	4.1 × 105
Nucleus accumbens	318 ± 25	357 ± 18	112 ± 6	NS	21 × 105	21 × 105
Caudate putamen	353 ± 11	417 ± 15	118 ± 4	0.002	31 × 105	29 × 105
Cerebral cortex	273 ± 18	236 ± 16	86 ± 6	NS	13 × 105	11 × 105
Anterior cingulate cortex	299 ± 21	407 ± 23	136 ± 8	<0.001	7.2 × 105	7.5 × 105
Thalamic DLG nucleus	840 ± 71	928 ± 38	111 ± 4	NS	10 × 105	11 × 105

Measurements of α4YFP fluorescence in various brain regions and changes with chronic nicotine (2 mg · kg⁻¹ · h⁻¹ for 10 d). Procedures were applied to each of the six mice in each group. Unless otherwise stated, analyses were performed on one brain section per mouse. Area-based measurements were conducted as follows: superior colliculus, four regions, 150 μm most dorsal aspect; medial habenula, lower two-thirds of each of two lobes; fasciculus retroflexus, two cross sections; interpeduncular nucleus, two sections; perforant path, four regions in the lower limbs of the medial perforant path; nucleus accumbens, two regions; caudate putamen, four regions in the dorsal aspect; cerebral cortex, two regions in layers 2–5 in the barrel cortex somatosensory area; anterior cingulate cortex, two regions 75 μm from midline in two brain sections per mouse; and thalamic dorsolateral geniculate (DLG) nucleus, one region in each of the two nuclei.